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Papa’s Got a Brand New… Fuel

Papa’s Got a Brand New… Fuel

Swift Fuels’ 94 Octane Unleaded Avgas

Earlier this month I burned 25 gallons of Swift Fuels’ 94UL unleaded Avgas in the 180 hp Lycoming O-360 in my 1960 Piper Comanche, Papa. 

Swift Fuels of Lafayette, Ind. has submitted its 102 octane unleaded (102UL) Avgas to the FAA for testing in the Piston Aircraft Fuels Initiative (PAFI) program, but it also announced in mid-2015 that it was producing a 94 octane unleaded (94UL) Avgas. 

In the last year and a half, 94UL hasn’t gained much traction even though it’s approved for operation in a wide range of GA engine and airframes. 

94UL is produced to ASTM Standard D7547, the specification for hydrocarbon unleaded aviation gasoline. This lead-free Avgas was developed at the request of the military in 1994 for use in its drone fleet. 94UL is a stable fuel with a “tank life” of two years. 

I am looking forward to the day when Avgas will be free of tetraethyl lead (TEL), and when I saw that Swift offered a lead-free Avgas that I could legally use, I wanted to try it. What I found was very interesting.

By the end of my flight testing I hadn’t seen one iota of discernible difference in any engine parameter—EGT, CHT, manifold pressure, rpm or oil temperature—between the 94UL and 100LL Avgas. 

 

Data collection

The data I’ve captured is by no means an exhaustive test. I haven’t done an extreme heat or extreme cold temperature starting test. I haven’t done a high altitude (18,000 feet MSL) operational test. I haven’t done an in-flight restarting test. Nor have I done a fuel system compatibility test. 

But thanks to the data collection feature of my Electronics International CGR-30P and 30C engine monitor, I could collect and plot the engine data gathered during the three test flights using EGView from EG Trends. 

I also asked Joe Godrey and Savvy Analysis to check my plots. He verified my findings.

 

Preparing for the tests 

There is one 30-gallon bladder-style fuel tank in each wing of my airplane. The fuel selector valve has three positions: left to the engine, right to the engine, and off. There’s no both position. 

After flying the right tank empty and sumping the remaining unusable fuel out through the system low point drain, I paid Rabbit Aviation Services at the San Carlos Airport (KSQL) $118.37 to pump 26.6 gallons of 94UL into the right-wing tank. 

I also topped off the left tank with 8.4 gallons of 100LL ($38.22). That crunches down to 100LL at $4.55 a gallon and 94UL at $4.45. (Vendors set the pump prices; when buying from Rabbit there’s minimal direct cost savings.) The fuelers at Rabbit asked if my airplane was approved for auto gas or 94UL Avgas before dispatching the 94UL truck. 

Initial observations

94UL smells different than Avgas and is clear. I checked the two fuels for weight. The 94UL is lighter at 5.79 pounds/gallon than the 100LL at 5.94 pounds. 

I flew three one-plus hour flights, switching back and forth between the left and right tanks. 

I switched during a full power climb; I switched with the mixture leaned to peak EGT on the first cylinder to peak; and I switched during my normal cruise power and mixture settings while level at 5,500 feet MSL. I also switched on descent and while idling before flight and after landing. 

In addition to collecting the engine parameters digitally, I also watched for any EGT difference in the seconds following the switches. I never saw the numbers change.

 

Users’ reports

John Poppy at the Portage Municipal Airport (C47) in Portage, Wis., a popular fueling stop near AirVenture, said he’s heard “zero negative feedback” about 94UL. 

Poppy has a 1,000 gallon tank and says he pays two cents a gallon for shipping for the five-hour drive from the Swift production plant in Lafayette, Ind. Poppy sells 94UL for $3.35 a gallon—59 cents per gallon less than his 100LL. 

Poppy told me that one customer who flies a Cessna 182 has been using it for over a year while commuting to another state. According to Poppy, the customer’s mechanic asked if he had taken his engine apart and cleaned it after pulling the cylinders for a top overhaul. 

Rich Volker of RV Airshows burns it in the 600 hp Pratt and Whitney R-1340 that powers the Harvard Mk IV he flies in his airshow routine. Volker told me he flies his routines at full power and in his opinion, his engine can’t tell the difference. 

Dennis Wyman runs the engine shop at G&N Aircraft in Griffin, Ind. Wyman told me that his experience is that running 94UL results in less deposits on pistons and valves. In his experience, the switch between the two fuels is transparent. 

The only change Wyman has seen is that the combustion chamber of an engine that uses 94UL looks slightly darker than a 100LL chamber. Can you use 94UL?

You can use 94UL is your airplane fits into one of the following options:

• Airframe/engine combinations that have an Auto Fuel STC (e.g., an STC from Petersen Aviation);

• Airframe/engine combinations OEM-approved for auto fuel (e.g., ultralights, LSAs and experimental aircraft);

• Airframe/engine combinations Type Certificated to operate on Grade 80 (listed as Grade 80/87 in ASTM D910) or Grade UL91 (ASTM D7547) Avgas; (Note: If the fuel data plate on the engine lists 80/87 as the fuel, you can legally use 94UL without an STC. This includes Piper singles such as PA-18, -20, -22 and 150 hp PA-28s.) 

• Airframe/engine combinations Type Certificated to operate on minimum 80 octane or lower (e.g., 73 or 65 octane) Avgas; or

• Airframe/engine combinations with an Avgas STC purchased from Swift Fuels.

The engine data plate on my Lycoming O-360-A1A specifies 91/96 octane fuel, yet my Piper PA-24 Comanche had never been approved for an auto fuel STC. My only avenue to use 94UL was buying an Avgas STC from Swift. 

Where can you get 94UL?

