Tight cam bearings

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RAT ROD AL said:
I had a machinist for along time do my machine work on quite a few engines, and never had a problem. Then one time on a particular 440 when I picked up the block he tells me to check the cam fit before I install the rotating assy, didn't say why. Got it home and sure as **** I couldn't get the cam in. He tells me to use a bearing knife to get it to fit , oil it and work it till it fits and loosen up. Long story short I took the block back and he put some new cam bearing in and the cam then fit fine. Had the same issue this past build on my /6, took it back to the shop (different shop down here in Florida did my /6 ) had them fix it. I think more often than not it's the shop not getting em in right the first time. Cam bearings are cheap. seized cam is not.
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I asked if the bearings might be wrong or something was wrong with them and he said no. That for some reason bb mopars have this problem from time to time. I just wonder if I should just get another set of bearings and get him out then in.
 
Holy Roller said:
I asked if the bearings might be wrong or something was wrong with them and he said no. That for some reason bb mopars have this problem from time to time. I just wonder if I should just get another set of bearings and get him out then in.
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I had a good relationship with the guy doing my race engines, he changed them and I don't think he even charged me. If you take it back to the guy bring your cam and let him stick it in. A lot of these guys have big egos and think they don't screw up.
 
Holy Roller said:
I asked if the bearings might be wrong or something was wrong with them and he said no. That for some reason bb mopars have this problem from time to time. I just wonder if I should just get another set of bearings and get him out then in.
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years ago, I sent a SB Comp cam back because it was bent. They sent a replacement, which was also bent. Third time was the charm.
To check for straightness, I rotated the cam in a matched set of v- blocks( placed under end journals), and indicated the middle journal. It's been a long time, but I believe they had about 0.030" or more runout.
 
rustycowll69 said:
years ago, I sent a SB Comp cam back because it was bent. They sent a replacement, which was also bent. Third time was the charm.
To check for straightness, I rotated the cam in a matched set of v- blocks( placed under end journals), and indicated the middle journal. It's been a long time, but I believe they had about 0.030" or more runout.
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Check the cam , is it a new one or one you had in it before the shop?
 
Holy Roller said:
New roller
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When I had my 440/505 block in the machine shop, he specifically said to bring the cam I was going to run in. He said big block Chryslers were notorious for came bores being off from the factory. When I got my block home I could see where he honed the cam bearing to fit.
 
RAT ROD AL said:
I had a good relationship with the guy doing my race engines, he changed them and I don't think he even charged me. If you take it back to the guy bring your cam and let him stick it in. A lot of these guys have big egos and think they don't screw up.
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He called me and asked me to bring the cam in so he could check it and then called me to come look at it when the cam wouldn't fit.
 
Holy Roller said:
Has anyone had a problem with tight fitting cam bearings on a 383/440 that required additional honing, buffing or machine work. Does a roller fit different than a stock can. I ran into this at the machine shop and wondered if anyone else had this problem.
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Believe it or not the factory had a large stepped reamer to fix this exact problem on assembly. The cam bores are not perfectly in line in all engines. This is why the service manual specifically says not to replace the cam bearings if they are NOT damaged. The factory line reamed them. A high end shop will have a cam bearing reamer. If the cam is straight this is the problem. So either use a bearing knife, a slotted old cam or find the "big old bearing reamer":

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famous bob said:
When I had my 440/505 block in the machine shop, he specifically said to bring the cam I was going to run in. He said big block Chryslers were notorious for came bores being off from the factory. When I got my block home I could see where he honed the cam bearing to fit.
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That's what he told me too Bob, he was even going to look it up on Google for me. Said that he's ran into the same problem on other 383 and 440 blocks.
 
The machinist I use for about 40 years, has ALWAYS made me bring the cam I was going to use with me when I dropped the block off. He would check the cam for being straight and test fit it in the block before giving it back to me. To me this is what a good machinist should do.
 
This guy has been in the business for 42 years, it's the first time I've ever used him, but a lot of people recommend him. I hope he's as good as people say Roy.
 
Q36 said:
Believe it or not the factory had a large stepped reamer to fix this exact problem on assembly. The cam bores are not perfectly in line in all engines. This is why the service manual specifically says not to replace the cam bearings if they are NOT damaged. The factory line reamed them. A high end shop will have a cam bearing reamer. If the cam is straight this is the problem. So either use a bearing knife, a slotted old cam or find the "big old bearing reamer":

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I'm hoping a little polishing will do the trick and it's just a minor problem .
 
Found the problem with the cam bearings, the cam was warped 16 thousandths. Called Summit and they shipped a new one. The machinist tried the old one and it slid right in. So he miched the journals on the Comp cam and found the center journal off.
 
Holy Roller said:
Found the problem with the cam bearings, the cam was warped 16 thousandths. Called Summit and they shipped a new one. The machinist tried the old one and it slid right in. So he miched the journals on the Comp cam and found the center journal off.
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I've heard you can straighten them, by using an air chisel. You rest the cam in v-blocks on the end journals, turn the high side up, and with an air modulated air chisel and a dull bit you can hammer next to the center journal. You and I would have to sneak up on it, but I'm sure the guys who do it all the time could do it in a fraction of the time it would take a rookie to do. Of course, its a casting so it could break, too, even if youre careful. Comp cam could probably fix the cam you returned.
At any rate, you did the right thing, and Summit did the right thing, too. Somewhat happy ending.
 
rustycowll69 said:
I've heard you can straighten them, by using an air chisel. You rest the cam in v-blocks on the end journals, turn the high side up, and with an air modulated air chisel and a dull bit you can hammer next to the center journal. You and I would have to sneak up on it, but I'm sure the guys who do it all the time could do it in a fraction of the time it would take a rookie to do. Of course, its a casting so it could break, too, even if youre careful. Comp cam could probably fix the cam you returned.
At any rate, you did the right thing, and Summit did the right thing, too. Somewhat happy ending.
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I can't wait to get the new one to try it in the bearings. And kudos to Summit for great customer service.
 
Bent cams are fairly common. Watch the delivery guy drop the box with the cam in it and you'll understand why...
 
Q36 said:
Believe it or not the factory had a large stepped reamer to fix this exact problem on assembly. The cam bores are not perfectly in line in all engines. This is why the service manual specifically says not to replace the cam bearings if they are NOT damaged. The factory line reamed them. A high end shop will have a cam bearing reamer. If the cam is straight this is the problem. So either use a bearing knife, a slotted old cam or find the "big old bearing reamer":

View attachment 1715195163
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Awesome first post :thumbsup:

Jeff
 
Many years ago, I built a 440 engine. When trying to install he cam, the rear bearing was too tight. Shop removed it, and installed another. Also too tight. Doing research, it turns out some big blocks had a undersized, bearing bore in the block, and the factory, installed unfinished bearings, and reamed to fit. Since it was very hard to get unfinished cam bearings in the aftermarket, my machinest resized the bearing bore in the block, to the correct size.
 
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