JE piston failure

[stpmotorsports]

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]

fuel starvation

#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

[Dirtrunner35]

I use a mechanical pump on a 600 hp motor on alky with a 4bbl, no problems.

[webessay kevin]

I agree this comment !!!
Detonation will go to whatever the weakest part of the piston is.

[Mosidebite]

Mechanical pump 8600 rpm and 690 hp for the last 4 years....just saying, wouldnt just blame the pump.

[powerslide]

Mechanical pump 8600 rpm and 690 hp for the last 4 years....just saying, wouldnt just blame the pump.

you two saying mechanical pumps are you on gas or alky? i always had trouble keeping the pumps together seemed like something was always going wrong w/ them

[Mosidebite]

On alky...have had really good luck with the pumps from speedway or the cheaper pumps from Motorstate. Had a couple Baker pumps and never lasted. The ones mentioned earlier seem to last for a couple seasons for me, When they start leaking oil I get a new one. Never gave up just dont like the mess. I figure if I buy a new pump every other year I would spend way less than buying a belt drive and then having the maint. and rebuilding costs

[charlie#two]

Had the same problem a few years ago with a 18 degree motor. We were running gas at the time, broke 2 pistons put 2 new ones in and broke 2 more, put a new set in changed to alky and backed the timing down to around 30 and have the run the motor 3 years now with no problems.

[Jet Jockey]

STPMotorsports, you may do well by giving Glenn a call at Clements. He knows all about JE pistons cracking and it is my experience that he will not hesitate to talk to you about it. I will suspect that he will recommend Diamond pistons due to their thicker head material. Not saying you don't have problems elsewhere, but he would be a great resource for you.

[stpmotorsports]

Thanks guys