Per the user map on the Swift Fuels website, there’s only one public source for 94UL west of the Mississippi River, and it’s in California. 

There are also 14 that are cited as “private users.” The 18 other public outlets for 94UL include three in Florida, one in South Carolina, one in Ohio, one in Missouri, four in Indiana and eight in Wisconsin. (Note: If you would like find out more about setting up a 94UL station, contact the folks at Swift. They have a team that will tell you how to get started.)

One of the potential roadblocks between availability and pumping 94UL at your airport is tankage. Most airports now have two tanks—one for jet fuel and one for 100LL. One option for adding a third is installing a box station from U-Fuel in Elk Mound, Wis. 

U-Fuel offers a split tank—94UL on one side and 100LL on the other. It appears that split models have the same footprint as existing single-fuel models. 

 

94UL is here now; PAFI fuel is a few years away

Since most privately owned and operated airplanes in the GA fleet can safely burn 94UL, and since Swift sells it for less than today’s 100LL, Swift’s 94UL seems like a winner. 

No one knows when the new unleaded 100 octane Avgas will be produced—it’s still being tested in the Piston Aviation Fuels Initiative (PAFI) program. 

The PAFI program is scheduled to complete the fuels testing in 2018, but there could well be a time lapse between the approval date and the production and delivery to your local airport. 

Based on my testing and my belief that TEL creates a wide range of problems in our air-cooled engines, I would be burning unleaded aviation fuel today if there was a pump with a Swift 94UL placard close by. 

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation (EllsAviation.com) and the proud owner of a 1960 Piper Comanche. He lives in Templeton, Calif. with his wife Audrey. Send questions and comments to

RESOURCES >>>>>

Engine monitors and cluster gauge replacements
Electronics International – PFA supporter

 

EGView software – data analysis tool
EG Trends Inc.

 

Engine rebuilding, engine overhaul and engine sales
G&N Aircraft, Inc.

 

Auto fuel STCs
Petersen Aviation, Inc.

 

94UL fuel service (West Coast)
Rabbit Aviation Services, Inc.

 

Savvy Analysis – engine monitor data organizer
Savvy Aircraft Maintenance Management, Inc.

 

94 octane unleaded Avgas, Avgas STC
Swift Fuels

 

Aviation fuel stations
U-Fuel 

  

Further reading
FAA PAFI program
Read more...
Is your Engine Worn Out? How to Tell & What to Do About It

Is your Engine Worn Out? How to Tell & What to Do About It

Smart owners who monitor key performance indicators can tell if an engine is still good or whether “it’s time.” If your engine is due for an overhaul or replacement, STEVE ELLS has a list of options which can save you time, money and maybe even both.

The day before the start of what I’m now calling the best EAA AirVenture Oshkosh ever (See page 52 for Steve’s AirVenture report. —Ed.), I stood before an enthusiastic group of Piper Flyer Associ-ation members at the annual Gathering at Waupaca, Wisconsin. It was 7:30 a.m. Sunday morning. I made sure everyone was awake by asking a scary question.

I asked how many owners thought they had an engine overhaul looming on the horizon. Seven hands went up. Those owners reflected the concerns of many owners. Engine overhauls are expensive; not to mention they can be time-consuming and stressful.

It is difficult for owners who don’t deal with overhauls on a daily or weekly basis to be able to tell when “it’s time.” An engine can be worn out, but it will still start, develop power and appear to be operating normally. On the other side of the coin, it’s also certainly possible for an engine to be running well and in good condition far beyond the manufacturer’s recommended time between overhaul (TBO).

I’m going to provide a few guidelines for determining your engine’s health.

The engine’s bottom end (and why it matters)

The air-cooled direct-drive engines we fly behind are stout; especially the “bottom end” portions. The bottom end includes the case, crankshaft, connecting rods, camshaft, lifters and accessory gears and accessory housing.

Just because the compression is low in one, two or all cylinders does not mean the engine is ready for an overhaul. Cylinders can be removed and rebuilt, or replaced with new cylinders without disturbing or compromising the bottom end. But when an engine’s bottom end is worn out, nothing short of an overhaul will restore it to airworthy condition. 


Oil pressure

Idling oil pressure when the engine is hot is an excellent indicator of the health of the bottom end of an engine. The hot idling oil pressure of our engines should always stay above the lower red line on the oil pressure gauge. 

The oil pressure limits and acceptable range are in every owner’s manual and pilot operating handbook (POH). As a rule, Lycoming engines have a 25 psi low oil pressure limit and Continental engines have a 10 psi low oil pressure limit. 

One of the most important factors in maintaining oil pressure is the clearance between the crankshaft journals and main crankshaft bearings. The spinning crankshaft in an engine is supported by a cushion of lubricating oil under pressure. 

Since there is a gap between the outside diameter of the journals of the crankshaft and the inside diameter of the main bearings surrounding each journal, the oil that’s pumped in also flows out through the gap between the two. The size of the gap is a major determinant of idling oil pressure. When the gap grows due to wear, the leakage through the gap increases and idling oil pressure goes down. Low idling oil pressure almost always signals that the bottom end of your engine is worn out, or that there’s another problem with the bottom end.

 

Oil consumption limits

It’s rare for an air-cooled Avgas-burning engine to not use any oil. Manufacturers are tasked with producing engines that must perform in conditions ranging from below zero F outside air temperature (OAT) to 100 F-plus OAT. The engines must produce rated power in missions where the aircraft may take off from extremely hot temperatures on the ground, only to climb rapidly to altitude where OATs are below freezing. Given all the metallurgical expansions and contractions that take place due to these extremes, air-cooled aircraft engines are intentionally built to larger tolerances than any automobile engine.

