[TR] high engine rpm

[Terry Geiger]

John,

Check your tach against a known good tach as the tachs can become inaccurate 
over time.  An electric tach can be used to test with.

Your car should be running about 3000 rpm at 60 mph in top gear (assuming no 
overdrive).  The speedo and tach were design to track with each other in top 
gear so 2krpm should get you 40mph, 3k rpm 60 mph and so on.

Terry Geiger
'74 Triumph TR6 | '63 Triumph Herald | '70 MGBGT | '84 Mercedes 300D Diesel
http://www.shoalsbritishcars.org/


----- Original Message ----- 
From: <acs25m at swbell.net>
To: <triumphs at autox.team.net>
Sent: Friday, July 20, 2007 3:36 PM
Subject: [TR] high engine rpm


>I own a TR250 that I am having problems with. The car had 185/65r 15 tires
> on it when purchased. I knew that these were not the right size tires and 
> it
> was causing my Speedo to be off. Well I recently purchased replacement
> 205/70r 15 tires and with my wife pacing me in another car the Speedo is 
> now
> correct. My problem is that the engine is still running at a higher rpm 
> than
> I think it should. At 60 mph my tack registers right at 3500 rpm. I
> downloaded an excel spread sheet that was talked about on line and the 
> only
> way to get that rpm reading would be with 4.55 gears. I don't have an
> overdrive and highway driving makes the car overheat. Short of removing 
> and
> disassembling the rear end is there any way to tell what rear-end gears 
> are
> really in the car.
>
> Any help would be appreciated,
>
> John R Maneke
> _______________________________________________