double valve springs for fast road na motor
Turbo Mini Forums

im rebuilding a fast road engine for my mpi cooper. usual fast road mods, overbore, sw5i cam, ported head etc

im going to overhaul the head whilst im in there. I currently have isky springs fitted. I don't know the poundage of them but they are far over what I need.

bearing in mind that the engine is driven up to 5k usually, with the mpi limiter at just over 6k

I have been considering either of these minispares items

http://www.minispares.com/product/Classic/...h/classic/valve springs.aspx|Back to search

http://www.minispares.com/product/classic/C-AEA526.aspx


what would people suggest I use? im thinking that the standard spec ones should be up to the job? cheers, dan

I've just fitted the 200lb ones but mines more a race engine than fast road.

The 525's should be fine with your cam, as its for fast road, i wouldn't want any stiffer, mainly because it'll end up wearing out your cam alot quicker

YES use the 525s dan they are good for
7k ish no bounce, no good overloading the valve train and sapping all the power

cheers steve, I ordered these earlier. what I have now are far too high a poundage for what the engine does.

It's not just a matter of fitting the springs though. They need to be shimmed to the right height to give the correct on the nose poundage that the cam profile requires.
Excessive pressure will cause increased wear, undersprung & the follower will not ride the cam profile properly.

Phil.

WWW.TURBO-MINI.COM

Agreed mine are 225's i think, which can be shimmed tou 280lbs. I do recall some mig's using 360's