28Eliminator

Long story short, I have a 502 MPI stock lower with Edelbrock aluminum heads and a side mount whipple charger. Last weekend it blew oil out the dip stick tube. We pulled the motor and have a hole in a piston. So I need to find a replacement set of pistons. Not sure if it needs bored yet, but wondering what brand and PN of piston I should order? JE, SRP, others; so I can get them ordered and start the rebuild process.
Thanks for any help you can provide me.

I obviously have developed a fuel delivery problem, and will be researching-posting for recommendations to replace the 2 merc pumps (lift & efi), whipple pump and filter seperator.

28Eliminator

yea, it has not had any problems like this before. Fresh tank of fuel, but how do you know you are getting 93 octain when you fill up, just because the pump says so. Also with 3 fuel pumps, and 3/8 fuel lines, it is marginal in size.
I have seen others here eliminating the VST system and changing everything to 1/2 lines, so I plan on replacing all of this to eliminate those possible causes.

Griswald

which hole went away?

28Eliminator

Number 6, and 4 wasn't far behind as it was deformed also.

ezstriper

put in a blower pistons now..KB mast nice ones

BillK

28,
Depending on which pistons are in the engine now, you may want to satay with the same thing. One thing you need to pay attention to is the weight of the replacement pistons compared to the originals. If they are mor than a few grams different, you will need to rebalance the crankshaft.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

28Eliminator

They are stock JE flat top pistons and I don't think they are available anymore. PN:J2700 is stamped on the bottom.
I have the parts in my suburban and will take it into the machine shop to see if it needs bored or just honed. I don't see any real scratches, but there is melted piston on the top of 2 of the cylinders.
BillK, good point on the balancing. I guess if I have to replace them then that will have to be done also. Not really sure how you would be able to find one about the same weight if it was a different piston.
ezstriper, are those Kieth Black pistons you are refering to? Are they blower pistons?

Rawpower

I used J&E blower pistons in my 502 blower motor with very good results. And yes you should re-balance the rotating parts.

I had previously melted the # 8 stock piston with the # 6 starting to go. Mine was BAD GAS. You are correct, you think you are buying 93 octane, but how do you really know?

28Eliminator

Did you notice any difference after installing them? It looks like the JE-257956 is 8.4cr with my 118cc heads and I think stock was 9.1cr.

sunchaser796

Too much boost which will cause melt down in #6 and #4 to follow. Will happen everytime..