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partial engine drop-engine running
I have been fighting a leak for a while now and have replaced the usual suspects to no avail. I have used mirrors and even bought a borescope(very cool tool) to look back there. I cant find it with this d@mn CIS in place.
My idea is to jack the rear up like an engine drop, drop the rear of the engine as far as I can without disconnecting anything, stabilizing the engine somehow, and starting it so I can get my head bach there and find this leak. Thoughts, other than to suggest my new nickname be "lefty" ![]()
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Donnie Currently Porsche-less..... ![]() |
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hmmm. flywheel seal?
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replaced it, three times. And the last time I measured the crank and bore to make sure they were not out of round.
Spent the last hour in the engine compt with a borescope: oil light dry, breather-dry, tstat & surrounding area-dry.
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Donnie Currently Porsche-less..... ![]() |
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my CIS had a rubber hose oil drain line fitted underneath to catch oil sucked in there from overfilling. It sometimes disconnects.
oil thermostat rubber O-ring breather housing gasket dries out. You can't see this leaking. oil psi idiot light sender may eventually leak all above on my '77 CIS etc
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Ronin LB '77 911s 2.7 PMO E 8.5 SSI Monty MSD JPI w x6 |
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replaced all cis hoses, and routed that line, it is dry, replaced breather gasket it is dry. Looked at the oil light switch through the borescope, it is dry.
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Donnie Currently Porsche-less..... ![]() |
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Where does the leak appear to be? Can you post photos?
You haven't mentioned replacing the seals for the on engine oil cooler. Good luck. Jerry Kroeger
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82 911SC Targa (05 Boxster S ) gone, but not forgotten 87 Suzuki GSXR-1100 1953 MG TD Mk II |
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It drips at the bellhousing/engine mating seam. Oil cooler is the only thing I have not done, as I rebuilt the engine 200 miles ago. But it is coming off tonight as well, just to clean and reseat them.
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Donnie Currently Porsche-less..... ![]() |
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I don't recommend the whole starting the engine thing with the engine fully mounted in the car. You mentioned stablizing the motor but how stable will it be and is it worth the risk to the car or your head? I would recommend removing the motor and look for the leak.
If it is dripping from the mating seam it seems like the list of culprits are limited. 1. The case halves mating seam. You are dealing with a mag case I presume. The case may need machining to get a good seal. I assume you use the orange loctite in the rebuild? 2. The oil galley plug under the flywheel needs to be thouroughly cleaned & an epoxy compound over it adds additional insurance. I have never experienced problems with these plugs but I have heard from many that have. I use the epoxy to be sure. 3. Flywheel seal...probably not considering you post above. 4. Transmission oil...The input shaft seal (inside the TO bearing guide sleave) can leak and cause a wet bellhousing that drips out the bottom. Just a few thoughts...Pics may help spur some new thoughts. FC |
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The engine is short term and I don't really care if it falls out at this point, I have a 3.0 I am building to 3.2ss to put in it.
But, I want to fix this leak, personal issues I guess, but I will not let it win. Mag case, yes 574. Galley plugs were re-epoxied input shaft seal on the trans was also replaced, but it is def. not gear oil.
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Donnie Currently Porsche-less..... ![]() |
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It almost HAS to be a case leak at this point, I would really like to pinpoint it though. Got my supplies ready for tonight. Gotta date with a leaky ho.
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Donnie Currently Porsche-less..... ![]() |
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Have you tried oil dye? Amazing stuff for finding leaks. Put some of the dye in, run the engine, put it in a dark garage and go over it with a black light. You'll see exactly where the leaks are from, very obvious.
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Donnie,
Good luck with it, be careful...May want to disconnect the shifter at the coupler just for good measure. FC |
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Get some oil leak detector, try here
http://www.autobarn.net/fluorleakdet1.html Have used this stuff with a ultraviolet lamp very successfully to locate where the stuff is coming from. Add some to the oil, go drive and at night put the lamp where you suspect the leak. Light yellow or green is blowing oil, bright area is the leak.
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Old Tee all 911s sold |
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I put dye in it a while ago, and it is spattered everywhere, but I jacked it up and really looked around again with the UV light, I think is something inside the bellhousing and being thrown out through the inspection holes in the bellhousing.
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Donnie Currently Porsche-less..... ![]() |
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Wash it down with varsol. Cover up the inspection holes and look again. U may well be right and you have your answer. Could your case be over pressurized? A compression check may be in order. Ring blow by? This has got to be a pain in the ass.
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Old Tee all 911s sold |
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pain in the everything at this point. So I lefted her rear and let it run till the thermostat opened. Looked for the dye and it is clearly coming from inside the bellhousing and splashing around. Man it is hot under there, I feel sunburnt. My sump plate was seeping some, so it will come off for a quick straighten/grind.
The only possibilities inside there are the flywheel seal, galley plugs, seam, and the 2 case nuts/studs. Either way it has to come out again. Oil pressure peaks at 60 psi under high revs, about 20 at idle. No leaks at the cylinder bases, or cylinder/head/tower joints.
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Donnie Currently Porsche-less..... ![]() |
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