Lt1 pistons
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On The Tree
Joined: Jul 2007
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Lt1 pistons I am rebuilding my camaro lt1,i'm making my 350 into 383 with all eagle forged internals , my mechanic told me it would be a good idea to put higher compression pistons , the thing is i dont know what to expect from those pistons , is it good o bad , what are the downsides to it,also what compresion ratio does my 1993 lt1 come with stock
Thanks
Thanks
The Eagle stuff is just crap in the end even if it holds up it will cost you as much as having run actually good parts. Hassles with hub and converter/pilot bearing dimensions being wrong, pain to balance etc., lots of guys have these problems but still Eagle maintains a good reputation, Scat is actually better stuff and by the time you are done buying and balancing forged the Callies Compstar line is about the same price and much higher quality parts.
Far as your mechanic I would strongly suggest you get another mechanic. With a 383 thin gasket for good quench and with the block decked for good quench you need a pretty hefty DISH to keep compression from getting too high.
If you left the deck height alone(bad idea) and ran a thin gasket(good idea) and bought a piston meant for a 383 but with the same valve reliefs as stock you would still endup over 11:1 compression. Deck the block to .010 and use a thin gasket and you are solidly over 12:1. start aiming for really good quench and you are over 12.5 in a hurry.
Stock piston is a flat top with 4 reliefs. Not like it is a low compression piston to start with.
Far as your mechanic I would strongly suggest you get another mechanic. With a 383 thin gasket for good quench and with the block decked for good quench you need a pretty hefty DISH to keep compression from getting too high.
If you left the deck height alone(bad idea) and ran a thin gasket(good idea) and bought a piston meant for a 383 but with the same valve reliefs as stock you would still endup over 11:1 compression. Deck the block to .010 and use a thin gasket and you are solidly over 12:1. start aiming for really good quench and you are over 12.5 in a hurry.
Stock piston is a flat top with 4 reliefs. Not like it is a low compression piston to start with.
Launching!
Joined: Aug 2006
Posts: 209
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From: Lewisville, TX
compression is a good thing, you gotta put new pistons in anyway since you're rebuilding, might was well get more power while you're there. only two things i can think of that come with shorter forged pistons. 1. it might introduce some cold start piston slap due to the short skirt (i assume you're using 6" rods on this stroker of yours) and thermal expansion rate of the aluminum. the alloy is different from the hyperutectics that come stock (10.5:1 comp). 2. because of the shorter piston there is very minimal but increased bore wear. but then nobody builds a 100k mile nitrous fed forged 383. ok i lied, there is a third downside that everybody here SHOULD already suffer from... you have to use premium fuel grade with high comp ratios.
Yes compression is a good thing but this "mechanic" is neglecting to consider the added stroke would increase comnpression even if using a piston with the same valve reliefs. Not to mention the stock gasket is very thick and almost all of us use thinner ones on rebuild or even heads/cam and that compression would be increased by at the bare minimum square decking the block but he should be looking at going further than that to improve quench. All said and done he will probably need a piston with bigger valve reliefs or maybe even a dish and will still substantially raise compression.
