[Healeys] exhaust popping

Bob Spidell bspidell at comcast.net
Sat Oct 11 20:33:45 MDT 2014


Similar to what happens when doing a 'mag check' in a light piston airplane.  In switching from one magneto to another, 
sometimes you accidentally turn both off, and a loud backfire often occurs.  If it's bad enough an engine shutdown and 
inspection of the exhaust system is in order.

On another note, didn't some other British cars--old MGs maybe--have an 'overrun' valve to prevent such 
backfiring/popping?  I presume the idea is to have the high vacuum open an alternate air source to dilute the mixture.

Bob


On 10/11/2014 2:17 PM, Ron Fine wrote:
> When I was 17 years old and in the army, training at Fort Ord, CA as a truck driver, someone showed me how to make a 
> lot of noise.  Driving a big truck downhill, coasting, just flip the ignition switch off and on again.  I blew apart a 
> muffler once with that trick.  It was hard explaining what happened to my sergeant.
>
> Ron
>
>
>
>


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Bob Spidell           San Jose, CA            bspidell at comcast.net

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