Question regarding O320 HP increase

[dmat]

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

[titanhank]

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.

[Mel]

You don't need STC paperwork for Experimental Amateur-Built aircraft.

[dmat]

Engine is currently an A1A and I don't need anything more than 160HP.

[BobTurner]

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.

[Boyd Birchler]

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.

[titanhank]

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.

[jrs14855]

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.

[dmat]

Thanks Gents, I think it makes sense to get the STC/new data plate from a resale standpoint.

[airtractor8]

Originally Posted by jrs14855

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.