3.5 up tp 3.9 now slow as hell

where have I gone wrong?

Range rover 4 speed manual box, 3.5 engine blow up, came across a 3.9 engine at the right price, dropped it in, used same manifold and carb of the 3.5. it will now only go at 45mph at around 4-5000 rpm, sounds like it needs 5 speed box.

any suggestion appreciated

regards

wayne

Ps I also fitted a Astra GTE dash with my current tyres 235 85 16 the Speedo is 2-3 mph out based on the gps reading. water temp needed a 14ohm resister in series to calibrate, still need to calibrate oil and fuel levels, rpm works fine.

regards

Wayne

Hybrid V8 3.9 RR chassis and running gear Series 2 body ( canvas top) series 3 front full arc cage, bucket seats and as of today 12 mot.

Reply to
wayne
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Is this the same box that was attached to the original engine and if so, what speeds did it reach at similar revs? Logically, the only thing thats changed is the engine so unless you've accidentally stuck it in low, the speed/rev comparison will be the same.

Thinking about that rev counter - presuming it takes its reading from each spark pulse, isn't the fact that it came from a 4 cyl car going to have an effect on its accuracy, given that its now reading a 8 cyl engine?

Mike.

Reply to
Mike Buckley

It is the same box, and it did quite happily get upto 60 mph on the motorway, you are quite correct about the rev counter but I am mainly basing the high rmp from the sound of the engine.

regards

wayne

Reply to
wayne

Fuelling will also be wrong, losing a lot of power, if running with the 3.5 carbs and needles. If strombergs, you won't get suitable needles so fit SU's and replace the needles with, say, BAC's as a starting point. Badger

Reply to
Badger

I have a modified manifold with a weber 38DGAS fitted.

Reply to
wayne

On or around Thu, 28 Aug 2003 08:46:05 +0100, "wayne" enlightened us thusly:

it'll still be wrong for the 3.9, though...

Reply to
Austin Shackles

Found the problem! the diff lock was engaged. seems to have rusted up. note to self put light on dash from gearbox switch!!!

Reply to
wayne

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