Oil usage is one of the trade-offs that result from building air-cooled engines that perform as well as ours do. 

If your aircraft’s engine uses oil, that’s normal. But how much is too much? Luckily, there’s a formula for that. 

Lycoming’s Service Instruction 1427C, “Lycoming Reciprocating Engine Break-In and Oil Consumption,” provides the following formula: 

0.006 x BHP x 4 ÷ 7.4 = quarts per hour.

Let’s find the allowable oil consumption for a 180 hp engine. BHP is an acronym for brake horsepower, so the formula works out like this: First, multiply 0.006 x 180 x 4 = 3.6. Dividing that by 7.4 yields a maximum oil consumption for a 180 hp engine of 0.58 quarts per hour, or a quart every 1.7 hours. 

The same formula applied to a 300 hp engine yields a maximum oil usage of 0.97 quarts per hour. 

The only drawback with very high oil consumption is that it limits flight leg length. If your engine has a 4-quart sump, you’re not going very far if your engine is going through 2 quarts an hour.

Many owners are unaware that each engine and airframe combination has an oil level “sweet spot,” where consumption slows. 

Above this level, much of the oil is discharged out the crankcase breather tube. The oil is not being consumed; it’s simply being pumped out the breather tube. If you see a lot of oil on the belly of your airplane aft of the breather tube, you are probably over-oiling your engine.

The sweet spot in my 1960 Piper Comanche 180 with a Lycoming O-360-A1A is 6 quarts in the 8-quart sump. The consumption rate for my current Lycoming O-360 is 1 quart every five hours. My average cross-country leg is around four hours so I just carry some oil and add about a quart at every stop. 

The key is to first fill to the sweet spot for your airframe/engine and then use consumption from that level to determine your engine’s oil consumption. 


Oil leaks

Damaged engine cases can cause persistent, hard-to-find oil leaks. Cases can and do crack, leading to loss of oil. 

Lycoming narrow-deck engines—the standard configuration before the mid-1960s—can develop a difficult-to-find leak when the engine case through bolts are loosened and then retightened during a cylinder change or top overhaul. The sealing O-rings between the case halves often fail to reseal the through studs after the cylinder(s) are reinstalled and torqued down. The result is a persistent oil leak past one or more of the through studs. 

There’s no way to stop that leak, nor is there a way to fix a leaky crankcase crack short of engine disassembly. 

Section 6-4.12 of Continental Motors Publication M-0, “Standard Practice Maintenance Manual for Spark Ignited Engines,” covers crankcase inspections and allowable cracks. There is a provision for continued operation of certain engines with limited cracks in noncritical areas of the crankcase. However, the engine will continue to leak oil through the crack. 

I once found a leak in my engine by thoroughly cleaning the outside of the engine, then adding a small amount of fluorescent dye to the oil. I bought the dye and a black light at the local auto parts store. I waited for a dark night, then after a ground run, found the leak by shining a black light on the engine. I rebuilt the engine soon afterward. (Be aware of all regulations and the potential hazards before introducing a foreign substance into an aircraft’s engine or oil. —Ed.)


Oil screen and oil filter inspections

Always cut open the spin-on oil filter and inspect the filter media for contamination. I cut the paper media at the edges so I can unfold it for visual inspection. 

Engines that don’t have a spin-on filter will have a pressure screen. Remove it at every oil change and flush it.

If the filter media or screen reveals a quantity of metal that exceeds a quarter teaspoon, Lycoming mandates grounding the airplane until the cause can be found. Lycoming Service Bulletin 480F describes proper procedures for oil filter or screen inspections as well as corrective actions if the inspection shows contamination. 

Jacqueline Shipe’s article “I Found This in my Oil” (May 2017 issue of Piper Flyer) provides a pictorial guide to oil filter inspection. —Ed.


Black oil

If the engine oil turns black in the first 10 hours after an oil change, yet the compression readings are good, combustion gas byproducts are blowing past the pistons and piston rings into the bottom end of the engine. The oil will continue to lubricate, protect and cool the engine, but due to the contamination from combustion byproducts, it’s a good idea to shorten the oil change interval. 


Compression tests and borescope valve inspections

Never pull a cylinder based on one compression reading. Compression test results can vary from flight to flight. Always fly the airplane to bring temperatures up into normal operating range. If you have a low reading, go fly a bit, and then perform a second, and possibly a third compression test. 

Lycoming’s guidelines specify that each cylinder’s compression reading should be above 70/80, and within 5 psi of the engine’s other cylinders. When compression readings fall below 70/80, Lycoming says that’s the result of wear and should be further evaluated. 

There are very detailed instructions in Continental Publication M-0, Chapter 6-4.11.1 through 11.3 describing procedures and guidelines for compression tests. For instance, tests are only valid if a calibrated compression testing tool is used. The calibration procedure provides a low limit compression reading number for that specific testing tool.

Any cylinder with a compression reading above that limit is airworthy, provided a borescope internal inspection of the cylinder does not show cylinder wall scoring or extreme wear and the exhaust valve does not show any signs of burning. 

Many A&P technicians are not aware of the proper compression testing procedure for Continental engines. If your mechanic calls saying your compressions are too low, make sure he reads and understands the Continental procedures which are spelled out in detail in Chapter 6-4.11.2 of Continental Motors Publication M-0.

I strongly recommend that all airplane owners download this manual (it’s free) from the Continental website. There’s a wealth of general information that, in my opinion, is useful to all air-cooled airplane engine operators.


Now what?

Let’s assume that you’ve gotten some bad news from these tests. You’re facing an engine overhaul or replacement. What are your options?

There’s a choice of factory new, factory overhauled, factory rebuilt, repair station overhauled or field overhauled engines.

