How to assess thayer valve compression

Wilco · by **Wilco** » 2019-05-08 4:45 a.m.

My shires thayer valves seem to have a good compression, but how to be sure? Is there a procedure for it? Valves have a big pop when I pull the tuning slides...

Specialk3700 · by **Specialk3700** » 2019-05-08 7:59 a.m.

Big pop = good compression

Burgerbob · by **Burgerbob** » 2019-05-08 11:00 a.m.

Pull a valve slide, wait a few seconds, then press the valve. Still a good pop? The longer, the better.

Wilco · by **Wilco** » 2019-05-08 3:51 p.m.

Thanks! 2 seconds: good pop. 4 seconds mild pop but still audible. Steady hiss sound after I pull a slide

Burgerbob · by **Burgerbob** » 2019-05-08 4:11 p.m.

Sounds pretty OK to me.

Wilco · by **Wilco** » 2019-05-09 1:41 p.m.

[quote="Burgerbob"]Sounds pretty OK to me.[/quote]

I checked my xeno bass as well, and there is a strong pop is still there well after 4 seconds. Is that a rotor thing??

Burgerbob · by **Burgerbob** » 2019-05-09 1:50 p.m.

They probably just seal better than your Thayers. It's easier for a rotor to do that, much less surface area to deal with.

MTbassbone · by **MTbassbone** » 2019-05-09 3:28 p.m.

A tech I went to a while back used a magnehelic gauge to measure the pressure. Not sure if this is correct way or not. I am also not sure what an acceptable reading is either.

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How to assess thayer valve compression