JE piston failure

**stpmotorsports** · 08-07-2011, 08:19 PM

Has anyone ever had a JE piston break the top off above the top ring land? Engine ran 5 nights and had a piston failure, blamed it on this that and the other, no definitive answer from the builder as to what actually happened. Bought 4 new pistons, JE wouldnt custom make just 1, valve job, surfaced heads, touched up cylinders and reassembled. Didnt make 20 laps and did same thing again, this time with the new piston.
So upon disassembly and close inspection, 4 of the pistons are cracked in the bottom of the intake valve relief. This made me look at the piston that actually failed, there is only about .050" material between the deep part of the valve relief to the top ring land.
My question is has anyone ever had this happen before, should JE be liable for a defective product? This is not something that an engine builder can really check, so I cant really blame him. I still have the 3 other new pistons but there is no sense in putting them in when another failure is nearly guaranteed.

**stock car driver** · 08-07-2011, 08:39 PM

The ultra light pistons even on 400hp motors or less as recomended by je often crack between the two valve reliefs. Guys I know who have had this happen say they only notice it when freshening the motor they never had them fall apart. Theres a 11-1 class here so lots of guys have used those pistons and had that happen.

It sounds like not enough ring gap to me, if it was a hyper piston that is what we would all say for sure? Easy to check if youve got it torn apart. Stick top ring in the hole and measure the end gap.

What carb are you running anything over a 4412 and your clearly over the 400hp rating of the lw pistons.

**hogracer3d** · 08-07-2011, 08:55 PM

Detonation is a very common cause lifting if the ring land

**stpmotorsports** · 08-07-2011, 08:56 PM

Ring gap on top rings are around .030",JE recommends .022". This is a 14:1 dome modified motor on alcohol. Ring gap ok, plugs and top of pistons show no signs of lean or detonation, bearings look perfect, engine NEVER got over 190*. Everything inside engine looks good except pistons. THis isnt the flyweight or 2-bbl pistons, its supposed to be the good stuff.
It has a C&S billet alky 4 bbl. We had 34* timing in it, it was about 160-170 on the track, got up to 190* when he pulled up to the trailer and we were looking at the smoke coming out of the header.
I am just totally disgusted, this is the best stuff I have ever had and had a reputable builder do it all.

**stpmotorsports** · 08-07-2011, 09:03 PM

I would agree if it was the KB hypers, seen plenty of them do this exact same thing. Thats what I thought of when I pulled the head, I could have spent $500 less money on pistons and had this crap happen. LOL

**stock car driver** · 08-07-2011, 09:57 PM

ok gotcha.

I figured the crack between the valve reliefs was only a 2 barrel piston fly weight deal.

I am surprised it would happen on a dome motor etc.

Im not experienced in alc but Ive heard its gotta be all right or this type of stuff can a happen.

**fast_crew** · 08-08-2011, 05:23 PM

Can almost guarantee it's not the pistons fault, either to lean or too much timing, or a combo of alittle of each, doesn't take much with high compression. (What kind of heads are on it?) Was the ring gap .033" at install or thats what they are now? Check ends for butting (shinny spots), If pistons got really hot the rings could still butt even with the .033. Are the bottoms of the pistons brown or discolored? The .050" at the bottom of the valve pocket should be fine, have heard of guys running that and alittle less if only in a real small area. On alky you can burn a piston in 2 laps if the tune is off.

**SLM98** · 08-08-2011, 06:45 PM

34* is probably a little on the edge timing wise, 30-32 would be safer

**stpmotorsports** · 08-08-2011, 09:11 PM

Engine has Dart Iron Eagle 215 heads. Engine builder said that ring gap was around .022"-.024" when he put it together, so I guess a little wear and losing tension opened them up to around .030".
The under sides of the pistons (with the exception of the one that came apart) have no color at all, look like new clean aluminum. This is what has me scratching my head, there do not appear to be any other signs of detonation, whether lean or timing other than the busted pistons. I guess that detonation is gonna be the blame.
Now with that being said, when we inspected it closer, 3 of the pistons on the left bank (#3,5,7) are all cracked in that area. What would cause just the left side to go lean and detonate?

