Hmmm... now that looks like some perty bad piston slap thar son. :+



That should buff right out. I can't wait to see what the piston looks like. Suffice to say shavings of it have pretty much ruined the cam journals and probably everything else. More pics coming as I get things taken apart.

wow :o

Wow. Either that bore was WAY outta spec, or you actually damaged the piston enough to cause that. There is no way you couldn't have heard that happening, unless it happened in fairly short order.

I want pics of that piston, and that rod bearing and journal. if it was rtocking that much, the rod bearing id going to come out concave and the journal hammered.

Yeah, detailed pics of everything are coming as I pull things out.

It happened over about 1k miles. It ran perfectly fine when warmed up, but I started to notice piston slap on cold starts, and it just kept getting louder every start. Also power output dropped off sharply. :rolleyes

Also, it was overheating badly towards the end. The headgasket was blown for sure on the Driver side rear corner, same location as dead cylinder. Probably warped the head with all the heat from combustion getting past the rings, or the extra friction from all the metal shavings everywhere.

Ironically, I still had 165 compression in that cylinder, and 180 in the rest.

Almost looks like the piston rings expanded too much for the available room in the cylinder..Piston slap usually will mark up the thrust faces on the cylinder wall..

Damn... I see your getting to the source of the bubbling coolant hugh?

oh yeah, i just noticed your PM, just got back from fresno. Ill send ya a reply shortly.

>Almost looks like the piston rings expanded too much for the
>available room in the cylinder..

That was my first thought after i read the word "overheating" and "blown headgasket" .. no fun. Makes me glad i'm at the wide end of JE's spec, i drove around with a blown HG, overheated almost every day, bores looked fine when the head came off.

Sorry bro. No Bueno.

thats a keeper...

u might beable to bore that 140 or 160 over but wow!

Bill

WTF....Now that got me all paranoid about my piston slap... I hope the pistons are salvageable. If not get some CPs. Let me know when you need a hand. No worries about the rally. I understand

However how come only number four is fucked? why not the rest, they slap just as much?.

Might be time for the FTY block, will save alot of time.

Goddam!

what the heck happened there Dan! that looks really nasty! It looks like the piston was rocking back and forth like mad! I remember when we put that back together the piston to wall clearances looked correct. If the head gasket was leaking into the cylinder real bad maybe it never let that piston heat up and expand correctly, just an assumption, i may be talking out of my ass. but that looks nasty!

lates
james

You guys built that block yourselfs? ^^ I hear CP's slap just as much as other forged pistons..

Ugh. Everytime I start my Daisy cold she reminds me of a diesel. Reading this thread makes me feel like someone kicked me in the nuts. I'm going to start saving money now. Ugh. :wince

Piston slap didnt cause that. A blown HG caused that. If you think about it, if the HG was leaking in that corner, that side of the cylinder was heating up too much, since leaking cylinder pressure was getting into the coolant passage next to that side wall of the cylinder, where it had very bad coolant flow. Too much cylinder heat did that...I'd like to see the rings..

Yeah, its definitely not piston slap because all 4 would show similar wear. The other cylinders were perfect, and had the same piston-wall clearances to within .001

So, it turns out the piston skirts melted, only on the sides , for no apparent reason other than overheating. This caused one of the wrist pin retaining clips to melt out of the piston. The actual damage was caused by melted portions of the oil rings, piston skirts, and the pulverization of one of the clips. The other clip was almost completely melted into the piston.



More pics here: http://whack.org/~dan/car/je-melted

Interesting things:
- A hole where the wrist pin clip exited the piston skirt (see pic#35 & 37)
- Rod, bearings, crank, wristpin were all totally undamaged.
- Piston-bore clearances are all still perfect
- Top fire ring is intact, still gapped at .025
- Middle (totalseal) rings were crushed together, the main one broke.
- Oil rings were totally burned up on each side, but fine in between.
- The rear thrust face before the fire ring was clean, theres no carbon deposits for about 2" ?? (see pic#31)
- The wristpin oiling grooves seem to die off on top? Don't remember if the groove is supposed to go all the way around? (See pic #57)
- I had to press out the wrist pin, it was stuck good.

- Weirdest: The thrust sides(front and back) of the skirts, as well as the rest of the piston, are more or less completely undamaged, and definitely not melted. Yet the thickest part of the piston, the wrist pin sides, are the only parts that melted... even the wrist pin insides to a slight degree. There's nothing to indicate fire was getting down past the rings on the sides at all.

I'm going to chalk it all up to simple overheating caused by the head gasket leak. The heat probably expanded the piston, and crushed the rings. It wouldn't have leaked if I had shaved off the back right head bolt 1/4" like I've told so many people. I've heard the headgasket/bolt problem had been fixed for the 1999 model year, but forgot the block I built was a *1996*. Stupid.

I would REALLY like to know why just the wrist pin ends melted so drastically though. That's weird.

Damn Dan ...(making mental note shave 1/4" off top right bolt) I guess the hopes of it being something not too drastic faded away...

>I'm going to chalk it all up to simple overheating caused
>by the head gasket leak. The heat probably expanded the
>piston, and crushed the rings.

Yeap. Unfortunate, but live and learn, i guess.

>I would REALLY like to know why just the wrist pin ends melted
>so drastically though. That's weird.

More metal there, more expansion. That's the side that was wearing the block, no?

Wow Dan, that's painful! hope u can get it fixed soon. was this the engine that you were going to break-in by driving pretty aggressively and redlining in the first few miles? I remember you were going to compare compression to someone else being easier on the first few hundered miles (was it Danny?) Do you think that's related to the condition of the rings?

I was comparing with Kaiser, but I found out he installed JE rings instead of Totalseals.

I seriously doubt the damage was caused by the breakin- I ran this engine REALLY hard for about 7 months before I overheated it and things went downhill from there.

Anyways, I was getting 180 across the board and he was getting 190's.

Could be the JE rings are better, could be the slow and easy breakin is better. Either way, I'm doing it the slow and easy route next time and see what I get.

I think the difference in compression can be attributes to the ring gap clearance.

Next time go the maternal approach to ring break in. Good thing it is only one piston, but not sure if you are gogint o replace all of them though.

Let me know if you still need my rings or not. By the looks on the cylinder surface, you may need somethign bigger than the 20 over rings I have. Drop me a line. I'll be at James' this sunday.

Hmm... could be the gap, but I doubt it. If that were the case, my compression numbers should be higher, because I obviously didn't gap them enough. Plus the totalseals dont HAVE a gap, so they should be higher still.

One of the Totalseal rings (cylinder #3) somehow spun around 180 degrees and became a conventional ring. My compression was 170 - 171 - 165 - 115. Note cylinder #3 is 5psi lower than the rest. So it looks like the "Total"seals might only give you 5psi extra compression.

Also, just a note, Mike W at RRE claims Totalseals are crap, and they won't use them in his shop. See the SocalDSM list.

that definitely sucks. but there is NOWAY piston slap caused that! at least you blew it up good! goodluck getting it fixed.

1999 Black C5
1997 Silver RS
Wiseco 8.8:1 Pistons(back to low compression!)
Eagle Rods
T3/T4 Turbo
Custom FMIC
Greddy Exhaust
440's
Most current 1/8th mile time: 8.3@90mph 2.015 60'(Nitto Drag radials, i suck)