LT1 Valve Adjustment: Comp Valvetrain
LT1 Valve Adjustment: Comp Valvetrain Alrighty, every place we've called and asked has told us different.
I've got all comp cams peices....
pro mag lifters, their pushrods, rocker arms, springs etc...
I've been told by the tech at comp cams to just go along and tighten them all till there is no play and then 1/4 turn...
Also have heard do it till there is no play and stop...
What the hell is right???
-Rick
I've got all comp cams peices....
pro mag lifters, their pushrods, rocker arms, springs etc...
I've been told by the tech at comp cams to just go along and tighten them all till there is no play and then 1/4 turn...
Also have heard do it till there is no play and stop...
What the hell is right???
-Rick
Launching!
Joined: Dec 2007
Posts: 208
Likes: 0
From: DeLaWaRe
Alrighty, every place we've called and asked has told us different.
I've got all comp cams peices....
pro mag lifters, their pushrods, rocker arms, springs etc...
I've been told by the tech at comp cams to just go along and tighten them all till there is no play and then 1/4 turn...
Also have heard do it till there is no play and stop...
What the hell is right???
-Rick
I've got all comp cams peices....
pro mag lifters, their pushrods, rocker arms, springs etc...
I've been told by the tech at comp cams to just go along and tighten them all till there is no play and then 1/4 turn...
Also have heard do it till there is no play and stop...
What the hell is right???
-Rick
Staging Lane
Joined: Oct 2007
Posts: 65
Likes: 0
what?????? if you go "all the way down" as you put it, he'll wipe out his cam and all his lifters while turning all his push rods into question marks within a few seconds
the proper way is to set them at zero lash, then go another 1/4 to 3/4 mostly depending on preference...i personally do 1/2 on a COLD engine and its all set, never had to touch them in 4 years..also remember to do them in the proper sequence
Proper Sequence? I'm assuming you mean with the Valve closed so there is minimum pressure on the rocker? Right? Or is there a certain order you're supposed to do these in that I'm not seeing?
-Rick
-Rick
Remember EOIC. (exhaust open-intake closed) You want the valve you are adjusting on the base circle of the cam. If you had the balancer marked for top dead center for each cylinder that would be the easiest. But since not, perform the following.
When the exhaust valve just starts to open, adjust the intake valve of that same cylinder. When the intake valve is just about closed, adjust the exhaust valve of that same cylinder. Work one cylinder at a time until you are done. Turn the adjusting nut down till there is no play in the pushrod and go another 1/4 turn and call it done, simple.
I actually have a button mounted in my engine bay just to be able to bump the engine over. Makes it a little quicker.
When the exhaust valve just starts to open, adjust the intake valve of that same cylinder. When the intake valve is just about closed, adjust the exhaust valve of that same cylinder. Work one cylinder at a time until you are done. Turn the adjusting nut down till there is no play in the pushrod and go another 1/4 turn and call it done, simple.
I actually have a button mounted in my engine bay just to be able to bump the engine over. Makes it a little quicker.
__________________
95 Pontiac Formula- Stock engine with ATI Procharger, Moser 12 bolt w/4:30 gears, Rossler trans, Neil Chance 4000 stall, M/T ET streets, 10.914@ 121.90mph, 1.452 60ft. GMHTP November 2010 Feature Car. Check it out at:
https://www.motortrend.com/features/...ebird-formula/
http://www.youtube.com/watch?v=abZ1z...ature=youtu.be
95 Pontiac Formula- Stock engine with ATI Procharger, Moser 12 bolt w/4:30 gears, Rossler trans, Neil Chance 4000 stall, M/T ET streets, 10.914@ 121.90mph, 1.452 60ft. GMHTP November 2010 Feature Car. Check it out at:
https://www.motortrend.com/features/...ebird-formula/
http://www.youtube.com/watch?v=abZ1z...ature=youtu.be
I do one cylinder at a time more time consuming but i feel better that way. Theres a way to big 1 on tdc and adjust certain ones then make one full resolution so 6 is at tdc and then finish them but i dont remember which ones can be done. Can find easily online.
Bring piston to tdc (both valve closed) and I take all the up and down play out of the pushrods and do a half turn. Everyone has differant opinions some will say 1/4 some 3/4 some 1 1/2 but ive always used the 1/2 and ive never had a problem. Personally 1 or more is way to tight in my opinion and 1/4 is a lil sloppy stick in the 1/2 to 3/4 range.
