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I’m going to drop the oil pan on my ’32 901 to clean out the sludge and install a new gasket. Does anyone know the fastener torque spec for reinstallation?

Also, I bought new rear main seal cork strips. How exactly do they install? Can they be done easily once the pan is removed?

Thanks in advance.

I’m not sure that torque wrenches were in common use at that time. It’s more important that the bolts are all torqued the same; the exact value is less important. I would suggest 11 ft-lbs, if the pan distorts excessively then do less. If the bolt is not convincingly tight, a bit more.

Torque is not important just tighten adequately. You should be under your car regularly and you can retighten them as you check things out. There should be a lock washer under all the bolts. You cannot distort the pan as it is heavy aluminum. Not sure what seal you are talking about. The pan gasket goes all the way around the pan and is in pieces that match up on the cut line. I had a problem with the gaskets I have received from MM as the holes did not line up exactly. Next time I will get mine from Olsons. I also used form a gasket sealer on both surfaces. The issue is the drain hole from the slinger which passes thru the pan flange. There is a dam in the pan where it connects to the engine and the rear main bearing. There are no fasteners in the middle so it has to fit tight so it does not leak into the bell housing portion of the pan. There is a drain hole in the bell housing portion to drain oil that may leak from the slinger. I put extra form a gasket around the slinger hole in the middle of the dam so that no leaks would occur and none have so far. You may get some oil in the drain hole from the Bijur that lubricates the throwout bearing but it should not be much. Where the pan connects to the front cover is a problem. If you can keep from distorting the lower portion of the front cover gasket you can resuse it. If not I cut mine off and used RTV on the bottom portion. Those front bolts are tricky if you have a front mud cover. You might have to remove the cover to get to the bolts. I reversed the bolts on mine and leave the bolts in place. The pan is somewhat heavy so keep that in mind. I used a transmission jack to put it back in place. You should remove the pan about every 2,000 or so miles as these engines create sludge especially if you do run the car on short runs. The general rule of thumb is run it for 10 miles or don't run it at all. The sludge is caused by condensation forming inside the engine during start up and must run long enough to get hot and dissipate the moisture. PM me if you need any additional info.

The crankshaft for the rear main has an oil slinger, there was no positive seal, at least on the engine I removed. The cork seals go on each side of the iron block holding 1/2 of the rear main babbitt bearing. This iron block slides into the aluminum crankcase. The seals prevent oil from leaking out past the sides of the iron block.

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  1932 901 Engine Back.jpg (95.29 KB)


  1932 901 Engine Back_Rear Main Cap Seals.jpg (98.54 KB)


  1932 901 Engine Crankcase Back.jpg (150.64 KB)

If the rear main bearing is seated up in the slot that leaves a gap across the bearing then maybe that cork gasket is needed. Mine does not ( see photo attached ) as you can see it is straight across the flange at the bearing. Not sure how that cork gasket can be installed and tightened up. I would be careful not to block the slinger drain which is the middle hole below the rear bearing. I see those bolts thru the flange but how would you access those to put nuts on ? as those bolts would be blind once the pan is installed. Maybe they did something different in later models as mine is an early one built around July 1931. But in any case very interesting. Always a puzzle with these cars.

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  Pan flange at rear main bearing.jpg (452.13 KB)

An oil slinger is: a helical groove(s) integrally machined around the outer cylinder of the rear portion of the crankshaft. It is in the same basic location that OTHER vehicles place a rear seal. It was Packard's very clever design often misunderstood. The journal that goes around it is very close clearance/tolerance and as the crankshaft turns the helical groove grabs escaping crankcase oil and "slings" or lightly pumps it back inward to the crankcase/main bearing zone...it works for the crankcase pressures of the era...and they really work quite well...

...now, the rest of a 50 year old story...however, a machinist back in 1977, who re-bored and installed new main sleeve bearings in my '41 110 6-cyl was not familiar with slingers and put some main bearing packing in the captured area around the slinger...it did no damage to the slinger, but pressure would build while driving it and it pee-ed out onto my new clutch plate and would weep out of the bell housing cover drain hole...a small oil patch every day...well, after a while, my clutch began to slip (oily) when I stood on the accelerator, so I was miff'ed since it was a brand new clutch and I milled the pressure plate flat..I disassembled it at the same time (as I was also ready to install the R9 OD transmission) and pulled the oil pan & rear main bearing block...lo and behold was the smashed main packing...I pulled it, checked all the clearances (no damage), cleaned and installed a new clutch plate (dry) and "Bob's your uncle"...it never dripped or weeped thereafter...that's saying something for any Packard.

They really work and I have the battle scars (and grease-laden T-shirt) to prove it.