New Valve lash question: Competing methods - The Ongoing Saga

oldmansmonte

G-Body Guru
Oct 29, 2010
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Buffalo, NY
First I want to thank you guys in this forum. You always help this dummy out even though you don't have to, and I appreciate it. This is a great community.


Details again: Gm perf 350 ho, hydraulic lifters, flat tappet cam. Attempting to adjust valve lash to eliminate a clacking sound I was getting. There seems to be competing methods to adjusting the valve lash.


1) Turn engine manually until cylinder 1 intake closes and piston it on compression stroke. Set lash on both intake and exhaust valves at the same time. Move laterally down the engine bank doing the same

2) Same basic method but follow the firing order. Once cylinder 1 is complete the intake valve for cylinder 8 is open. Rotate engine until closed and set lash on this 2 valves. And then follow through the order.

3) E-O I-C method. Pick any cylinder, rotate the engine until the exhaust valve begins to open then adjust intake lash. Continue to rotate the engine on the same cylinder and when the intake valve opens and cycles and is about to close adjust the exhaust valve.


Thoughts?
 

JAMES L EUBANK

Apprentice
Feb 18, 2018
60
38
18
CLARKSBURG, WV
First I want to thank you guys in this forum. You always help this dummy out even though you don't have to, and I appreciate it. This is a great community.


Details again: Gm perf 350 ho, hydraulic lifters, flat tappet cam. Attempting to adjust valve lash to eliminate a clacking sound I was getting. There seems to be competing methods to adjusting the valve lash.


1) Turn engine manually until cylinder 1 intake closes and piston it on compression stroke. Set lash on both intake and exhaust valves at the same time. Move laterally down the engine bank doing the same

2) Same basic method but follow the firing order. Once cylinder 1 is complete the intake valve for cylinder 8 is open. Rotate engine until closed and set lash on this 2 valves. And then follow through the order.

3) E-O I-C method. Pick any cylinder, rotate the engine until the exhaust valve begins to open then adjust intake lash. Continue to rotate the engine on the same cylinder and when the intake valve opens and cycles and is about to close adjust the exhaust valve.


Thoughts?
I've never done valve lash adjustment on a Chevy engine, but every engine is basically the same method. It makes no difference which cylinder is done first or last or anything in between. The priority is to adjust the valve lash of each cylinder one at a time and only when both valves are completely closed at the beginning of the compression stroke. The trick is to find the compression stroke of each cylinder. Hope this helps.
 
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bracketchev1221

Royal Smart Person
Jan 18, 2018
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I always use the EOIC method. That way I can do any engine without knowing the firing order 1 cylinder at a time. It also helps when doing large duration race cams that may not have the valves on the base circle like a stock cam might. If you are really good, and know the firing order you can rotate the engine 1 time and do all the intakes and then rotate it again and do all the exhausts.
 
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79 USA 1

Royal Smart Person
Sep 2, 2011
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Cheektowaga, New York
I've used melloelky's method on my brothers Dart based 400 Chevy, Full solid roller cam. My SB406 (Flat tappet cam, full roller rockers) I used the exhaust at full lift, adjust the intake, Intake at full lift adjust the exhaust. Both methods worked every time. I also followed the method in the GM manuals which calls for only 2 crank rotations to adjust 16 valves on my 88 Sticker Sport. That led to some being loose and some too tight.
 

pontiacgp

blank
Mar 31, 2006
29,270
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Kitchener, Ontario
I have a roller cam so I use the GM suggested method. I have a harmonic balancer with the degrees so it makes it easier. I also remove the plugs to make it easier to line up the marks

Valve Lash Adjustment
:
1.
Position engine at
TDC on # 1 cylinder in firing position.
Adjust Intake valves on # 2 & # 7 cylinders.
Adjust Exhaust valve on # 4 & # 8 cylinders.
2.
Rotate Crankshaft ½ Revolution Clockwise.
Adjust Intake Valves on # 1 & # 8 cylinders.
Adjust Exhaust Valves on # 3 & # 6
cylinders.
3.
Rotate Crankshaft ½ Revolution Clockwise.
Adjust Intake Valves on # 3 & # 4 cylinders.
Adjust Exhaust Valves on # 5 & # 7 cylinders.
4.
Rotate Crankshaft ½ Revolution Clockwise.
Adjust Intake Valves on # 5 & # 6 cylinders.
Adjust Exhaust Valves on # 1 & # 2 cylinders


If you are having trouble getting the feel of spinning the pushrod you can use the feeler gauge method. You can use a 26 thou feeler gauge. You tighten the valve down until the feeler gauge is lightly pinched

hylifters.jpg


feeler_gauge2z.jpg
 
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oldmansmonte

G-Body Guru
Oct 29, 2010
594
348
63
Buffalo, NY
So here's where I'm. I settled on EO-IC method to adjust the valves after several cycles through the procedure I determined that a 1/4 turn was not enough for the engine to run right, so a half turn it got. Upper valve train seems quiet and normal as far as I can tell;, but the original ticking sound still remains. Car was brought to the exhaust shop that installed it, they don't believe it's exhaust. Disconnected transmission-not a transmission issue. Seems loudest under the car on the drivers side sort of behind the front wheel well. I've made an appointment at a local service/performance shop to have it looked at next week. These guys seem pretty cool and I'm comfortable they'll be interested in helping me resolve the problem.

Now here's the dilemma I have. One of my close friends is a very good mechanic. He's built a few really nice cars in terms of presentation and performance. The guy really knows his sh*te and has given my lots of great help and advice over the years. Only problem he works for the US post office and bringing my car to the shop is out of the question. He's also doesn't have a ton of time for me as his family is always up his *ss to fix their POS cars. He is in disbelief that this issue is serious. He's is disbelieving that a 7 year old GM Crate motor with 8k on it that hasn't been beat on much and has been maintained would have a damaged main bearing or cam. He doesn't believe a lifter tick to be serious. He thinks I should either "just drive it", put diesel oil in it to adding Lucas oil treatment to it.

Here's where I'm at. "Just drive it" is not an option. I'm a fanatic of my car and hearing the tick ruins the experience for my. And adding fluids to mask a sound isn't the direction I want to go. If it was a 2007 Tahoe with 188k on it and I just wanted to squeeze more life out of the car I would do that. But it doesn't seem like the point of dropping a new crate engine in a summer car is to leave it's problems unresolved.

Thoughts?
 

Wraith

Royal Smart Person
Jan 13, 2013
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DFW, TX
Hmmm, Chevy crate motor. Even with the torque converter disconnected I'd look at the flexplate. Or start holding a candle or flame around the exhaust leak points and look for a leak no matter what an exhaust place says.
 
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oldmansmonte

G-Body Guru
Oct 29, 2010
594
348
63
Buffalo, NY
Hmmm, Chevy crate motor. Even with the torque converter disconnected I'd look at the flexplate. Or start holding a candle or flame around the exhaust leak points and look for a leak no matter what an exhaust place says.

Flexplate was swapped because it had issues. I agree on the exhaust. It could have been that the exhaust guy was distracted by the wobbling flexplate(I have no inspection cover when I brought it in last fall.
 

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