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Thread: Recondition factory timing cover? oil pump?

  1. #1
    Bulltear forum member New to the forum
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    Recondition factory timing cover? oil pump?

    I have what I believe is the original 1975 timing cover and oil pump on my 304, 1975 CJ5.
    Is it feasible to have Bulltear re-machine the oil pump cavity?

    Engine was completely rebuilt about 5000 miles ago (15 years ago) by local machine shop with Edelbrock performer cam and timing chain set. Bulltear midplate, Sealed power oil pump kit.
    I did all the assembly of timing chain, oil pump, cover..... as a rookie.
    I reused that original timing cover back then because there was talk about the poor quality of aftermarket covers even back then.
    Oil pressure has never been great, but ok. (I don't remember exact numbers as the jeep has been sitting for a couple years now because distributor drive gear failed.
    Of course now the oil pump walls are scored because of that gear failure.

    Regarding the distributor drive gear failure:
    I think I must have reused the original distributor drive gear on the cam back then.
    I have detailed receipts and I cannot see where I purchased a new gear.
    It looks like one of my mistakes back then was installing a new MSD distributor with the steel gear with the original drive gear on the cam.

    I have been doing a lot of reading on this site and others, so I see the many other things I need to look for.
    I likely did not check the oil path from the cam bearing out thru the timing set back then either.

    thanks for any help!
    -Ben
    1975 CJ5 AMC 304, edelbrock performer cam and intake.

  2. #2
    Thank you from BT ULTIMUS MAXIMUS STATUS tufcj's Avatar
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    The cover isn't rebuildable. If the side clearances are above clearance specs, the only thing to do is replace the cover. Some scoring can be ignored if it isn't deep. Did you check end clearance and get the right gasket when you did the mid plate? If the gasket is too thick, the clearance will be high and the pressure will suffer. You'll want to pull the pan and remove any metal fragments, install a new matched set of gears. While at it, check the upper timing gear and make sure the oil path is open through it, and that the oil paths align in the cam and distributor gear. There are tiny oil holes in the distributor drive gear that keep the gears oiled. The oil has to have a path to get there. The only other thing is to match the size of the oil port between the front cover and block. There is usually room to enlarge the hole in the front cover. Use the gasket as a guide.

    Bob
    tufcj
    1969 AMX
    1967 Rambler Rogue

    If you need a tool and don't buy it...
    you'll eventually pay for it...
    and not have it.
    Henry Ford


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  3. #3
    Bulltear forum member New to the forum
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    I remember checking end clearance back then, but I will do a more thorough job of it this next time.
    There was originally some scoring in the pump cavity side walls but it is definitely worse now with the more recent distributor drive gear failure.

    I guess I will order new pump gears first, and check the side clearance, then decide whether or not to order a new cover.

    What RPM should I spin the pump with a drill in order to get a good idea of what pressure I might have at engine idle vs cruising RPM?
    or What low limit should i give up on the cover while testing with a 1/2" drill?
    1975 CJ5 AMC 304, edelbrock performer cam and intake.

  4. #4
    Thank you from BT ULTIMUS MAXIMUS STATUS tufcj's Avatar
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    The oil pump turns about 1/2 the RPM of the crank, so a simulated idle would be about 500 RPM at the pump. The pump, if it builds 50-60 cold PSI will nearly stall a 1/2" drill. I agree with trying new gears first, then replacing the cover if needed, chances are you won't. End clearance is much more critical than side clearance, so get that right. Make sure the relief valve is free to move, and use a new spring (should come with the oil pump kit). Old springs weaken with heat and age, and the plunger could stick from varnish. You could also plug the filter bypass, or Bulltear makes a replacement cover/plug. Run a quality filter (I like Wix or Napa Gold). The new oil filter adapters don't even have the bypass machined. Think about Bulltear's HRC pump gear set. In my AMX and Rambler (also in the Jeep I sold) I ran the HRC gears, mid plate, and filter bypass plug. The Jeep and Rambler are on the original covers, the AMX has a nickel coated cover. None have any oil pressure problems with the mods above.

    http://www.bulltear.com/catalog/inde...160985ef4f09af

    Bob
    tufcj
    1969 AMX
    1967 Rambler Rogue

    If you need a tool and don't buy it...
    you'll eventually pay for it...
    and not have it.
    Henry Ford


    Vote for BULLTEAR on top4x4sites.com ===> VOTE BUTTON

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