Best way to adjust solid cam - Team Camaro Tech
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post #1 of 20 (permalink) Old Apr 18th, 08, 08:49 AM Thread Starter
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Best way to adjust solid cam

What technique do you use to adjust the rockers on a solid cam? I have not done this myself yet and I need to. I think one cylinder is way out of adjustment because I have a slight pop sound on the passenger side exhaust.

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post #2 of 20 (permalink) Old Apr 18th, 08, 09:15 AM
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Re: Best way to adjust solid cam

exhaust opening-intake closing method recommended by most cam manufacturers. Here's the idea off of cranes website:

Setting Valve Lash on Mechanical Cams

All the valves must be set individually and only when the lifter is properly located on the base circle of the lobe. At this position the valve is closed and there is no lift taking place. How will you know when the valve you are adjusting is in the proper position with the lifter on the base circle of the cam? This can be accomplished by watching the movement of the valves.

1. When the engine is hot (at operating temperature) remove the valve covers and pick the cylinder that you are going to adjust.

2. Hand turn the engine in its normal direction of rotation while watching the exhaust valve on that particular cylinder. When the exhaust valve begins to open, stop and adjust that cylinder's intake valve. (Why? Because when the exhaust is just beginning to open, the intake lifter will be on the base circle of the lobe, so the intake is the one we can now adjust.)

3. Use a feeler gauge, set to the correct valve lash, and place it between the tip of the valve stem and rocker arm. Adjust until you arrive at the proper setting and lock the adjuster in place.

4. After the intake valve has been adjusted, continue to rotate the engine, watching that same intake valve. The intake valve will go to full lift and then begin to close. When the intake is almost closed, stop and adjust the exhaust valve on that particular cylinder. (Again, when we see the intake valve almost closed, we are sure that the exhaust lifter is on the base circle of the lobe.) Use the feeler gauge and follow the procedure described before in step 3.

5. Both valves on this cylinder are now adjusted, so move to your next cylinder and follow the same procedure again. In the future you may find shortcuts to this method, but it still remains the best way to do the job correctly.

Using Valve Lash to Help Tune the Engine

The engine only responds to the actual movement of the valves. Since the valve cannot move until all the running clearance (valve lash) has been taken up, the amount of valve lash you use affects the engine's performance. For example, if you decrease the amount of (hot) valve lash, the valve will open slightly sooner, lift higher, and close later. This makes the camshaft look bigger to the engine, because of a slight increase of actual running duration and lift. If you increase the amount of (hot) lash the opposite occurs. The valve will open later, lift less, and close sooner.

This shows the engine a smaller cam with slightly less actual running duration and lift. You can use this method on a trial basis to see what the engine responds to and keep the setting that works the best. Just remember, the more lash you run, the noisier the valve train will be. If the clearance is excessive it can be harsh on the other valve train components. Therefore, for prolonged running of the engine we do not recommend increasing the amount of hot lash by more than +.004" from the recommended setting. Nor do we recommend decreasing the hot lash by more than -.008".

Warning:

"Tight Lash" camshafts cannot deviate from the recommended hot lash setting by more than +.002" increase, or -.004" decrease. "Tight Lash" cams are those which have recommended valve settings of only .010", .012", or .014" on the specification card. These lobe designs have very short clearance ramps and cannot tolerate any increase in the recommended valve lash. The extra clearance can cause severe damage to valve train components.

With "Tight Lash" cams, we recommend using only the prescribed amount of hot valve lash, and that close inspection of the engine be maintained. Please realize that changing valve lash settings from the recommended design specifications will change the harmonic characteristics of the valve train, possibly causing valve spring deterioration and breakage.
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post #3 of 20 (permalink) Old Apr 18th, 08, 09:20 AM
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Re: Best way to adjust solid cam

The method I prefer is exhaust opening adjust intake, intake closing adjust exhaust.
In other words, turn the motor over until the cylinder you are looking at's exhaust valve JUST STARTS to open, then you lash that cylinders intake. Then crank it over until the intake fully opens then is almost closed, adjust the cylinders exhaust.
Make sense?

