This is my first V8 rebuild and it's gone pretty smoothly until now. I'm installing roller rocker arms and when I do the "sharpie" test the wear on the valve is not in the center (see picture). Is this something I need to worry about? I've been told the geometry isn't right if the wear is not in the center of the valve. The engine is from a 1989 Lincoln Town Car with HO top end from a 1989 Mustang. The roller rocker arms and pushrods are Comp Cams and the pushrods are the stock length. Any help is appreciated.

 

Those heads have pedestal mount rockers which aren't adjustable so there isn't anything you can do about it anyway. Did you swap in the HO cam too or does it still have the tiny Towncar/Crown Vic cam?

 

I thought you could adjust the angle with longer/shorter pushrods? Yes I put in the HO Cam and upgraded to forged pistons too.

 

Depending on which way you want to move the contact point, IIRC, I was able to get a shim kit that fit under the pedestal mount. It is primarily for setting lifter preload, but you prolly have roller lifters.

 

Longer pushrods will only work if you also shim the pedestal base to achieve correct lifter preload spec which is only just beginning to compress the lifter plunger, that may improve the rocker geometry though. Shorter pushrods are a complete no go since you can't make the pedestal shorter to maintain lifter preload.. well you can but that would involve removing the heads and having a machine shop shave them down, and that is probably the wrong direction to go anyway.

Overall I don't know if it's worth bothering with as I doubt the current rocker geometry is any worse than it is with the factory rockers. Have you measured one of those? Why did you use 1.6 aftermarket rockers anyway? Did you have them kicking around or stumbled on a great deal? You could have used 1.7 rockers with the existing springs.

 

Not to put a wet blanket on here, but you really wasted your $$$ on those roller tipped rockers. Should have bought the full roller pedestal mount rockers. The roller trunion in the full rollers is where the real frictional loss occurs, not in the roller tips. If you'd watch a non roller tip function in slow motion, you'd see that it "rolls" across the valve stem in operation, the face of the rocker is curved, not flat to let this happen. With the full rollers, you just bolt em down and torque to 25 ft/lbs and you're done. The geometry if changed, amounts to nothing.