On Fri, 27 Sep 1996, Nystrom Kim NTC/Espoo wrote:
> Hi experts!
>
> Anyway, the diff is making more and more noise, i.e. high whining sound and
> I fear it will die on me soon.
>
> Is it possible to tell what kind of diff it is, if in fourth gear at 3000
> rpm's I do ca 50 mph, and 4500 rpm's ca 70 mph? In other words, is it a
> 3.89, a 3.29 or whatever..?? I just want to figure out if it is the right
> diff, cause the acceleration needs improving... And is it possible to fit a
> four-point-something diff to get better acceleration?
Kim, allowing for nonoriginal tire sizes and speedometer error, it's
likely to be a 4.11, but it could easily be a 3.89. At one time or
another, for various applications, the following ratios have been
available for this same basic diff: 3.27, 3.63, 3.89, 4.11, 4.55, 4.875
and 5.143 (the last a special-order-only item for early Heralds and
probably best used for either mud trials or after having converted your
Herald to power a sawmill ;-) ).
One way or another, any of those
gearsets is usable in any unit, but it might or might not be as simple
as unbolting one set and bolting in another. I'll leave that issue to
folks who know the insides of diffs far better than I. [Barry Schwartz,
mjb, whoever -- feel free to jump in anytime! ;-)]
Anyway, a couple of Web resources that might be of help to you, if you
can access them:
<http://ourworld.compuserve.com/homepages/spitfire/serial.htm> -- this
page from Amicale Spitfire lists the range of Herald, Vitesse, Spitfire
and GT6 serial numbers for components, along with final drive ratios
associated with each. Generally one can determine the ratio of the diff
from the serial number on the bottom (although, of course, gearsets can
be swapped).
<http://www.vtr.org/maintain/gearbox-ratios.html> -- this page from the
Vintage Triumph Register site gives transmission and final drive ratios
for most all postwar small Triumphs -- pretty much every Triumph that
used the basic Standard 10 and/or Herald-derived gearbox and/or final
drive unit. This also includes references to mph per 1000rpm in top gear
(assuming original equipment tires on each vehicle).
> Kim Nystrom,
> from an already cold Helsinki, Finland
--Andy, from a rapidly chilling upstate NY, USA
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* Andrew Mace e-mail: amace@unix2.nysed.gov *
* *
* Mrs Irrelevant: Oh, is it a jet? *
* Man: Well, no... It's not so much of a jet, it's more your, er, *
* Triumph Herald engine with wings. *
* -- The Cut-price Airline Sketch, Monty Python's Flying Circus *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
|