This is also an excellent time to research the STC data on the FAA website to find out if there are any engine upgrades such as installing a more powerful engine in place of the original engine. Some airframes may be eligible for engine upgrades via STC. An upgraded engine may be able to give you better performance and/or reliability. As an example, RAM Aircraft, LP offers a couple of popular STCs to upgrade Piper PA-28s. 

Finally, you may want to consider replacing your worn-out engine with a lower-time used engine. 

Factory engines

Obviously, buying a new “zero-time” engine from Lycoming or Continental will be the most expensive option. A factory rebuilt zero-time (exchange) engine is usually the next most expensive, followed by a factory “time since major” overhaul where the manufacturer overhauls your current engine. 

There are some very good reasons to deal directly with Lycoming and Continental. First, the price quoted is fixed, meaning there won’t be any unexpected price “modification” phone calls. 

Second, it’s broadly accepted that a factory zero-time engine will add value to any airplane. Remember that there are two flavors of factory zero-time engines. A brand-new factory engine is built from all new parts. A rebuilt engine is built with a combination of new parts and used parts which meet new limits. Both come with fresh, zero-time logbooks.

Third, and maybe the most important, is that you can continue to fly your airplane until the day your new engine is drop-shipped to your hangar or the nearest maintenance shop.

It’s a great advantage to have the removed engine and the new engine side-by-side during an engine change. This ensures that all the fittings are available and that routing questions can be answered without having to rely on memory or digital photos taken prior to engine removal. 

All Continental and Lycoming factory engines are sold with a core charge. The core charge for a Lycoming O-360-A1A engine is currently $16,400. If a buyer wants to keep the engine that’s been removed, or can sell it for a better price than the core charge, he/she is free to do that. However, the core charge must be paid if an engine is not returned to the factory.

The window to return the removed core engine is usually 90 days. 

 

Repair station or field overhaul

There are excellent non-manufacturer overhauls and not-so-good non-manufacturer overhauls. The excellent ones are built to new limits. The not-so-good are built to what’s called service limits. It’s legal for a shop to build an engine to the worn end of the manufacturer’s service limits guidelines. Of course, the engine won’t last as long as a “new limits” overhaul. When you’re gathering quotes from overhaul shops, make sure that you specify that you want your engine overhauled to new limits. 

Choosing a factory overhaul means your airplane will be down while your engine is removed, boxed for shipping, overhauled and shipped back. During a repair station overhaul or field overhaul of your engine your airplane will be down while the engine is disassembled, the parts inspected and certified, and the engine is reassembled and tested. Smaller repair stations and field overhaul shops typically must box and ship the ferrous parts and the engine case to a specialty shop for inspection and certification. 

There are 77 Type 1 (less than 400 hp) engine repair stations listed in the FAA’s repair station directory. Repair stations have submitted organizational plans and plans for parts accountability and quality assurance to the FAA.

What is included in an overhaul?

Factory engines typically come with a carburetor or fuel injection system, two magnetos and ignition harness, spark plugs, starter, oil cooler and engine-driven fuel pump. This is also the case with most non-factory overhaul options, but you’ll want to double-check to make sure these items are included.

It’s important to take notice of and budget for what’s not included. Time and money must be devoted to inspecting, purchasing, repairing and in some cases overhauling the turbocharger and wastegate (if installed), the exhaust system, the engine mount, the cooling baffles, the generator or alternator, hoses, engine mount and vibration isolators, propeller, prop governor, vacuum pump and fuel boost pump. 

Though you don’t necessarily have to replace or rebuild all of these items at the same time as the engine overhaul, it’s certainly more cost-effective to address them when the engine is already off the airplane. Access is easier, and you can minimize installation and removal hours. 

Most of the larger overhaul shops have worked out favorable pricing with over-the-road shipping companies but shipping costs must also be included during overhaul budget planning. 

It’s also critical to compare the warranties offered by each vendor as there is no industry standard for coverage. 

Can I overhaul my engine myself?

The FAA considers the overhaul of all except a very few engines to be minor repairs, not major repairs. This assumes that the person doing the work adheres to the procedures in the manufacturer’s engine overhaul and inspection manuals. 

You as the aircraft owner (or anyone else) may overhaul your engines, as long as a certificated A&P mechanic oversees the work and he/she is willing to sign off the overhaul. 

If you or your mechanic aren’t ready to do it yourself, there’s no reason a local machinist with years of engine building experience can’t build your engine. Again, this assumes the factory overhaul procedures are adhered to and an A&P is willing to supervise and sign off.

There are some caveats to this approach. 

• Your A&P must agree to this option, and must oversee it to the extent that he/she will sign it off.

• You (or the builder) must use aircraft quality parts.

• You (or the builder) must comply
with applicable engine manufacturer Service Bulletins.

• You (or the builder) must comply
with all applicable Airworthiness Directives (ADs).

• You (or the builder) must follow the machining processes outlined by the engine manufacturer. 

• You (or the builder) must follow the engine manufacturer’s break-in procedures.

If you’re not sure about the details involved in a light aircraft engine overhaul, there’s a 36-minute video on rebuilding a Lycoming engine on YouTube. (See Resources for the link. —Ed.)

Once you watch the video, it’s easy to see that these engines aren’t complex, nor are they difficult to overhaul. 

Aircraft owners have another option to enhance their knowledge prior to attempting an overhaul. Lycoming offers engine teardown and assembly classes throughout the year in Pennsylvania.

 

Used guaranteed engines

Another option to get your aircraft back in the air is to buy a used, serviceable engine from an aircraft salvage yard. This is not as radical an option as it may sound. All reputable salvage yards guarantee (warranty) their engines.

