Rocker Arm position

[Steve Wood]

Someone emailed me about a thread on another board regarding rocker arm layout...in essence, ChallengerMike gave the correct answer.

See the shop manual pages at the bottom of this link.

http://www.vortexbuicks-etc.com/rocker_shaft_assembly.htm

Originally, from the factory, all rockers were the same.  Then GM issued service parts with a bit of offset in them to improve the geometry.

[challengermike]

I remember looking at them for along time trying to figure them out on my engine,lol

[SuperSix]

Great info Steve!!

[Turbodave]

I've looked mine over with a fine tooth comb, and there are no such markings.  ??
They're the shafts and rockers off of my original 86 GN's motor. Got everything cleaned up spiffy clean getting ready for re-install, and no markings???

[ULYCYC]

Marked rockers were only available as a service replacement part.

[Steve Wood]

I would have sworn that was what I posted....LOL

[challengermike]

Here is where the difference is,this is the pic off steves site.I circled where to look for the difference.As you can see the offset is where the pushrod sits.

[Steve Wood]

yep, it is pretty obvious in that picture....Tal king to Ed about it while ago, he remembers that GM had problems with some heads rubbing the pushrod lightly and hence the change in the service replacements.  This was on the n.a. engines and not just the turbo versions.

[SuperSix]

Wow. Thanks for pointing that out, I had missed it. That seems like a pretty drastic geometry change.
Should I think about getting upgraded/replacement rockers?

[Steve Wood]

Look at your pushrods.  Are some of them worn from rubbing against the holes in the top of the head?  If not, I would not worry about it

[Just a Six?]

Look at your pushrods.

[Steve Wood]

Thank Mike...he is the guy that put the correct info out there....

[ULYCYC]

A tip on getting the neopreme retainers snapped  in.  Soak them in a cup of boiling water for a few minutes.

[SuperSix]

A tip on getting the neopreme retainers snapped

[Turbodave]

Odd how that offset is so obvious.  My stockers have NO such offset and no markings, and I just took a look at the pushrods and they have no evidence of touching anything.  

Guess I'm on of the lucky one's.  I'm reusing the shafts and rockers, have new buttons installed, and a new set of pushrods ready to go in.  Just have to save up for a new cam and lifters to complete the longblock assy.