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8.5:1 Pistons!?!?

Old Mar 26, 2007 | 11:34 PM
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8.5:1 Pistons!?!?

Ok, as some of you might know, I blew my motor. I took it apart last saturday and found that as usual I blew the ring land on cylinder 4. Anywho, I took my head to work today, and were gonna CC the combustion chambers, surface it, possibly throw it on the flow bench, then do a full radius valve job, and port the hell out of it, then maybe throw it back on the flow bench. With all this crazy head work, I want 8.5:1 pistons to go with it, to make the motor more reliable, because 20 psi with 9.5:1 compression is too much (even though after the head work I'll prolly be at like 16 or 17 psi). Bottom line...
I CAN'T FIND ANY 8.5:1 PISTONS!!!!!!!!!! HELP!!!!!
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Old Mar 26, 2007 | 11:36 PM
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Contact diamond and get a custom set made, or use a lower compression 2.2 piston rod combo.
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Old Mar 26, 2007 | 11:45 PM
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How much would it cost for a set of custom diamonds?
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Old Mar 26, 2007 | 11:52 PM
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j body performance has some wiseco pistons that are 8.5:1. i was honestly thinking of getting them myself. they are a little bit expensive, but still sheaper than a new motor.
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Old Mar 26, 2007 | 11:53 PM
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Screw the Eaton, get a Whipple
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Old Mar 26, 2007 | 11:55 PM
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Originally Posted by HackAbuse
Screw the Eaton, get a Whipple
The adaptor plates are almost done, we just need to get them CNC machined
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Old Mar 27, 2007 | 12:17 AM
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As posted in another thead try calling the fellow who is involved in my pistons.

Adam Silverthorn

Wiseco Piston Canada

Phone: (519)537-6281 Ext. 4103

Fax: (519)537-8508

asilverthorn@wiseco.com

www.wiseco.com
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Old Mar 27, 2007 | 12:31 AM
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Originally Posted by Blown 4-banger
I CAN'T FIND ANY 8.5:1 PISTONS!!!!!!!!!! HELP!!!!!
I wouldn't change the Rod length, because if you start going shorter, you will lose some of the torque that our motors are known for. Sure you can possibly gain horsepower, but I wouldn't want to turn into a Honda motor.

Hey witt- The 2.2L rods are only tested "safe" to 250hp, I think Blown4 is gonna be goin higher than that.

Don't forget if you can't get all the way down to a 8.5:1 piston, you can use a 8.75 piston and get a slightly thicker head gasket, that can drop CR alittle bit. Maybe .05-.1CR, but it can help. Just make sure it is a high quality gasket.

You are using ARP head studs now right? Cause our head studs are torque to yield, so they must be replaced after each use.
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Old Mar 27, 2007 | 12:34 AM
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Thanks a lot man! I will definatly shoot him an email!

Originally Posted by victory_red_SS
As posted in another thead try calling the fellow who is involved in my pistons.

Adam Silverthorn

Wiseco Piston Canada

Phone: (519)537-6281 Ext. 4103

Fax: (519)537-8508

asilverthorn@wiseco.com

www.wiseco.com
Thanks a lot man I will definatly shoot him an email!

Originally Posted by Archie
I wouldn't change the Rod length, because if you start going shorter, you will lose some of the torque that our motors are known for. Sure you can possibly gain horsepower, but I wouldn't want to turn into a Honda motor.

Hey witt- The 2.2L rods are only tested "safe" to 250hp, I think Blown4 is gonna be goin higher than that.

Don't forget if you can't get all the way down to a 8.5:1 piston, you can use a 8.75 piston and get a slightly thicker head gasket, that can drop CR alittle bit. Maybe .05-.1CR, but it can help. Just make sure it is a high quality gasket.

You are using ARP head studs now right? Cause our head studs are torque to yield, so they must be replaced after each use.
You don't change the stroke to lower compression. You change the dome or dish of the piston, also if you use a head gasket to lower compression, HELLO DETONATION!!!!

Last edited by Blown 4-banger; Mar 27, 2007 at 12:34 AM. Reason: Automerged Doublepost
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Old Mar 27, 2007 | 12:39 AM
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Originally Posted by Blown 4-banger
Thanks a lot man! I will definatly shoot him an email!


Thanks a lot man I will definatly shoot him an email!



