Rear oil seal leak

[Fresh6]

I am about 250 miles into running my rebuilt engine and have a pretty good engine oil leak that comes out mostly through the weep hole at the bottom of the bell housing. I lose 4-6 oz of oil on a 20 mile drive, and rustproof a good bit of the undercarriage at the same time (lol). When i return from the drive, and before I shut her down, i look under the car and there is a drip or two on the bell housing, but as soon as I shut it down, a steady stream of oil comes out, about 1/2  oz. After about 10 minutes, check the dipstick and its down 4-6 oz. It was losing about 8 oz for awhile, but maybe its getting better.

History of the rebuild and the problem: after initial rebuild, with about 5 hours on the engine and no appreciable oil leaks (that I noticed), I had my GP2 cam seize in the block at highway speed. After pulling the motor, and removing the camshaft it was not obvious what caused the issue (oil starvation at the seized bearing location due to a clogged orifice, clearances too tight, extra pressure from stiffer valve springs and higher lift rockers ? - nothing conclusive). All valve train components, etc were fine - motor just stopped when the cam shaft sprockets sheared off.  Had Richard Good put in cam bearings (should have done that initially with my rocker/spring set up and that cam) and put motor back together (after an extremely thorough block cleaning), but with same rings and did not rehone cylinders. Also installed valve guide seals. Motor back in car and broke in the new cam properly and then started driving again, but now with a significant oil leak as described above. Also discovered I had overfilled the crankcase by about 20 oz when checking my notes. Drained and refilled with 4.5 quarts (brings it to the middle of the dipstick).

So pulled gearbox and it was definitely coming from around the oil seal (used dye and UV light - all other gallery plugs, cam plug, seal housing bolt with copper washer were good) - did not appear to be more than a weep at the rear sealing block. So replaced the crankshaft seal with new one and made sure it was centered before and after tightening the housing bolts and the oil pan bolts, and checked again for a groove on the crankshaft - clean. Put gear box back in and started driving again, breaking in motor with varied RPMs, long steady accel pulls and closed throttle decels and the oil leak was still there after every drive. I have been thinking the rings are taking a long time to seal and maybe excessive blow-by is pushing the oil out. I am using a PCV set-up connected to the intake manifold (Good parts set-up) and not blowing oil anywhere else - I was getting it around dipstick, valve cover, etc when I was connected in the stock set-up from valve cover to vacuum ports on side of the Z-S (which are in front of the throttle plate), but not anymore with the PCV and connection to manifold vacuum, plus I have more break-in time on the engine.  By the way, it's a '74 with '74 carbs, but they have been made to be as close to the earlier Z-S carbs found on the TR250 or '69 TR6 as possible, including adjustable jets, no flame traps, no dizzy vacuum connections, no EGR, closed off TBV, etc. The car runs great, strong, starts with a blip of the starter even when cold, so I can't complain about that - I will say she is cold blooded and takes 15-20 minutes on the road to come up to temperature, which means it likes a little choke below 2000 RPM until warm. Could probably use a dizzy remap to match my cam and valve train, but that will be a winter project.
I also tried running for awhile with the valve cover vented to atm and into a catch can with no difference in oil leak that I could discern. Possibly a slight difference in fuel mixture.

I suppose the rear seal has gone bad agian, but that would be two now. Possibly the rear end of the crank was turned by a PO to remove a gouge and now the standard seals are too big?

At any rate, I am interested in any thoughts you all may have - if you got this far, thanks for reading!
 

[astontr6]

11 hours ago, Fresh6 said:

I am about 250 miles into running my rebuilt engine and have a pretty good engine oil leak that comes out mostly through the weep hole at the bottom of the bell housing. I lose 4-6 oz of oil on a 20 mile drive, and rustproof a good bit of the undercarriage at the same time (lol). When i return from the drive, and before I shut her down, i look under the car and there is a drip or two on the bell housing, but as soon as I shut it down, a steady stream of oil comes out, about 1/2  oz. After about 10 minutes, check the dipstick and its down 4-6 oz. It was losing about 8 oz for awhile, but maybe its getting better.

History of the rebuild and the problem: after initial rebuild, with about 5 hours on the engine and no appreciable oil leaks (that I noticed), I had my GP2 cam seize in the block at highway speed. After pulling the motor, and removing the camshaft it was not obvious what caused the issue (oil starvation at the seized bearing location due to a clogged orifice, clearances too tight, extra pressure from stiffer valve springs and higher lift rockers ? - nothing conclusive). All valve train components, etc were fine - motor just stopped when the cam shaft sprockets sheared off.  Had Richard Good put in cam bearings (should have done that initially with my rocker/spring set up and that cam) and put motor back together (after an extremely thorough block cleaning), but with same rings and did not rehone cylinders. Also installed valve guide seals. Motor back in car and broke in the new cam properly and then started driving again, but now with a significant oil leak as described above. Also discovered I had overfilled the crankcase by about 20 oz when checking my notes. Drained and refilled with 4.5 quarts (brings it to the middle of the dipstick).