**joeltjen** · 08-08-2011, 10:00 PM

are you running total seal rings???? just sayin' i won't use them any more. didn't pull pistons apart but chewed up the cylinder walls and we had way more end gap than they recomended.

**50j** · 08-09-2011, 08:08 AM

Originally Posted by stpmotorsports

Engine has Dart Iron Eagle 215 heads. Engine builder said that ring gap was around .022"-.024" when he put it together, so I guess a little wear and losing tension opened them up to around .030".
The under sides of the pistons (with the exception of the one that came apart) have no color at all, look like new clean aluminum. This is what has me scratching my head, there do not appear to be any other signs of detonation, whether lean or timing other than the busted pistons. I guess that detonation is gonna be the blame.
Now with that being said, when we inspected it closer, 3 of the pistons on the left bank (#3,5,7) are all cracked in that area. What would cause just the left side to go lean and detonate?

I've seen 3&5 run leaner on a sbc. Could also be a leaking intake gasket, or carb problem.

**let-r-eat** · 08-09-2011, 02:00 PM

ditto all the above. Get the engine some fuel!!! it needs it. You are having a lean/detonation problem. The intake valve and relief get very hot very quickly due to its physical *thinner/edge* and is the first place usually that shows problems. Since your on alcohol that makes the problem even worse.

Butting usually takes the whole ringland to top of piston for the whole intake valve and beyond. The lean or misfire/detonation taking out the intake valve relief will usually look like you took off the edge just outside the intake valve to the ringland.

**parrot69777** · 08-09-2011, 04:00 PM

Detonation will go to whatever the weakest part of the piston is.

**stpmotorsports** · 08-09-2011, 05:25 PM

Ok, thanks guys, all opinions are respected and appreciated.
THe rings are JE, not Total Seal.
Seems that detonation is the general concensus, although I am still puzzled as to why there were no signs of anything going wrong. THe engine never wanted to gain heat, even in a 25 lap feature. The plugs showed some tan color, the engine builder and others that looked at them said they looked good. There is no discoloration on the bottom of any of the pistons, with the exception of the 1 that is apart, if it was lean wouldnt the bottom side of the pistons show that they had been hot? THe motor was very responsive and never quit pulling, never acted like it was running out of fuel.
The first time that it came apart, we had been turning it at the top 7500-7700 rpm, we changed gears and were only turning it 7000-7200 this time.
IF the plugs, engine temp and other signs show good, how do I tune it to prevent this from happening again? Does anyone use a pyrometer in the header tubes? Thats what my drag racing buddies say to do.
Again, thanks for the responses

**let-r-eat** · 08-09-2011, 05:33 PM

Can you post a pic of the plugs? Pistons? Cylinder walls? Are you running a throttle bypass and how is the fuel system setup?

I forgot to mention a pic of the exhaust ports.

**stpmotorsports** · 08-09-2011, 08:28 PM

Fuel system is all new, we just put the car together early this summer. -10 blue line from the cell to pump, long inline cartridge filter with stainless element, C&S mechanical pump, Diaphragm bypass behind the carb with return to cell. Its a C&S 900 cfm carb with the billet venturi sleeves. The carb, bypass and pump have been on other engines with no problems.
I have pics and am trying to figure out how to upload them.

**joeltjen** · 08-09-2011, 11:00 PM

#1 make sure you have your filter element in the right way. if you have it backwards it will starve for fuel

#2 i know i'm gonna catch chit here but get rid of that mechanical pump. they're ok for a 2 barrel on alky but not even close on a 4 barrel if you're trying to make over 500 hp. ya need a belt drive! you have the right bypass for a belt drive pump, 3 psi at idle , 9-10 WOT.

#3 what size jets you running? check with others that are running the same carb. i've never ran your brand of carb so i cant say, but i run another brand ( well respected carb builders but i wont mention name) i started with jets they recomended and i wasn't even close. they had me on 142 and 144 and the engine banged and popped about 1/2 way off the corner. a freind of mine told me of his experience with same brand carb and now i'm up to 166 and 168---awesum numbers on dyno