You don't change the stroke to lower compression. You change the dome or dish of the piston, also if you use a head gasket to lower compression, HELLO DETONATION!!!!
How does a different head gasket = detonation. It is a common thing used for the Muscle car guys. Although, I haven't done my research on Supercharged motors yet.
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Old Mar 27, 2007 | 12:42 AM
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Originally Posted by Blown 4-banger
The adaptor plates are almost done, we just need to get them CNC machined
Your car with a ported whipple, make sure you dont send me a sound file, cause i will seriously, no joke, cream my pants.
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Old Mar 27, 2007 | 12:47 AM
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no he was talking about fabbing the plate not porting the blower.
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Old Mar 27, 2007 | 12:49 AM
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Originally Posted by Archie
How does a different head gasket = detonation. It is a common thing used for the Muscle car guys. Although, I haven't done my research on Supercharged motors yet.
No, a new head gasket with same compression is fine, new head gasket with higher compression is fine, but lowering it with a head gasket messes with the quench and allows detonation.
Originally Posted by HackAbuse
Your car with a ported whipple, make sure you dont send me a sound file, cause i will seriously, no joke, cream my pants.
I'll keep that in mind
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Old Mar 27, 2007 | 01:17 AM
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Originally Posted by Blown 4-banger
No, a new head gasket with same compression is fine, new head gasket with higher compression is fine, but lowering it with a head gasket messes with the quench and allows detonation.
Hmm, in the 400 I rebuilt for my GTO, I lowered the CR from 10.75 to about 10.1 with piston and a slightly thicker head gasket. I never had any problems with detonation, but it might be different with new motors. Although it was only .01 thicker.
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Old Mar 27, 2007 | 02:08 AM
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Its different with boosted motors, detonation is a lot more touching when you throw boost into the mix.
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Old Mar 27, 2007 | 02:33 AM
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Call Diamond you bum! I heard that you can get them done for not much more a regularly stocked piston.
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Old Mar 27, 2007 | 05:35 PM
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Well Wiesco said a set of 4 8.5:1 forged pistons with rings and pins is $775 Canadian... This would mean a lot more if I knew how much that is in USD
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Old Mar 27, 2007 | 05:41 PM
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$650-675 if my estimation is right
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Old Mar 27, 2007 | 05:47 PM
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Originally Posted by Blown 4-banger
Well Wiesco said a set of 4 8.5:1 forged pistons with rings and pins is $775 Canadian... This would mean a lot more if I knew how much that is in USD
Today that would be $669.744.
When you need to know the exchange rate go here http://www.xe.com/ucc/
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Old Mar 27, 2007 | 05:58 PM
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Originally Posted by Archie
Hey witt- The 2.2L rods are only tested "safe" to 250hp, I think Blown4 is gonna be goin higher than that.
umm, I'm sure he knows I meant 2.2 forged rods. There are a few more off the shelf piston choices available by ditching the 23mm wrist pin.

Originally Posted by Blown 4-banger
No, a new head gasket with same compression is fine, new head gasket with higher compression is fine, but lowering it with a head gasket messes with the quench and allows detonation.


I'll keep that in mind
The only effective quench are on an ecotec contains too much of a gap to actually be effective. Anything over .045" and quench doesn't happen.

Last edited by Witt; Mar 27, 2007 at 05:58 PM. Reason: Automerged Doublepost
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Old Mar 27, 2007 | 06:07 PM
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Contact diamond like I told ya to do how many months ago.
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Old Mar 27, 2007 | 06:11 PM
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Originally Posted by DWK5150
Contact diamond like I told ya to do how many months ago.
You ca lead a horse to water but...yada, yada, yada
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Old Mar 27, 2007 | 11:03 PM
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LOL! I didn't think diamond was able to make then, considering they only sell pistons with extremly high compression ratios. I didn't think they would know how to make a 8.5:1 piston
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Old Mar 28, 2007 | 01:16 AM
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Just cause they don't doesn't mean they can't. All they have to do is shorten the top slightly. Nevermind that concept might be a little too much for a trusted piston company that took the time to be one of the first to make pistons for the LSJ. I mean they can figure out how to make 9.5:1, 10:1 and 10.5:1 but moving the other directions takes an entirely different approach to making pistons.

You should really be looking for rods too. They aren't rated for much more than the pistons.
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Old Mar 28, 2007 | 01:23 AM
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yeah blown you need pistons and rods
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