Timing tape on a LT1/LT4
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Safety Car
Joined: Dec 2007
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From: Sandhills of North Carolina
Timing tape on a LT1/LT4
Anyone ever do it? I'm starting to wonder if this MSD opti with this adjustable timing bolt is correct or not. If this is off won't it affect the whole timing tables all the way to WOT?
Not hard to do it seems. Piston stop on #1, rotate crank in both directions until the piston hits the stop and mark damper where each direction stops, put "O" on the tape in the center of these two marks. Mount a pointer on this "O". This is TDC. Get a light and have at it.
Not hard to do it seems. Piston stop on #1, rotate crank in both directions until the piston hits the stop and mark damper where each direction stops, put "O" on the tape in the center of these two marks. Mount a pointer on this "O". This is TDC. Get a light and have at it.
Le Mans Master
Joined: Aug 2007
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From: WV
Just make sure you shoot a picture or write down where the tape is in relation to the balancer (0) mark.. If the tape comes off some day you will have to redo the whole thing again if you have no reference..Pete K sent me a picture of mine for my file when he built my motor,just in case the tape comes off...
..WW
..WW
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Safety Car
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From: Sandhills of North Carolina
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Thread Starter
Safety Car
Joined: Dec 2007
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From: Sandhills of North Carolina
Just make sure you shoot a picture or write down where the tape is in relation to the balancer (0) mark.. If the tape comes off some day you will have to redo the whole thing again if you have no reference..Pete K sent me a picture of mine for my file when he built my motor,just in case the tape comes off.....WW
..WW
Race Director
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From: Slidell Louisiana
Thread Starter
Safety Car
Joined: Dec 2007
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From: Sandhills of North Carolina
So, it's been about 25-30 years since I used a timing light. I'm going to have to buy one I guess. Now they are digital and lots of bells and whistles. Isn't a basic old 40.00 light good enough?
Melting Slicks
Joined: Feb 2006
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From: backwoods upstate ny
on an L98, can't use a timing light for anything except a disco strobe unless the 'set timing' connector is unplugged...what will ewe do, with the LT1's opti/ecm to 'flat-line' the timing ?
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Safety Car
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From: Sandhills of North Carolina
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Safety Car
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From: Sandhills of North Carolina
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shoebox
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The only way to actually know what timing the MSD is giving the engine is to rig up a timing pointer, verify with a scanner the advance the computer is providing and then observe the advance on the pulley. That's a lot of trouble. Some have noted that the screw does not alway engage properly and that would definitely skew the intended amount of advance/retard. That is one of the things I don't like about the MSD.
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Rob B 95Z A4 Tech Page (Part numbers / locations, How to's, Schematics, Diagnostic Trouble Codes...) Home Page - shbox.com
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The only way to actually know what timing the MSD is giving the engine is to rig up a timing pointer, verify with a scanner the advance the computer is providing and then observe the advance on the pulley. That's a lot of trouble. Some have noted that the screw does not alway engage properly and that would definitely skew the intended amount of advance/retard. That is one of the things I don't like about the MSD.
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Safety Car
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From: Sandhills of North Carolina
"Sure, it could affect things in either direction, either causing knock retard or hard starts, or even the lower dyno #s compared to what you were expecting. I don't know how the screw works exactly, but I would suspect it wouldn't show up on a data-log, yeah, since it's happening after the PCM".
Last edited by Weav's Vet; Jul 1, 2010 at 09:31 PM.
The screw is a nice gimick to make a gross adjustment and that's it.
Thread Starter
Safety Car
Joined: Dec 2007
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From: Sandhills of North Carolina
But if I don't check it and set it to what he PCM is displaying how can it be correct? If it's advanced say 2 degrees and I leave it that way isn't the whole timing table advanced 2 degrees? Same if it's retarded.