Gearbox advice - ratios

[richlowndes]

Hi all

I have a 1600tp which has recently had an engine rebuild. It’s running well, but it seems to be geared really low. It won’t go above 60mph and at that speed it’s revving fast and is noisy. I’ve had three 1600 bay windows before, and this definitely doesn’t seem normal. The chap that did the rebuild says he thinks it might have the commercial gearbox. I’ve looked at the gearbox number and it starts with CA which appears to be the normal gearbox. Apreabrly CB is the ‘Mountain Ratio’ box.
However, as far as I can work out, the only difference between the normal and the Mountain Ratio boxes is the final drive ratio, so I wonder whether the difference is in h the differential rather than the gearbox itself. Any ideas?
It’s running standard 14 inch steels and stock tyres.
Many thanks

 

[Bluesnailman]

id suggest you get a rev counter fitted, even if only a temporary measure.... Is the engine really running 'that' fast? Also, does your speedo agree with the speed on a sat-nav? 60mph does sound fast if you've no soundproofing, but 70mph should be achievable on a flat bit assuming your engine has run in.

Just thinking that you might want to be really really sure before you do anything else.

 

[fallingoffalot]

Also you may find it's louder at say 55-60 mph - 3000rpm, then quietens down at 70 - 3500rpm.

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