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if i would like to attain a 11:1 CR with some wiseco 300zx pistons swaped into my sr20de do i need to shave the dome and flatten the piston surface or just install as is (with dome and all) and keep in mind i want a 11:1 comp. ratio
If your gettting aftermaket pistons, you can just tell them u want sr20de 11:1 high compression pistons. 300zx require some mods to fit, and people are usualy usually using oem stock vg30de pistons. Inside the sr20de, they produce a 11:1.
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"A couple of Nissan Sr20's will pull a premium one week before race wars." (Johnny Tran, fast and furious) LOL
ok heres the deal i just installed some 300zx pistons in my car , had to bore the block from 86mm to 87 mm to accommodate the bigger pistons but the guy who i bought them from and did the work on my car ( he's a very good mechanic ) said that the pistons had to be shaved ( they came with a bulb /dome on top of em) to get the CR down to 11.0:1 , i also have an correction to make ,they are not wiseco, but had previous work done to em, so my ques is is this the norm?(have other ppl done this before and also had to flatten the piston head by shaving them?) or was it a mistake to shave em?
Well as std the dome is about 4.8cc, you need to do the calculations, but if it was skimmed and or a thinner head gasket then yes, you will need to skim the piston crown.
yes the rods fit nicely prep. work was already done ...i am using a genuine sr20 head gasket we shaved the dome off completly it is now flat ( i can't wait to do a compression test on it ) but i have a feeling that what we did was a bad move...the only reason why i even wanted them shaved was to keep it at a 11:1 CR ***** of the 90 octane gas we have here in JA.
yes the rods fit nicely prep. work was already done ...i am using a genuine sr20 head gasket we shaved the dome off completly it is now flat ( i can't wait to do a compression test on it ) but i have a feeling that what we did was a bad move...the only reason why i even wanted them shaved was to keep it at a 11:1 CR ***** of the 90 octane gas we have here in JA.
You are now close to 10:1. Stock Z pistons are 11:1.
i know that i can get the 11:1 by doing that but i didn't want to it becasue by doing that you'll increase the quench vol. i wanted to just install the pistons and thats it ...if i new that it would only be at 10:1 i wouldn't shave them,as a matter of fact i would just install some sr20 10:1 pistons. just my luck
Last edited by venom2727 : 12-31-2006 at 04:01 PM.
if u wanna bmp the cr real nice for cheap....vvl sr16ve pistons in the de! i did that and my de went from 10:1 to 11.8:1 and then i shaved the head so now its at about 12.4 or 12.5 to 1 and that things moves.....but that IMO *** i paid 125 for my barely used vvl pistons and rings from a forum member
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RaciN' *** DreadZ N GoldZ.........
i know that i can get the 11:1 by doing that but i didn't want to it becasue by doing that you'll increase the quench vol. i wanted to just install the pistons and thats it ...if i new that it would only be at 10:1 i wouldn't shave them,as a matter of fact i would just install some sr20 10:1 pistons. just my luck
When you skim the block you reduce the quench volume which I thought was a good thing, the only reason you need it (quench gap) is to stop the piston banging into the head at max revs and TDC, because the rods are so stout you can go down to about 30-35 thou very safely.
If they were skinny rods you would need 40-45 thou, if they were titanium rods you would need 60 thou...
i bored the block from 86-87mm because of the 300zx piston size (87mm) i didn't skim the block ...200sx what is the size of the sr16ve pistons in width ,is it 86 or 87mm ?
Which pistons did you buy? OEM or forged? If you going Natrally aspiated and want to raise your compression, you might as well go higher. 10:1 compression is like the jdm stock sr20de, 10:1 compression and 10 more hp. I would rather go 11:1 or so after all the trouble of doing blockwork. It sounds like your going through a lot of trouble maching and getting these vg30de pistons to fit. If your going to build it, mightas well go either low comp turbo, or high compression NA. IMO
i bought them from a guy they look like forge pistons to me he paid $420 for six of em , now heres the kicker ,why i beleive that they are not OEM's they fit the sr20 rods without any problem plus the doom on the piston were much higher than that of the OEM ones..i am going to find out the name of the site that he bought them from and keep u guys updated ...but if when i do a compression test on the engine and it is 10:1 and not 11:1 has i had wante di am going to turbo the 10:1s a run low boost, honda guys do it all the time.
