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adjusting valves in 350 sbc

Old 07-15-2013, 10:47 PM
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Default adjusting valves in 350 sbc

never done it before but my buddy needs help getting his engine back together before the weekend, I found this sequence for adjusting the valves from a google search and I just want verify with you guys that this an acceptable method before I just dive into this thing. here is what the article says:

Here is the ONLY way I will adjust Chevy hydraulic lifters. Sure beats the hell out of doing it when the engine is running by a long shot. Bring the number one cylinder to TDC. You'll know that by the timing mark being on or near zero and if you stick a screwdriver in that spark plug hole the piston will be all the way up. Loosen the rocker arm stud on both valves and then tighten one up while slowly turning the pushrod with your fingertips. When the pushrod can't be turned then stop and adjust the nut down 1/4 to 1/3 turn more. Then do the other one on number one cylinder. Now here's why this is so easy...you can adjust more valves without turning the engine over while the motor is in the number one position. Here's the sequence...you can adjust the exhaust valves on cylinders 1,3,4, and 8. Then you can adjust the intake valves on 1,2,5, and 7. All done the same way by turning the pushrod...etc etc. Rotate the engine one full turn or 180 degrees coming back to the zero timing mark. Now number 6 cylinder is up in firing position. Adjusting the rest of the valves in this order....exhaust on 2,5,6, and 7...then the intake on 3,4,6,and 8. Once the valves are set like this just button the engine up and if you did it right they will not need touched again. I've done many, many small blocks this way and 4 and 6 bangers as well. Not once have I had to go back and do it again. Sure beats the hell out of doing it with the motor running spraying oil all over the engine bay.


I was also thinking that zero lash on the pushrods was up and down movement not rotational movement, which is the correct way to set the lash?

Last edited by 87MagnumII; 07-15-2013 at 10:50 PM.
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Old 07-15-2013, 11:30 PM
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I don't know about the process described in the article you found, but here is a way I used MANY times in my drag racing days. Easy and accurate.

Pull the plugs so the engine turns over easy by hand. Rotate engine clockwise (looking from the front) until the intake valve of the #1 cylinder is about closed (valve spring moving up). This means the lifter on the #1 cylinder exhaust cam lobe is on the base circle, so you adjust the exhaust valve. Continue rotating the engine clockwise and adjust all exhaust valves using this method following the firing order of 1-8-4-3-6-5-7-2. Now do the same for the intake valves but this time watch for the exhaust valve to just begin opening (spring moving down). Now the intake lifter of the same cylinder is on the base circle of the cam. Again, just follow the firing order and you're done.

Sounds more complicated than it actually is. Just remember, intake up, exhaust down.

Last edited by 4mulafastech; 07-15-2013 at 11:33 PM.
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Old 07-16-2013, 09:30 AM
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Easy way to think of it is that you adjust the valve when the lifter is resting on the opposite side of the cam lobe.
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Old 07-16-2013, 04:57 PM
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That is the correct method. Both descriptions give you the same result as flysfloatsor indicates, it is just making sure the lifter is NOT on any section of the cam with lift! That is what is important. 4mula way works because if the exhaust valve is open, the intake valve has to be closed, so you set intake then. Opposite for exhaust. You can either do it by watching the valves or by watching the cam location.

The rotation of the pushrods stopping lets you know when the rocker first makes contact with the pushrods/valve. You then tighten further to preload the hydraulic lifter some. Too loose and you will hear a ticking sound from under the valve covers. To tight and the valve may not close all the way or close/open early killing power.
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Old 07-16-2013, 06:51 PM
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Originally Posted by befu
That is the correct method. Both descriptions give you the same result as flysfloatsor indicates, it is just making sure the lifter is NOT on any section of the cam with lift! That is what is important. 4mula way works because if the exhaust valve is open, the intake valve has to be closed, so you set intake then. Opposite for exhaust. You can either do it by watching the valves or by watching the cam location.

