1fastmr2

haha hummm

lart951

Okay I got some close ups of the pistons sides, where they came in contac with the walls, any thoughts..

George D

I already told you what I thought. What a shame. I've got a dear friend with a similar motor. You can hear the slap at start up then quiet down when warmed up.

Send this to the builder so thay can learn what NOT to do in the future for their trusted customers, their money, time and effort to just get a good car running better.

2bridges

EEEEEK!
4500 miles and that???
Wow what a ****ter.

Clearly something was setup wrong.
Did you check piston to wall clearance out of curiosity?
My knee jerk reaction is to think thees were very loose in the bores

what do you think Lart?? did they feel extraordinarily loose?

RKD in OKC

That anti-friction and heat coating didn't last very long.

Chris White

OK -heres an odd thought - you compression ratio look a little high.

Papamurphdog

Ok, I have a silly idea; check the bores for alignment. a friend of mine had a motor done by a builder who shall remain nameless, we'll call him numb nuts, and he actually misalligned two of the the bores vertically, they were each off axsis by a few thousandths; in different directions! Caused the exact same problem you are having. Ended up swappng the block and all was better. Could never get the othe block quite right and it is still sitting in a box...

RKD in OKC

8.5:1 ?

ehall

I'd be looking for a piece of the builders ***!

Chris White

If you (or lart) gets the job number off the botom I can check the cc and recheck the compression ratio - the dish looks a little small, if they used the cc bowl volume from a 2.5 piston on a 2.8 piston you will get a much higher compression ratio.

lart951

Bottom of the piston?

2bridges

Dude - what the hell is up with the wrist pins? they appear gouged up........ and are already showing a bunch of wear with 4500 miles. WTF

This thing is screwed

ehall

so these were JE pistons coated to work in re-nickasiled cylinders? Is that correct? What was the coating that was used?

Chris White

Lets see here…
The pistons are 3.9526” dia for a suggested bore of 3.9566” (100.4976mm) – a clearance of .004”. This should only have made noise if it were a cold day on start up. If it had significant piston slap I would think that the bores were finished larger than 100.5mm
The bowl is -22.6 cc – that will give you almost exactly a 9:1 compression ratio.
Detonation is sounding like a possible cause….

Kool

So the detonation caused the piston slap? That also explain the HG failure correct?