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Cam issue... I need help

Discussion in 'The Hokey Ass Message Board' started by chopitdano, Mar 4, 2012.

  1. chopitdano
    Joined: Feb 22, 2011
    Posts: 102


    I received my cam the other day and when I went to stick it in, it is super tight on the third bearing. When I had the block machined I had them put new cam bearings in. Also, I did use a generous amount of lube and was super careful not to nick the bearings. Has anyone else run in to this problem? If so what did you do to fix the problem? :confused:
  2. I have not run into this problem, but it might help others here if you gave more info like type of engine etc.
  3. You did not state what engine or make. SBC I do know can have an oddly bored cam journal from the factory from time to time. They had corrective bearings for that. Or it can be just as simple as the bearing pressed in the wrong journal. In a set of 5 for SBC they are marked to tell where they belong. Take the block back to builder and have them correct it.
  4. Somewhat common problem. For your info and anyone reading this, always have the cam your going to run ready with the block for the machinist to check for fitment at time of cam bearing install, OK. I know sometimes its not possible, but always try.

    There could be several issues going on here, everything from the bearings not installed correctly, out of order, or the block journals not cleaned well and prepped befor installing bearings, to the cam itself.

    That said many times a common fix for this issue is what's called a
    " bearing scraper ". It basically looks like a 3 sided or triangular knife. Like a prime-evil getto stabber kind of deal. If the crank is out, and you have room to use this, you didn't mention what engine, you very lightly scrape the leading and trailing edges of the bearing in question. Now clean everything well, and lube up nicely and try to install the cam again.

    This sounds crude and hokey to someone who hasn't been there, but it is done this way for decades with no negative after effects.

    Sometimes there is no alternative but to knock out the old/new bearing, buy a new kit and instal again. If you were close by, I would do this for you free of charge and quarantee the work too. Good luck, TR
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  5. 19Fordy
    Joined: May 17, 2003
    Posts: 6,504


    I had the same thing happen years ago and found out it was slightly bent. Took it to Crane cam and they straightened it. Then it fit fine and is still in the car. If you have access to a lathe with "true" enters put it between lathe centers (not in the chuck) between the spindle and the tailstock and check it with a dial indicator.
  6. 19 is correct, only 1 aspect of what I mentioned about the cam itself being bad. If you have a friend who is a capable machinist with a reasonably good engine lathe and a dial indicator, you can check the cam for straightness to eliminate that from the equation. Straightening new cams is just another part of what seperates a engine builder from a engine assembler. TR
  7. chopitdano
    Joined: Feb 22, 2011
    Posts: 102


    Sorry, Its a sbc and the crank is in it. I am a machinist. I will check the cam on Monday to see if that is the issue. Thanks guys.
  8. 39 All Ford
    Joined: Sep 15, 2008
    Posts: 1,531

    39 All Ford
    from Benton AR

    Want to talk about a crude fix?

    It is my understanding that sometimes core shift can cause cam bearing alignment issues. This isin't a big issue for factory builds because the cam bearings are machined AFTER they are installed in the block, however the problem becomes apparent when new per-machined cam bearings are installed.

    I have put a lot of engines together, and had never experienced this problem till a couple of months ago when I tried to install a new cam in an already mostly assembled 400M.

    I searched around the internet and found that a common fix (it is even on the comp cams website) is to take the old cam, cut across the face of the journal in a slightly diagonal manner, de-burr the edges and use the cam to ream out the bearings....

    It kind of freaked me out a little but it worked fine, and the engine has great oil pressure.

    Was going to post up the link, but I don't have time now...
  9. Engine man
    Joined: Jan 30, 2011
    Posts: 3,476

    Engine man
    from Wisconsin

    As a machinist, you probably have equipment to measure the cam bearings or just see if the old cam fits. Also, measure the journals on the new cam to make sure there wasn't a machining problem. If the cam is bent, I personally wouldn't use it especially if you bought it new. I've seen enough cams break to not want one that has been stressed. That being said, if you return it, they might straighten it and send it back. Mark it so you can tell.

    Most machine shops that install cam bearings have a cam and they check the bearing fit after installation. Especially a sbc.

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