Ideally, you’re looking for a first run or first overhaul engine which is mid-time or less. For instance, as of the writing of this article, Wentworth Aircraft had an O-360-A3A with 217 hours since major overhaul for sale for $15,500. Though this engine wouldn’t do me any good (I have an -A1A, not an -A3A, and the two aren’t interchangeable), it does illustrate that there are cost-effective used engines available. The used route is dependent on finding the correct engine. 

An advantage of installing a used engine is the lack of core charge. The $15,500 cost mentioned above could be reduced by a few thousand dollars if you’re able to find a buyer for your core. Your worn-out engine may be just what another owner or kitplane builder is looking for.

Another source for used serviceable engines are engine upgrade specialists. Check the Piper Yellow Pages online or call PFA for more information about
Piper Flyer supporters. 

You can also often find good engines on the buy-and-sell pages of various online forums, via the For Sale/Wanted thread on the PiperFlyer.org forums or through the advertisers in this magazine. 

Takeaways

Not every engine showing trouble signs needs an immediate overhaul. However, if you and your mechanic have determined an overhaul or replacement is needed, there are several options. Take your time, do your research and you’ll be back up in the air soon. 

Steve Ells has been an A&P/IA for 44 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation (EllsAviation.com) and the proud owner of a 1960 Piper Comanche. He lives in Templeton, California with his wife Audrey. Send questions and comments to .

RESOURCES >>>>>

Further reading and research

Lycoming Service Instruction 1427C, Lycoming Service Bulletin 480F, and Contintental Motors’ publication M-0
PiperFlyer.org/forum
under “Magazine Extras”

 

FAA STC data
rgl.faa.gov/Regulatory_and_Guidance_Library/rgSTC.nsf/MainFrame?OpenFrameSet

 

FAA Repair Station directory
av-info.faa.gov/repairstation.asp

 

Factory engines/rebuilds/
factory overhauls – PFA supporters
Lycoming Engines
lycoming.com/services


Continental Motors Group
continentalmotors.aero/engines/
gasoline-engines.aspx

 

FAA Repair Stations – PFA supporters
Airmark Overhaul, Inc.

airmarkoverhaul.com

Poplar Grove Airmotive
poplargroveairmotive.com

 

Other rebuild and overhaul resource
– PFA supporter

Progressive Air
progressiveair.com

 

Millennium cylinders, PMA parts
– PFA supporter
Superior Air Parts
superiorairparts.com


Salvage yards – PFA supporters
Dodson International Parts, Inc.
dodson.com

 

Preferred Airparts, LLC
preferredairparts.com

 

Wentworth Aircraft
wentworthaircraft.com

 

Engine rebuild video
SkywardTech Inc.
Read more...
Record-Breaking Attendance Expected at the 14th Annual Gathering at Waupaca

Record-Breaking Attendance Expected at the 14th Annual Gathering at Waupaca

40+ Aviation companies step up with sponsorships, door prizes and seminars. 

Cessna Flyer and Piper Flyer Association members will be descending on Waupaca, WI for the 14th annual Gathering at Waupaca. Members from 20 states and Canada will spend the weekend relaxing, learning and mingling before boarding the air-conditioned motor coach to AirVenture on MondayTuesday and Wednesday with an optional night bus on Wednesday to accommodate viewing the night air show. 

Seminars for this year:

Electronic Ignitions by Michael Kobylik, Electroair; Brake Systems by Vern Rogers, Parker Hannifin; De-icing Principals by Ken Heath, UTC Aerospace; Getting the Most from your Engine by Neil George, Continental Motors; Fuel System Maintenance by Kurt Hartwig, Eagle Fuel Cells; Owner Performed Maintenance by Steve Ells, Contributing Editor. Meals, the bus ride and a full slate of seminars are all included in the event and the friendships formed last through the years. 

Save the date and plan to join us next year: Jul 20–21, 2019. Three exciting seminars are already booked for 2019 with more to come.

Platinum/Bus Sponsors

Tempest Plus | tempestplus.com

 Electronics International | buy-ei.com

 Univair | univair.com

 

T-shirt Sponsor

 Continental Motors | continentalmotors.aero

 
Goodie Bag Sponsor

 Tanis | tanisaircraft.com

 

Banquet Sponsor

SCS Interiors | scs-interiors.com

 

Bronze Sponsor

Air Capitol Dial | aircapitoldial.com

 

Proud Supporters

 Aircraft Spruce & Specialty | aircraftspruce.com

 AOPA Insurance | aopa.com

City of Waupaca | cityofwaupaca.org

 Electroair | electroair.net

 Flight Resource | flight-resource.com

 Lycoming | lycoming.com

Mountain High Oxygen Systems | mhoxygen.com/

Smooth Power | smoothpowerllc.com

Turbine Conversions | turbineconversions.com

 

Door Prizes:

 Aero LEDs | aeroleds.com

 Aerox | aerox.com

Aircraft Spruce | aircraftspruce.com

 AvBlend | avblend.com

Bruce's Custom Covers | aircraftcovers.com

 CiES | ciescorp.net

 Concorde Battery | concordebattery.com

 David Clark | davidclarkcompany.com

 Great Lakes Aero Products | glapinc.com

 Guardian Avionics | guardianavionics.com

 Icom | icomamerica.com

JP Instruments | jpinstruments.com

Lycoming | lycoming.com

Lyons Studios | lyonsstudios.com

McFarlane Aviation | mcfarlaneaviation.com

 Oasis Scientific | oasisscientific.com

 Parker | parker.com

 Precise Flight | priceflight.com

Smooth Power | smoothpowerllc.com

 Sporty's | sportys.com

Strut Wipe | strutwipe.com

 Superbird | superbirdclean.com

 Superior Air Parts | superiorairparts.com

Turbine Conversions | turbineconversions.com

Van Bortel | vanbortel.com

Vantage Plane Plastics | planeplastics.com

Wag-Aero | wagaero.com

 Whelen | whelen.com

Read more...
Superior Air Parts Educational Forums at Aeroshell Oshkosh 2018 Forum Series

Superior Air Parts Educational Forums at Aeroshell Oshkosh 2018 Forum Series

Superior’s V.P. product support, Bill Ross (A&P/IA) will present two forums: Owner’s Guide to Engine Operations and Maintenance, and Engine Leaning Made Simple at the AeroShell Tent (#450) during Oshkosh/AirVenture 2018.

