cam bearing help

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robert87ss

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hi guys, I'm building my first big block. this is only the second time ive ever installed cam bearings. I used the proper tool and seen it done many times. however this is my first big block. I was told to use the old cam to "square" the bearings because big block mopars are notorious for having cam bearing alignment issues. i find this very hard to believe that i would need to hit the old cam with a hammer to "square" the bearings. also was told its normal for the cam to be tight! i have never ever done this before on any engine ive ever built. also the new cam supplied with the kit has a larger base circle, does this mean i will need shorter push rods? note this is a bone stock rebuild.
 
They are already installed. But the cam won't turn by hand. Just got block back from machine shop. He was too busy to install the bearings. So I picked it up and did it myself. I really wish he would've installed them.
 
robert87ss said:
They are already installed. But the cam won't turn by hand. Just got block back from machine shop. He was too busy to install the bearings. So I picked it up and did it myself. I really wish he would've installed them.
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b block mopars , many times need the cam bearings honed so the cam will turn. the cam bores on many of them are not perfect from the factory. you can figure out which ones are binding when installing an old cam, hone that one accordingly, and work on thru.
 
famous bob said:
b block mopars , many times need the cam bearings honed so the cam will turn. the cam bores on many of them are not perfect from the factory. you can figure out which ones are binding when installing an old cam, hone that one accordingly, and work on thru.
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That's pretty much exactly what I was told, but neither the machine shop or my uncle who has built a bunch of big blocks seemed to want to hone the bearings. My uncle was helping me and he says they use the old cam so they can hit it with a brass punch and hammer on both sides of each journal top and bottom to "square" up the bearings. I do not like this at all, and very skeptical that it works. It seemed to get a little better, but still can't turn it by hand. My uncle said once oil gets in there it will free up. I told him it's too tight for oil to get between the cam and bearing. He looked at me like I had just spoke a foreign language. Albeit I've never seen him mic a crank, measure piston to wall clearance, ring gap, or anything. He just throws them together.
 
What's the best/easiest way to Hone the bearings? I was thinking maybe Emory cloth by hand. But my hands are too big to reach inside the bearings from the bottom.
 
robert87ss said:
What's the best/easiest way to Hone the bearings? I was thinking maybe Emory cloth by hand. But my hands are too big to reach inside the bearings from the bottom.
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It seems to me that some folks have cut grooves on the old cam at an angle (think cutter) and slide it in and turn it.

There was a thread a while back with pics.
 
Yep I cut grooves in my old cam at about a 45* angle. using motor oil on it, I slowly cut the new bearings until the cam would turn without using a lot of force. It worked perfect.
 
73AbodEE said:
Yep I cut grooves in my old cam at about a 45* angle. using motor oil on it, I slowly cut the new bearings until the cam would turn without using a lot of force. It worked perfect.
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I found an old thread. He used a "Wix wheel" to cut the cam. I dunno what a Wix wheel is. But I imagine a cut off wheel would do the trick. I might try it. What did you use? And you cut them on a 45* angle instead of just straight across?
 
73AbodEE said:
Yep I cut grooves in my old cam at about a 45* angle. using motor oil on it, I slowly cut the new bearings until the cam would turn without using a lot of force. It worked perfect.
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Hey Lance, come to think of it you did chime in on the thread I'm thinking about. It seems to me there was a pic posted, did you post it?
 
I'm an ASE Master Machinist.I use an old cam with grooves cut into the cam journals at a 45 degree angle, one into each journal works too.It works great you don't have to hammer on the cam it removes any high spots and cleareances the Block.Don't worry about how the bearings look I've not had a cam bearing failure ever.
 
It's normal for them to have tight spots. One does not ever "hone" a bearing. Honing material will embed in the bearing as you do it. BEst way to do it (and retired ASE Master here) is to use the cam you're running, and either a bearing knife or I use a utility knife blade to scrape away the high spots. Appearance is not a huge deal but the cut cam deal is a bit neanderthal and I do worry about material that might comeoff and be left within the oil passages above the bearing to the head, or in the passages to the crank. When you're done the cam should be able to be turned with one or two bolts in the front, with fingers alone. Cam fitting on e fresh engine should be done prior to the lower end being put together to minimize the possibility of crap in the oil system.
 
moparp215 said:
I'm an ASE Master Machinist.
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Yeah and I stayed in a Holiday Inn once.

There'a a real nice how to I did on putting cam bearings in a big block floatin around here somewhere. If you do it just like that, the chances of the cam being tight are all but eliminated.
 
Bad Sport said:
Hey Lance, come to think of it you did chime in on the thread I'm thinking about. It seems to me there was a pic posted, did you post it?
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I think I took a couple pics but I couldn't find them. They seem to have went with the old soft ware lol. I just used a regular cut off wheel and made sure there wasn't any burrs on the grooves. Oil it up, stick it in and spin a couple times, pull it out, clean out the shavings, repeat
 
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common problem. sometimes we put the cam in a lathe and make the journals smaller with sandpaper. hydraulic lifters will compensate a small range
 
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