3rd rear main seal on new engine - oil pressure the cause?
#23
I'm going to agree with pat here, BPs shouldn't leak if built properly. I brake clean the flywheel bolts and wire brush them, apply blue loctite, and they don't leak. Biggest issue I've had with leaks is 6-speed cases leaking. I've resealed a few, but the labor and minor leak aren't generally worth it. That's a foot or two behind the weep hole though.
#26
I never said all turbo BP engines leak. Most unfortunately do, they are difficult to seal by design. The high heat and vibration just turns blue loctite into powder. Would definitely recommend using sealer around the through holes in the flywheel. I used silicone, but anaerobic sealer would also work.
#27
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Joined: Dec 2015
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From: Brisbane, Queensland, Australia
As an update on mine, the engine builder asked for compression and leak down before the engine was removed from the car
1:140
2:80
3:140
4:140
Number 2 had 80% leak down.
Oil did not improve the numbers, and it sounded like it was venting through the intake side. I don’t think that explains the rear main leak.
The engine is now out and with an engine builder to strip and assess.
I will report back with what is found.
1:140
2:80
3:140
4:140
Number 2 had 80% leak down.
Oil did not improve the numbers, and it sounded like it was venting through the intake side. I don’t think that explains the rear main leak.
The engine is now out and with an engine builder to strip and assess.
I will report back with what is found.
#28
Tips
Leaking rear radial seal is one of the biggest pains in the rear. I never had problems with them, even though I many times didnt loctite the bolts or used special tools for installing the seals, but I am always careful of:
Before installing the new seal, always inspect the contact area on the crankshaft where the old seal was running. It is usually a very shiny polished 1mm wide strap around the crankshaft. Inspect this shiny ring for any damage or dents or scratches which could harm the radial seal. If damage is directly there, check if you can install the seal a little deeper or less deep to avoid it. You will have to clean the surface well also in this case.
Be careful about area after this shiny surface(towards gearbox), which is usually surface rusty/brown colored and harsh. I think installing the new seal not deep enough(usually 0.5-1mm deeper than cover outside plane), rubber will run on this rusty material and get sanded/destroyed where it contacts.
Also, always make sure that the seal skirt is facing inwards, seen cases where people installed radial seals the arong way around, since they probably felt they fit better this way. Taper on radial seals always faces inwards, use the tool to install or gently work the edge around being careful not to cut or fold the inner contact area.
Last thing I would suggest is not to lubricate the outer(gearbox) side of the seal and crankshaft too much. Dust from clutch will stick to it and also create abrasive acting film. This is the old advice from suspension guys from motocross, the trick is that oiled fork seals wont last long since dust and sand sticks to it and creates the same effects. I always lubricate crank surface with finger sticked into engine oil evenly around and only inside surface of the radial seal, not too much.
Never had issues, hope someone solves those nightmare situations. Good luck have fun!
Before installing the new seal, always inspect the contact area on the crankshaft where the old seal was running. It is usually a very shiny polished 1mm wide strap around the crankshaft. Inspect this shiny ring for any damage or dents or scratches which could harm the radial seal. If damage is directly there, check if you can install the seal a little deeper or less deep to avoid it. You will have to clean the surface well also in this case.
Be careful about area after this shiny surface(towards gearbox), which is usually surface rusty/brown colored and harsh. I think installing the new seal not deep enough(usually 0.5-1mm deeper than cover outside plane), rubber will run on this rusty material and get sanded/destroyed where it contacts.
Also, always make sure that the seal skirt is facing inwards, seen cases where people installed radial seals the arong way around, since they probably felt they fit better this way. Taper on radial seals always faces inwards, use the tool to install or gently work the edge around being careful not to cut or fold the inner contact area.
Last thing I would suggest is not to lubricate the outer(gearbox) side of the seal and crankshaft too much. Dust from clutch will stick to it and also create abrasive acting film. This is the old advice from suspension guys from motocross, the trick is that oiled fork seals wont last long since dust and sand sticks to it and creates the same effects. I always lubricate crank surface with finger sticked into engine oil evenly around and only inside surface of the radial seal, not too much.
Never had issues, hope someone solves those nightmare situations. Good luck have fun!
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soflarick
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06-10-2008 03:23 PM