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#41965 01/26/2002 8:23 PM | Joined: Jan 2002 Posts: 14 Member | | Member Joined: Jan 2002 Posts: 14 | Just pulled engine to replace rear main oil seal. discovered the crank shaft is all corroaded and pitted very bad.Is there some sleave that can be shrunk fit on? How can I repair? | | |
#41966 01/26/2002 8:46 PM | Joined: Feb 2000 Posts: 95 Wrench Fetcher | | Wrench Fetcher Joined: Feb 2000 Posts: 95 | John: Welcome to the board. I hate to give you the bad news, but the only way to repair your crank is to have it ground. Find a reputable auto/machine shop, and they can help you out. Talk with the machinist, and explain your engine troubles/needs and other possible needed engine repairs. Pitted crankshaft journals is caused by crankcase dilution. Lots of idling, and/or cold start-ups and short distance driving also aggrevate/support dilution. Diluted gasoline molecules are boiled into the crankcase oils and create acids. It's these same acids that pit the crankshaft and bearings. Most likely your other journals/bearings will be in the same shape. Good Luck. Think Chevy!  :mad: 
Houston? , We have a problem!
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#41967 01/26/2002 10:41 PM | Joined: Jan 2000 Posts: 1,586 Extreme Gabster | | Extreme Gabster Joined: Jan 2000 Posts: 1,586 | On a 261 I did last year, the seal surface was pitted , however The crank journals were in unusually fine shape. The machinist took a some off the seal area but some deeper pits remained.He didn't want to reduce the diameter too much.When I assembled the engine, I used a NOS rope seal.No leakage at all after a summer of use.My crank wasn't like the surface of the moon, but it had enough pits in it that a lip seal would have leaked .I guess its a judgement call if it won't clean up to well to go with or weld, replace, or whatever. | | |
#41968 01/27/2002 12:53 AM | Joined: Jan 2002 Posts: 14 Member | | Member Joined: Jan 2002 Posts: 14 | Thank You Chevyman & Tony. Being a rookie I wasn't sure, however it makes sense. | | |
#41969 01/28/2002 3:18 AM | Joined: Dec 2000 Posts: 64 Member | | Member Joined: Dec 2000 Posts: 64 | Are you sure these "pits" aren't the grooves cut in the rear seal surface of the crankshaft to pull the oil back into the crankcase. The 216's: 235's: 261's all used a rope seal and the crankshaft had grooves cut in the seal area.
kdot em3
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#41970 01/28/2002 12:17 PM | Joined: Jan 2000 Posts: 1,586 Extreme Gabster | | Extreme Gabster Joined: Jan 2000 Posts: 1,586 | None of the 3 engines I did had the grooves, but I have seen the drainage grooves on some cranks | | |
#41971 01/29/2002 7:59 PM | Joined: Jan 2002 Posts: 14 Member | | Member Joined: Jan 2002 Posts: 14 | The engine is a 216,with a rope seal. No grooves and is pitted. Question? if some grooves where machined in and a new rope seal installed wouldn"t the new seal take the shape of the grooves and seal the oil? (pipe dream) | | |
#41972 01/29/2002 8:58 PM | Joined: Jan 2000 Posts: 1,586 Extreme Gabster | | Extreme Gabster Joined: Jan 2000 Posts: 1,586 | John, the grooves are small lines machined into the crank seal journal area at a 30 or so degree angle to help "screw" the oil away from the seal. | | |
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