Adjusting valves, EOIC method - how much room for error on IC?

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Adjusting valves, EOIC method - how much room for error on IC?

Post  4604X4 on March 16th 2017, 4:58 pm

I just finished my cam swap (hydraulic lifters), adjusted all the valves using the EOIC method, then put everything back together and did the first run. I heard some tapping on the left bank.
so I pulled the valve cover (not an easy task), and did not see anything obviously wrong/loose. Then I started the engine, but I didn't really hear anything tapping this time.
But since the valve cover is off, I'm going to readjust/check all the valve adjustments again.

Question: I want to double check my adjustment method (especially since there seems to be a lot of variation regarding when to actually stop rotating the engine to adjust the exhaust valve).

When adjusting the Exhaust Valve, after the Intake reaches full open and then starts closing how much more rotation should there be before the exhaust valve adjustment is done.
Meaning does it matter if the intake valve is "halfway closed", "just starting to close" or does it need to be "almost fully closed" before the exhaust valve is adjusted? Reading about this on line - it seems some adjust the exhaust right after intake starts to close, and others says to wait until intake is almost fully closed.

I was aiming to have valve "almost fully closed" but that position is hard to tell, when rotating engine. "Almost fully closed" is very close to "fully closed". How much rotation error is allowed in the closing of intake before it will cause the exhaust setting to be wrong?
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Re: Adjusting valves, EOIC method - how much room for error on IC?

Post  rmcomprandy on March 16th 2017, 6:49 pm

4604X4 wrote:

When adjusting the Exhaust Valve, after the Intake reaches full open and then starts closing how much more rotation should there be before the exhaust valve adjustment is done.
Meaning does it matter if the intake valve is "halfway closed", "just starting to close" or does it need to be "almost fully closed" before the exhaust valve is adjusted? Reading about this on line - it seems some adjust the exhaust right after intake starts to close, and others says to wait until intake is almost fully closed

I was aiming to have valve "almost fully closed" but that position is hard to tell, when rotating engine. "Almost fully closed" is very close to "fully closed". How much rotation error is allowed in the closing of intake before it will cause the exhaust setting to be wrong?

Almost to fully closed ... it is closed when it is not moving anymore.

You could bar the engine backwards and adjust the exhaust when the intake just starts to move.

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Re: Adjusting valves, EOIC method - how much room for error on IC?

Post  Curt on March 16th 2017, 9:14 pm

I doubt that you've got anything radical enough to matter. Or a camshaft ground with a bench grinder.
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Re: Adjusting valves, EOIC method - how much room for error on IC?

Post  4604X4 on March 17th 2017, 6:03 am

rmcomprandy wrote:

Almost to fully closed ... it is closed when it is not moving anymore.

You could bar the engine backwards and adjust the exhaust when the intake just starts to move.


Backwards - That's a good idea.

So if the intake valve was to be "half closed" (mid travel) when I adjust exhaust that would be bad? I suppose I should study the lobe profile diagram.
Cam is mild. 216/224 @.050 adv. 278/286

Thanks
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Re: Adjusting valves, EOIC method - how much room for error on IC?

Post  68galaxie on March 17th 2017, 9:32 am

Why are you using EOIC method?
With such a small hydraulic cam setting both I and E adjustable rocker arms at TDC compression would work for me.
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Re: Adjusting valves, EOIC method - how much room for error on IC?

Post  rmcomprandy on March 17th 2017, 10:55 am

4604X4 wrote:
rmcomprandy wrote:

Almost to fully closed ... it is closed when it is not moving anymore.

You could bar the engine backwards and adjust the exhaust when the intake just starts to move.


Backwards - That's a good idea.

So if the intake valve was to be "half closed" (mid travel) when I adjust exhaust that would be bad? I suppose I should study the lobe profile diagram.
Cam is mild. 216/224 @.050   adv. 278/286

Thanks  

With a camshaft that small, it probably would make no difference.

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