Swap 3.9 for 4.4.

My D1 is a 3.5 auto and the hiline is a 3.5 manual.

both of these when towing you slowly find your self going down and staying in low gears.at 80-110kmh.
then you look at the tacho and see and see 3000-4500 on this areas sweeping hills and forgetting to up shift.if it wasnt for the radiator fan you never up shift.

cant do that with the leyland..Ive owned P76 with 3.89 gear sets and they do buz along and 4000-5000[160KM/h] but for how long.
how many cranks ended there life in terrier trucks doing hyway runs.

Thanks for all the advice guys, I hadn't heard about the crank issues. Armed with that knowledge I can watch how I drive, I regularly check my tacho and find that with the 3.9 I'm usually under 4000 rpm. I don't drive the disco to be fast. The motivation behind the 4.4 is the added torque. At least Zi can keep the 3.9 and if the 4.4 has a meltdown, then I can always put the 3.9 back in.

Interesting thread and posts from everyone :D

For increasing power and torque, what about fitting a supercharger to the 3.5 and 3.9.

There are some good cheap blowers on eBay regularly and the Rover engine is already low-compression and ideally suited for conversion.

If I had the pennies I would have a go at doing my Disco. There is a kit available here CAPA Performance but they want $7000 for it!

Cheers Charlie

I considered going the supercharged route, but to me the kits are very expensive. Plus I need to do a lot of work to my existing engine just to stop all the leaks.
I only paid around $650 for the 4.4 shipped to my door.
I can have the 4.4 turned into a 6 litre for around $4000 by an engineering shop if I so desired, but would rather DIY it.
I can take my time, and have some pretty good backup advice on hand.
By the way, I'm still unable to find any other mention of breaking cranks in these motors. I'll keep looking though, there may be a fix for the issue.

Quote:

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Originally Posted by Disco95

By the way, I'm still unable to find any other mention of breaking cranks in these motors. I'll keep looking though, there may be a fix for the issue.

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It's all so long ago, P76's are now 38 years old. I broke a crank in 1990, a P76 rally car driven across the desert broke one that I personally know of. I used to sell a few cranks to the engine reconditioner who supplied the SA Education Dept with rebuilt engines for the Terrier (P76) engined buses here, due to crack testing rejects. I remember the local Terrier engined school bus being driven in Lobethal SA, it hit peak RPM in every gear or it hardly went. (I drove one of these buses once and they are terrifyingly gutless.)

Have your crank thorougly crack tested and balanced, treat it kindly and you'll be fine.