So pulled gearbox and it was definitely coming from around the oil seal (used dye and UV light - all other gallery plugs, cam plug, seal housing bolt with copper washer were good) - did not appear to be more than a weep at the rear sealing block. So replaced the crankshaft seal with new one and made sure it was centered before and after tightening the housing bolts and the oil pan bolts, and checked again for a groove on the crankshaft - clean. Put gear box back in and started driving again, breaking in motor with varied RPMs, long steady accel pulls and closed throttle decels and the oil leak was still there after every drive. I have been thinking the rings are taking a long time to seal and maybe excessive blow-by is pushing the oil out. I am using a PCV set-up connected to the intake manifold (Good parts set-up) and not blowing oil anywhere else - I was getting it around dipstick, valve cover, etc when I was connected in the stock set-up from valve cover to vacuum ports on side of the Z-S (which are in front of the throttle plate), but not anymore with the PCV and connection to manifold vacuum, plus I have more break-in time on the engine.  By the way, it's a '74 with '74 carbs, but they have been made to be as close to the earlier Z-S carbs found on the TR250 or '69 TR6 as possible, including adjustable jets, no flame traps, no dizzy vacuum connections, no EGR, closed off TBV, etc. The car runs great, strong, starts with a blip of the starter even when cold, so I can't complain about that - I will say she is cold blooded and takes 15-20 minutes on the road to come up to temperature, which means it likes a little choke below 2000 RPM until warm. Could probably use a dizzy remap to match my cam and valve train, but that will be a winter project.
I also tried running for awhile with the valve cover vented to atm and into a catch can with no difference in oil leak that I could discern. Possibly a slight difference in fuel mixture.

I suppose the rear seal has gone bad agian, but that would be two now. Possibly the rear end of the crank was turned by a PO to remove a gouge and now the standard seals are too big?

At any rate, I am interested in any thoughts you all may have - if you got this far, thanks for reading!
 

Welcome to the forum!  Can we have a name please?

When you removed the last crank seal did you examine the sealing edge to see if you had nicked the sealing edge during assembly and check to see if the garter spring was ok? As I have known these to come apart?

Bruce.

Bruce.

[john.r.davies]

Fresh6, or Dave Roberts of Saint Inigoes, Maryland?

Welcome to the TRR BB.    I already gave you a suggestion on the Triumph Experience board, but I'll repeat it here, to see what others  think of it.

As I said there, repeated oil seal failures point to another cause.   Your say your camshaft seized? The sprocket sheared off the end of the camshaft but you could find no evidence of a burnt/worn/oil-starved bearing!! That is an extraordinary event, but one I have heard of before, associated with a faulty damper pulley, that allowed excessive vibration of the crank nose, transmitted to the timing chain and sprocket.

It's difficult to link a faulty damper pulley to a rear oil seal leak, but have you tested the pulley? To actually test the function of the pulley as damper is almost impossible without special equipment (I can do it, but I'm a long way away!) A simple test is to check that the TDC mark on the pulley still coincides with the true TDC? If not, then the outer 'inertia ring' of the pulley has shifted as the rubber has lost adhesion, and the damper is useless.

JOhn

[ntc]

Lets try this one, did you just bolt the seal housing without rotating the crank ? 

[PodOne]

3 hours ago, ntc said:

Lets try this one, did you just bolt the seal housing without rotating the crank ? 

I presume this was to better self centre the seal on the crank?

Think I'd play close attention to the crank surface where the seal lip rides for a groove and check/measure to see its not been skimmed by a previous owner. Sleeve it with a SKF if its out of tolerance. From the previous failure with the cam I make sure the oil galleries are all nice a clean.

Andy

[ntc]

19 minutes ago, PodOne said:

I presume this was to better self centre the seal on the crank?

Think I'd play close attention to the crank surface where the seal lip rides for a groove and check/measure to see its not been skimmed by a previous owner. Sleeve it with a SKF if its out of tolerance. From the previous failure with the cam I make sure the oil galleries are all nice a clean.

Andy

Note the size of the holes compared to bolt size? correct practice is finger tight ie loose rotate crank to center the seal.  

[PodOne]

3 minutes ago, ntc said:

Note the size of the holes compared to bolt size? correct practice is finger tight ie loose rotate crank to center the seal.  

I've never thought about until now but it makes sense, I'll bear in in mind next time around. Thanks.

[Fresh6]

7 hours ago, astontr6 said:

Welcome to the forum!  Can we have a name please?

When you removed the last crank seal did you examine the sealing edge to see if you had nicked the sealing edge during assembly and check to see if the garter spring was ok? As I have known these to come apart?

Bruce.

Bruce.

Hi - its Dave

I did, but I could have missed it.  the spring was fine.

 

Thanks - Dave

[Fresh6]

7 hours ago, ntc said:

Lets try this one, did you just bolt the seal housing without rotating the crank ? 

i did not rotate the crank, but I did use calipers to center the housing opening on the crankshaft before and rechecked after tightening the seal housing to block and oil pan to housing bolts.

[Fresh6]

3 hours ago, ntc said:

Note the size of the holes compared to bolt size? correct practice is finger tight ie loose rotate crank to center the seal.  

yes, proper length bolts matched to bolt holes, and copper washer on the top one since it goes into the crankcase cavity.

[Fresh6]

3 hours ago, PodOne said:

I presume this was to better self centre the seal on the crank?

Think I'd play close attention to the crank surface where the seal lip rides for a groove and check/measure to see its not been skimmed by a previous owner. Sleeve it with a SKF if its out of tolerance. From the previous failure with the cam I make sure the oil galleries are all nice a clean.

Andy

that's my plan I think.  yes, I cleaned the oil galleries and the entire bare block extremely well.  I now have about 200 miles on it since putting in the new cam.

[ntc]

On 11/12/2020 at 10:24 PM, Fresh6 said:

yes, proper length bolts matched to bolt holes, and copper washer on the top one since it goes into the crankcase cavity.

Length has nothing to do with it the diameter is the point.