Oil leak at crank pulley retaining bolt

[bostonhatteras]

I took off both crank pulleys some years ago to replace the front crank seals. Not an issue and all went back together fine and dry until now. The crank pulley retaining bolt didn't have any type of gasket under the washer on either engine. Didn't give it a thought then but now I assume the crank #1 journal is drilled entirely through to the retaining bolt threads. so the question is how to seal. Cork or fiber gasket, maybe just permatex #2 on the bolt threads? . don't know the torque value yet but that may have a part to play in whatever gasket is employed.

[Captain Ralph]

I do not see how oil gets to those bolts.
Any oil laden bolts on DDCs had copper washers.

Loctite 515 is a good thread sealant.

Some balancers were fluid filled. Is your harmonic balancer failing?

[bostonhatteras]

Thanks for the reply Ralph. Its the big center bolt and I think the next step is to pull the bolt clean up area with brake cleaner/compressed air and try to look down the threadway. I didn't think about a balancer failure but I don't see any viscous coupling on it. In the service manual in section for crankshaft: remove crankshaft: line 11 states 'If used, remove the vibration damper (except on 16v engine). I think that line is interesting and apparently 'if used" refers to engines with a crankshaft cap which is fitted in place of dampers. Further on the manual states aspects of inspection of crank about cracks and failing dampers but these cracks seem to be indicated happening mainly in rod journals not main journal so likely remote enough from leaking area to not be my first suspicion. No where does it definitively state that 871 engines do not have dampers but only 12v and 16v engines have sections for dampers removal and install. I always wondered about damping on the 871s because what is on the front is seemingly just a series of pulleys with nothing of true mass to provide damping. The second paragraph of section Crankshaft states the crank is entirely static and dynamically balanced as a unit, so there's that to confuse matters. One clue Ill chase down is the torque spec of the pulley bolt which is 300 lb ft. I'm pretty sure I didn't torque to that spec. I think my proto torque wrench does max 250. I'll post my findings, Thanks Russell

[JD5652]

Replaced both my dampers about three years ago on my 671's. From the photo, it doesn't appear this engine has a damper unless it's a VERY small diameter and hiding behind the pulley.

[bostonhatteras]

Finally got around to removing the crank pulley and retaining bolt. The threads are bottomed with a very obvious stop. Only thing in the threads is my anti seize. Oil appears to be working its way around the oil slinger at the crank snout just inside the crank seal. The first photo is the spacer between the pulley and a machined face on crank, readily seen is oil inside. The spacer is a machined slip fit on the crank snout with precise machined surfaces for crank face and pulley face. Oddly the pulley has its keyway machined the entirely of the bore length but, the heavy washer on the crank pulley bolt just barely covers the keyway and that's the actual means for the oil escaping. I could remove the seal to see what may be happening with the oil slinger but I doubt that has issues as it's a simple stamped metal piece with no stress, at least I think so. Alternatively, I could use JB Weld and close up the last .25" of keyway in the pulley and effectively create a seal the entire way around the pulley bore diameter. The woodruff keys don't even come close to the end of the pulley so not much to lose going that route. I wonder if oil got past the oil slinger in rough weather and sort of stayed there inside the pulley . Any opinions? 0/3 on getting pics correct

[Captain Ralph]

That sleeve is supposed to bottom on the crank and seal it self from passing that oil. Tapered knife edge crushes and does not leak as in your picture. It can not be re-used or re-torqued.
Order a new sleeve and torque it down correctly.
OR, clean up all well with break cleaner, RTV the heck out it of it and reassemble.

Other (later) sleeves may have a groove for an O ring. In your picture,, with some imagination, I can almost see a groove for a missing O ring almost half way down.

[bostonhatteras]

Thanks for the knowledge! What you're saying makes sense. looks like the part in question is called Oil Seal Spacer and used in place of dampers. Thanks again Ralph

[Captain Ralph]

Thanks for the knowledge! What you're saying makes sense. looks like the part in question is called Oil Seal Spacer and used in place of dampers. Thanks again Ralph

Yes, The lip seal will rub / wear on this and not the crank shaft.
Your forward/port PTO pulley (Cam driven, behind the H/E) that usually drives the alternator, is set up the same way.