Coppell, TX (June 25, 2018)  — Scott Hayes, vice president, sales and marketing for Superior Air Parts, Inc., announced today that the company has accepted an invitation to be a presenter during the new AeroShell Forum series during Oshkosh AirVenture 2018.

AeroShell will host a series of forums on topics ranging from engine care to unleaded avgas. Follow them on Twitter @Shell_Aviation or visit the EAA Oshkosh AirVenture 2018 Schedule of Events at https://www.eaa.org/en/airventure/eaa-airventure-schedule-of-events for updates.

Superior’s vice president of Product Support, Bill Ross, who has been an FAA A&P/IA for 33-years, will present two educational forums. Ross will present “Owner’s Guide to Engine Operations and Maintenance” on Tuesday, July 24, and “Engine Leaning Made Simple on Friday, July 27.” 

Both presentations will begin at 1:00 and be held at the AeroShell tent (#450), which is directly across from the AOPA exhibit.

“Superior Air Parts is extremely excited to be a part of the AeroShell Oshkosh Forum series,” Hayes said. “Helping pilots save money has been our philosophy for over 50 years and educating pilots on the many ways they can more efficiently operate their engines has proven to be a very effective way to do that.” 

Hayes also said that along with the two forums at the AeroShell tent, Ross will also be hosting the Superior Air Parts Oshkosh Forums. The free, 45-minute Forum sessions will be held daily at the Superior Air Parts tent (#257), which is just north of Hangar B. Forum times are 9:3011:00 and 12:30, Monday, July 23rd through Saturday, July 28th.  

In addition to all the other valuable information, all forum attendees will receive a free digital copy of Bill Ross’ popular 144-page book, “Engine Management 101.”

For more information and complete forum schedule, visit: http://superiorairparts.com/about-us/event/oshkoshforums2018/

About Superior Air Parts, Inc.

Superior Air Parts, Inc., is a wholly owned subsidiary of the Superior Aviation Group. Founded in 1967, Superior Air Parts is the leading manufacturer of FAA approved aftermarket replacement parts for Lycoming and Continental aircraft engines. In addition, the company manufactures the FAA certified Vantage Engine and the XP-Series Engine family for experimental and sport aircraft builders. For more information, visit: www.superiorairparts.com

Contact:

Dale Smith

Media Relations Representative 

Superior Air Parts, Inc.

904.400.1000

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A Step-by-Step Guide to Overhauls

A Step-by-Step Guide to Overhauls

 

Most engines are “sent out” to specialty shops for overhaul. Peek behind the doors at Triad Aviation as author Jacqueline Shipe guides you through engine overhaul procedures.

The single biggest repair expense most airplane owners will ever face is an engine overhaul. Overhaul costs increase every year along with parts prices. The engine overhaul process has become somewhat of a specialized procedure. Most mechanics won’t consider overhauling an engine themselves. The engine is typically removed and sent out for overhaul. 

 

When is an overhaul necessary?

The first step in the overhaul process is determining that an engine does in fact need an overhaul. Mere time since the last overhaul doesn’t always equate to needing to overhaul an engine. Part 135 operators must legally comply with engine manufacturers’ recommended times between overhauls. However, the only legal requirement for everyone else is engine condition. 

An engine that is run regularly (at least once a week) with cylinders that have good compressions with no exhaust valve leakage is a good candidate to keep running. Regular oil changes must consistently demonstrate that no excessive metal is being produced by the engine. Such an engine can safely and legally go beyond the manufacturer’s recommended time between overhauls (TBO). 

Cylinder issues can be resolved by replacing the affected cylinder, or by completing a “top” overhaul and replacing all the cylinders.

So, what might indicate it’s time for an overhaul? Excessive amounts of metal that have been determined to be coming from the bottom end parts (camshaft, lifter bodies, gears or crankshaft bearings) is one sign. If an engine has crankcase cracks that are outside allowable limits, it’s time. If an engine has problems producing its rated power even though cylinder compressions are good and fuel and ignition systems are within limits and working properly, an overhaul is likely needed in the near future.  (For more, see “Is Your Engine Worn Out?” by Steve Ells in the October 2017 issue of Piper Flyer. —Ed.)

 
The overhaul process

An overhaul always includes a complete disassembly of the engine, thorough cleaning and inspection of parts, repair of parts as needed and disposal of defective parts. 

Major items such as the crankshaft, crankcase and connecting rods are subject to special inspections. 

Parts that are subjects of Airworthiness Directives or Service Bulletins are typically replaced or repaired in accordance with the steps outlined in the AD or bulletin. 

Parts are measured for excessive wear and proper clearances. The allowable dimensions and clearances are given in the manufacturer’s overhaul manual in two separate columns; one for manufacture (new) limits and one for service limits. The service limits are larger and allow for looser fits than manufacture limits. Some shops rebuild engines based on manufacture limits, while others use service limits. 

 
Crankshaft

The crankshaft is arguably the most important component in an aircraft engine. It absorbs the force generated by the reciprocating strokes of the pistons and rods and transforms it into rotational force for the propeller. The crankshaft is continuously subjected to loads and stresses from engine operation and the rotating propeller. Cracks or defects on a crankshaft can cause sudden engine failure or excessive, premature wear on the bearings. As a result, the crankshaft is probably the most inspected, measured and scrutinized part in the entire engine during the overhaul.

