C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

optispark oil leak

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Old Apr 15, 2019 | 09:00 AM
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Default optispark oil leak

ok here goes my 1st post Im a virgin here. been reading for many years and have searched for days on the internet to find a answer to my oil leak problem. the car is a 1996 lt1 ce with 71 k miles I just bought a few months ago. I have been fixing it up to make it more reliable. I installed the ltcc to help with the optispark problem which it does fine the only problem after replacing the front timing cover seals i have more oil leaking now than before. it was leaking before I tired to stop the leaking. I put some dye in the oil broke it down which is no east task to get to the timing cover, its leaking from the optispark seal. after researching it for many days it seems this area is a real leak problem. the water pump seal isnt leaking just the optispark. seal, the crank seal is good . i just put in a new seal and it looks good Im just not sure this is a good designed seal. I did read that the original seal a long time ago was a lip seal rubber type with a spring in it. since the replacement seal is a different desgin it flexes and doesnt fit tight on the optispak. the opitspark is the orignial doesnt seem to have a lot of play in the input bearing the surface is smooth I see no reason for it to leak. doesnt seem to be any real answer to this problem it seem to seals or it doesnt and people just live with oiling the under side of the car back to the exhaust and smelling it burn. it didnt leak right a way after changing the seal so it did work a short time, I have been driving it pretty hard to get a email tune so dont know if the seal just cant handle the high rpm. someone out must have had this problem before and knows what Im going thru. if you have and have a answer it would be appreciated. Im hoping someone found a better seal and has a part number the seal that fel pro is using now just doesnt stop the leaking on my car anyway.. sorry about the typing errors im a electronic tech not a typist.
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Old Apr 15, 2019 | 09:23 PM
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Originally Posted by dxn1999
ok here goes my 1st post Im a virgin here. been reading for many years and have searched for days on the internet to find a answer to my oil leak problem. the car is a 1996 lt1 ce with 71 k miles I just bought a few months ago. I have been fixing it up to make it more reliable. I installed the ltcc to help with the optispark problem which it does fine the only problem after replacing the front timing cover seals i have more oil leaking now than before. it was leaking before I tired to stop the leaking. I put some dye in the oil broke it down which is no east task to get to the timing cover, its leaking from the optispark seal. after researching it for many days it seems this area is a real leak problem. the water pump seal isnt leaking just the optispark. seal, the crank seal is good . i just put in a new seal and it looks good Im just not sure this is a good designed seal. I did read that the original seal a long time ago was a lip seal rubber type with a spring in it. since the replacement seal is a different desgin it flexes and doesnt fit tight on the optispak. the opitspark is the orignial doesnt seem to have a lot of play in the input bearing the surface is smooth I see no reason for it to leak. doesnt seem to be any real answer to this problem it seem to seals or it doesnt and people just live with oiling the under side of the car back to the exhaust and smelling it burn. it didnt leak right a way after changing the seal so it did work a short time, I have been driving it pretty hard to get a email tune so dont know if the seal just cant handle the high rpm. someone out must have had this problem before and knows what Im going thru. if you have and have a answer it would be appreciated. Im hoping someone found a better seal and has a part number the seal that fel pro is using now just doesnt stop the leaking on my car anyway.. sorry about the typing errors im a electronic tech not a typist.
not sure if this helps , but i put a thin coating of rtv high temp silicone around the outer edges of the optispark seal assembly (the rubber grommet w/ spring inside & outer edge of recessed dimple in the back of metal optispark housing).

no idea if thats where its leakin for your situation. Obviously you cant seal the spinning shaft.

Last edited by dizwiz24; Apr 15, 2019 at 09:24 PM.
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Old Apr 16, 2019 | 09:13 AM
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During my searches on this problem I saw a few videos where people suggest the same thing putting rtv between the optispark and the timing cover. Putting rtv in that area wouldn't stop the leaking at the seal but it would contain leaking oil to that one area and just might slow down the leaking. I just ordered the GM seal its just a little different than the fel pro seal it has less flexibility in the seal contact area. when I get it I will post a picture to show any difference between the two.. Thanks for your suggestion Im going to try it, rtv in that area sure couldn't hurt.
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Old Apr 16, 2019 | 09:24 AM
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First use a good quality seal if you aren't already. 2nd, use some assembly lube on the seal and opti bushing. 3rd, when installing the opti do not install screws until the opti is fully seated and centers itself as best it can.
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Old Apr 16, 2019 | 09:46 AM
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I used a fel pro seal and it leaked after a few day of use. The instruction that come with the fel pro TC kit says not to lube the seal at the optispark. They say its a dry install. It seems if that seal should be installed dry or lubed has lead to a lot of debate, I followed what fel pro suggested and it leaked. In my mind it makes sense to lube the seal but they say the seal has a special coating of Teflon that doesn't need lubing. Once its installed dry or with lube it will soon see oil once the engine starts so why install it dry? It makes no sense that seal passes a lot of oil for being a dry install..
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Old Apr 16, 2019 | 10:08 AM
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Dry is more about install. I wonder about opti drive surface or run out. Possibly a crack in cover.
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Old Apr 16, 2019 | 10:57 AM
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Im going to pull the timing cover today so I will check for cracks but from the leak dye its pretty clear the seal is leaking and not in just one place. Im going to install a new optispark so that will eliminate that being any factor in the leaking. The optispark that was in their was the original with 71k on it. it seems to be fine no big play in the input bearing and seal surface looks to be good. My gut feeling is the replacement fel pro seal is the problem it fits tight on the optispark shaft but is easy to get out of shape its very soft material with no spring in the seal to keep tension on the optispark shaft .. If you had the seal in your hand you could push on the seal surface and see how it flexes and goes out of shape then slowly returns to sealing shape. bad design in my opinion.
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Old Apr 18, 2019 | 03:10 PM
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here is a picture of the fel pro on the left and the gm seal on the right. they look the same only difference the fel pro is made in Mexico and the gm seal is made in the USA.Im going to use the gm seal and see if that helps.

the water pump seal wasnt leaking oil but I added this 1/8 hole to the bottom of the seal housing area. the two top holes were letting oil in and iit was like a reservoir for the oil to collect around the seal. the new drilled hole will let the oil drain out.

this is the gasket maker rtv I applied to the optispark. it should seal the optispark to the timing cover case around the seal.

the only thing I noticed different between the old optispark and the new one is the new one had zero input shaft bearing wobble.
its all back together I have started it a few times and no leaks yet but I cant drive it yet its been snowing and raining here. once the roads get dry I will drive it to see if the leaking has stopped.
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Old Apr 18, 2019 | 03:50 PM
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The little bit of wobble might have been the cause. Hopefully it's fixed.
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