Seizing Piston?

CumminNotRunnin

CumminNotRunnin

Internet Mechanic
Joined
May 7, 2007
Messages
1,090
I started taking apart my pulling engine. Found some noticeable vertical scoring on the cylinder walls.

The engine had standard factory pistons with flycuts in them.
Now I measure the bores bottom the top was no more than .001 out of round.

However
# 1 and # 6 piston had next to no scoring. They measure bore and 4.0185- 4.0195

Then pistons 2-4 measure on average 4.019-4.021 and they are the ones that have scoring. More noticeable in some then others but I a little lost as to why. I thought 6 would be the hottest and tighten up first.

The other thing I noticed it not all the scoring is perfectly vertical. Some of it looks like cracking and runs a small S pattern down the bore on a couple of them.

Any insight would be much appreciated.
 
Are the piston skirts messed up? Is that where the scoring is coming from or is it rings? If its rings what did you gap them to?
 
I believe they should be total seal rings so I would be hopeful that not where its coming from. I have not pulled all six out yet for examination.

We had this engine built by someone awhile ago and pretty upset because it only had about 3 hooks on it.
 
If they are stock pistons total seal only makes the second ring. The others are not total seal. I would pull the rings and check the gaps. How high in the cylinder does the scaring go?
 
Last edited:
Piston to wall clearance might be tight for a pulling engine
 
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