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Question regarding O320 HP increase

dmat

Well Known Member
Advertiser
Ok, so I have a 150hp 320 engine which will need an IRAN. It sat and will need to be gone thru to make certain everything is looking good.

I also am contemplating upgrading it to higher compression pistons while I'm at it.

I was quoted by a shop for $450 for the pistons and $750 for the STC paper work.

Do I really need an STC for an experimental? Could I just purchase pistons and have them replace them while they are doing the IRAN?

I don't know the in's and out's of a engine shop hence the questions.

Thanks in advance,
D
 
I have an 0320 b2b, originally 160hp. I overhauled the engine last year with 10-1 combustion technologies pistons with no stc paperwork, new lycoming cylinder that were ported and polished by lycon, dual pmags and drilled the carb main jet to #37 for more fuel flow. My engine has the longer through studs and hold down plates. It is now putting out 180+hp and i am getting better than 180hp numbers out of my rv6.

An stc is not required for an experimental engine and the dataplate needs to be removed so the engine would not be installed in a certified airplane in the future.

If you have a straight 150hp, narrowdeck, no cylinder hold down plate engine, i would not advise anything over 8.5-1 pistons. This would give you 160hp with minimal case stress added.

Mine runs cool and will do 172ktas at 8000ft DA on 10gph.
 
You don't need STC paperwork for Experimental Amateur-Built aircraft.
 
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Engine is currently an A1A and I don't need anything more than 160HP.
 
As others have noted, the shop will want to remove the data plate - which will guarantee a 40 hour (not 25) phase 1, if that matters to you.
 
Why remove the data plate? Just stamp it EX or EXP in front of the engine designation on the tag! Then note the same in the log books with an explanation of the changes.
 
If the dataplate is defaced, the engine can never be installed in a certified aircraft again. By removing the dataplate and retaining it unmolested, the engine can be returned to a certified configuration, dataplate reinstalled and installed in any aircraft. I consider it a value retention proposition in the long run.
 
Engine

Mahlon has posted extensive information on Lycoming forum on this subject. Not quoting Mahlon but my understanding is that STC upgrades from 150 to 160 hp are eligible for a new data plate from Lycoming.
Considering the cost of 15 hours fuel and the potential resale value of the engine it might be worth the cost of keeping the engine certified. Of course this would require a certified prop which is another can of worms.
The narrow deck 320's with no cylinder plates are quite rare. My understanding is that these engines are 0320"dash nothing", so 0 320A1A would be eligible for certified 160 hp upgrade. All of this and much more can bee found on the Lycoming forum which I think is still active.
 
Thanks Gents, I think it makes sense to get the STC/new data plate from a resale standpoint.
 
Mahlon has posted extensive information on Lycoming forum on this subject. Not quoting Mahlon but my understanding is that STC upgrades from 150 to 160 hp are eligible for a new data plate from Lycoming.
Considering the cost of 15 hours fuel and the potential resale value of the engine it might be worth the cost of keeping the engine certified. Of course this would require a certified prop which is another can of worms.
The narrow deck 320's with no cylinder plates are quite rare. My understanding is that these engines are 0320"dash nothing", so 0 320A1A would be eligible for certified 160 hp upgrade. All of this and much more can bee found on the Lycoming forum which I think is still active.

As soon as it is installed in an experimental aircraft it is not a "certified" engine anymore. Better off spending the $750 on fuel to punch holes in the sky. :)
 
Certified

As long as the engine is operated within limits and maintained to certified standards the engine remains certified. Let's say you buy a Cherokee 180. You have no way to determine if a previous owner has overspeed the engine, operated the engine with low oil pressure, exceeded CHT limits etc. At best you are accepting the previous AI sign off that the compression is ok, the standard work has been performed and the AD's are up to date.
 
As long as the engine is operated within limits and maintained to certified standards the engine remains certified. Let's say you buy a Cherokee 180. You have no way to determine if a previous owner has overspeed the engine, operated the engine with low oil pressure, exceeded CHT limits etc. At best you are accepting the previous AI sign off that the compression is ok, the standard work has been performed and the AD's are up to date.

No, this is untrue. The issue is the paper trail. A certified engine must have records detailing all maintenance performed, and it?s assumed that this rule is followed. An EAB may be maintained by anyone, with no records kept. And so it may have been altered from its type certificate with no record. It can be returned to certified status following a complete inspection for TC conformance by an AI.
 
Certified

I specified maintained to certified standards which means all maintenance and records etc. A non mechanic can do limited maintenance on a type certificates aircraft. Examples spark plug cleaning, oil and filter change etc as long as operation is part 91. A non certificates mechanic can also do illegal maintained On a type certificates airplane with the hangar doors locked and it is virtually impossible to catch these people.
 
To me the more important question is "who last overhauled/rebuilt/IRANed the engine" and not whether or not it is "certified." Lots of excellent (better than "certified"??) engines out there. I wouldn't spend the money for an STC to keep the engine certified. I don't think it will affect the resale value of the plane at all. BWTHDIK
 
Having the engine maintained in a certified state won't affect the value of the plane. It would only affect the value of the engine if you were to take it off the plane and try to sell it into a certified aircraft. With the scarcity of good used engines for RV's these days, you're more likely to sell it to another amateur-builder anyway, and they won't care about an STC.
 
Sump

Sure, lots of options. Twin Commanche sump is horizontal rear mount and can be modified to front mount. Lots of other options although more options for 360 than for 320. 360 sumps have been used on 320's but the induction bore on the 360 is larger. The easiest method of all is a 90 elbow for the bottom mount sump. A shop like Barrett is a good source for details, especially if they thing you might buy a very expensive sump. Multiple sources for aftermarket new sumps.
 
No, this is untrue. The issue is the paper trail. A certified engine must have records detailing all maintenance performed, and it’s assumed that this rule is followed. An EAB may be maintained by anyone, with no records kept. And so it may have been altered from its type certificate with no record. It can be returned to certified status following a complete inspection for TC conformance by an AI.

bob is right on this. first off there is no reason to remove the data plate on the engine. An experimental has no requirement to have a data plate on the engine, but you do not need to remove it.

what makes a certified engine, as bob states, is the paper trail of the engine. once an engine goes on a experimental, it is experimental for all practical purposes. because any maintenance on an EAB can be done by anybody that nullifies the certification because it is not maintained IAW FAR 43.3. example, when you bolted the exhaust on the engine is that a procedure that is approved appendix A ? is bolting a light weight starter on it part of appendix A?

My job as an IA is not technically to inspect the aircraft to deem it airworthy, it is to insure the aircraft is in compliance with the type certificate of the aircraft. that by definition makes it airworthy. anything not maintained as per FAR43 is not in compliance.

the only legal way to put an engine on a certified airframe that was on a EAB is to have a conformance inspection done on the engine and have it documented in the logbooks.

now, as to hangar fairies doing work on certified aircraft, that does happen, and if I find evidence of it on an annual its not getting signed off until the proper maintenance and paperwork is done.

bob burns
rv-4 N82RB
 
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