Oil leak from pulley

[johnairey]

Is this a common problem?
Since my engine rebuild the engine has always collected an oily dust across the front of the engine.
On checking the fit of the seal to the pulley with engineers blue applied to the pulley seal surface it was found that the seal contact with the pulley left approx. an eighth of the contact surface untouched.
Seal surface on the pulley checked and found to be within a couple of thou of the nominal size 1 5/8". Inside diameter of seal 1 9/16" to give a 1/32" interference all round to make seal.
Timing case dowels on assembly were a good fit. Pulley bore and seal surface I believe would have been machined at the same time. So it Looks like a possible mismatch of timing case bore centre with the pulley/crankshaft centre for some reason.
To try and eliminate the oil leak a Speedi- Sleeve has been fitted along with a new oil seal giving a 100% contact. Fingers crossed.

[Keith Clements]

The oil leak is very common, if not universal! The problem is usually a worn pulley which the sleeve should cure. Can you post details of supplier and part number pls.
I was more worried about the concentricity of the rear crank oil seal, but both could be out of line, particularly if all the castings are not a matched set ( and i have my doubts whether all the engines that left the factory had all the journals and oil seal housings line bored together).
I found checking the concentricity not easy. My limit gauges were not small enough. Ideally a bush turned to size would be best either using narrow feeler gauges or blue to gauge gap.

There may be double lipped oil seals of the correct size available. If anybody can find a source please post part numbers on here.

[johnairey]

Keith,
The location dowel holes in the engine halfs and the timing case cover are blind so can not be machined together and must have been jig drilled and reamed. The out of alignment must be due to drill jig wear not kept in control over time.
My pulley has a groove worn in the seal face, on rebuilding the engine I positioned the oil seal in a different place which should have worked if the alignment had been O.K. The pulley bore in the timing case is 1/2" long the seal is 5/16" so room to reposition if required. It has been mention in the past that two oil seals can be fitted but in the case of misalignment of bores this would be of no help.
The Speedi-Sleeve is a SKF product No 99162 for diameters 1.622"- 1.628". it has a wall thickness of 10thou adding 20thou to diameter which looks like enough material to fill the gap I have on my seal surface. Length 1/2", length of seal face on pulley 3/4" long. Your local bearing supplier will have to order one for you.

[PJGD]

John,
Not sure that I have grasped the relevance of your first sentence in your last post re the inability to line bore the engine assembly.

No matter, another reason for an oil leak at the front of the engine, if it is centrifuged off the front of the crank pulley is the fact that the fold-over tab washer that retains the starter crank dog does not necessarily completely cover the key way in the pulley [see sketch]. Oil under crankcase pressure is liable to find its way past the stack of bronze gear and pulley, along the keyway and out at the front. It is a poor design feature, but you need to make sure that the end of the keyway is covered and that the dog is fully torqued up. Judicious use of Hylomar or similar in that general area may also be helpful.

Philip

[johnairey]

Hi Philip,
Thanks for the reminder re. The oil leaking past the keyway. My leak is from behind the pulley as confirmed on my marking blue test showing a gap in the seal contact and wet oil sitting on the flange at the bottom of the timing case.
Re. the first sentence. I envisaged the timing case not being line-bored I see it as a separate component manufactured just to bolt on. Ideally the front timing case could be line bored for a prefect fit.
With all the holes to be jig drilled in the case I would be tempted to take the opportunity to bore out for the seal at the same time.
My guess re. the mis-match is that either the drill jigs have worn over time or as we know two ramdom engine halfs will not fit together because of the crankshaft centre floating around during the production life of the engine. I don't believe any attempt was made to stamp up timing cases or bellhousings to identify them as a part of an engine set.
I know from experience lots of timing cases and bellhousings have been moved to other engines that have passed through the section refurbs. Bellhousings have always been checked for line ability untill a suitable one was found. Perhaps we now need to check timing cases to make sure the match will give a leak free performance.

[johnairey]

Pulley oil seal leak up date.

At the same time as I fitted the speedy-sleeve I did add a second seal on finding both seals would run on the speedy-sleeve. After 1000 miles the area of the leak behind the pulley is free from wet oil. Will moniter over an extended mileage before claiming a success.

Further investigation carried out to try and identify where the problem stems from on a part assembled engine with a crankshaft set on front and rear bearings.

First checked the seal face on a pulley, found two thou run out.

Whilst rigged up to check the pulley seal surface I slipped a seal onto the pulley to check the run out between the inner and outer diameters of the seal, in several positions run out varied between seven and ten thou.

Five timing cases fitted to the engine and the seal bores clocked in relationship to the crankshaft, the greatest error found was ten thou vertically, five thou off centre.

With 1/32" deformation allowance all round between the seal and the pulley seal face I believe the seal would cope with all the errors found.

Findings inconclusive, I need to carry out a check on the timing case that was leaking on the engine next time the engine is dismantled.