BIG TIMING CHAIN OOPS, Need Help.
Thread Starter
Racer
Joined: Jul 2005
Posts: 474
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From: Almost Northern Virginia
Cruise-In VII Veteran
St. Jude Donor '06
BIG TIMING CHAIN OOPS, Need Help.
Well I started the job of replacing my timing chain. Got everything apart pulled the harmonic balancer and then the front cover. Thought I had it at TDC but after i took the chain and gears off I noticed that the intake valve was pushed openon no 1 cylinder. I think i'm 180 out. How can I know for sure. I'm afraid of turning the cam or the crank seperatly cause I may run a valve into the piston.
Help Please!!!!!!!
Help Please!!!!!!!
Racer
Joined: Apr 2005
Posts: 408
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Not to worry. Were your dots lined up when you took it off? The sbc is not interference fit. You can spin the cam or the crank to line your dots back up. If your intake valve is open, then the dot on the cam sprocket was probably in a different position. If you have moved nothing, cam or crank, then just put the chain and sprockets back on. The sprockets can only go on one way. If you did move something however, then put then rotate until your dots are lined up and put it back on with the chain. This could cause your distrubuter to be 180 out, but only if you go one complete revolution on either the cam or crank, and you shouldn't need to do that to get the dots lined back up.
Last edited by lt4red; Aug 20, 2006 at 11:20 PM.
Thread Starter
Racer
Joined: Jul 2005
Posts: 474
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From: Almost Northern Virginia
Cruise-In VII Veteran
St. Jude Donor '06
Really?? I always thought that when you had the engine at 0 degrees TDC that the dist would point to no 1 cylinder and it was at full compression ready to fire? Both valves in the up position.
Racer
Joined: Apr 2005
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Originally Posted by 1991 C4
Really?? I always thought that when you had the engine at 0 degrees TDC that the dist would point to no 1 cylinder and it was at full compression ready to fire? Both valves in the up position.
Thread Starter
Racer
Joined: Jul 2005
Posts: 474
Likes: 0
From: Almost Northern Virginia
Cruise-In VII Veteran
St. Jude Donor '06
So then if both #1 valves are up and the dots are together then I'm at 0 degrees or TDC right?? and the dist should be pointing at # 1 cylinder?
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Racer
Joined: Apr 2005
Posts: 408
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Originally Posted by 1991 C4
So then if both #1 valves are up and the dots are together then I'm at 0 degrees or TDC right?? and the dist should be pointing at # 1 cylinder?
Melting Slicks
Joined: Aug 2003
Posts: 3,399
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From: Lakeville MI
With #1 at tdc in firing position, the distributor should point to #1, both valves should be closed and the timing set should appear in a dot over dot position (both dots at 12 o'clock, instead of the dot-to-dot alignment which would mean the cam sprocket dot at 6 o'clock and crank sprocket dot at 12 o'clock).
If you are aligned dot to dot, that is fine and is probably the most common way to align the timing set, but in this configuration the #6 cylinder is the one actually in firing position. You should be able to verify distributor position pointing to #6 also.
If you are aligned dot to dot, that is fine and is probably the most common way to align the timing set, but in this configuration the #6 cylinder is the one actually in firing position. You should be able to verify distributor position pointing to #6 also.
Racer
Joined: Apr 2005
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Originally Posted by scorp508
Correct me if I am wrong, but 180* out doesn't really matter on the cam. The crank turns 2x as fast as the camshaft does anyways. Every 2nd turn the cam dot will be 180* off anyways.
Thread Starter
Racer
Joined: Jul 2005
Posts: 474
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From: Almost Northern Virginia
Cruise-In VII Veteran
St. Jude Donor '06
Thanks for the help guys!! Thought i really screwed up but I see now I'm ok. what would I do without this forum. This place rocks!!!!
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
Originally Posted by lt4red
What can happen however is if the distributer is removed, the crank, or cam or both are moved, then the distrubuter can not go back in the same place it was removed.
