Legal Certified engine "enhancements"

Subsonic

Subsonic

FRIEND
Merritt Island, FL
Quick question:

Are there any rules against blueprinting a certified engine? That is the question.

I'm talking Lycon ported cylinder heads, and the "hottest" legal cam and lifters I can put in my O-320 A1A - 150 HP with 7.0:1 compression and Auto Gas STC. I want to retain the gas STC. Does anyone know what those cam and lifter part numbers might be? Do 8.5:1 pistons negate the STC?

In my situation, its about Not having really good information about how my engine was rebuilt, and I'm a little concerned a reground cam and lifters are in there with the risk of lifter spallation and death.. I'm at around 340 hrs SMOH. 2820TT.

I was told that a "Retired Lycoming factory mechanic" rebuilt my engine. Details in logs are minimally worded. I have tags and receipts from that time for replaced parts.

I rigorously (I have both my A&P and IA look at the cut open filter - using Steve's video technique - I buy the beer) evaluate every oil filter change at 25 hours and use a certified oil additive.

Since a cam/lifters swap involves splitting the cases, having the cylinders 'zero-timed' or better seems like a good idea...match weighted rods...CC'd head volumes...

More power and efficiency are always nice to have. My TP with full tanks and me in it climbs a 1000 fpm or better at 75 to 80 mph at sea level every time - any time. At gross weight taking off at 5,500 feet and DA of 7,000 a few years ago, it was 400 fpm.

Comments appreciated.

-Subsonic
 
If you are not getting metal in your filter quit worrying about your cam and lifters. If metal does show up you typically have many hours of engine left. As Steve said to me when mine was making metal “airplanes don’t fall out of the air from cam and lifter problems. At least O-320’s don’t.
I’ve seen some serious metal spalling in aircraft that flew int his shop for an annual and the owner was not aware of a problem.
Stephen Adams had some LyCon work done. Maybe he will comment here.
 
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Save you money/time/effort until you wear that engine out. Then if you really need more power figure out how to make it work for you. Spend you money on extra training, Better pilot skills will usually outperform 5 more HP any day of the week.
DENNY
 
Ok. Just about the best response I could have hoped for. Thanks Gilbert and Denny. Roger/copy to continue to moniter oil, and tune up pilot skills.
 
I have changed a lot of cams and followers over the years and have never seen anything catastrophic. I am sure there was a degradation in performance over time but they still ran good. I have a LyCon engine in my Super Cub. Luckily the guy I built the airplane for paid for the engine work before I bought the airplane. The cylinders were flow matched, parts cryoed, balanced, best cam, cam gear combo. I have the dyno data and it is impressive but you have to remember it was run in optimum conditions with straight pipes. It pulls hard and after flying other Super Cubs with same prop and pitch I believe the numbers. in all honesty I had just as much fun in my old beater Super Cub with the engine past TBO although I did install a new set of Lycoming cylinders that Ken at LyCon had ported and polished.
 
There is nothing wrong or illegal with blueprinting an engine. All engine parts are designed to a certain exact dimension. For production, building to this exact dimension would be cost prohibitive so the designer calculates the potential issues with a build up of tolerances and publishes the plus or minus tolerances. Blueprinting just brings the engine as close to the exact design dimensions as possible. A good example is the Mercedes AMG engine. It is blueprinted and brought as close to design as possible. The engine is also about twice the cost. Blueprinting is very labor intensive. If you have the time and money it probably will result in a smoother running engine. With a four cylinder engine, it will be very hard to detect. During normal operations the manufactures engine assembly tolerances and weight difference requirements of components will suffice. When you start increasing the RPM’s and BMEP is when blueprinting shows it’s value. With the low RPM restrictions on our aircraft, you will probably never notice a difference. Money might be better spent having a dynamic balance preformed.
‘Going to higher compression pistons would probably negate the auto gas STC. At the least you would need to run a premium octane fuel with the higher compression pistons.
Cam and lifter spalling is frustrating but I have never heard it as the primary cause of an engine failure. I personally would fix it if I found the issue in my engine. I have had an engine fill with aluminum shavings from the old style piston pin plugs.
N2709P
 
Things like pistons and cam shafts are listed in the IPC, changing to a different part number (higher compression, different lift cam) would be Major Alterations requiring FAA approved data. There are ways to conver one model engine to another using a Lycoming SB, but then you need approved data to install the new model engine in your airframe.