Sean

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post #4 of 20 (permalink) Old Apr 18th, 08, 09:20 AM
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Re: Best way to adjust solid cam

Beat me Jody, your version is definitely a more thorough description.....

Sean

1968 rs, with an old school, antiquated "junkyard, never even had the valve covers off" 354" SB2.2 pump gas motor........

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post #5 of 20 (permalink) Old Apr 18th, 08, 10:05 AM Thread Starter
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Re: Best way to adjust solid cam

Thanks guys!!!

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post #6 of 20 (permalink) Old Apr 18th, 08, 11:17 AM
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Re: Best way to adjust solid cam

Idling right along warmed up using the old "feelie" method the old mechanics taught me back when I was a kid.

And if I was running guided rockers, I'd narrow the feeler gages I needed to use and go!

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post #7 of 20 (permalink) Old Apr 18th, 08, 02:34 PM
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Re: Best way to adjust solid cam

Jody: what does one do when there's no cam card, nor any other info available ?

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post #8 of 20 (permalink) Old Apr 18th, 08, 02:39 PM
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Re: Best way to adjust solid cam

Not Jody, but I'd still like to offer that you warm it up, then set it at .022" and .024" for starters and then drive it and come back and do a lash-loop on it to see how the engine like's it.

And while you are at it check them all and see how far off the other one's are from this. You then might want to redo it and set it at what the others are??

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post #9 of 20 (permalink) Old Apr 18th, 08, 02:47 PM
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Re: Best way to adjust solid cam

, thanks pdq
I took a "friend's advice" and got 'em totally f~ed up, had to start over from scratch, and seem to be fairly close now, but with not knowing the exactlys of the cam, it's a beginner's guess for this kid.

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post #10 of 20 (permalink) Old Apr 18th, 08, 04:36 PM
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Re: Best way to adjust solid cam

Cant you just pull the valve covers and take the plug out, then with your thumb in the plug hole you turn the motor over until the compression blows your finger off which will be TDC, and then both valves will be closed and rockers will be loose and ready for an adjustment.

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Last edited by Skeeter55; Apr 18th, 08 at 04:56 PM.
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post #11 of 20 (permalink) Old Apr 18th, 08, 05:19 PM
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Re: Best way to adjust solid cam

Quote:
Originally Posted by Skeeter55 View Post
Cant you just pull the valve covers and take the plug out, then with your thumb in the plug hole you turn the motor over until the compression blows your finger off which will be TDC, and then both valves will be closed and rockers will be loose and ready for an adjustment.
no, the problem there is although both valves are closed, they are not both on the base circle. One or both (depending on where you stop the engine at) of the valves will be on the ramp, and adjusting them there would have them too loose when the lobe came around to the base of the lobe again. Picture the lobe starting to ramp up, taking out the lash but not enough to open the valve; that's the scenario you'd have.

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post #12 of 20 (permalink) Old Apr 18th, 08, 05:28 PM
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Re: Best way to adjust solid cam

Hey Jody thanks for the heads up and great detailed specification on the cam adjustments. I will do your way the next time its ready for an adjustment. My question now is will it run any different, because it sure runs great now.

But yes when i do need to adjust ill be looking for this thread, and yes it makes total sense.

Thanks Again: Skip

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post #13 of 20 (permalink) Old Apr 18th, 08, 05:46 PM
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Re: Best way to adjust solid cam

It seems to me that my way is not only the wrong way, but it sounds like i may be loose on adjusting one or the other valves. Which means that on that one or the other valve it may not be lifting as high as the others. Now that also means that it may be loosing some of that nice big lope sound on the valves that were not adjusted correctly on the heal of the lobe. Is this correct.

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post #14 of 20 (permalink) Old Apr 18th, 08, 07:49 PM
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Re: Best way to adjust solid cam

Intake ALL the way up and you ARE on the base circle of the exhaust and visa versa to be sure you are on the base circles.

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post #15 of 20 (permalink) Old Apr 18th, 08, 08:28 PM
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Re: Best way to adjust solid cam

Dam makes me want to go out and adjust my valves all over.... I wounder if ill get a little more lift .002 or so.

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