Triumph Repair: RPMs, richard ferris, spitfire 1500

Question
Jim,
I own a 1973 Spitfire 1500, I just finished a restoration and am wondering how many RPMs you feel I should be running at? At 50 MPH Im at 3000, is this normal? It seems like its running hard. This is my first LBC so Im not sure what
is normal. I still have 3/4 of a gas pedal left at 50 MPH but it seems to be cranked up pretty good.
THX, Again,
Richard Ferris  

Answer
Richard,

That sounds about right for the 1500s.  From what I recall of the factory handbook in 4th gear it's about 18mph/1000rpm.  So 3x18=54....  or thereabouts

England didn't have an extensive motorway system in the 50s and 60s when most of the cars were being designed, so there was no expectation that the cars would need to hold 65mph (or 75 or more) for hours at a time.

A common option for the cars is an electrically controlled overdrive unit that is part of the transmission.  Unfortunately not many American owners seemed willing to spend the extra $50 or $75 for the overdrive when the cars were new so it can be a struggle to find a car originally quipped.

It is possible to retrofit an overdrive into your Spitfire but it will be expensive.  Used overdrives start at about $500 and a rebuilt unit can be $2k or more.  Plus you'll need to change the driveshaft (or shorten it), and locate the appropriate small bits.  Most sellers seem to forget the shift lever when offering the trans, and those are also tough (and $$$) to find.

As to performance, my '73 1500 was capable of hopping up over 80mph without too much of a struggle.  But yes, if you're used to a nice modern quiet smooth car, the Spitfire will seem quite rough and noisy.


Cheers,

Jim