Cam Bearings

I don't press bearings in, I pull them in with this contraption I made. The blue threaded delrin blanks keep the threaded rod true to tunnel.
I've had engine shops install bearings years ago that said they had to ream a bearing i.d. because there was misalignment. The only misalignment was the way they installed the bearing. Same block using my contraption, cam fit perfectly without any reaming needed. Careful installation means a lot.

 

IF op trys in car install, durabond autoparts store stock bearings are narrower than TA dual groove, maybe a better chance of sneaking them in. Of course less cam support using those too.

 

Yes they are, and that front one, along with not being clocked right, is not even lined up with the hole in the block.

 

I read about that, and it makes sense.

 

Thanks for all the replies. I don't think I have any alignment issues as this block has been gone over more than once over the years, and something like that would have been fixed by now. I would always opt for pulling the motor without a second thought and do it right on the money, and with the way things are now that would not be for a very long time. I'll try to do it in the car, and if its not working out I'll just mothball it until it can be done right, it is what it is. Like they always say, you want it right, do it yourself.

 

I wish I had known about the cam tunnel alignment issue before I did my last build, although I had no issues with my original block( Im now using) with the cam bearings (no reaming needed) I DID have issues with the '78 350 block I WAS running, the cam bearing bores had a knurled pattern inside the bore. Leads me to believe the tooling was wearing out in the later years of 350 production.
Its interesting these issues are coming to light now in the (precision) machining operations that are done by reputable machinists, something that wasn't even considered years ago.
Apparently the factory wasn't perfect, although most of us thought they were, EXCEPT for the few true machinists who are dedicated to their occupation.

 

Do not use coated cam bearings. Most of the coating will need to be removed, by hand or some other rotary method to give prove journal clearance. I have these, may cam would not go in all the way, even partially in it would not turn by hand. A call to a reputable Buick engine builder confirmned my issue. So Ill have to pull these out and replace them with uncoated

 

Alignment is everything. Check your cam runout on V-blocks with a .0001 indicator.
I had a Voodoo cam that was bent .007 from 1st journal to 3rd. Lunati warranted it......Piece of crap......

 

My experience has been different with the coated bearings. Cam spun fine in them

I agree cams can be untrue

 

In theory, the cam should never touch the bearings, coated, uncoated, this is in theory tho, it SHOULD ride only on the film of oil, in theory

 

I have used coated cam bearings but had to polish the cam for clearance. Not happy with machine shop that said "if you cam turn cam by hand it is OK". No...I want proper measured clearance and it should spin freely.
The best was when they said "it will clearance itself when you run it" Ha??
Even better..."hit cam gear with rubber mallet and rotate 90deg and repeat"

 

From the pictures of the lifter tracking and the thrust wear on the front of the block, I’d suspect that you may have cam to crank centerline alignment issues. It’s trying to "corkscrew" toward the rear.
More often than not I see that needing correction. The .020” oversize T/A bearings work well. I machine my own back groove in oversize bearings.

As always, check and correct cam for runout as well. I find they need correction more often than not.

 

This is a prime example of a block needing the cam tunnel corrected/indexed. Oddly enough, I get people saying it’s "overkill" and "not necessary". I sure do a lot of them though.

 

That won't work. Get creative! You need the diameter of the bearing o.d.(just slightly smaller)
A 350 intake valve works. You can put a long enough length of pipe over the valve stem and pound the shells out.
Catch the shells and metal fragments with a cardboard tube cut lengthwise, or fab up a tin foil tube tray.

 

I did, I welded a washer to the journal and sanded it to size, got two of them out so far.

 

Thanks, In my case that wear on the front of the block was from a defective cam that had a thrust surface that was not machined 90* to the cam journal. Boy was I pissed when I found that. It does not look it got any worse since then. I'll check the cam too, others have said the same thing.

 

Your block needed cam tunnel work. Coated bearings work excellent when the cam tunnel is correct. A reputable Buick engine builder would know this.
Sure, there is slightly less clearance, which makes alignment and size that much more critical, but to wholesale proclaim that coated bearings are bad is incorrect.

 

Wow, some great quality control! The tracking on the base circle and lift lamps is still a little concerning though..

 

That's what I said. TA made good on it, something they had to take up with their vendor. What tracking are you referring to? I never posted a picture of the cam itself.

 

There you go!......