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Thread: SR20VE Pistons from CP Pistons ***Available Soon***

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Posts: 11-20 of 85
2008-08-13 22:29:14
#11
Originally Posted by jer_760
12:1 with a VE head. Are those comp numbers that you posted going to be 8.5 and 9.0 WITH the VE head or before? I would love it if they would go ahead and cut some deep/er valve reliefs also, lets say 2mm deeper than the 16ve pistons


Yes, it's the number with the VE head. Why do you need deeper valve reliefs? We checked it using the N1 cams and the exhaust valve only dented the clay about 1mm and the intake didn't come close. And that's with oversized valves. We were actually thinking about making them shallower to strengthen the piston. Let me know what data you have.

Mark
2008-08-13 22:34:08
#12
Sounds good
2008-08-13 23:06:47
#13
Originally Posted by Mazworx
Yes, it's the number with the VE head. Why do you need deeper valve reliefs? We checked it using the N1 cams and the exhaust valve only dented the clay about 1mm and the intake didn't come close. And that's with oversized valves. We were actually thinking about making them shallower to strengthen the piston. Let me know what data you have.

Mark


i think people want deeper valve reliefs for safety if they chose to run big cams and play with the overlap. Non-turbo

I seriously doubt there will be a huge market for 12:1 90mm pistions but people would just like to pay less for these
2008-08-14 00:11:14
#14
You will need deeper valve reliefs to safely play with cam timing using the new Kelford built motor cams and several people have expressed interest in running those.
2008-08-14 00:30:43
#15
Originally Posted by Clint
You will need deeper valve reliefs to safely play with cam timing using the new Kelford built motor cams and several people have expressed interest in running those.


Yeppers, those were what I was looking into.
2008-08-14 00:51:51
#16
You're fine if you're running SR16VE pistons and not advancing the cams but they're pretty close. Cook Motor Racing who have just rebuilt my engine and Kevin Ban from Kelford work together a lot so Kevin should have or can get all the info. As I'm not an engine builder so it's best to talk to Kelford before deciding yes or no to the 184-C cam, rather than relying solely on what I say.

Originally Posted by Mazworx
Here's what they plan to make:

Bore x CR

86.0 x 8.5
86.5 x 8.5
87.0 x 8.5
90.0 x 8.5
86.0 x 9.0
86.5 x 9.0
87.0 x 9.0
90.0 x 9.0

What would be your suggestion on high compression pistons?

Mark
[email]mark@mazworx.com[/email]


Isn't 88mm as big as you can go without sleeving the block? In that case it may be a good option for those who don't want to go as far as sleeving.
2008-08-14 06:56:09
#17
Originally Posted by Clint
You're fine if you're running SR16VE pistons and not advancing the cams but they're pretty close. Cook Motor Racing who have just rebuilt my engine and Kevin Ban from Kelford work together a lot so Kevin should have or can get all the info. As I'm not an engine builder so it's best to talk to Kelford before deciding yes or no to the 184-C cam, rather than relying solely on what I say.



Isn't 88mm as big as you can go without sleeving the block? In that case it may be a good option for those who don't want to go as far as sleeving.


Some people have had bore shift with 88mm, the liner is getting a little thin if you go that big.

Also 1mm for an exhaust is closer than I would have in an engine of mine, if the valve lofts a little and or wobbles a bit the 1mm soon goes (look at those spintron videos) and leeway for more overlap would be good.

Mike
2008-08-14 13:27:02
#18
What centerline are you all motor guys running? Maybe on the high compression motors we can get the reliefs deeper and turbo cars we can make them shallower.

Thanks for the feedback, keep it coming.

Mark
[email]mark@mazworx.com[/email]
2008-08-14 19:00:42
#19
Originally Posted by Mazworx
What centerline are you all motor guys running? Maybe on the high compression motors we can get the reliefs deeper and turbo cars we can make them shallower.

Thanks for the feedback, keep it coming.

Mark
[email]mark@mazworx.com[/email]


That sounds like a very good idea, all motor needs much more radical cams to keep up with a snail driven car, and much more overlap needed. One of the C3&SR16V piston guys got to a decent power, but couldnt take it further because the cam was in danger of touching, sorry I dont remember if it was inlet or exhaust.

Mike
2008-08-15 04:06:21
#20
Sweet glad they will have shelf pistons for when the hell I get around to do my rwd VE lol.
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