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cam walk

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    Senior Member jdekruyf's Avatar
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    Default cam walk

    Looking for some advice on how to set up/deal with cam walk when using a magnaflow pump with a 3 inch extension. Confused on where to start with figuring out the tolerance. There's the mock up of the set up in the picture below. Thanks in advance.
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  3. #2
    gn7
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    Quote Originally Posted by jdekruyf View Post
    Looking for some advice on how to set up/deal with cam walk when using a magnaflow pump with a 3 inch extension. Confused on where to start with figuring out the tolerance. There's the mock up of the set up in the picture below. Thanks in advance.
    I saw your post overon the V-drive section and i will tell you, there is no easy way out of this. You can do the method that obnoxious mentioned with the torrington that rides on the cover, or you can use the drive shaft to take the load. No matter, there is some machining involved. I have talked to Bob at Glenwood about this, and when using the drive shaft it does not load the bearing. The load is taking up by the front cover of the pump, and is the reason they now make the cover twice as thick as the original pump. It appears you have the thick cover.

    Its this simple if you use the pump to take the load. Assemble the cam and pump arrangement, and find out the end play of the cam. The end play is most likely too much. Then figure the amount of end play you what, and determine the amount that needs to be removed from the extension housing to get there. If you have .015 of end play, and want .005, you need to remove .010 from the extension housing. ALL THIS IS WITH THE T COVER GASKET IN PLACE, AND WHAT EVER SEALER YOU PLAN ON USEING BETWEEN THE EXTENSION TO COVER.

    I measure for zero end play on the cam, and the sealer between the extension and the cover makes my end play.

    I wish it was easier, but its not.
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    Senior Member jdekruyf's Avatar
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    Thanks gn7. That is good advice especially if glenwood themselves is saying the load won't be put on the bearing.
    Both ways sound like a good way to go about it but when just using the pump it seems a little simpler.

    I just dont want to run into any problems down the road and set it up right the first time.

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    Some guy obnoxious001's Avatar
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    Quote Originally Posted by jdekruyf View Post
    Thanks gn7. That is good advice especially if glenwood themselves is saying the load won't be put on the bearing.
    Both ways sound like a good way to go about it but when just using the pump it seems a little simpler.

    I just dont want to run into any problems down the road and set it up right the first time.
    The huge advantage of doing it with a thrust bearing under the cover is that you can swap extensions and/or pumps and not having to check or set end play again.

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    gn7
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    Quote Originally Posted by obnoxious001 View Post
    The huge advantage of doing it with a thrust bearing under the cover is that you can swap extensions and/or pumps and not having to check or set end play again.
    Also, when you consider that the BBC t cover block mounting surfaces and cam locating face are on the same plain, then so long as any cover you use is machined to the same depth, it should work as well. I may have to look into the method! The only varible becomes the gear thickness.
    Last edited by gn7; 10-24-2011 at 03:33 PM.
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    Some guy obnoxious001's Avatar
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    Quote Originally Posted by gn7 View Post
    Also, when you consider that the BBC t cover block mounting surfaces and cam locating face are on the same plain, then so long as any cover you use is machined to the same depth, it should work as well. I may have to look into the method! The only varible becomes the gear thickness.
    And the thickness of the pump drive, not sure that they are all equal? I would also wonder how exact the cam gear thrust surface of the block is in relation to the timing cover mount surface of the block. Couple of thousandths here or there might cause an issue, so probably best to measure or check each one.

    I didn't measure from the block surface of the cover, since it is fairly easy to use a caliper or depth micrometer to measure from the pump surface to the pump drive bolts(I actually checked all three bolts), and then do the math for the necessary machining, but no reason the measurement could not be from the flange I suppose.



    Here you can see some of my calculations. I had a few options for washer thickness, considered using a .060" in the cover instead of the .090. Bottom line was .150", added .005" for desired cam thrust. As it turned out, I ended up changing bolts since the measured thrust was just over .010"





    Here's a shot with a washer and the bearing on the pump drive. With the .155" recess in the timing cover, the .090" washer stays in place well while bolting on the cover. Don't start jumping up and down, the oil galley plugs (with oiling holes) did get put in place prior to final assembly.



    Once it's all bolted on for the final time, thrust is verified again with the dial indicator


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    gn7
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    I like it!
    The cam surface and the t cover surface are machined at the same time on the line. Everything on the front of the block is. Water inlets, motor mounts, etc, If its machined, it was all done at once. One cut straight across the block unless it was remachined later by someone else.
    LINK:GN-RACING.COM

    "there are too many pigs for the teats"
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