I began having a bad oil leak and tracked it to the rear main. I read many post and decided to take the oil pan down with the engine still in the car and see what the problem was. I was able to get the cotter pins and nuts off the rear main but can not get the bearing block to come down. After cleaning and tapping I finally got it to move a little bit I still can not get it out. It will move about 1/16 but that is it. Any one that can help would be great.
Rear Main Problems
- Thread starter JP31
- Start date
Phil
Senior Member
It can and must come down. Try some penetrating oil on the bolts from the area between the block the main cap and work it up down until it frees up.
Might try some mild hear with an electric heat gun (not a torch) then spray pent. Oil around the bolts. Keep working it gently til it frees up.
Might try some mild hear with an electric heat gun (not a torch) then spray pent. Oil around the bolts. Keep working it gently til it frees up.
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darrylkmc
Well-known member
JP31,
The rear main bearing bolts are just a round headed bolt, but the side against the block is flat and prevents the bolt from turning.
There is enough room to gently force the bolts up and out of the way, maybe try just one side. You need to be able to pull them back down again when you go to put it back together.
Darryl in Fairbanks
The rear main bearing bolts are just a round headed bolt, but the side against the block is flat and prevents the bolt from turning.
There is enough room to gently force the bolts up and out of the way, maybe try just one side. You need to be able to pull them back down again when you go to put it back together.
Darryl in Fairbanks
Tom Wesenberg
Well-known member
The heads on the rear main bolts have a flat side against the block which keeps them from spinning. You can use a wood dowel or smaller bolt to tap them up.
I type too slow.
I type too slow.
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pat in Santa Cruz
Well-known member
good point.
But since he has a bad rear main leak, if it is a modern seal it will need replacing anyway to repair the leak which requires removing the engine and crank shaft.
one sometimes wonders about "improvements" to the original design.
But since he has a bad rear main leak, if it is a modern seal it will need replacing anyway to repair the leak which requires removing the engine and crank shaft.
one sometimes wonders about "improvements" to the original design.
I did use a wooden dowel to drive the bolts back they would only move about 1 1/2" and appear to be hitting something above the block. After much moving up and down I did finally get it off and do in fact have the modern seal. Very unhappy about this since I now must remove the engine. The question is how to fix it? Should I go back with the modern seal or have the slinger put back in. What are people thoughts? Also I have been concerned about how my spark plugs looking very sooted up I also have black oil spraying from the tail pipe. I did check my compression before I started this job and found it to be 60,60,60,62 when slightly warm. I have recently rebuilt my carburetor and adjusted all 4 jets to Tom Endy recommendations. So what do I need to do and check while I have the engine out?
James Rogers
Well-known member
With all this, sounds like a rebuild is in order. I would suggest having the slinger replaced or the crank replaced with one that has never been modified when you have new mains done.
darrylkmc
Well-known member
JP31,
Any idea when the engine was rebuilt so that you can determine what type of seal was used?
With a bit of luck, maybe you can figure out what you need for a replacement seal. At least for a bit of labor and a few bucks for a seal you could get back on the road in a short time. It may still leak, but it could buy you some time in order to gather up the parts that you need to make a permanent fix.
Darryl in Fairbanks
Any idea when the engine was rebuilt so that you can determine what type of seal was used?
With a bit of luck, maybe you can figure out what you need for a replacement seal. At least for a bit of labor and a few bucks for a seal you could get back on the road in a short time. It may still leak, but it could buy you some time in order to gather up the parts that you need to make a permanent fix.
Darryl in Fairbanks
James thank you for your reply. I am not at a point financially where I can rebuild right now. Are there things that can be done as a partial fix to get me back running right now. Do you have thoughts on the oil in the exhaust? Does compression seem ok? Is there a two part seal that can go back in so I don't have to remove the engine? Thank you for your expertise.
darrylkmc
Well-known member
JP31,
Any way of finding out who rebuilt the engine to see if you can determine what type of seal was used.
I must admit that I don't know the first thing about modern seals, I have only ever worked on the original slinger systems. So I haven't any idea of all of the variables as far as what may have been used on your engine.
Darryl in Fairbanks
Any way of finding out who rebuilt the engine to see if you can determine what type of seal was used.
I must admit that I don't know the first thing about modern seals, I have only ever worked on the original slinger systems. So I haven't any idea of all of the variables as far as what may have been used on your engine.
Darryl in Fairbanks
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darrylkmc
Well-known member
JP31,
Are your certain that it is oil "Spraying" out of your exhaust?
Is it possible that it is just black sooty condensation, since you mentioned that your spark plugs are sooty also?
Seems your plugs would be oily if it is in fact oil coming out of your exhaust.
