Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Dash light rheostat

Have we jumped threads?????

I'll check the gearing at the weekend, but 2000rpm and 60mph doesn't sound right at all. That indicates 30mph per thousand revs in top which is long legged. My BGTV8 pulled a shade under that so 90mph was a tad over 3000rpm. The Roadster though is much lower geared to suit the red line. I suspect that something on your Mog isn't reading right if the rear wheels are standard size. You can calibrate the speedo using satnav, then get the official mph/1000 revs figure and this will provide the true revs.

Dave, sorry, I think I have jumped:I asked a friend to drive in front of me this afternoon on a long stretch and signal when he reached 60mphin fifth-sure enough my counter showed 2000 in fifth
so what am I to make of that? 3000rpm is eighty, never varies so maybe the gearing has been altered. I remember Kevin Vernon telling me that he thought it was quicker than his plus eight. Maybe I should just be thankful, well , for something. Sorry about the thread jump. Meabh.If you or anyone else has an idea please let me know.

What engine do you have???
There are two rough & ready checks that you can do if you don't mind getting underneath.
To determine 5th gear ratio, engage 5th - (engine not running).Then mark the propshaft (tippex works well). Turn the crank one full revolution. If the prop turns exactly one revolution it's 1:1. If it turns less than one complete rev then you have an overdrive 5th gear. It may be hard to turn over but you can push the car.....
If you jack it up to do this and don't have an LSD, it's difficult to get both wheels to turn the same amount without a helper!!

To check the diff, use the mark on the prop and see how far the wheels rotate for one revolution of the prop. If they turn a shade over 3 turns, then it's 3.07:1. If they turn more than 3.5 turns, then it's probably 3.7:1.
You need plenty of grunt to pull 30mph per 1000 revs, so unless the engine is special, I would suspect the revcounter. Can you get it calibrated with a multimeter?

Hi Dave; 1989 M16, pluseight gearbox.I don't know its history prior to my purchase in 97;no mention on the build record of anything special. One owner prior to me. Extensively worked on in 2004 by Omex industries (700 series ems replaced the stock item) big power increase and remodelled torque profile, pulls from near rest in fifth; rev limiter at 6500. It will pull from rest through the gears up a slight incline for three kilometers without touching the loud pedal. Anyway I'll run you checks as soon as my sciatica goes away. Thanks again. Meabh.