Does anyone know what the proper procedure is for adjusting valves on a set of heads? I have heard two different ways. One by doing each valve at a time and the other is by getting the piston to TDC and then setting the valves by getting zero lash and then preload. Does anyone know which is correct or the better procedure?
I have always just put the piston at TDC and loosen the rocker arm nut then tighten until there is no play in the pushrod. Then tighten an aditional 3/4 turn.
Steve
That all depends on the engine. On my 3.1 there is no adjustment, just tighten and torque.
"Weedahoe" wrote
What engine are you talking about? There are few, if any engines that GM uses anymore that can have their valves adjusted.
I'll assume that you are probably talking about a small block chevy. The easiest way to adjust valves on these engines is to set the engine to #1 TDC and adjust these valves.
With the engine in the number 1 firing position, adjust the exhaust valves for cylinders number 1, 3, 4, and 8 and the intake valves for cylinders number 1, 2, 5, and 7.
Turn the engine one complete revolution which will put the engine at #6 TDC and adjust these valves.
With the engine in the number 6 firing position, adjust the exhaust valves for cylinders number 2, 5, 6, and 7 and the intake valves for cylinders number 3, 4, 6, and 8.
You can find this information in any half decent manual.
The other option is to turn the engine over until each cylinder comes up on it's particular TDC, and adjust each cylinder individually, but this is just a waste of time and it is not a better way to do it. The first option I gave you is the factory manual method and it's been that way for years.
The one other option is to adjust them while the engine is running, but with newer small blocks, this method is really messy and there is no particular advantage to doing it this way.
Ian
"Weedahoe" wrote
Well, that certainly changes things. I'd suggest that you do each cylinder separately, and perhaps you might also want to consult the builder of this adjustable valve train and see what they recommend.
Ian
Hydraulic valve lifters actively 'take up the slack' and won't require adjustment, if there is no hydraulic lifter, the valves can be adjusted, after a certain mileage or if you hear a 'noisy valve'.
Of course, you must find what the adjustment spec is, do not just tighten it down. There is usually a certain clearance to allow for full closure of the valve (essential to disappate the heat in the valve) and to allow for warm up expansion in the parts. You will normally be putting in a feeler guage of say 6 or 10 thou. This may be different for the exhaust and intake valves. Do not adjust your valves unless you know what that spec is supposed to be.
"Rick De Visser" wrote
It depends on the engine. Small block chev's have hydraulic lifters....and they also can be adjusted. Usually, it's simply a 'starting' adjustment.....but they can be adjusted.
Ian
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