mz3bo

Hi, some might find this question stupid but I never bought this kind of stock before. My engine is a 94 LS engine with 160kmiles running strong with string compression. I want to put in SRP pistons to go FI but don't know what bore to get? Can someone help me by explaining how we make this kind of choice . I want to go the cheapest way possible.

Thanks

liam821

Got a few choices. You can keep the stock bore and just have the cyl honed to fit, or bore it 20 over (.5mm). With the amount of miles on the motor i recommend going with oversized pistons.

Its not a good idea just to slap in forged pistons in a motor as forged pistons need more cyl wall clearence. (Ive seen people get the clearences wrong and the piston wall clearence is too close and starts rubbing which heats up the pistons until the point where it gets stuck..and then breaks a rod.)

So all in all, i recommend getting 20 over pistons, and then getting the whole bottom end of the motor rebuilt, new rings and bears etc etc.

Good luck

liam

sweet

iTrader: (5)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by liam821 &raquo;</TD></TR><TR><TD CLASS="quote">Got a few choices. You can keep the stock bore and just have the cyl honed to fit, or bore it 20 over (.5mm). With the amount of miles on the motor i recommend going with oversized pistons.</TD></TR></TABLE>

yep what he said. the forged pistons need a bit more clearance than the stock pistons for expansion when at full temp. if the motor has higher mileage than most likely there is quite a bit of wear on the cylinder walls, possibly an out of round condition, which would require oversized boring/pistons to bring it back to round. you definantly don't want to just buy new pistons, hone the sleeves for new rings, and then throw the new forged pistons in there. that won't be good.

choose the pistons for your particular setup, most likely in an in 81.5mm bore.
if it's possible to do so, you may want to check the sleeves first to see what size and condition they're in. but most likely you'll go with the .5mm oversized pistons.
then when you get your pistons have a machinist bore it out slightly to the correct size for clearance, then a quick cross-hatch hone for the new rings.

BTW, look into the different piston brands before buying anything. SRP is ok, but they are basically the bottom of the barrel. i used them before and they were fine, but JE (same company but a bit better design), Weisco, Endyn, Arias and Ross make really nice forged pistons for all applications. i personally will never buy SRP again. i believe it's better to just pay the extra $$ and get the best.

-iLLuZioN-B18C1

true, spend some extra money to get better pistons! youll thank yourself down the road when you might decide you want more boost.

XDEep

cant you just measure for out of roundness and clearances, and use the stock bore? im getting a good deal on used ones. maybe do a heavier hone?