After engine disassembly, the crankshaft is cleaned and degreased in a chemical vat, dried and inspected. Most shops have a Magnaflux machine to inspect the crankshaft for cracks. 

The crankshaft is clamped between two copper-plated pads and an electric current is sent through the crankshaft to magnetize it. 

The crankshaft is then coated with a fluorescent solution containing magnetic particles. If there is a fracture in the crankshaft, the magnetic particles will align along the edges of the fracture. The fluorescent solution makes cracks easy to see under a black light. 

Once the magnetic particle inspection is complete, the crankshaft is cleaned again, and each journal is polished. Some shops have a machine that spins the crankshaft while a polishing rag is held stationary on one journal at a time with a special tool. Other shops use a machine with a circular cloth that is spun around each journal. The polishing process removes light scoring and surface corrosion as well as providing a clean journal surface so that good measurements can be obtained of each journal. 

Excessive scoring or pits caused by corrosion that cannot be removed by polishing the crankshaft can usually be removed by grinding off a specified amount of material. The manufacturer sets the sizes to which the crank can be reground, and it varies based on the engine model. Most Lycoming crankshafts can be ground to three-thousandths, six-thousandths or ten-thousandths of an inch undersize. Continental usually allows five-thousandths or ten-thousandths undersize. 

Once the crankshaft has been ground down to limits (referred to in the field as “ten under”), any further scoring or pitting defects in the journals will most likely result in the crankshaft being scrapped at the next overhaul. Reground crankshafts require oversize bearings to maintain proper clearances.

When all the machining and polishing processes are complete, the diameters of the main bearing journals and connecting rod bearing journals are measured with a micrometer at several points around the circumference of each journal. The smallest measured diameter is used to determine if each journal is within limits. 

The inside diameters of the connecting rod and crankcase main bearings are measured by installing the bearings and temporarily installing the bolts and nuts, securing the case halves and connecting rod halves together. A telescoping gauge is then used to measure the inside diameter of the bearings. Clearances are obtained by subtracting the journal diameter from the bearing internal diameter. Clearances must fall within the limits set by the manufacturer.

The crankshaft is also measured for straightness (or run-out) using a dial indicator. The crankshaft is placed in a holder that supports the crankshaft while still allowing it to rotate. A dial indicator reading is then usually taken on the rear main journal as well as the crankshaft flange. The readings must not exceed allowable limits. 

It is a fairly rare occurrence when a crankshaft is rejected. Aircraft crankshafts are constructed with high-quality metals at manufacture and, barring misuse or a prop strike, generally pass inspections through multiple overhauls.

If the crankshaft needs to be replaced for any reason, it adds a significant amount to the cost of an overhaul. Some shops try to help owners by finding a serviceable used crankshaft, which is usually one-half to one-third the cost of a new crankshaft. 

 
Crankcase

The crankcase provides the housing to hold all the internal components (crankshaft, camshaft, rods) as well as providing a place to attach the cylinders, accessory case and oil sump. The crankcase is made of cast aluminum and must be strong enough to absorb all the opposing forces of the engine as it is in operation. 

Crankcases receive a thorough cleaning and inspection at overhaul. 

Some shops use abrasive media to clean the case and some use a chemical vat. Chemical-only cleaning processes are preferred because residue from blast material is difficult to remove from all the creases and recesses in the case. Any leftover media causes scratching and scoring once the engine is placed back in operation. 

Crankcases are inspected for cracks using a dye penetrant inspection. The case is saturated in fluorescent colored penetrant, then rinsed. The penetrant seeps into cracks making them easily seen once the case is sprayed with developer or examined under a black light.

Some cases are more prone to cracking than others. As an example, Lycoming “narrow deck” cases crack far more often than the thicker “wide deck” cases. Narrow deck cases utilize cylinders that have a thinner hold-down flange. The cylinder base nuts are Allen head (internal wrenching) types; while the wide deck cases have cylinders with thicker hold-down flange with standard six-sided nuts. Cracks can sometimes be welded and repaired depending on their location. 

Cases can have fretting damage or small areas of corrosion where the case halves are joined, especially near through-bolts. Cases with damage are generally sent to specialized machine shops such as DivCo or Crankcase Services to have the mating surfaces machined smooth. Some shops “line bore” the center bearing areas so that the crankshaft main bearings are perfectly straight and aligned with the each other. 

Regardless of whether the case is simply cleaned and inspected or sent out for further machine work, the mating surfaces of the case halves must be smooth and perfectly flat to ensure a proper seal once they are assembled. A silk thread is used to seal the case halves along with a special non-hardening compound designed to hold the thread in place as the case halves are assembled. Any irregularities in the mating surfaces will result in case leaks. 

Crankcases, like crankshafts, are expensive to replace and can add significantly to the cost of an overhaul if replacement is required. 

 
Connecting rods

Connecting rods are Magnafluxed, cleaned and dimensionally checked at overhaul. Connecting rod bearings along with the bolts and nuts that secure the rod halves are always replaced at overhaul. Connecting rod bushings are not always replaced, depending on the wear and condition on the bushings. 

The rods are checked with special dowel tools to be sure they aren’t bent or twisted. The connecting rod is turned sideways and held in a vertical plane. One dowel slides through the connecting rod bushing and the other through the crankshaft bearing. After they are inserted, the ends of the dowels are laid on perfectly-matched metal blocks. The four ends of each dowel pin should lay perfectly flat if the rod is not twisted at all. 

