Setting LT4 timing- ASAP
Thread Starter
Racer
Joined: Sep 2005
Posts: 417
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Setting LT4 timing- ASAP
I dont know if STL is on but maybe someone can help me. I just changed cams and I need to put rocker arms back on my LT4 and I need to set the timing.
STL said the following....
"With the #1 piston at TDC compression stroke adjust the intake valves on 1,2,5,7 and exhaust 1,3,4,8. Then rotate the engine one revolution with #6 at TDC and adjust intake 3,4,6,8 and exhaust 2,5,6,7. I use 1/2 turn past 0 lash.
LT4. If you are reusing the stock rocker arms there is no need to find 0 lash. Just tighten to 18 lb-ft."
Do I do all of that or for my LT4 do all I have to do is set the rocker arms to 18 lb-ft and I'm good to go?!?!? Oh also...do they have to be open or closed or whatever? Thanks guys
STL said the following....
"With the #1 piston at TDC compression stroke adjust the intake valves on 1,2,5,7 and exhaust 1,3,4,8. Then rotate the engine one revolution with #6 at TDC and adjust intake 3,4,6,8 and exhaust 2,5,6,7. I use 1/2 turn past 0 lash.
LT4. If you are reusing the stock rocker arms there is no need to find 0 lash. Just tighten to 18 lb-ft."
Do I do all of that or for my LT4 do all I have to do is set the rocker arms to 18 lb-ft and I'm good to go?!?!? Oh also...do they have to be open or closed or whatever? Thanks guys
Last edited by Achilleus07; Jul 3, 2006 at 05:47 PM.
Race Director
Joined: Feb 2001
Posts: 13,914
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From: Manassas VA
NoVa Events Coordinator
St. Jude Donor '14
I like to set the rocker arms by pulling the injector fuses and cranking the engine over.
First I tighten all the rocker arms by spinning the push rod with my fingers until i can't turn them anymore. I crank the engine over and tighten the ones that are loose. I do this 4 or 5 times then I start the engine and try to spin each push rod while the engine is running. Tighten as needed. Finally I go back and give each one another ¼ turn.
The timing is controlled electronically.
robert
First I tighten all the rocker arms by spinning the push rod with my fingers until i can't turn them anymore. I crank the engine over and tighten the ones that are loose. I do this 4 or 5 times then I start the engine and try to spin each push rod while the engine is running. Tighten as needed. Finally I go back and give each one another ¼ turn.
The timing is controlled electronically.
robert
Last edited by Bluewasp; Jul 3, 2006 at 06:14 PM.
Race Director
Joined: Jan 2002
Posts: 12,264
Likes: 88
From: O'Fallon Missouri
As Bluewasp stated, if you install the opti correctly the timing will be set.
Sorry, if my previous post confused you. Forget about the TDC method. On an LT4 you just need to tighten the rockers to 18 lb-ft. Just to double check, I would then turn the engine over 1 revolution and recheck the torque.
-Mike
Sorry, if my previous post confused you. Forget about the TDC method. On an LT4 you just need to tighten the rockers to 18 lb-ft. Just to double check, I would then turn the engine over 1 revolution and recheck the torque.
-Mike
Thread Starter
Racer
Joined: Sep 2005
Posts: 417
Likes: 0
Awesome....we were having trouble figuring out dead center and getting intake and exhaust right. We have it all down perfect now...or so we think. Everything lines up right when we turn the crank. So they are at 18 lb-ft and a 1/4. Thanks Guys
Also...any good tips on putting the hub back on? I know thats going to give us problems. Again thank you for everything...I would be lost without the forum.
Also...any good tips on putting the hub back on? I know thats going to give us problems. Again thank you for everything...I would be lost without the forum.
Race Director
Joined: Jan 2002
Posts: 12,264
Likes: 88
From: O'Fallon Missouri
Originally Posted by Achilleus07
Also...any good tips on putting the hub back on? I know thats going to give us problems. Again thank you for everything...I would be lost without the forum.
Race Director
Joined: Jan 2002
Posts: 12,264
Likes: 88
From: O'Fallon Missouri
Oh, one more tip. Before you reinstall the water pump and refill the coolant. Breifly start the engine to make sure the opti is installed correctly. A few here have installed the opti wrong and had to tear it back down to realign.
Thread Starter
Racer
Joined: Sep 2005
Posts: 417
Likes: 0
Originally Posted by STL94LT1
Oh, one more tip. Before you reinstall the water pump and refill the coolant. Breifly start the engine to make sure the opti is installed correctly. A few here have installed the opti wrong and had to tear it back down to realign.
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Melting Slicks
Joined: Dec 2004
Posts: 2,137
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From: Howard PA
What aren't we understanding about an LT4 and it's rocker nuts???
THEY ARE NON ADJUSTABLE!!! Tighten them to 18Ft Lbs. and that's it!
It makes no difference where the rotation of the motor is, you're locking the nut down fully on it's shoulder.
If you try to go another 1/4 turn you're going to break something and that will be a bad thing.
If you try to set a lash on them them they will come loose, they are not jamb nuts!
THEY ARE NON ADJUSTABLE!!! Tighten them to 18Ft Lbs. and that's it!
It makes no difference where the rotation of the motor is, you're locking the nut down fully on it's shoulder.
If you try to go another 1/4 turn you're going to break something and that will be a bad thing.
If you try to set a lash on them them they will come loose, they are not jamb nuts!
Last edited by ALLT4; Jul 3, 2006 at 10:34 PM.