Hey everyone I am rebuilding a 283 and I am having some concerns about the cam bearings. The block is from 62/63. Cam bearings changed from CH-4 to CH-8 in 1963 so I bought a set of both to give to the machine shop. He installed the CH-8 bearings. Come time to install the camshaft I find that I can't fit the camshaft into the block. The bearings are too tight, so I take the block back and he changes the bearings with another set he had (not my own CH-4's). I get the block back but when I look at the rear bearing I notice that it is narrower than the surface that the bearing is supposed to be pressed into. I look at my set of CH-4's (numbered CH-4-1, CH-4-2, CH-4-3, CH-4-3 and CH-4-4) and there is one wider bearing(CH-4-4), which is for this rear part of the camshaft. The (uninstalled) Ch-4 bearings fit snug over the new camshaft. What should I do? Are ch-4 and ch-8 bearings different in other ways? If I press this bearing out and just install the ch-4 rear bearing what other complications might I run into?
Is that wide rearnone grooved....if it is it needs to be in there....i think i read that some where Sent from my SM-G900V using Tapatalk
I can’t see a groove in there. There’s a step where the cam bearing presses in, which is the same width as the Ch-4-4 bearing and about 6mm wider than the one that’s in there Sent from my iPhone using The H.A.M.B. mobile app
Oh right. I’ll have to double check when I get home. I don’t believe there are any grooves in there though Sent from my iPhone using The H.A.M.B. mobile app
The break seems to be at 63/64. The top of this chart is Cam bearings by the number. Scroll down and you see the differences in the bores of the bearings. That is as far as position 1-2-3-4-5 You can check out Ch-4 and Ch-8 easily. http://www.melling.com/portals/8/pdf_catalog/durabond.pdf The width of the 5 position bearing is wider on the Ch-4 set. I've seen more cam bearings that were damaged by a cam bearing driver that was worn or didn't fit right than anything else. In my high school days we had a set of bearing drivers in the school shop that a former student had turned out on the lathe to fit various cam bearings. Never damaged a bearing with those even as a green high school kid.
Okay so it seems that it should take CH-4. Do we know if there’s any difference in inside/outside diameter? And if the camshaft fits as is, whether I should worry about it. The CH4 does have an extra lubrication port on that rear bearing. Sent from my iPhone using The H.A.M.B. mobile app
the bearing should be the same diameter. The difference in the bearings is because the rear cam journal on "early"cams used a flat spot to meter the oil to the cam and top end of the engine. CH 4 is to be used with only the flat spot cams. These haven't been available since the late sixties. All cams since use a full round rear cam journal. It is fairly common for cam bearings to be "tight" on SBC as the factory bearing are line bored after install in the fresh block. Aftermkt replacements are not. Your machine guy should know that. I have an old camshaft that I fit the bearings to, after install. Thus eliminating come backs.
Good point on the onstallation lack of detail....sometimes leaves a small lip from the tool, have to ensure its relieved to allow the cam to go easily Sent from my SM-G900V using Tapatalk
So the ch-4 set is for the pre 64 camshaft rather than the block itself? I have a new Melling RV cam with no flat spot so I should just stick with the CH-8 bearings that old mate put in there... Sent from my iPhone using The H.A.M.B. mobile app
I guess no one is pointing out anything wrong with leaving these bearings in, so I will, unless there’s any reason I should be concerned, but it seems there isn’t eh? Sent from my iPhone using The H.A.M.B. mobile app
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