Forged Pistons
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Forged Pistons
I'm looking to swap out the pistons in an LS2 shortblock I just received. I want a forged piston with a -4cc valve relief. I would REALLY like to use the stock rod and the stock bore. I'm going to spray the car and I'm also running a heads/cam combo that will require cutting the pistons. I wouldn't have a problem cutting the pistons, but I'm not sure how well they will hold up to the nitrous with a relief cut in them. I would feel better just puting a new piston in it. Is there a piston that will work for this application?
Info or a part number would be great.
Thanks!
-Biz
Info or a part number would be great.
Thanks!
-Biz
#4
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I'm looking to swap out the pistons in an LS2 shortblock I just received. I want a forged piston with a -4cc valve relief. I would REALLY like to use the stock rod and the stock bore. I'm going to spray the car and I'm also running a heads/cam combo that will require cutting the pistons. I wouldn't have a problem cutting the pistons, but I'm not sure how well they will hold up to the nitrous with a relief cut in them. I would feel better just puting a new piston in it. Is there a piston that will work for this application?
Info or a part number would be great.
Thanks!
-Biz
Info or a part number would be great.
Thanks!
-Biz
If you shop around for pistons look for something like a 4.005 bore, 3.622 stroke, for stock 6.098 rods with a .945 pin. You can then use Scat I beam forged rods 6.098 length, .945 pin, with ARP rod bolts from Speed Inc. They only cost $299.99. That way you're really only spending an extra $219.99 on putting in forged rods at the same time. You'd be kicking yourself if you didn't later down the road.
Why if your are using a -4cc dish would you need to cut an additional valve relief in the piston? Even if you did why not get a larger valve relief piston to start with?
Here's what I'd build if I was you.
Pistons = Wiseco K398F3 = 2618 material, 4.005 bore, 6.098 rods, 1.304 compression height, for a 3.622 stroke = $535
Rods = Scat I beams = 6.098 length, .945 pin = $299.99 OR extra money = Scat H beams = 6.098 length, .945 pin, ARP 2000 rod bolts = $529.99
Crank = Stock cleaned up
Get everything rebalanced, honed, align honed, and you're good to go. If you have an extra $200 I'd put ARP main studs in. Your block has to be align honed for those.
I was messing with a compression ratio calculator and that setup that I just put together, .005 out of the hole, and .055 compressed thickness GM gaskets the compression ratio comes out as:
70cc Chamber: 9.894436516622516:1
69cc Chamber: 10.001511846508816:1
68cc Chamber: 10.111196634690188:1
67cc Chamber: 10.223587447781734:1
66cc Chamber: 10.338785676683289:1
65cc Chamber: 10.4568978416548:1
64cc Chamber: 10.578035920838879:1
63cc Chamber: 10.702317704360208:1
62cc Chamber: 10.829867176355531:1
61cc Chamber: 10.960814927538708:1
60cc Chamber: 11.095298601186698:1
59cc Chamber: 11.233463375748254:1
58cc Chamber: 11.375462487632586:1
What heads and cam do you plan on running? I don't really see why you'd need an extremely large valve relief unless you were building something with a n extremely large cam.
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I would be cutting the stock pistons not the forged ones. The -4cc relief would be plenty for what I'm running. I also already have ARP rod bolts. I'm just on a pretty tight budget. I wasn't going to run forged pistons at all, but the ones in the motor have detinaton marks. So, I'm looking to replace them.
I'm running a set of Patriot Heads 2.055/1.60. The heads are milled .035, so that puts the chamber at about 58cc.
I'm running a comp custom grind cam, 236/248 601/615 110+2
I'm running a set of Patriot Heads 2.055/1.60. The heads are milled .035, so that puts the chamber at about 58cc.
I'm running a comp custom grind cam, 236/248 601/615 110+2
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If you shop around for pistons look for something like a 4.005 bore, 3.622 stroke, for stock 6.098 rods with a .945 pin. You can then use Scat I beam forged rods 6.098 length, .945 pin, with ARP rod bolts from Speed Inc. They only cost $299.99. That way you're really only spending an extra $219.99 on putting in forged rods at the same time. You'd be kicking yourself if you didn't later down the road.
basically the features of an Eagle H beam for the price of Scat I beams.
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I would be cutting the stock pistons not the forged ones. The -4cc relief would be plenty for what I'm running. I also already have ARP rod bolts. I'm just on a pretty tight budget. I wasn't going to run forged pistons at all, but the ones in the motor have detinaton marks. So, I'm looking to replace them.
I'm running a set of Patriot Heads 2.055/1.60. The heads are milled .035, so that puts the chamber at about 58cc.
I'm running a comp custom grind cam, 236/248 601/615 110+2
I'm running a set of Patriot Heads 2.055/1.60. The heads are milled .035, so that puts the chamber at about 58cc.
I'm running a comp custom grind cam, 236/248 601/615 110+2
^ Nice! I wish I would have known about those before I got scammed on here trying to buy a set of Scat H beams.