Swapping valve springs from P6 to 3.9 heads ?

DamianZ28

Active Member
Hi Guys,

Am in the middle of engine rebuild, back in Sept 2010 I refurbed the old P6 heads with standard new double valve springs, so my questiion is can I use the new double springs for my new refurbed 3.9 heads which are single springs ? Or is it not possible due to size/ collett difference for example/ and will it make any diffence ?
Cheers Damian
 
The heads are a different shape IIRC. The P6 heads have a register for the outer spring, with a raised centre that the inner spring sits on, which isn't there on the later heads. ISTR the heads can be modified to take double springs, and you need different spring caps as well. Some or all of which I may or may not have dreamt.
 
Hi Damian,

As Harvey said, the springs are not a straight swap, there is machining involved. There is essentially no difference in terms of the force required to compress either spring arrangement.

Ron.
 
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