Darryl in Fairbanks
Are your certain that it is oil "Spraying" out of your exhaust?
Is it possible that it is just black sooty condensation, since you mentioned that your spark plugs are sooty also?
Seems your plugs would be oily if it is in fact oil coming out of your exhaust.
Darryl in Fairbanks
darrylkmc
Well-known member
JP31,
The sooty condensation will appear carbon black, which is what it is, dry some on a piece of paper. It should have no or very little oil residue, ideally it should appear like lamp black from a lantern which builds up on the globe of an oil lamp.
Hopefully it will look just like what is appearing on your spark plugs, dry powder, which simply means you are running to rich and the exhaust has not been heated for a long enough time for the condensation to dry out from your exhaust system.
After all, water is a product of combustion.
Darryl in Fairbanks
The sooty condensation will appear carbon black, which is what it is, dry some on a piece of paper. It should have no or very little oil residue, ideally it should appear like lamp black from a lantern which builds up on the globe of an oil lamp.
Hopefully it will look just like what is appearing on your spark plugs, dry powder, which simply means you are running to rich and the exhaust has not been heated for a long enough time for the condensation to dry out from your exhaust system.
After all, water is a product of combustion.
Darryl in Fairbanks
Tom Wesenberg
Well-known member
Some engines were converted to use a 2 piece Chevy seal in the rear. I guess it would depend on the diameter of your seal area, since I don't know how much was turned down.
pat in Santa Cruz
Well-known member
if your seal is a black neoprene seal that must be stretched over the flywheel flange, odds are its a Burtz seal. They are recommended to be set in permatex. They are available from most suppliers. They require a specific diameter seal surface, so check to be sure. The specs are usually included with the seal, or the supplier can tell you. A 350 chevy seal will not exchange with this one. If the seal surface is the right diameter, a new seal should stop the leak if its installed following the instructions and tested before re installing the engine.
Bummer that the engine has to come out, but look on the bright side: once you decide to do that, you can take advantage and adjust your bearings like a civilized mechanic, that is standing over an inverted engine thats on an engine stand, instead of groveling under the car with oil dripping in your face. Pulling an engine really is not that difficult. There are times when I have had to take up the bearings when I actually considered pulling the engine just to avoid oil in my eyes. Its a lousy job underneath a car but quite enjoyable (and arguably more accurate) on an engine stand. Its also a good time to replace the timing gear if it shows wear and the front seal too.
I also suspect the "oil" in the tail pipe is soot. Did it start after you rebuilt the carburetor or before? That much soot is usually from an over rich fuel mix. Perhaps your float is sinking or just set too high or maybe a jet came loose.
Bummer that the engine has to come out, but look on the bright side: once you decide to do that, you can take advantage and adjust your bearings like a civilized mechanic, that is standing over an inverted engine thats on an engine stand, instead of groveling under the car with oil dripping in your face. Pulling an engine really is not that difficult. There are times when I have had to take up the bearings when I actually considered pulling the engine just to avoid oil in my eyes. Its a lousy job underneath a car but quite enjoyable (and arguably more accurate) on an engine stand. Its also a good time to replace the timing gear if it shows wear and the front seal too.
I also suspect the "oil" in the tail pipe is soot. Did it start after you rebuilt the carburetor or before? That much soot is usually from an over rich fuel mix. Perhaps your float is sinking or just set too high or maybe a jet came loose.
Terry Burtz Calif
Senior Member
Since Pat mentioned my name, I feel like I need to reply.
If your engine has lots of miles on it, your problem may be excessive main bearing clearance (crankshaft wobble). If your engine is new, your problem may be because the seal rubbing surface on your crankshaft is not concentric with the rear main bearing journal.
A radial lip seal has a lip that deflects and is preloaded against the seal rubbing surface.
In a static or low speed application, the lip will flex and can easily keep up with deflections to maintain contact even with large run-outs and clearances.
As speed increases, the lip has a harder time keeping up with deflections due to run-out and crankshaft wobble.
Radial lip seals (with flexible lip) can accommodate greater run-out and wobble than packing type seals (without a flexible lip) before leakage.
If your engine has lots of miles on it, your problem may be excessive main bearing clearance (crankshaft wobble). If your engine is new, your problem may be because the seal rubbing surface on your crankshaft is not concentric with the rear main bearing journal.
A radial lip seal has a lip that deflects and is preloaded against the seal rubbing surface.
In a static or low speed application, the lip will flex and can easily keep up with deflections to maintain contact even with large run-outs and clearances.
As speed increases, the lip has a harder time keeping up with deflections due to run-out and crankshaft wobble.
Radial lip seals (with flexible lip) can accommodate greater run-out and wobble than packing type seals (without a flexible lip) before leakage.
