is my cam a "small duration" cam?
10-29-2008, 10:54 PM
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is my cam a "small duration" cam? These rocker installation instructions are straight from the 1998 GM Service Manual: http://zigzautonotes.googlepages.com...structions.gif
My LS1 build book says this about installing rockers:
"On engines using stock or small duration camshafts, it's possible to install and tighten the rocker arm bolts eight at a time at just two different positions of crankshaft rotation." I assume they're referring to the GM Service Manual method.
My camshaft is a TSP XS Series Camshaft: 233/239, .595"/.603". Here are the full specs on the cam: http://www.texas-speed.com/shop/item...d=169&catid=44
So is the TSP XS cam a small duration cam and am I ok to proceed with installing the rockers the way the 98 GM Service Manual says to?
Thanks to anyone willing to take the time to answer.
My LS1 build book says this about installing rockers:
"On engines using stock or small duration camshafts, it's possible to install and tighten the rocker arm bolts eight at a time at just two different positions of crankshaft rotation." I assume they're referring to the GM Service Manual method.
My camshaft is a TSP XS Series Camshaft: 233/239, .595"/.603". Here are the full specs on the cam: http://www.texas-speed.com/shop/item...d=169&catid=44
So is the TSP XS cam a small duration cam and am I ok to proceed with installing the rockers the way the 98 GM Service Manual says to?
Thanks to anyone willing to take the time to answer.
10-30-2008, 10:04 AM
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That would be the method I'd recommend as well!
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10-30-2008, 08:11 PM
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i appreciate the responses, guys. i got yella terra rockers and I found an installation article for those type rockers here: http://www.ls1howto.com/index.php?ar...21&printable=y
matt, you have a pm
matt, you have a pm
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10-31-2008, 07:01 AM
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This thread caught my attention. So, it sounds like there is no adjustment of the rockers for a stock LS1. Correct? Just tighten to torque specs and go? Is there ever any reason to go back and re-torque at any point?
10-31-2008, 07:42 AM
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What I always wondered was, how do you know if the piston is at tdc if you can't see through the heads? i know that if you are at dot to dot that's pretty damn close for the number ONE piston, but for the others i really don't know. also if the piston is at tdc, will both valves be ALL the way closed?
I wouldn't think so because you have to measure for ptv clearance...
10-31-2008, 09:08 AM
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I see no PM from you. Send again please!
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10-31-2008, 09:41 AM
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From what I understand, you just need to make sure the lifters are not on the apex of a cam lobe. As long as they are at the base of the lobe, you are good to torque. Someone PLEASE correct me if I'm wrong.
What I always wondered was, how do you know if the piston is at tdc if you can't see through the heads? i know that if you are at dot to dot that's pretty damn close for the number ONE piston, but for the others i really don't know. also if the piston is at tdc, will both valves be ALL the way closed? I wouldn't think so because you have to measure for ptv clearance...
What I always wondered was, how do you know if the piston is at tdc if you can't see through the heads? i know that if you are at dot to dot that's pretty damn close for the number ONE piston, but for the others i really don't know. also if the piston is at tdc, will both valves be ALL the way closed?
I wouldn't think so because you have to measure for ptv clearance...
There are several ways to accomplish this:
A) You can place a small stick/rod/straw/something into the spark plug hole and have a buddy turn the crankshaft by putting the stock 24mm crank pulley bolt in and turning the bolt with a wrench. You should be able to feel when the piston comes up to the top.
B) This method is a bit more elegant. Rotate your motor over by hand until your cam gear and crank gear are dot to dot like you set them up as earlier. At this position, piston 1 and 6 should be at top dead center. You can change the 4 springs on these 2 cylinders now using the instructions below. After you change those 4, then, rotate the crankshaft a full 90 degrees, and the cam gear dot will turn 45 degrees, as if it is pointing to 7:30 if it were a clock. Now piston 8 and 5 are at the top and can be changed. Rotate another 90 degrees on the crank and your cam gear dot will now be at 9 o'clock. Piston 7 and 4 can now have their springs changed. And FINALLY, rotate the crank another 90 degrees and the cam gear dot will be at 10:30. You can now change your remaining four springs on piston 3 and 2.
Once again, that's 1 & 6, rotate 90, 8 & 5, rotate 90, 7 & 4, rotate 90, 3 & 2.
A) You can place a small stick/rod/straw/something into the spark plug hole and have a buddy turn the crankshaft by putting the stock 24mm crank pulley bolt in and turning the bolt with a wrench. You should be able to feel when the piston comes up to the top.
B) This method is a bit more elegant. Rotate your motor over by hand until your cam gear and crank gear are dot to dot like you set them up as earlier. At this position, piston 1 and 6 should be at top dead center. You can change the 4 springs on these 2 cylinders now using the instructions below. After you change those 4, then, rotate the crankshaft a full 90 degrees, and the cam gear dot will turn 45 degrees, as if it is pointing to 7:30 if it were a clock. Now piston 8 and 5 are at the top and can be changed. Rotate another 90 degrees on the crank and your cam gear dot will now be at 9 o'clock. Piston 7 and 4 can now have their springs changed. And FINALLY, rotate the crank another 90 degrees and the cam gear dot will be at 10:30. You can now change your remaining four springs on piston 3 and 2.
Once again, that's 1 & 6, rotate 90, 8 & 5, rotate 90, 7 & 4, rotate 90, 3 & 2.
10-31-2008, 10:44 AM
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This may be a dumb question but if the rockers are tightened down to a torque spec instead of adjusting for a set amount of lash clearance, why does it matter if the lifters are on the base of the circle or not? My '67, 400 motor was just tighten down the rockers to a torque spec and I didn't have to find any cylinders @ TDC.