Help friends! LT-1 HELP!!!
Melting Slicks
Joined: Feb 2006
Posts: 3,105
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From: Sunrise FL
Remove #1 spark plug, rotate clockwise with either the starter or wrench on the crank balancer, feel for compression with your finger. If you are just working on the Opti, it will set itself only 1 way, no need for TDC.
If using starter, disable ign first!
If using starter, disable ign first!
Last edited by mikem350; Jul 25, 2010 at 12:15 PM.
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I can not understand http://www.ls1.com/forums/archive/in...p/t-33630.html
Trust me it is a lot better to use #6 TDC but both are correct. Let me explain why. When you have the number 1 cylinder at top dead center you line the timing marks from the crank shaft gear (small gear) in the 12 O'clock & the cam shaft gear (big gear) in the 12 O'clock position. This is an ok method but the timing marks are far away.All the time people get the timing marks off by one tooth.
Using the #6 at TDC method. Remember this, for every one crank shaft revolution the timing gear moves 180 degrees. So you get the crank shaft gear to #6 TDC the dot will be at 12 O'clock. Then all you do is rotate the cam shaft gear 180 degrees so the timing mark is at 6 O'clock and install the chain. This is a little more accurate because your marks are now only an inch or two away. Here is a diagram showing the timing chain setup at #6 TDC http://shbox.com/ci/sprockets.jpg
Using the #6 at TDC method. Remember this, for every one crank shaft revolution the timing gear moves 180 degrees. So you get the crank shaft gear to #6 TDC the dot will be at 12 O'clock. Then all you do is rotate the cam shaft gear 180 degrees so the timing mark is at 6 O'clock and install the chain. This is a little more accurate because your marks are now only an inch or two away. Here is a diagram showing the timing chain setup at #6 TDC http://shbox.com/ci/sprockets.jpg
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Joined: Jul 2010
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What aren't you understanding?
Trust me it is a lot better to use #6 TDC but both are correct. Let me explain why. When you have the number 1 cylinder at top dead center you line the timing marks from the crank shaft gear (small gear) in the 12 O'clock & the cam shaft gear (big gear) in the 12 O'clock position. This is an ok method but the timing marks are far away.All the time people get the timing marks off by one tooth.
Using the #6 at TDC method. Remember this, for every one crank shaft revolution the timing gear moves 180 degrees. So you get the crank shaft gear to #6 TDC the dot will be at 12 O'clock. Then all you do is rotate the cam shaft gear 180 degrees so the timing mark is at 6 O'clock and install the chain. This is a little more accurate because your marks are now only an inch or two away. Here is a diagram showing the timing chain setup at #6 TDC http://shbox.com
Using the #6 at TDC method. Remember this, for every one crank shaft revolution the timing gear moves 180 degrees. So you get the crank shaft gear to #6 TDC the dot will be at 12 O'clock. Then all you do is rotate the cam shaft gear 180 degrees so the timing mark is at 6 O'clock and install the chain. This is a little more accurate because your marks are now only an inch or two away. Here is a diagram showing the timing chain setup at #6 TDC http://shbox.com
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
My Russian is pretty weak, but I'll give this a shot. If you are installing the timing chain as mentioned above, there are two ways to install the timing gears, the 12 o'clock crank and 12 o'clock cam position is TDC for number one cylinder.
However since the cam rotates at one half crank speed if you make one turn of the crank after installing the gears as above the crank gear mark will of course be back at 12 o'clock, the cam gear only made one half turn so the mark will now be at 6 o'clock.
This 12 o'clock crank and 6 o'clock cam position is actually TDC for #6 cylinder but because the marks on the gears are pointed at each other and very close together many prefer using it to assure correct gear indexing.
To prove it to your self install the gears using either method then rotate the crank one full turn, when the crank mark is at 12 o'clock the cam gear will always be at either 12 or 6.
The opti indexes to the cam so you cannot get that part wrong.
However since the cam rotates at one half crank speed if you make one turn of the crank after installing the gears as above the crank gear mark will of course be back at 12 o'clock, the cam gear only made one half turn so the mark will now be at 6 o'clock.
This 12 o'clock crank and 6 o'clock cam position is actually TDC for #6 cylinder but because the marks on the gears are pointed at each other and very close together many prefer using it to assure correct gear indexing.
To prove it to your self install the gears using either method then rotate the crank one full turn, when the crank mark is at 12 o'clock the cam gear will always be at either 12 or 6.
The opti indexes to the cam so you cannot get that part wrong.
Race Director
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
How about a little more information on why you are trying to find TDC?
Unless the front timing cover is removed this information is useless.
"Trust me it is a lot better to use #6 TDC but both are correct. Let me explain why. When you have the number 1 cylinder at top dead center you line the timing marks from the crank shaft gear (small gear) in the 12 O'clock & the cam shaft gear (big gear) in the 12 O'clock position. This is an ok method but the timing marks are far away.All the time people get the timing marks off by one tooth.
Using the #6 at TDC method. Remember this, for every one crank shaft revolution the timing gear moves 180 degrees. So you get the crank shaft gear to #6 TDC the dot will be at 12 O'clock. Then all you do is rotate the cam shaft gear 180 degrees so the timing mark is at 6 O'clock and install the chain. This is a little more accurate because your marks are now only an inch or two away. Here is a diagram showing the timing chain setup at #6 TDC http://shbox.com/ci/sprockets.jpg"
Unless the front timing cover is removed this information is useless.
"Trust me it is a lot better to use #6 TDC but both are correct. Let me explain why. When you have the number 1 cylinder at top dead center you line the timing marks from the crank shaft gear (small gear) in the 12 O'clock & the cam shaft gear (big gear) in the 12 O'clock position. This is an ok method but the timing marks are far away.All the time people get the timing marks off by one tooth.
Using the #6 at TDC method. Remember this, for every one crank shaft revolution the timing gear moves 180 degrees. So you get the crank shaft gear to #6 TDC the dot will be at 12 O'clock. Then all you do is rotate the cam shaft gear 180 degrees so the timing mark is at 6 O'clock and install the chain. This is a little more accurate because your marks are now only an inch or two away. Here is a diagram showing the timing chain setup at #6 TDC http://shbox.com/ci/sprockets.jpg"
