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Discussion Starter #1




Excerpt from Bret Powell's post on setting valve lash with big camshafts:
Adjust the intake when the exhaust starts to open.
Adjust the exhaust when the intake is almost closed...not when it starts to close.
 

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is there a method for hydralic lifters?? the motor is on a stand and new lifter. i heard there is a way to do it.
 

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Discussion Starter #3
This is the sequence for hydraulic and solid camshafts.
 

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Arrow Direction

On the top Valve Lash Adj. Chart by D.Davis I see an arrow that points clockwise,when you look at the rotor spin in the dist it spins C. Clockwise is this correct? :roll: Thanks Tore
 

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Discussion Starter #7
Re: Arrow Direction

Tore said:
On the top Valve Lash Adj. Chart by D.Davis I see an arrow that points clockwise, when you look at the rotor spin in the dist it spins C. Clockwise is this correct?
The curved blue arrow is illustrating the direction of engine rotation (when facing the front of your engine after opening the hood). This is also the direction you'll be turning the engine's crankshaft when going through the valve adjustment sequence.

The engine runs clockwise (facing front of engine).
The distributor turns counter-clockwise (as viewed from top).
http://www.boxwrench.net/specs/ford_429-514.htm
 

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Danny Cabral said:




Excerpt from Bret Powell's post on setting valve lash with big camshafts:
Adjust the intake when the exhaust starts to open.
Adjust the exhaust when the intake is almost closed...not when it starts to close.
Would't the valve adjustment procedure change when using a performance camshaft?

Wouldn't changes in the duration and intake centerline affect which valves are at the bottom of the lobe?
 

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Discussion Starter #9
jrocco said:
Would't the valve adjustment procedure change when using a performance camshaft?
No. (Unless you've done the '2-8' firing order swap, which is only for high output race users who wouldn't use this method for adjusting valves anyway.)
jrocco said:
Wouldn't changes in the duration and intake centerline affect which valves are at the bottom of the lobe?
No. The valve is still closed on the base circle (bottom of a lobe, as you said) of each lobe.
 

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OK so I flailed around about 4 times trying to get the valves adjusted right and finally called Comp Cams Tech Support.

So here's the story.

The charts above work for a factory stock cam. Once you install a performance cam you can disregard that information.

This is because the performance cam will have a different duration and different intake centerline that affects which valves are open at a certain point.

So the only way to adjust valve lash on a performance flat tappet hydraulic cam with adjustable lifters is as follows:

Remember EOIC (Exhaust Open - Intake Close)

For each cylinder, roll the crank until the exhaust valve just starts to open (move down) then adjust the intake valve to 0 lash and turn another 1/2 turn.

Then roll the crank until the Intake just starts to close (full open and just starting back up) and adjust the exhaust valve to 0 lash and turn another 1/2 turn.

Repeat for each cylinder.

Hope that helps. It worked for me.
 

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Discussion Starter #11
jrocco said:
The charts above work for a factory stock cam. Once you install a performance cam you can disregard that information.

This is because the performance cam will have a different duration and different intake centerline that affects which valves are open at a certain point.
Wrong! What size camshaft are you using?
When adjusting valves, you are on the base circle of each camshaft lobe. The lift, duration and separation angle are on the opposite end of the lobe...so why the heck would it matter (unless it's a radical cam with enormous lift and duration)? If your valves are open on the base circle of your camshaft, you've got a serious problem!



You're the first person that I've heard have a problem with the chart. Then you say it doesn't work with performance camshafts? I've got news for you...I wouldn't have posted this if it only worked with stock camshafts. Furthermore, I could care less what the Comp Cams 'tech guy' thinks he knows. I often link this page as a reference for others and now it's infiltrated with this useless dialogue!
 

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Hi Danny
I did not mean to create a big argument here about valve adjustments or to upset you in any way. I was only trying to pass on the experience I had to help others that may have the same problem.

In my particular case the Comp Cams method solved a bogging problem that I was having above 5,000 RPM. When I set the valves using the Car Domain method, my engine pulled hard to 5,000 RPM then fell on its knees.

It only makes sense (to me at least) that the cam grind and how the cam is degreed on installation will affect when the valves are on the base circle of the cam as compared to the 0 reference point on the balancer.

If the cam is installed 4 degrees advanced or retarded, would not the base of the cam be 4 degrees off when the balancer is on 0?

Refering to the Car Domain chart, when you set the balancer on 0 and adjust No 1 intake, No 1 exhaust, No 7 Intake, etc, on a cam that is installed 4 degrees advanced you are not on the lowest point of the cam.

It also follows that different cam grinds affect the overlap of the intake and exhaust valves, so again the low point of the cam lobes can be different relating to 0 on the damper.

For all of those reasons I found that the EOIC method guaranteed having the cam lobe at the correct position to adjust the valve. After using that method, my engine pulled hard all the way to 6500 RPM when I shifted.
 

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Hi Danny



It only makes sense (to me at least) that the cam grind and how the cam is degreed on installation will affect when the valves are on the base circle of the cam as compared to the 0 reference point on the balancer.

If the cam is installed 4 degrees advanced or retarded, would not the base of the cam be 4 degrees off when the balancer is on 0?

Refering to the Car Domain chart, when you set the balancer on 0 and adjust No 1 intake, No 1 exhaust, No 7 Intake, etc, on a cam that is installed 4 degrees advanced you are not on the lowest point of the cam.

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Just to point out that whether the crank is rotated to "0" or "350" or "10" degrees the cam will still be on the base circle because the number of degrees of crank rotation from TDC (on compression stroke) is much more than 4 degrees. In other words when the engine is at TDC the valves don't start to move with just 4 degrees of crank movement. The base circle is from #9 to #6 on the profile drawing (actually a little more).
 

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Here's the cam profile chart for a 304 degree Isky solid cam. You can see that the valves are both closed for around 240 degrees. If you allow a bit for the clearance takeup ramp you'll still have around 200 degrees to work with. This won't change much with any camshaft. The valves can't be open on the power or compression strokes. That's why that chart has to work. Anybody who claims it won't better go back to elementary motor mechanics!!
 

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I used this method for years on my 1970 Torino with a 429SCJ. I even put marks on the balancer so it was quicker to hit the marks. Just an interesting note my cam was advanced I think 8 degrees as per the Ford Muscle parts instructions and it always worked for me with over 30,000 street and racing miles on it. Wish I had that car back!!
 

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nice info. not to be a a$$ but you have a chart for X brands. i run a ford but like all three brands and run them to.
 

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Does the three position chart system work as well as the 90* chart. I used the three position system, it seems to run ok but I just want to make sure it runs the best it can. The system I used was a lot easier because I adjusted them by myself.
Thanks.
 

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You can always get a cylinder so the valves are in the split overlap position (both valves open) and set the valves on the cylinder that's four down in the firing order.
 
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