Javcolin

Hi Everyone,

I had to pull the head off my turbo engine, to check if my head gasket was ok, and to check some other things, Glad I did, as i found my pistons were barely kissing the Head, So I need a thicker Head gasket, me myself prefer to use the OEM one, currently boosting 22 PSI on my PTE 6062,

So what do you guys think is the best bet to buy a thicker cometic Head gasket or to add an extra layer on top of an OEM HG, I have a couple of them, i need at least .005" - 0010" thicker HG I have not measure it yet but this is more of a guesstimation,

Thanks

LightningTeg

What drove you to pull the head off and "check the headgasket" in the first place?

Javcolin

My engine suddenly was getting warmer, and triggering my heat warning light I set it to 212, at the same time, I Spun a bearing, and I'm doing some upgrades, reason why I took the head off.

LightningTeg

The spun bearing is likely the cause of the pistons touching the head. I had the exact same thing happen to me. Pulled motor apart and cylinder where spun bearing was had just started to knick the head surface.

Javcolin

That is what i thought as #3 piston is the only one making contact with the head and wiseco calls .026" Piston to Head Clearance, what i see is that is not making contact with the quench pads rather the combustion chamber outer ring as my pistons are 81.5 - .020" over bore, but I wanted to be on the safe side, giving .0030 - 0.0035" as I'm reving to 9k rpms thus my question to get a cometic thicker HG or just add an Extra layer of the OEM HG on top of a new HG of course

LightningTeg

Mine were 84mm in a 81mm combustion chamber so it was very noticeable on the outside. Also Cyl 3

Javcolin

That # 3 Cylinder Bearing Right!! What HG are you using/pistons compression power, Rev limit to??

LightningTeg

OEM/Golden eagle, Eagle Rods , CP pistons @ 9.5:1, 8800, 600whp+

Javcolin

Roughly same set up, but the bore, OEM HG, Skunk2 Alpha rods, Wiseco with upgraded pin, @ 9.8:1. 500WHP, king bearings 9,000k rpm, did you find out why you spun a bearing? I just gave more clearance to mine, 0.0020" instead of the .0018"

are you sure your piston is no longer kissing the head with the OEM HG crush? maybe tomorrow I will slap the pistons back, at the moment I'm changing/upgrading my fuel lines for e85, once i'm done will continue with the pistons to check P2D and all.,

LightningTeg

Yeah it was detonation. Playing with fire at 30lbs of boost on 93 oct lol. When I rebuilt clearances were anywhere from 0.0015 to 0.0020 rods and mains. And yeah there was no issue after the rebuild, which I confirmed the last time I pulled the head to go to LS/VTEC a couple years ago.

Javcolin

Hahahha, and I thought i was pushing on 93 octane, Lol. only boosting to 22psi, and 23-25 with Meth, last year when i got my B16 i did 30 psi, but for a few pulls, before i go Ls/Vtec, and upped the Compression from 8.9:1 to 9.8:1, I never have problems with mains nor 1, 2 or 4 just that #3, 3 times now, so decided to go on the lose end, I even went from 50/30 to 10/40 rotella, it helped a bit, so I hope with the new clearance eveyrthing stay together

motoxxxman

I'd like to see pics of what you (OP) think is proof of pistons touching head. I say this because many times people get detonation damage that leaves marks on the pistons and head, and they think it's from making contact with each other, but is in fact just detonation damage, typically from a not good enough "tune"

LightningTeg

I know Im not the Op, but....






That was really from me limping it home several miles after the event occured and I knew something was wrong.

Javcolin

Not an Expert but I'm pretty sure it is not Detonation, but the piston making some contact to head, on cylinder # 3 due to spun bearing, the rest all good.

Here are some pics. You can See a shiny kind of bezel, that is where piston contacted the CC outer edge
This is slightly better view
and the piston, you can see some kind of bezel
you can see here some wear on the edge

Javcolin

I can see, yours really make much more contact than mine, seems like on my set up the intake side made contact only, your bearing is indeed much worst than mine, as I was always listening to my engine after a pull, so i stop and went home, but that is the same thing my bearing did, deform on one side,

How do you know you spun a bearing due to detonation?

did your crankshaft survived?

LightningTeg

I had just done a pull and immediately after oil pressure dropped 20 psi and oil temp gauge was pegged past 300 degrees.

Crank was lost.

Javcolin

So, did mine, in the process to rebuild my engine