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Pulley Seal O-Ring Replacement
I have a pretty major oil leak around the pulley. Iknow I can replace the seal pretty easily, but it looks to be coming from around that whereI beleive the o-ring is. Can I pull the end off and replace the o-ring too?
I beleive the answer is no, so any ideas or potential fixes? John
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1985.5 944 GTS |
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Ok, so I now believe that the case needs to be split in order to fix this issue. My questions are this:
Why is it leaking so badly? Is the O-Ring slit or crushed? What else should I do while in there? Issues w/#8 My plan is to spilt the case make this repair and seal back up. This is a zero hour motor. TIA, John
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This seems to be one of the hardest places to get a good seal. One problem I ran into was trying to use a Performance Products "tech tip" that was a bad idea. They said to use a later (thicker) o-ring there to prevent leaks. Well the thicker o-ring is too thick and it squeezed out into the seam between the case halves. Lucky for me I noticed it and took the case apart to fix before going any further.
I also had that same engine leak with the correct o-ring when I lubed it with Dow 111 grease. My theory there is that the grease got into the seam in the case and displaced some of the anarobic sealant. Then the oil pushed the grease out and caused the leak. The last engine I did I installed that o-ring dry and I used the white expensive silicon on the case seam. That engine is dry as a bone. -Andy
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I bought the longblock rebuilt. When I cranked the engine oil would leak around the o-ring and start to a steady stream out the bottom. This is not a little leak that anyone could live with. Just trying to identify any obstacles or concerns I may face.
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John,
How do you know it's the o-ring and not the pulley seal? This is a big repair so lets be sure!
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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As Chris suggested.... just recently, I had a leak at the pulley. turned out the harmonic balancer ground a hole in the face of the seal. This happened upon startup. The leak was still only a pinprick. Changed the crank seal, removed a bit of material from the pulley and problem solved.
Doug
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I know it's hard sometimes with all the oil squirting around there... I'd be really really double damn sure before going down the route of believing it's the o-ring because you have to split the damn case.
You may be able to stop the leak with some good sealant around the nose bearing, even saw someone use JBWeld successfully there to avoid having to yank and rebuild the engine. Remember the oil around the nose-seal is pretty full up because of the nose-bearing oil-feed.
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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I cleaned the area thoroughly and watched with a flashlight for the leak. It started around 1:00 on the o-ring and ran down the right side. The pulley seal is perfect.
I'm debating the locktite or JB fix as we speak, but gathering the parts for the correct fix.
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Damn John... The o-ring doesn't hold back oil-pump pressure, just whatever oil is there and positive crankcase pressure, so sealing it may work well enough to at least get you through the season....
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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Thanks. My plan is to seal it and try and run a weekend. I'm just preparing to fix it properly and would need to do that is a fairly short amount of time.
Coming to Mid Ohio next month?
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John,
I've got my fingers crossed for you! I'm presenting at a drivers school for Midwest Council April 15 and doing on-track instruction on the 22nd... First NASA race will be Putnam I think.
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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Thanks and see you then. Hopefully I'll be in GTS3 and not 4.
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As long as I'm not right behind that leaky ol' engine.
![]() There's a few GB'ers threatening to be at Putnam as well...
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Chris ---------------------------------------------- 1996 993 RS Replica 2023 KTM 890 Adventure R 1971 Norton 750 Commando Alcon Brake Kits |
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Well after a few sideline projects I finally got to do the full engine run-in. The crank/pulley leak is back......so, looks like pulling the motor (again) and splitting the case is the only option.
I'm trying to see the easiest way to dissassemble and reassemble based on my goals. Wondering if I can pull the carbs, pull the cam towers and head as one assembly, pull the cylinders w/pistons in them, and then split the case to fix the issue. I guess I'd have to pull the rockers and cam in order to get the chains free too. Pitfalls or concerns? ![]() ![]() Thanks, John
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John,
You pretty much nailed the dissassembly part, but you shouldn't have to pull the cams to remove the chains. You will need to remove the cam sprockets and tensioners anyway to get the chain housings off. Then pull the heads/towers and the pistons/cylinders as units. At least this is the way my 2.7 came apart but I didn't keep the pistons and cylinders as one unit. Dion
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fancytown
Join Date: Aug 2002
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Others here have had luck with Dow 730. It's $80/tube, but seals like a mutha! Do a search in the rebuild forum here, and you'll probably find a few that tried it.
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