oil pump drive

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    I am trying to put a ’27 80 series motor back together. The oil pump is worn, any place to get parts for that? Also the fiber gear (it is fiber?)that drives the oil pump has 20 degrees of play at least to the cam gear. Is this OK? Can that fiber gear still be found? How does one remove that fiber gear?



    For replacement gears, first try Then & Now Automotive in Weymouth, MA (AKA Antique Auto Cellar, best known for fuel pump rebuilding–see link). Clearance of oil pump end plate should be 0.002 (mine was 0.012 before machining inside surface). The two matched pump gears are more critical than the upper drive gear; the slop in the (upper) drive gear really doesn’t have much effect, in my opinion.

    The drive gear is accessed via the square cast plate attached with 4 bolts and located at left rear of engine underneath manifolds. Oil pump is driven by a vertical piece of 1/2-inch square tubing (available at hardware stores) which, believe it or not, dangles from the drive gear assembly by a cotter pin! The oil pump drive has a tapered tip above the square section that fits into the square tubing to permit ‘threading’ the pump drive into the tubing.

    Originally, the oil pump was secured to oil pan by 6 studs and nuts. I strongly recommend replacing those studs and nuts with cap screws to make it MUCH easier to ‘thread’ the tapered tip of the oil pump drive into the square tubing should you need to do so later when the pan is on (I found this out the hard way). Be careful–3 of the 6 threaded holes are blind or closed, so ensure that the cap screws are not so long that they will break the cast aluminum pan. I put flat washers under the heads of the cap screws and use Permatex #2 on the threads of the cap screws.




    Excellent, Thank you.

    Another question. The piston wrist pin has a clip and a brass plug. The brass plugs are hitting the cylinder walls. are they necessary? Will the clip fall out with out the plug? Can I use newer style spiral locks instead of the clip?



    Really can’t help you with the wrist pin issue (haven’t had mine that far apart) except to say that whatever a competent engine builder determines is an appropriate means of securing the wrist pins should be OK. This is one area where we should embrace more modern technology!




    When I rebuilt my series 81 engine I used the spiral type locks and they worked just fine. As for the gears I had a new set made using the old ones for samples, the pin that holds the gear in place on the cam shaft is a taper pin so you will need a set of taper reamers, drill a hole on only one side of the gear and line it up with the hole in cam shaft then with a smaler drill bit drill through the other side then ream to size with the taper reamer, the hole in the oil pump shaft is a streight pin so with a hole drilled in one side of the gear and lined up with the hole in the shaft just drill through that side install the pin and pean it over or you can use a modern roll pin.

    Joe Knowles

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