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Dohc pistons in sohc

Posted: Mon Jun 03, 2013 11:18 pm
by niss720
Hey I'm sure this has been asked a thousand times, but can you use vr4 or dohc forged pistons under the 63 sohc head?

Posted: Tue Jun 04, 2013 12:25 am
by bigmoz
yes

Posted: Tue Jun 04, 2013 6:06 am
by OLD FART
bigmoz wrote:yes
More info The 4v heads are interference =Valves will get intimate with pistons if belt breaks .That won't happen in a SOHC 63/64 so VR4 pistons are ok

Posted: Tue Jun 04, 2013 10:56 pm
by redzone
It's something i've been telling everyone to do for 7 years.. The benefits are many, i cant believe anyone would actually buy starion pistons when you can get VR4 pistons cheaper and they actually dont break ring lands anywhere near as easy...

Posted: Wed Jun 05, 2013 12:53 pm
by ProZac
What sort of compression ratio do you end up with when using VR4 pistons with an 8V head?

Posted: Wed Jun 05, 2013 6:58 pm
by niss720
Thanks guys and what compression ratio would 9:0:1 pistons bring with the sohc

16 valve pistons

Posted: Thu Jun 06, 2013 7:12 am
by pajeroturbo
Once I have just finished my engine today I will tell you the whole story.
I have a pajero 89-90 model and I am using a starion motor in it for 10 years now.
The engine is stock motor with a tc-06 turbo. Before 5 years I did a full rebuild of the
Motor and used the 16 valve pistons everything fits ok and the car made 241 hp on 1 bar boost using a haltech e8 and a multipoint injection from the 4g64 motor. With these pistons the engine has a 7.2 compressor ratio and that makes the car having no power on off boost
Last week I decided to change the pistons and put the pistons the l200 used with the1mm dish that makes the compressor ratio to 9.5 I did a drive with the car and man the car of boost goes crazy good. Boost comes up very faster than before. The only thing is that I do not know how much the pistons will last with this set up. If there is anything you can tell me please say it with no problem.

Posted: Thu Jun 06, 2013 3:33 pm
by DrDeath
Im running the 9.0:1 CP pistons on decked block and head with .6mm gasket i think. I think that gives me around 7.9:1 compression. Problem is I don't know how much they took off the head. Its a non jet valve 8v head too. Don't know if that makes a difference to the size of the combustion chamber? Stock length rods and stroke too.
Doesn't feel sluggish off boost anyway.

Posted: Fri Jun 07, 2013 6:30 pm
by niss720
So the comp will stay low with any piston under the sohc head. But good to know! thanks for all yor help guys!