cam bearing issue

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motorhead446

motorhead446

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Anyone ever have a problem getting cam in last bearing? Im installing a lightly used hemi grind cam in my 440. The engins has about 40k miles. The cam will not go into the last (back of block) bearing without tapping in with a mallet. It will not turn by hand once in. I tried another cam with the same results. The stock cam was tight coming out until it cleared the same bearing. Im thinking new bearing time. Can these be installed while in car?
 
How many miles on the cam that was in it?could it be turned by hand easily
Before removed
 
I put new bearings in my motor this winter and when I put my cam back in it was a little snug on the back one also. I used a lot of assembly lube and once I rotated it a few times it felt good.
 
If you have an old cam, take a wiz wheel and cut a small diagonal slot on the rear cam journal. Install it and rotate it until it frees up. It's an old trick and works well. You'll need to clean up any bearing material when you're done.
 
If I understand what your saying, the motor has 40k miles on it before you removed the original cam? And it was still tight coming out? When new cam bearings are replaced, you are suppose to test fit them as they are installed with a cam, Most shops don't do this anymore. But they are easy to get them cocked a little and make the cam hard to install.
 
This is a low mileage engine from a 78 motorhome. It was untouched internally until today. The stock motorhome cam is kind of a slug so i wanted to install this hemi grind cam a friend gave me. The untouched motor has about 40 k miles on it. It runs great just kind of a dog. The stock was tight coming out until it cleared the rear bearing. It did turn freely before removing. I do have the stock rv cam, i will try the "shaving" idea. Thanks for the input.
 
The cam bearings are larger from the first to the smallest in the rear. So the cam will feel nice and free until it reaches it's specific location/bearing. It is normal for it to "feel" snug when you try to install the cam in its final journal. Just as long as it isn't to tight. I don't know how to convey the to tight feeling to you it's just something you learn over a long time. I hope this helps you out.
 
If you use the correct high quality tool, like one from Lisle, it is nearly impossible to put one in crooked. You'd damn near have to do it on purpose. Most of what I see comes from inconsistant bearing thickness. That's why an old school machinist will have old cam cores on hand.
 
Update; i pulled my engine to replace cam bearings and update my torque convertor. What I found after installing new cam bearings and having the same issue is that the rear machined hole is egg shaped. I got a .004" feeler gauge between the bearing and the cam. (pictures to follow) Looking from the rear of the block, the odd spot is at about 2-3 o'clock. I can see light thru the void looking into the lifter vally at the rear journal with the core plug removed. The old bearing has no excessive wear spots or burnt spots. Ive never had any oil pressure issue either. Can this be fixed, Are over sized cam bearings available for this?
 
Read post #4. Do it. Run it. It'll be fine. None of them are perfect. It's not like the cam bearing can go anywhere.
 
here are some pics.
motorhead446
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After you install the new cam, put the timing gear on and see if you can then turn it by hand. If you can, you will probably be ok.

If you try to machine the cam bearing hole, you may make it oversize and then the bearing will not have a tight enough fit and eventually spin on you.

Unfortunately, Chrysler has been known to let "out of tolerance" parts get out when they get in a pinch... Very sad.
 
Did you inspect that cam bearing bore THOROUGHLY to make sure a bearing has not spun there in the past? Also, is that .004" feeler gauge the largest you can get in there? If that bore looks good like nothing has ever spun and .004" is all you can get in there, I say assemble it and go. Remember, that to calculate bearing clearance, you'd need to divide that .004" times two for .002" on either side. I don't know what the spec is, but I suspect .002" would be good. As for oversized cam bearings, the only ones I have ever seen are oversized for UNDERsized cam journals. That would be going towards the inside diameter, when you need to go towards the outside.
 
StrokerScamp said:
Did you inspect that cam bearing bore THOROUGHLY to make sure a bearing has not spun there in the past? Also, is that .004" feeler gauge the largest you can get in there? If that bore looks good like nothing has ever spun and .004" is all you can get in there, I say assemble it and go. Remember, that to calculate bearing clearance, you'd need to divide that .004" times two for .002" on either side. I don't know what the spec is, but I suspect .002" would be good. As for oversized cam bearings, the only ones I have ever seen are oversized for UNDERsized cam journals. That would be going towards the inside diameter, when you need to go towards the outside.
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The.004 was in an isolated area of the opening. As if something moved while machining the hole.
 
motorhead446 said:
The.004 was in an isolated area of the opening. As if something moved while machining the hole.
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Core shift. Really....there's not much you can do except run it, or get another block if it bothers you bad enough. It wouldn't bother me at all.
 
StrokerScamp said:
Core shift. Really....there's not much you can do except run it, or get another block if it bothers you bad enough. It wouldn't bother me at all.
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i agree... mine was tight too did the old cam shaving trick problem solved and the car runs great! ;)
 
440dart209 said:
i agree... mine was tight too did the old cam shaving trick problem solved and the car runs great! ;)
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It's one of those great old timer tricks. I've had people scoff at me for doing or recommending it, but it works well.
 
If the journal bore shifted why would it be tight?Seems like it would be aliitle loose.Pullthe cam out till it rests against the rear bearing and rotate the cam to make sure the cam is straight(used cam right) and that the bearing is centered.It might be in a bind from the hole being off center.
 
Align boring the crank and cam bores eliminates these types of issues, but for your intended use, cutting a slot in the old cam core works just fine.

Bearing clearances are not determined by measuring and dividing in two! That can be backed up by checking ID and OD specs given by either the manufacturer or the bearing supplier.
 
ramcharger said:
Align boring the crank and cam bores eliminates these types of issues, but for your intended use, cutting a slot in the old cam core works just fine.

Bearing clearances are not determined by measuring and dividing in two! That can be backed up by checking ID and OD specs given by either the manufacturer or the bearing supplier.
Click to expand...

That would require an oversized OD cam bearing....which I have never seen.
 
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