[Top] [All Lists]

Re: Inaccurate Tach

Subject: Re: Inaccurate Tach
From: Bullwinkle <>
Date: Fri, 07 Sep 2001 21:46:56 -0600

1) Find a stretch of highway with several miles marked out.  Many
US and interstate highways have one mile markers.

2) Drive as steady a speed of 60 mph indicated and note the time
it takes for each mile.  It should take 60 seconds or one minute
for each mile.  If the time is off, adjust the speed until you
can do a fairly consistant 60 mph actual.

3) Make a note of the RPMs the engine turns at 60.  If the MGA is
a 1500 or 1600, it normally has a 4.3 rear axle.  The engine will
be turning 3530 RPM if the tires are of standard diameter.  If
they are smaller the RPM would be slightly higher.

4) If the MGA is a MKII, it normally has a 4.1 rear axle.  It's
engine turns 3320 RPM at 60.

I've actually reset the needle on tachs and speedos this way. 
However the mile counter would not be right if the speedometer
gearing is off.


/// mailing list
///  (If they are dupes, this trailer may also catch them.)

<Prev in Thread] Current Thread [Next in Thread>