1969 240 Mk 2. Can I marry up my BW35 1969 240 box to a 1968 340 engine I have just bought, both 7J engines?
Many thanks in advance for any info.

 

From my experience the engines should be identical where the gearbox fits.

 

Thank you for that Homersimpson, now next is does anybody know what the difference inside the BW35 gearboxes are between those fitted to the 240 and 340 Mk2’s and what this might mean in the real world when driving, I’m guessing there are differences in ratios and or hydraulic selectors but don’t know nor what it means in driving. I have also bought the rear axle so have the correct differential for this engine.
Once again thanks in advance. Jim

 

There are no variations in the box, the variation is in the diff gears. Your box will just bolt up to the 340 engine, and uses the same linkage for drive selection. It was the same for the manual change boxes, one box for all engine sizes. The downside for those with the 2.4 litre engine was that the box, (auto or manual), was not optimised for the 2.4 litre power and torque bands, because the majority of sales were 3.4/3.8 litre cars. However, people buying 2.4s weren't usually interested in outright performance.

 

Thank you Fraser that has put my mind at rest, as they say a little knowledge is a dangerous thing, I can now proceed with more confidence. If anybody has any tips or knowledge of swapping these two engines that might make my life easier please feel free to comment. I have enjoyed my first endeavour into this web site forum thanks to all for allowing and helping on my first post. 🤗

 

If the 240 was fitted with an over drive and your 340 wasn't, or vise versa, then you would have to use that axle that was meant for said transmission, AFAIK.
The 240's and 340's were not normally fitted with an over drive unless requested.

 

Hi Jeff
Thank you the ratio of the differential I have got is 3.77 and came off the 340 manual with O/D that I got the engine from hopefully it will be ok, I’m sure it will be better than the diff off my 240 which was a much lower ratio. I started another thread regarding the speedometer as I was wondering if I need to do something with that also.

 

a automatic 340 used a 3.54 diff.
Even then it will rev a lot, as the autobox has no overdrive.

regards,
Peter Jan