Reproduction Parts for 1916-1964 Chevrolet Passenger Cars & 1918-1987 Chevrolet & GMC Trucks


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#467936 03/15/22 07:54 PM
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Grease Monkey
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I've developed an engine noise in my 32 sedan. Is it possible for the oil pump to distributor drive connection to separate /wear enough to make the oil pump skip on the end of the shaft. Noise seems to be in that area and I can feel a bumping slightly on the oil pan near the middle. I don't think I'm getting sufficient oil to the rockers. I do show very good pressure at the gauge. I haven't dropped the pan yet but didn't know how much room there is between the pickup screen and the pan if the pump could drop enough to disconnect/ skip on the shaft connection.

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not sure it could skip, if it is driven same as my 1929, slotted drive. check the screw/bolt in the block under distributor, it holds the oil pump in place !! if it is loose then the il pump can drop down into the pan, not sure it can fall all the way out.

cam drives distributor, distributor drives oil pump. not sure it can move up and down on a 1932 based on the oil screen setup.

if you have good pressure at the gauge then hopefully you have good flow, they are not pressure driven but flow driven. could have a clog in line somewhere as well. pull the valve cover run the engine and see the flow wink

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What Gerry said. If you’ve got oil pressure, the pump is engaged to the distributor and pumping but the pump could be loose. The screw and nut below the distributor on the outside of the block is a pointed pin flathead and the large nut around it is a lock nut. Use a automobile type stethoscope and listen around on the block and pan. I have seen one instance where the distributor retaining screw was tightened so tight it cracked the distributor housing which is pretty crazy due to the thickness of the distributor body. There is also supposed to be a spacer/washer between the bottom of the distributor gear and the top of the oil pump. A 30 I’m currently working on didn’t have that washer and the distributor gear was severely worn which must have created a lot of noise. It is also possible that somehow your pan got bent up and the oil pump screen is contacting the bottom of the pan. I took my own 31’ for an inspection sticker here in Mass and one requirement is that the front end be jacked up and the front wheels checked for play. I told the guy I wanted a few rags made into a pad put on top of floor jack which he did but it was good I was standing just outside the overhead door as he was lining up the floor jack with my oil pan rather than the I beam axle! I hollered whoa! really loud and asked him what the hell he was doing. He told me “we do this all the time, the pans are plenty strong enough!”. I told him to stop, walked back into the office, and told the guy behind the counter that I did want that guy doing the inspection because he has no idea of and antique car and how to even jock it up. The manager apologized and finished up the inspection himself.

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I forgot to add, if your car has not had the pan dropped in many years, it’s a good idea just for a general sludge clean up. Purchase two oil pan gasket sets from the filling station and pull the pan. If you screw up a gasket on your attempt to put the pan back, you’ll appreciate having that second set as you just can’t run down to oreillys and get another. If you need to pull your distributor for any reasons, before you do, pull the cap and take note of exactly where your rotor is facing. You can use a hand crank and move it to TDC on the crank then look at where the rotor is facing. Take a cell phone picture of the distributor for reference as it will make retiming the motor much easier. Getting the distributor timing gear and the pump groove in the correct position to mate while the distributor drops in takes some patience. You will notice the rotor turns as you lift it up so pay attention to the location of the rotor tip as the distributor come free of the block as you need to put it back in this location when you put it back in. When you order the pan gaskets don’t forget to order the distributor washer also. You didn’t describe the sound you’re hearing and I assume by your questions it’s a vibrating rattle and not a rolling type striking sort of noise. A description of what your hearing helps in the diagnosis.

Last edited by Chistech; 03/16/22 09:59 AM.
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I finally had time to dig into the 32 engine some more. Dropped the pan and found #2 rod babbit almost gone! Good news is the crank still measured standard sized and still round. Ordered a standard size NORS rod from FS along with gaskets. I was able to maneuver the rod out the bottom end and install the new one. I plastigaged it at .0015, all the rest of the rods were at .001. Reinstalled the pan for a test start and life is good. Going to give it 50 - 100 miles and pull pan and check everything again. Still has the vain pump that's showing 10 -15 pounds on the gauge. Pan was very clean besides the glitter pile.

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My suggestion would be to readjust the new rod as the high spots should be worn in........015 with Plastigage may be too loose. I would adjust using the directions in the shop maual.


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Having rebuilt several thick babbitt engines, I have found Plastigage to only be good as an indication of the gaps. It also needs to be of recent manufacture. If older it has hardened and will not be even close to accurate. Tapping the rods side to side has proven to be a good way to set the proper amount of rod shims. I have also rotated them on the crankshaft journals with light lube that proved to be good as well.


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I put on 50 miles and dropped pan for inspection. Removed shims till it was to tight to turn by the crank, then added .0015 and it turns nice and can just move rod side to side. Reinstalled pan and have put another 50 miles on and everything sounds good and runs good. Set the points at 18 and timing at 18 advanced new Autolite 386 plugs at 40. Big difference in acceleration. Making a trip to the Rhinebeck show next weekend, I think she's ready for the trip.


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