Thread: Piston scuff and cracked Darton sleeve

Ive never seen a cp wrist pin clip fail. lol. Not if installed properly. Ive seen people bend them removing them and then try to reuse them and they dont sit right in the groove. They should be very tight going in and snap all the way around.

I actually used the upgraded pins and Carr locking clips on mine for added security and again, seen one break or pop out if done right.

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Thats definitely not piston slap either. In the wrong position for that. Definitely appears to be wrist pin damage or detonation damage to the rings causing that wear.

I have to agree with Ashton here. Looking at the scuff marks up close the other day, they do start right up where the first compression ring sits in the bore. This is why I'm sceptical about it being a wrist pin.

The cr was clearly just too high for the pump gas we have here.

I must say though, the car was a beast compared to my last setup. During break in it would break traction by 3000rpm in 1st gear with anything more than about 50% throttle.

Detonation

Too much timing, not enough octane, etc.....

The plugs looked good and showed no signs of detonation when I checked them initially. I suspect the re-using of the Mazworx head gasket added to this as some coolant may have leaked into cyl 4 causing the cr to rise to unmanageable levels from their already high values.

I had the timing turned down really low on the standalone.

update?

I was wondering about this just yesterday. Updates, please?

Hey guys,

I'm sitting for CFA exams in 2 weeks so I will only pull the block out after then. Will definitely update this thread with pics of the block and possible cause.

Looking at how high those scuff marks go ( basically up to the first compression ring) I am pretty sure it can not be a wrist pin that caused this.

Damn that sucks there needs to be more successful big bore VE builds in the world...

this sucks

Just wondering, what oil were you using?

i think you nailed it. broken ring due to detonation.