Installing Cam Bearings

Installing Cam Bearings

All of the cam bearings, that I can think of right now are classified as "pre-finished".

This may be a little misleading to the first time installer.  The basic idea is once they are pulled in you are ready to go.  If there is a need to replace cam bearings in your block, which there almost always should be as the block cannot be hot tanked with them in, then you have probably two possible courses of action.

The first, and the easiest, is to have the machine shop do the job, most likely they have a universal  cam bearing installing puller.

The second option is to make your own puller and do the job yourself.  The latter option should make a more satisfying job of it as long as you go about it the right way.

To make a puller you will need to source several things, the most difficult of which if you don;t have a lathe are the three spigoted bearing pullers that should ideally be made of some sort of aluminum alloy, as shown in the drawing.  The other things are a length of 1/2" diameter "Allthread" with nuts and washers, and a piece of metal bar about 2" X 4" X 3/8" thick with a 9/16" hole in the center.

The dimensions for the alloy pullers are shown in the chart to the right.

We have seen blocks where someone has attempted to knock the bearings out ... somehow! 
This has resulted in scoring to the block, and if the bearings are put in with the block in this condition then problems are guaranteed when the cam is installed.

If you should happen to have a block in this condition be sure to clean up any scores before installing the bearings. 
Just running a Flex-Hone (dingle ball hone) through the block really seems to help installation.
A dab of oil shouldn't hurt either.
The bearing can be squeezed smaller by a damaged block, then the cam will not fit!

The last, and probably most obvious point, is to line up the oil holes in block and bearing shell.  There is a little latitude here, if 75% of the hole is showing that's fine.

After the bearings are installed there are usually high spots that bind the cam a little and the best way to try and deal with them is to go over  them with a kitchen scouring pad which scuffs them up just a little and normally does the job.  If there is a tight spot you may need to look for the shiny spot on the bearing and carefully remove it with a bearing scraper.

One tip is that it is advisable to remove the cam bearings before the block goes for hot tanking, this can help with removing deposits that might be stuck in the oil gallery at the back of the bearing.

These are the parts you will need.
We use 1/2" dia. "Allthread" threaded bar, which normally comes in 36" lengths, but 12mm would be OK too.