At 10:34 AM 10/9/98 -0700, Skye Poier wrote:
>Word on the street is that Barney Gaylord said:
>> ....
>> Yes, 1060 turns per mile, and probably the wrong speedometer for your
application.
>
>Possibly not - I forgot to mention my '66 has a later model 4 sync + OD
transmission shoehorned in thanks to the PO. I'm *guessings* its the black
label LH type tranny.
Oh what a tangled web we weave, .... I had a feeling this story was gonig
to get even better.
>> Get a 1280 speedometer and you'll be correct within 1% on miles. Your
1060 speedo likely also reads 20% too high an speed as well, so when it
says 60 you're likely only going about 50.
>
>Another "gift" of the PO is that the speedo has been adjusted so that it
tries to read out kph instead of mph. It was a bit of a shocker when I
first got the car and noticed "hey it says I'm going 100 mph. Hmm."
Who was that spider anyway? I would think it would have been easier to up
the gear ratio between the tranny and the speedo to make it run about 60%
faster, thereby making the odometer also read out in kilometers. If
someone has tinkered with the innards of the speedo to change the needle
reading or gearing of the odometer, I'm afraid you're on your own, way out
in left field. First order of business might be to check the rotation
ratio of the speedo drive at the gearbox. Jack up the car, turn the rear
wheel, and count the rotations of the speedo cable relative to the rear axel.
>> .... small potentiometer inside .... If you have enough hands and eyes
you could set it to read 3270 while cruising at 60 mph on the freeway in
direct drive (4th gear, no OD). ....
>
>I gather the adjustment would take place with the tach popped out of the
fascia.. *pictures the passenger steering and me with my head in the
footwell with one hand on the accellerator and the other behind the dash
going 60 mph down the freeway* - not a good scene ;)
Yeah, you got the idea. Of course it could be the passenger doing the
adjusting while you're doing the driving. Sorry, didn't mean to spoil the
fun.
>Sigh. My speedo seems to be all gummed up now that the weather has turned
a little cold. I suppose I should yank that too and look for stripped
teeth gears etc. Rises and falls very slowly and often gets "stuck" -
rapping the glass will move it a bit.
Yep, sounds like a general cleaning is in order. You can find a crash
course (or four) in MGA Speedo Tech on my web site. The gear ratios will
be a bit different, but the function is the same. Check here:
http://www.ntsource.com/~barneymg/mgtech/speedo/st1.htm
Happy tinkering,
Barney Gaylord
1958 MGA with an attitude
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