Rocker Arm Installation

[Chuck]

We are replacing the no-name pink rocker arms on our 302 with Comp Cams. Got them installed, except for tightening down the polylocks.

The Comp Cams come with detailed instructions, including adjustment tips involving rotating the crankshaft, etc.

Although I intend to follow the instructions to the letter, I was curious as to how critical adjustment of rocker arms is when hydralic lifters are used. I can understand the need for precisions with solid lifters, but is it as critical with hydralic lifters?

Picture of the new ones, ready to be adjusted attached.

 

[Randy V]

Chuck - If you have the lash properly adjusted, all you need to do now is to hold the adjuster in place with a 5/8" wrench and tighten the lock screw in the middle up against the rocker stud. You don't have to tighten it like it's the only lug-nut on the bus, just snug it down..

In terms of how critical the adjustment is on hydraulics - you have a pretty fair amount of room for error. You can tighten the lash anywhere from Zero lash to a +1 turn pre-load. I choose zero to 1/4 turn preload.

 

[Chris Duncan]

We are replacing the no-name pink rocker arms on our 302 with Comp Cams. Got them installed, except for tightening down the polylocks.

The Comp Cams come with detailed instructions, including adjustment tips involving rotating the crankshaft, etc.

Although I intend to follow the instructions to the letter, I was curious as to how critical adjustment of rocker arms is when hydralic lifters are used. I can understand the need for precisions with solid lifters, but is it as critical with hydralic lifters?

Picture of the new ones, ready to be adjusted attached.

depends how close you want it to blueprint

when you change the adjustment you change the geometry, when geometry changes, valve open height changes, which leads to imbalanced cylinders. for a perfect blue print all the rocker adj nuts should be at the same height

in other words, try to get all the adjuster nut heights even

this can all go out the window with something like an AFR head, the rocker stud thread holes are inaccurate. wrote a detailed post on that fiasco a while back

 

[Chuck]

Kalum:

Interesting observation. When I originally changed the valve covers I noticed that there was a significant variation in the height of the adjuster nuts - perhaps an eighth to 3/16 inch. Contacted the engine builder and he did not not seem concerned, so I wasn't either.

Today we adjusted the lash, following the Comp Cam directions as closely as possible. (First time we have done this project). When finished we placed a straight edge across the adjuster nuts. They were even, less than a sixteenth inch variation, if that much. Your observation is reassuring.

Tommarrow we will start it up after putting in fresh plugs, then do some serious carb adjusting. We are curious to see if the new rocker arms will make any difference.

Attached is a pic of the no name rocker arms we removed. Perhaps it is my imagination, but one can see variations in the top surface about midway between the roller bearing and the main bearing, almost as if some of these rockers were stressed. Does not show up well in the pics. In any event, probably a good thing we swapped these out.

 

[Jac Mac]

Attached is a pic of the no name rocker arms we removed. Perhaps it is my imagination, but one can see variations in the top surface about midway between the roller bearing and the main bearing, almost as if some of these rockers were stressed. Does not show up well in the pics. In any event, probably a good thing we swapped these out.

You get that when trying to do a neat job on a monday morning with a disc grinder and a dose of the shakes, should have specc,ed rockers from wednesday or thursdays production run .

 

[Jack Houpe]

Chinese pro comp or comp pro, is what they look like. I think T and L engines tried these and then went back to comp cam after some people complaining. There was a tread on this last year, when I got my engine from T and L the first thing I checked to see what rockers it had, it had comp cam installed.

 

[Chuck]

Fired it up today and the new rocker arms seem to work just fine. But the carb / ignnition problems persist, as noted in our other post.

One issue at a time. . . . .