Top Dead Center on LS1?
01-04-2003, 01:57 PM
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Top Dead Center on LS1? I was discussing doing my camswap with a couple friends that have done many on older small block Chevys and other non-LS1 motors, and they asked me how I plan on handling timing the cam.
I said, what do you mean? The cam Im getting just needs to be lined up dot-to-dot, and they asked how would I know if I was at top dead center. I said, you can tell just by looking at the position of cylinder 1 (I will have my heads off when doing my cam swap). Then they said, how would I know if thats at the top of the exhaust stroke or the combustion stroke.... They had me there.
Since the LS1s are a distributorless engine and rely entirely on computer timing for the exhaust and combustion strokes, what needs to be done to assure that I am putting my cam in and timing chain back on properly? Does the computer just adjust once its back together or what? I've read alot of the cam swap how-to guides and this is never mentioned.
Can someone shed some light on this for me? Thanks!
I said, what do you mean? The cam Im getting just needs to be lined up dot-to-dot, and they asked how would I know if I was at top dead center. I said, you can tell just by looking at the position of cylinder 1 (I will have my heads off when doing my cam swap). Then they said, how would I know if thats at the top of the exhaust stroke or the combustion stroke.... They had me there.
Since the LS1s are a distributorless engine and rely entirely on computer timing for the exhaust and combustion strokes, what needs to be done to assure that I am putting my cam in and timing chain back on properly? Does the computer just adjust once its back together or what? I've read alot of the cam swap how-to guides and this is never mentioned.
Can someone shed some light on this for me? Thanks!
01-04-2003, 03:00 PM
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Re: Top Dead Center on LS1? If you align the dots before you take the cam out your number one piston will be on TDC. Just install the new cam with the dots aligning and you are there.
Now if you remove the lower cam chain gear and turn the crank you will need to put number one cylinder on TDC again. At least on the Mustangs the low gear will go several ways. But if you don't take that lower gear off no problem.
Now if you remove the lower cam chain gear and turn the crank you will need to put number one cylinder on TDC again. At least on the Mustangs the low gear will go several ways. But if you don't take that lower gear off no problem.
01-04-2003, 04:10 PM
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Re: Top Dead Center on LS1? If the engine is at TDC and your installing a cam, it is "you" who determines the placement of the valves. Remember, all valves are closed when installing a cam.
01-05-2003, 01:21 AM
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Re: Top Dead Center on LS1? i does not matter if it is at TDC on compression or overlap. in matter of fact, you can remove a timing chain, move the cam gear exacly 180 degress, reinstall the chain and the engine will still start up on time. as long as you get it dot to dot it will start up fine. then the engine uses the crank sensor to figure the spark timeing.
01-05-2003, 02:47 AM
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Re: Top Dead Center on LS1? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by taqwache:
<strong> then the engine uses the crank sensor to figure the spark timing. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thats how.
<strong> then the engine uses the crank sensor to figure the spark timing. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thats how.
01-05-2003, 08:05 PM
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Re: Top Dead Center on LS1? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by taqwache:
<strong> i does not matter if it is at TDC on compression or overlap. in matter of fact, you can remove a timing chain, move the cam gear exacly 180 degress, reinstall the chain and the engine will still start up on time. as long as you get it dot to dot it will start up fine. then the engine uses the crank sensor to figure the spark timeing. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">This is exactly the answer I was looking for. From how I figure it, as long as everything is put back together properly and the gears are dot to dot, there is no other timing that needs to be done. Am I correct in my thinking?
<strong> i does not matter if it is at TDC on compression or overlap. in matter of fact, you can remove a timing chain, move the cam gear exacly 180 degress, reinstall the chain and the engine will still start up on time. as long as you get it dot to dot it will start up fine. then the engine uses the crank sensor to figure the spark timeing. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">This is exactly the answer I was looking for. From how I figure it, as long as everything is put back together properly and the gears are dot to dot, there is no other timing that needs to be done. Am I correct in my thinking?