Bring piston to tdc (both valve closed) and I take all the up and down play out of the pushrods and do a half turn. Everyone has differant opinions some will say 1/4 some 3/4 some 1 1/2 but ive always used the 1/2 and ive never had a problem. Personally 1 or more is way to tight in my opinion and 1/4 is a lil sloppy stick in the 1/2 to 3/4 range.
I do one cylinder at a time more time consuming but i feel better that way. Theres a way to big 1 on tdc and adjust certain ones then make one full resolution so 6 is at tdc and then finish them but i dont remember which ones can be done. Can find easily online.
Bring piston to tdc (both valve closed) and I take all the up and down play out of the pushrods and do a half turn. Everyone has differant opinions some will say 1/4 some 3/4 some 1 1/2 but ive always used the 1/2 and ive never had a problem. Personally 1 or more is way to tight in my opinion and 1/4 is a lil sloppy stick in the 1/2 to 3/4 range.
Bring piston to tdc (both valve closed) and I take all the up and down play out of the pushrods and do a half turn. Everyone has differant opinions some will say 1/4 some 3/4 some 1 1/2 but ive always used the 1/2 and ive never had a problem. Personally 1 or more is way to tight in my opinion and 1/4 is a lil sloppy stick in the 1/2 to 3/4 range.
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Am i the only one that does it with the engine running??? I'm running the pro mags as well and at a 650rpm idle there's hardly any oil coming up to the top. When i changed heads i just put all the nuts on, tightened em all down as far as i could go finger tight, bump the engine over a few times and do it again. Then crank the car, and tighten and losen em as i need to. I have them a lil' on the tight side right now though, going to readjust in another 300 or so miles.
Remember EOIC. (exhaust open-intake closed) You want the valve you are adjusting on the base circle of the cam. If you had the balancer marked for top dead center for each cylinder that would be the easiest. But since not, perform the following.
When the exhaust valve just starts to open, adjust the intake valve of that same cylinder. When the intake valve is just about closed, adjust the exhaust valve of that same cylinder. Work one cylinder at a time until you are done. Turn the adjusting nut down till there is no play in the pushrod and go another 1/4 turn and call it done, simple.
I actually have a button mounted in my engine bay just to be able to bump the engine over. Makes it a little quicker.
When the exhaust valve just starts to open, adjust the intake valve of that same cylinder. When the intake valve is just about closed, adjust the exhaust valve of that same cylinder. Work one cylinder at a time until you are done. Turn the adjusting nut down till there is no play in the pushrod and go another 1/4 turn and call it done, simple.
I actually have a button mounted in my engine bay just to be able to bump the engine over. Makes it a little quicker.
as long as you don't have a high volume oil pump you can do the dynamic adjustment with the engine running. IMO that's the only way I'd do it Besides if you have an HV pump, you can easily make a shield.
Besides if you have an HV pump, you can easily make a shield. 
i cut templates out of cardboard that fit inside the head and lean back twords the wheel wells to catch the oil, then i put rags over the fenders to catch anything else, and adjust them while they are running, i turn them all so you stop hearing any clacking noise, then back them off one by one, as one starts clacking, i tighten it untill it stops, do 1/2 turn and put in the poly lock then go to the next one, this worked for me on 2 cam swaps with no later adjustments.
Lots of good info sofar but one BIG detail has beenbarely touched on.
How to find zero lash. This seems to cause the most trouble.
Spin the polylock down with your fingers till it just touches. You can do this while trying to move the pushrod inline between the lifter and rocker and get a good idea what zero is.
You will see info posted about "spinning the pushrod" and that almost always results in way too tight because the parts are so well lubed that by the time you feel drag you have bottomed out the pluger in the lifter.
If you think you went too far adjusting back it off and leave it alone for a little while so the plunger can come back up.
How to find zero lash. This seems to cause the most trouble.
Spin the polylock down with your fingers till it just touches. You can do this while trying to move the pushrod inline between the lifter and rocker and get a good idea what zero is.
You will see info posted about "spinning the pushrod" and that almost always results in way too tight because the parts are so well lubed that by the time you feel drag you have bottomed out the pluger in the lifter.
If you think you went too far adjusting back it off and leave it alone for a little while so the plunger can come back up.