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Several years ago I bought new cylinders from LyConn and had the cylinders port and polished. The most significant thing they did was grind the valve seats at three different angles to smooth and increase the flow. The hp increase they quoted was probably optimistic. But, I did see a significant rpm increase. My previous 77 inch prop became worthless. The engine jumped from hitting just under rpm redline to well over 2800 rpm in flat out level flight (I quit pushing it). It was redlining on climbout. I went to an 82 inch prop to get the flat out rpm back under 2700 rpm. The new port and polished cylinders also cost me a new prop.
 
Performance comes from cubic dollars.

I spent a bunch of Money at LyCon. A chunk was spent on piece of mind; “O” ring crankcase and sealed cylinder studs.
 
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LyCon pulls all the studs out of the case and reinstalls with the proper Loctite primer and thread lock. The crankcase shops do not do this. I asked Ken why he does it and he replied that he got tired of fixing leaks under warranty. I got into twice, once on pre-buy when a small cylinder hold down stud was leaking and again when I top an O-320. I did not realize Loctite is activated by 2 ferrous metals so when being used on aluminum it takes a different product.

As far as port, polish and balancing, I have flown behind several LyCon engines that had it done and the were noticeably smoother than other 320s I had flown behind. Years ago I installed new factory reman in a friends Dad's Bonanza that LyCon simply pulled the cylinders and did their port/polish and valve job on. The owner had run 2 other factory remans to TBO and said this was by far the smoothest engine he had ever flown behind. He said it was as smooth as a sewing machine. less vibration, less cracking etc.
 
I duplicated Lycon’s O-320 B2B build that produced 197Hp on the dyno. Lycon converted my O-320 A2B 150 Hp case to the -39 case and added the “O” ring groove. Used their wide deck STC to convert 150 to 160 hp with a written authorization for the STC deviation to use the STC on a narrow deck. I did add the banana plates. This changed the engine data plated to the B2B. Millennial cylinders with the porting and flow match. They balance the crank and flywheel. Kent White and I balanced the rods and pistons. Lycon’s build also included the Leading Edge exhausted system. I installed a 74” 62 pitch prop. It pulled 2480 static. ECi engine monitor so I know the RPM is accurate. When I had the prop repitched to 59. Dominion said I didn’t need it because it made so much power, but I wanted less pitch for short field work. Easily red lines the engine in level flight. I haven’t upgraded my mogas STC for using 91 octane fuel..can’t get it anyway so why bother. There is a non integral cam shaft Lycoming used that has an extra 2 degrees of valve overlap from the late 50’s. I don’t have the part number handy…Lycon used that cam in their build too. I bought that cam from Colorado Air parts. They should have the information.


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mmoyle said:
I duplicated Lycon’s O-320 B2B build that produced 197Hp on the dyno. Lycon converted my O-320 A2B 150 Hp case to the -39 case and added the “O” ring groove. Used their wide deck STC to convert 150 to 160 hp with a written authorization for the STC deviation to use the STC on a narrow deck. I did add the banana plates. This changed the engine data plated to the B2B. Millennial cylinders with the porting and flow match. They balance the crank and flywheel. Kent White and I balanced the rods and pistons. Lycon’s build also included the Leading Edge exhausted system. I installed a 74” 62 pitch prop. It pulled 2480 static. ECi engine monitor so I know the RPM is accurate. When I had the prop repitched to 59. Dominion said I didn’t need it because it made so much power, but I wanted less pitch for short field work. Easily red lines the engine in level flight. I haven’t upgraded my mogas STC for using 91 octane fuel..can’t get it anyway so why bother. There is a non integral cam shaft Lycoming used that has an extra 2 degrees of valve overlap from the late 50’s. I don’t have the part number handy…Lycon used that cam in their build too. I bought that cam from Colorado Air parts. They should have the information.


