I just learned this from my father who used to do this on old Ford V8s.
It can be frustrating trying to track down 1 or 2 noisy valves. And when there is wear on the tappets, gauging the gap to 0.010" may not actually lead to the correct gap. The solution is to be able to check valve clearances while the engine is running. But how?
The m20 engine will run with the valve cover off! Who knew? I always assumed that because the engine runs on a vacuum it wouldn't run at all (or barely run) with the cover off. Wrong! I was also worried that it would spray oil everywhere but that didn't happen either.
Once I had the cover off and the engine running, it was very easy to stick a 0.002" feeler gauge in the gaps of all the valves. If the valve quiets down you know it's set improperly. It's also much easier to find the noisy valve as you can do the old shadetree stethoscope trick and put a screwdriver on the rocker covers while holding the handle up to your ear. I was instantly able to identify which valves were noisier and tighten them down a thousandth or too.
Voile! My valves are quieter than ever and properly clearanced. The engine sounds perfect! Hopefully this tip is useful :up:
Now if you're concerned that your valves are too tight, obviously you need to check all of them the old fashioned way. But valves loosen over time, they don't tighten. So unless your valves were improperly set the last time they were adjusted, you should not ever have to worry abut them being too tight.
It can be frustrating trying to track down 1 or 2 noisy valves. And when there is wear on the tappets, gauging the gap to 0.010" may not actually lead to the correct gap. The solution is to be able to check valve clearances while the engine is running. But how?
The m20 engine will run with the valve cover off! Who knew? I always assumed that because the engine runs on a vacuum it wouldn't run at all (or barely run) with the cover off. Wrong! I was also worried that it would spray oil everywhere but that didn't happen either.
Once I had the cover off and the engine running, it was very easy to stick a 0.002" feeler gauge in the gaps of all the valves. If the valve quiets down you know it's set improperly. It's also much easier to find the noisy valve as you can do the old shadetree stethoscope trick and put a screwdriver on the rocker covers while holding the handle up to your ear. I was instantly able to identify which valves were noisier and tighten them down a thousandth or too.
Voile! My valves are quieter than ever and properly clearanced. The engine sounds perfect! Hopefully this tip is useful :up:
Now if you're concerned that your valves are too tight, obviously you need to check all of them the old fashioned way. But valves loosen over time, they don't tighten. So unless your valves were improperly set the last time they were adjusted, you should not ever have to worry abut them being too tight.
<-- F*** that guy
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