oil leak 47 clipper

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bakerallen
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oil leak 47 clipper

Post by bakerallen » Fri Jul 27, 2018 6:33 am

I've posted about this before, and this probably seems like a dumb question, but here goes. In an earlier post I was told the engine for the 47 clipper does not have a traditional oil seal at the rear of the engine. I don't know a lot about motors, but it seems there must be a seal at the end of the crankshaft. It also seems that if this seal leaks, there would be oil leaking from the motor. What am I missing here? I am dealing with the smaller 8 cylinder motor.
Assuming there is a seal at the end of the crankshaft, is there anything special about the way is is installed? Thanks for your help.

Dave Czirr
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Re: oil leak 47 clipper

Post by Dave Czirr » Fri Jul 27, 2018 7:10 am

I seem to recall we've been over this before? Your car does not have a traditional rear seal (neither do most earlier Packards); rather it uses a "slinger" which is an intergral part of the crankshaft; it runs in a groove which had a hole leading back to the sump. In addition a "back spiral" groove on the crankshaft returns any surplus oil the crankcase. The slinger method was very widely used and completely effective as long as the return oil hole to the sump hasn't become plugged or restricted.

GJBINSC
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Re: oil leak 47 clipper

Post by GJBINSC » Fri Jul 27, 2018 8:44 am

Dave: Is this similar to the 901 rear seal ( photo attached ) which cost $ 20 for two small pieces of cork. I have the same problem and loose about 1/4 cup of oil every 20-30 miles. I plan to replace the seal in a couple of weeks, but as you know you have to remove a lot of stuff to get to it. I hope these small pieces of cork to the trick. Could the 47 use similar seals ?
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Rear Main Seal 32-901.jpg

Dave Czirr
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Re: oil leak 47 clipper

Post by Dave Czirr » Fri Jul 27, 2018 8:46 am

Yes, your 901 has the same arrangement as my '34 1100 as the '47 Eight, just a slinger. The cork strips really aren't a rear main bearing seal in the conventional sense in that they don't seal around the crankshaft, they just seal the edges of the rear main bearing block.

GJBINSC
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Re: oil leak 47 clipper

Post by GJBINSC » Fri Jul 27, 2018 9:21 am

Ok, so how does the leak occur ? will the seal stop the leak ? or could it be something else ? Same for the 47 in the thread. It seems like a lot of oil is leaking out the transmission drain hole. The drain tube is not clogged as the pan was cleaned out completely when I did the top engine rebuild recently which I hoped would cure the problem, such is not the case, it still leaks the same as before.

Dave Czirr
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Re: oil leak 47 clipper

Post by Dave Czirr » Fri Jul 27, 2018 10:25 am

At this point I'm stumped. Are there any oil galleries in the back of the block within the bell housing that might have a leaking plug? I'd go out and look at my 34 block but it's not all that easy to get at.

bakerallen
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Re: oil leak 47 clipper

Post by bakerallen » Fri Jul 27, 2018 3:57 pm

you are correct, I have asked this question before. The engine did not leak before a complete overhaul. The first time I brought it home it was leaking a lot of oil. I took it back and the mechanic took another look at it, and tried to stop the leak. This time when I brought home the leak was smaller, but I still had a puddle on the garage floor. The car is scheduled to go back to the shop in the next few days, but I don't know how the problem can be fixed if no one knows what causes it. I apologize for beating the same horse, but my knowledge of motors is limited. Am I correct in assuming there is no seal at all the end of the crankshaft on the end of the motor that connects to the transmission? I have searched the internet trying to find a diagram of that end of the motor, with no luck. Does anyone know where I might find one? Thank you for your patience and help.

GJBINSC
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Re: oil leak 47 clipper

Post by GJBINSC » Fri Jul 27, 2018 5:23 pm

I have one theory, but not sure it applies to the 47. The oil pan on the 901 is cast aluminum, and has a bulkhead that separates the oil from the lower end of what you might term the bell housing. There is no separate bell housing as it is combined with the oil pan at the bottom and the transmission with the top section. The bulkhead inside the pan has a blind flange with no bolts holding it tight to the bottom of the crank block. If the flange were some how not making proper contact with the block, a leak could occur where the slinger oil return tube mates with the pan flange. That connection is just flange to flange with a thin paper pan gasket. I did make sure the hole in the gasket lined up with the hole in the bearing so that is not the issue. If the flange were even slightly loose, bowed of warped a bit, it could leak on the outside of the bulkhead and run down the inside of the pan under the ring gear and out the hole. You could not see if it was tight it when you bolt up the pan, it would only be visible from the rear with the transmission, clutch and ring gear removed. Another question, is there a cap on the end of the cam shaft, that could also leak into the pan, and out the hole ?

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Re: oil leak 47 clipper

Post by Dave Czirr » Fri Jul 27, 2018 5:52 pm

No shortage of engine illustrations showing the slinger, in parts books, shop manuals, service letters, Motors and Chiltons manuals, etc. However none really show much detail, not that there is that much to see anyway. Here's one from Motor's Manual and a cropped/enlarged image from it, it clearly shows the slinger, it's cavity, and the helical coil on the crank behind the slinger to bring any oil which might have evaded the slinger forward and thence to the sump. As always, left click to enlarge the image.

I wish I could recall if there are any opening at the rear of the block like an oil gallery or the end of cam cavity which might not have been closed properly and could leak into the clutch but that's where I'd be looking now.

Just a thought - you say the engine was rebuilt and often that means that the crankshaft journals were turned undersize; is it possible that in that operation the slinger was accidently altered?
Attachments
Motor scan.jpg
Motor scan crop.jpg

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