The dowels are left in place and a special gauge is attached to the end of the crankshaft bearing dowel. This gauge telescopes and it is extended until it touches the end of the shorter connecting rod bushing dowel.

After this measurement is made, the gauge is removed and placed on the opposite end of the crankshaft bearing dowel. If the rod is square and not bent, the gauge will line up and touch the short dowel on the opposite side without being extended or shortened.

 
Camshaft and lifters

The camshaft and lifter bodies are generally replaced or sent out to be reground to remove any light scoring marks or surface deformities. The camshaft lobes go through a carburizing process to harden them at manufacture. The depth of the carburized layer of metal is not very deep (about fifteen-thousandths of an inch) and it is possible for machine shops to accidentally grind below that layer. The camshaft lobe would wear down rapidly once placed in use if that happened. Additionally, the lobes are not only elliptically shaped, but they have a slight taper across the top of the lobe to ensure that the lifter body spins as it contacts the lobe. It takes very precise machine work when grinding the lobe to maintain its original shape and the taper across the top. Camshafts should only be sent to high-quality, experienced machine shops like Aircraft Specialties for machining work.  

Camshafts are not terribly expensive when purchased new (compared to major parts like crankshafts or cases). Typically, the cost of buying a new camshaft and all the lifters is only a few hundred dollars more than having the old ones reground. 

(For more on camshafts and lifters, see Jacqueline Shipe’s July 2017 article in Piper Flyer. —Ed.)
Accessory case, oil sump, gears

The accessory case and oil sump are typically cleaned, inspected and reused. The Lycoming oil sumps that have intake pipes routed through the sump are reswedged around the intake pipe end to ensure there are no leaks down the road. This involves using a special tool which swells the pipe back out a little so that it forms a better seal when it is inserted into the sump opening.

The accessory case is inspected with dye penetrant and cleaned. The gears in the accessory case are cleaned, Magnafluxed and reused. 

 
Cylinders

Individual cylinder assemblies can be overhauled, but by the time the valves, guides and seats are replaced, the cost is almost equal to the cost of a new cylinder. Most overhaul facilities that I’m familiar with install new cylinders rather than overhauling the old ones. 

The cylinder must absorb the heat and pressure of combustion every time it completes a cycle while in operation. Metal fatigues over time and with a relatively low cost difference between new and overhauled cylinders, new cylinders are the best choice for long-lasting operation. They also typically come with their own warranties, so shops like them. 

It’s important to note that there is no logbook tracking for individual cylinder assemblies. Times in operation are kept of engines, but not of the individual engine parts. Therefore, it is impossible to really know how much operating time cylinders have on them when purchasing overhauled cylinders outright. The times that are on the existing installed cylinders on an engine can be difficult to trace unless they were new at the time of installation. 

 
Fuel system

The fuel injection system or carburetor is generally sent out for overhaul at a specialty shop or replaced with a new unit. Very few overhaul facilities overhaul the fuel system components in-house. Even Lycoming gets all the fuel injection system components and carburetors for both their new and rebuilt engines from Avstar Fuel Systems in Florida. 

 
Accessories and other items

All other accessories are typically sent to specialty shops for an overhaul or are replaced with new. Magnetos, ignition harnesses and vacuum pumps are generally replaced with new units. Alternators and starters are generally rebuilt. 

Oil coolers should always be sent out for specialized porting and cleaning to be sure all metal particles and sludge buildup is completely removed. The oil passages through the coolers make several 180-degree turns. Small metal particles and contaminants build up in the coolers around the curves and it is impossible to remove all the debris with just a simple flushing. Oftentimes, new oil coolers are fairly inexpensive, and it is easier and cheaper to simply replace them rather than overhaul them. 

All hoses should be replaced at overhaul. Hoses deteriorate with age and exposure to heat, and should be replaced periodically. New hose installations also help prevent contaminating the freshly overhauled engine with any sludge or debris remaining in the hose. 

It’s also a good idea to replace all the SCAT hoses. Most of the tubing (like the aluminum oil return lines) is cleaned, inspected and reused.

 

Choosing an overhaul facility

Engine overhauls are extremely expensive. When it’s time to overhaul an engine, choosing a high-quality facility to do the job is important. The best way to choose where to send an engine is usually by personal referral. Ask other owners what shop(s) they have used and what the long-term results have been. Owners or operators that have put three to five hundred hours on an engine usually know by that time whether the overhaul was a good one. Low cylinder compressions, oil leaks or other problems are signs that the overhaul may not have been the best. 

Most Part 91 owners only have to face an engine overhaul once. The process can be stressful to go through. Owners who do lots of research ahead of time, understand the process and ask lots of questions can help to avoid major problems down the road. 

 

 

Jacqueline Shipe grew up in an aviation home; her dad was a flight instructor. She soloed at age 16 and went on to get her CFII and ATP certificate. Shipe also attended Kentucky Tech and obtained an airframe and powerplant license. She has worked as a mechanic for the airlines and on a variety of General Aviation planes. She’s also logged over 5,000 hours of flight instruction time. Send question or comments to


RESOURCES >>>>>


ENGINE OVERHAULS
Airmark Overhaul
airmarkoverhaul.com

Granite Air Center
graniteair.com

Poplar Grove Airmotive
poplargroveairmotive.com/engine-shop


RAM Aircraft
ramaircraft.com


Triad Aviation
hhtriad.com

CRANKCASE INSPECTION / REPAIR
Aircraft Specialties Services
aircraft-specialties.com


Crankcase Services, Inc.
crankcaseservices.com


DivCo, Inc.
divcoinc.com


FUEL SYSTEM OVERHAUL
Avstar Fuel Systems, Inc.
avstardirect.com

 
Aircraft Accessories of Oklahoma
aircraftaccessoriesofok.com

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