The rotation of the pushrods stopping lets you know when the rocker first makes contact with the pushrods/valve. You then tighten further to preload the hydraulic lifter some. Too loose and you will hear a ticking sound from under the valve covers. To tight and the valve may not close all the way or close/open early killing power.
+1
You will be fine either way. I do think SBC specs say to turn 1/2 - 3/4 after the push rod stops rotation. Be carefull of the push rod rotational friction, because if the lifters are new and have no oil in them, they can compress rather easy. You want to make the 1/2 turn after the push rod starts to compress the hydraulic lifter.
Also make sure to lube the cam, lifters and push rod ends when assembling.
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Old 07-17-2013, 04:53 PM
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Originally Posted by 87MagnumII
never done it before but my buddy needs help getting his engine back together before the weekend, I found this sequence for adjusting the valves from a google search and I just want verify with you guys that this an acceptable method before I just dive into this thing. here is what the article says:

Here is the ONLY way I will adjust Chevy hydraulic lifters. Sure beats the hell out of doing it when the engine is running by a long shot. Bring the number one cylinder to TDC. You'll know that by the timing mark being on or near zero and if you stick a screwdriver in that spark plug hole the piston will be all the way up. Loosen the rocker arm stud on both valves and then tighten one up while slowly turning the pushrod with your fingertips. When the pushrod can't be turned then stop and adjust the nut down 1/4 to 1/3 turn more. Then do the other one on number one cylinder. Now here's why this is so easy...you can adjust more valves without turning the engine over while the motor is in the number one position. Here's the sequence...you can adjust the exhaust valves on cylinders 1,3,4, and 8. Then you can adjust the intake valves on 1,2,5, and 7. All done the same way by turning the pushrod...etc etc. Rotate the engine one full turn or 180 degrees coming back to the zero timing mark. Now number 6 cylinder is up in firing position. Adjusting the rest of the valves in this order....exhaust on 2,5,6, and 7...then the intake on 3,4,6,and 8. Once the valves are set like this just button the engine up and if you did it right they will not need touched again. I've done many, many small blocks this way and 4 and 6 bangers as well. Not once have I had to go back and do it again. Sure beats the hell out of doing it with the motor running spraying oil all over the engine bay.


I was also thinking that zero lash on the pushrods was up and down movement not rotational movement, which is the correct way to set the lash?

You are on the right track. For those that are not assembling motors all the time, I recomment jiggling the pushrod up and down while tightening the rocker nut just until the slop is taken out, then go 1/2 turn. The issue with the twisting of the push rod is often winds up too tight, before the 1/2 turn, as when twisting the point you are supposed to stop is at when you first feel drag on the push rod. When too tight, performance is way down and premature wear occurs. I promise if you use the jiggle method you will have it spot on the first time, but I also do one cylinder at a time just to bee 100% sure I dont skip or adjust the wrong valve. It only takes 3 extra minutes to go cylinder by cylinder.

If it is flat tappet, moly lube the cam and botooms of the lifters and add zddp to the engine oil, make sure it starts right away. Get the dizzy facing about 5:30 on a clock(basically aiming at #1cylinder), make sure you are at TDC compression stroke advance the balancer to about 8* stick it in, make sure the carb has fuel in the bowls and start it up. If it doesnt start after a few cranks...double check your work. It needs to start up right away to get oil to the cam/lifters. Dont let it idle, get it to 2000-2500rpms for 20 mins, change the oil and its go time.

If its roller cam, oil on the cam set it to start, fire it up and get it wet.

Good luck

Last edited by MEANGREEN231; 07-17-2013 at 04:59 PM.
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Old 07-17-2013, 05:15 PM
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This is the best and easiest way, I just did mine

TDC pointer at "0". Firing @ #1, You can now adjust the following valves:

INTAKE on cylinders 1,2,5,7
EXHAUST on cylinders 1,3,4,8

Loosen the adjusting nut until lash is felt by rotating the pushrod. Then
tighten the adjusting nut while rotating the pushrod until all lash is
removed. Now tighten the adjusting nut 1/2 full turn. This "centers" your
lifter.

After you have adjusted the above valves, rotate you engine 360 degrees
bringing the pointer around to the 0 TDC mark. This is
TDC firing @ #6. Adjust the following valves in the same manner:

INTAKE on cylinders 3,4,6,8
EXHAUST on cylinders 2,5,6,7
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