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Click to expand...

Mark, I looked into 8.5 - 1 pistons on my A2B narrow deck, but finding the long through bolts needed for the banana plates was impossible. Plus they were listed at $1000 each. How does LyCon do it?

LyCon did wonders for my cylinders. And, I would like to have the seal they install on the case.
 
Legal Certified engine "enhancements"

The case is heated, all studs are removed. From there the case is inspected and machined. During reassembly the longer cylinder base studs and case through bolt are installed. I may have a new set of the B2B studs and through bolts. Think I ordered them from AERO instock or Glacier Airparts. The banana plates I bought used from Colorado Airparts. Be aware you need the correct cylinders to use the banana plates, the 160 hp cylinders have one less cooling fin. Millennial 150hp cylinders are not flat on the bolt side of the cylinder base flange.


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Re: Legal Certified engine "enhancements"

mmoyle said:
The case is heated, all studs are removed. From there the case is inspected and machined. During reassembly the longer cylinder base studs and case through bolt are installed. I may have a new set of the B2B studs and through bolts. Think I ordered them from AERO instock or Glacier Airparts. The banana plates I bought used from Colorado Airparts. Be aware you need the correct cylinders to use the banana plates, the 160 hp cylinders have one less cooling fin. Millennial 150hp cylinders are not flat on the bolt side of the cylinder base flange.


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Click to expand...

Thanks for the info. I already have a set of banana plates. I looked up the numbers for the studs. If I remember most are stock in the 360. The long bolts were impossible to get. I wonder if LcCon does something different. I measured the clearance on my ECI cylinders, they seemed to have clearance. But...maybe not.
 
mmoyle said:
There is a non integral cam shaft Lycoming used that has an extra 2 degrees of valve overlap from the late 50’s. I don’t have the part number handy…Lycon used that cam in their build too. I bought that cam from Colorado Air parts. They should have the info
Click to expand...

I’m making a plan and gathering parts to OH my O-320 (corroded lifters from sitting with previous owner). I want to maximize its performance.

Can anyone verify the part number for the better cam mentioned above? Based on tons of Googling I think it is #76097, but still uncertain.
 
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The Lycoming cams available new now have the same duration on intake and exhaust. The older cams have a longer duration on the exhaust stroke. new Lycoming tappets have a DLC coating and do not spall like Lycomings are known for according to my sources. My engine on my Super Cub was built by LyCon just before I bought the airplane. It made 191 hp at 2700 rpm and straight exhaust stacks with everything tweaked to maximum performance. It had the cylinders flow matched and 3 angle valve job and parts were cryogenically treated. It does pull.
 
Steve Pierce said:
The Lycoming cams available new now have the same duration on intake and exhaust. The older cams have a longer duration on the exhaust stroke. new Lycoming tappets have a DLC coating and do not spall like Lycomings are known for according to my sources. My engine on my Super Cub was built by LyCon just before I bought the airplane. It made 191 hp at 2700 rpm and straight exhaust stacks with everything tweaked to maximum performance. It had the cylinders flow matched and 3 angle valve job and parts were cryogenically treated. It does pull.
Click to expand...

Are the older, longer duration, cams incompatible with the DLC lifters?
 
Steve Pierce said:
Lycoming is the only one using the DLC coating.
15B26262 Hyperbolic (will use a bit more oil pressure)
15B26588 standard
More explanation:
https://www.lycoming.com/parts/tappets
Lycoming Service Instruction 1011N that calls out applicable part numbers.
https://www.lycoming.com/sites/default/files/attachments/SI1011N%20Tappets%20and%20Lifters.pdf
Click to expand...

Thanks for the links to all that tappet info!

Still trying to verify that the better early cam Pt number is 76097. Is that the best one?
 
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