Cam bearing location

[eastwoodad]

I know cam bearings have been discussed quite a bit, but I still seem to have a few questions, so here goes;

I am in the process of rebuilding a 84-85 block. I got the Federal Mogul/SpeedPro rebuild kit and am having the machine shop install the cam bearings. Looking at the front cam bearing, there is a large slotted hole which from reading the Ruggles literature and elsewhere is a bit too big. I don't believe the 84/85 block is grooved and I will have to check to see if my aftermarket cam is grooved.

Here's my thought; can I just have the machine shop rotate the front cam bearing slightly to block some of the slotted portion of the hole or will this create issues? Does there need to be at least a groove in the cam or in the block? Help!!

Thanks,
Aaron

 

[eastwoodad]

I checked, and the cam's front journal is grooved.

 

[JDEstill]

You have to have a groove somewhere to get oil from the passenger side over to the drivers side gallery. The groove can be in the block (86/87), in the cam journal (85 and earlier), or in the back of the cam bearing (TA Perf cam bearings).

Since you have an older block you need the groove in the cam, unless you were going to run the TA bearings. Instead of drilling the smaller holes and rotating the bearing I'm sure you can just have the shop rotate the bearing a little bit, so the existing slots are slightly mismatched. I don't see the difference, except that the hole drilling method is a little more exact. I kinda wonder if the holes sizes listed by Ruggles is all that critical anyway...

Anyway, I think the answer is yes, you can do as you suggested, so long as you make sure that neither hole is completely blocked off.

John

 

[eastwoodad]

Thanks for the reply! The hole I am trying to make "smaller" is on the drivers side. The hole in the bearing is like a slotted hole...pretty large. The oil comes in from the passenger side and exits the drivers side, right?? I guess my concern was/is that by rotating the cam bearing to make the drivers side hole smaller I may be restricting the passenger side (supply side). Any advice?

Thanks

 

[JDEstill]

The Ruggles mod was to drill two new, smaller holes and then rotate the whole bearing so the two new holes lined up with the two passages. One hole was to be bigger than the other, 0.125" on the passenger side and 0.090" on the drivers side. If you can rotate the bearing so that both holes are about the equivalent of a 0.125" opening, I'm sure that would be plenty good. The difference between the drivers side hole being 0.125" instead of 0.090" isn't going to be that great IMO. I think the clearance between the lifters and their bores is going to have a bigger effect on your oil pressure than the size of that hole.

John