My Pete rebuild

[Nostalgic]

Piston 2882630



Liner 4311633


Bowl and center are approx the same depth



Of course ring spacing is different, since the new pistons are anti-polish



Area above wrist pin is different, but appears to be the same height



Bottom of skirt is different

[Nostalgic]

(12-27-2019 )Rawze Wrote:  

(12-27-2019 )tree98 Wrote:  What does the combustion chamber of the head look like compared to an OEM head (if you still have the old head) maybe that's where the compression ratio was changed?

the bottom of the head is flat. - However, recessed valves because the head was re-machined can change the compression ratio by quite a bit (lowering it).

I snapped some pics - #6 shows carbon trailing from the intake valves.

[Rawze]

Looking at only the bottom of the head, the combustion on it looks good. #2 seems to look really good actually, the rest are close to this.

-- Given this, and the fact you say you had a lot of excess turbo slobber, could it be all that build-up form oil ingestion? -- Is possible, but it would have to be considerable. - Was the intake getting wet wit oil too? - or just a tiny bit on the turbo side when idling a lot.


If that is the case, I still can't see it making a scuff on the liner like you show pics of... it would be flaked carbon making vertical streaks down the liner walls.

just some thoughts.

[Nostalgic]

(12-28-2019 )Rawze Wrote:  Looking at only the bottom of the head, the combustion on it looks good. #2 seems to look really good actually, the rest are close to this.

-- Given this, and the fact you say you had a lot of excess turbo slobber, could it be all that build-up form oil ingestion? -- Is possible, but it would have to be considerable. - Was the intake getting wet wit oil too? - or just a tiny bit on the turbo side when idling a lot.


If that is the case, I still can't see it making a scuff on the liner like you show pics of... it would be flaked carbon making vertical streaks down the liner walls.

just some thoughts.

The first turbo pushed enough oil through that it was dripping from the clamps on the intake side onto the power steering reservoir. The 2nd one appeared dry, but showed a lot of oil on the hot side after a while.





The intake has a film, but not wet - yet the vaporized oil would still affect the mix in the cylinders to some degree.

I've been all over the place with theories on this - ask me again in 20 minutes and I'll have a new one lol, but I do think that the oil being pushed through as being a contributing factor.

[tree98]

A LOT of trucks out there burning oil, some for many many miles! They don't end up like this right??

[Nostalgic]

(12-28-2019 )tree98 Wrote:  A LOT of trucks out there burning oil, some for many many miles! They don't end up like this right??

I'd bet there's a lot worse. I know gas engines do. I've pried rings out of pistons in pieces because they had so much carbon packed around them. Worn rings, increased oil vapor from PCV system and worn out spark plugs.

Different ballgame though.

[tree98]

How much oil was it using?

[Nostalgic]

1 gallon every 5-6k depending on how hard it was worked.

[Nostalgic]

Would you roll in new mains? I’m leaning towards not now...