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E31 vavle adjustments

444 Views 5 Replies 4 Participants Last post by  zmachines69
Stock - L24
Stock - E31 heads

My books say, TDC, adjust: I- 3,8,11 & E-1,7,9, then turn 1st cam lobe straight down and adjust the rest. However, I cannot adjust #11 Intake valve because at TDC, its lobe is already starting to push on the valve. ?????????????
Any directions would be greatly appreciated
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I would get a remote starter switch and bump the engine over till the lobe above the valve I want to adjust is pointing straight up. $20 Autozone.


Post Edited (Sep 27, 11:50am)
i just unhook the coil and tap the ignition to crank it over a half or quarter turn and see what i can adjust then when i get to the last few i watch the cam lobes and get the ones that need adjusting to point up by just tapping the ignition. I think most every1 here does it that way. I always adjust cold works fine.
I also remove the retaining springs on all valves and replace them as I set the valve clearance. Brain hurts less this way.

I always adjust the valves on any engine by adjusting the cylinder that is at TDC. Just going by "see what i can adjust" then turn the engine again doesn't assure you are on the right part of the lobe to adjust the valve correctly. This means moving the engine to 6 different positions but isn't a big deal to do, just put the car in 4th gear on level ground and roll the car (use the tire for leverage) to move the engine to the next position. removing the plugs makes this even easier but isn't nessasary.

You can either look at where the dizzy rotor is pointing or for me, it's easier to just watch the valves. When a cylinder is on overlap (the exhaust valve has just closed and the intake has just started to open), adjust the cylinder opposite it in the firing order. It will be obvious which one that is because that pair of lobes will be "level" to the head above the camshaft. Then roll the car to the next set on overlap and adjust the next opposite set.

On a Z it's even more simple because when a set is on overlap, the set on the opposite end of the engine is ready to adjust. i.e. OL #1 adjust #6, OL#5 adjust #2, OL #3 adjust #4, OL#6 adjust #1, OL#2 adjust #5, OL#4 adjust #3. It sounds complicated in writting but when you're rolling the engine watching the valves it's simple to see this relationship. Takes me about 3-4 minutes to adjust the valves this way.

The other "trick" it to not totally loosen the locknut. Just loosen it enough to move the adjuster and hold the locknut "snug" with one wrench while you move the adjuster. The reason is, the adjustment changes when you lighten the locknut. If you keep the locknut snug, it won't change when you tighten it the rest of the way. Also for a newbie adjusting valves, the go-no-go gauges help.

This adjustment makes a big difference in the performance and playing with different settings plus/minus .002" is worth doing to see which you like better. .008/.010 will give better top end power but .010/.012 will give a smoother idle and a little better bottom end power with a stock camshaft. Hope this helps.
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Thanks for all the info & tips!
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