1998 defender Cummins swap

Breathless5.9 · Dec 13, 2021

300bhp/ton said:
Just checked some figures and a Cummins site says a dry but dressed 5.9 is 1100lbs (almost 500kg). A wet Td5 with flywheel & clutch is 244kg. Which is a pretty big difference.

I'm not knocking the engines, but if you can't notice 250kg+ over the front axle, there is something wrong with your driving.

Also worth noting that this will also reduce your maximum payload by at least 250kg, but possibly more as I'm guessing the gearbox weighs more and maybe other changes you've made to the vehicle. Not sure what spec 90 you have, A fully optioned Station Wagon comes in at 1976kg kerb with a GVW of 2505kg, i.e. 529kg payload. With the Cummins engine you are at best down to only 279kg carrying capacity, but possible even under 200kg depending on how much the other stuff weighs. The reality of this means, depending on spec of your vehicle. If you had 2 average sized adults (driver & passenger). Then you might legally be down to about 35kg carry ability in your 90. And you'd be illegal and overweight if you had 3 or 4 people (inc driver) on board.

If you vehicle is a no option 90 pickup, then there is capacity for 200kg extra hauling ability over a fully optioned CSW.

Oh well, guess I can't drive then. Salisbury front axle adds to your weight limit or the big Dana's that are sometimes fitted. You stick to what works for you and I will for me huh Carrying capacity in the vehicle isof no concern to me.

Breathless5.9 · Dec 13, 2021

Turboman said:
That's why they have low box.

Then you're limited to top speed until you stop again to change range

Turboman · Dec 13, 2021

Breathless5.9 said:
Then you're limited to top speed until you stop again to change range

No you aren't. You can change low to high on the move.

Breathless5.9 · Dec 13, 2021

Turboman said:
No you aren't. You can change low to high on the move.

Clunk! Shudder shudder..,. But as we already discovered I can't drive.... Look all I'm saying is if you want to tow, heavy and often, you aren't worried about load capacity in your vehicle only what's behind it then a lorry engine is a good option for making things easier, quieter and more fuel efficient... Yes the Cummins does more MPG than the TDI.

Turboman · Dec 13, 2021

Breathless5.9 said:
Clunk! Shudder shudder..,. But as we already discovered I can't drive.... Look all I'm saying is if you want to tow, heavy and often, you aren't worried about load capacity in your vehicle only what's behind it then a lorry engine is a good option for making things easier, quieter and more fuel efficient... Yes the Cummins does more MPG than the TDI.

Oh dear, looks like you can't drive, then!

Double de-clutch transfer box, 3 low into 2 high, it usually isn't a problem, or just slow right down, and go slow and gentle into 2 high.

I don't have a problem with your conversion. If you like it, that is good.

For me, it would be a lot of hassle and expense to tow a trailer, though. Probably cheaper to get a lorry.

300bhp/ton · Dec 13, 2021

Breathless5.9 said:
Oh well, guess I can't drive then. Salisbury front axle adds to your weight limit or the big Dana's that are sometimes fitted. You stick to what works for you and I will for me huh Carrying capacity in the vehicle isof no concern to me.

You have a Salisbury front axle? This will add to the kerb weight, but it won't increase your Gross Vehicle Weight, it would need re-type approving for that. And Land Rover never sold the 90 with a front Salisbury, so you are probably close to needing an IVA and being on a Q plate also.

The risk is all yours, it isn't about what I like or dislike. But you'd probably want to make sure your vehicle is actually road legal and that you wouldn't have your insurance refused should you be in a road traffic accident.

Breathless5.9 · Dec 13, 2021

300bhp/ton said:
You have a Salisbury front axle? This will add to the kerb weight, but it won't increase your Gross Vehicle Weight, it would need re-type approving for that. And Land Rover never sold the 90 with a front Salisbury, so you are probably close to needing an IVA and being on a Q plate also.

The risk is all yours, it isn't about what I like or dislike. But you'd probably want to make sure your vehicle is actually road legal and that you wouldn't have your insurance refused should you be in a road traffic accident.

I didn't say mine has a Salisbury front... I don't need it as I'm not over weight. The 130 front rover axle was higher rated as well even though it's exactly the same axle so it would be only a paperwork exercise to uprate the axle limit to this weight as no design change has occured. We often put extra axles under 3500kg vans and plate them at 5000kg. DVSA MOT man has a look to make sure she's good and we get the green light. It's not ground breaking stuff that requires a Q plate at all.

I think you under estimate how much of the extra weight is carried by the rear of the vehicle. My rear prop is around 500mm long.

With the extra pressure available for the pas box, the clutch being air assisted and the front on hd springs it genuinely feels 'lighter' to drive than the old TDI and is perfectly within legalities.

Breathless5.9 · Dec 13, 2021

Turboman said:
Oh dear, looks like you can't drive, then!

Double de-clutch transfer box, 3 low into 2 high, it usually isn't a problem, or just slow right down, and go slow and gentle into 2 high.

I don't have a problem with your conversion. If you like it, that is good.

For me, it would be a lot of hassle and expense to tow a trailer, though. Probably cheaper to get a lorry.

Yes that sounds much easier than with the Cummins, double declutch and do 10 movements for each gear whilst constantly trying to not loose the very little momentum you've gained through the last tiny ratio or get too far off the boost or you're going to have to drop back down again .. and then at the next bend/hill do it all again.
Why would I want a lorry? I don't like lorries and it can't get across my fields!
Hassle? It's been a hobby project, restoration with a twist. Expense? The lorry I got engine out of paid for itself from all the other parts I sold off it so the engine and gearbox were free. The transfer box gears were the only real expense you wouldn't have restoring a standard Defender.

300bhp/ton · Dec 13, 2021

Breathless5.9 said:
I didn't say mine has a Salisbury front... I don't need it as I'm not over weight. The 130 front rover axle was higher rated as well even though it's exactly the same axle so it would be only a paperwork exercise to uprate the axle limit to this weight as no design change has occured. We often put extra axles under 3500kg vans and plate them at 5000kg. DVSA MOT man has a look to make sure she's good and we get the green light. It's not ground breaking stuff that requires a Q plate at all.

I think you under estimate how much of the extra weight is carried by the rear of the vehicle. My rear prop is around 500mm long.

With the extra pressure available for the pas box, the clutch being air assisted and the front on hd springs it genuinely feels 'lighter' to drive than the old TDI and is perfectly within legalities.

It's all a bit vague, the radically altered vehicle regs: https://www.gov.uk/vehicle-registration/radically-altered-vehicles
And largely self cert, but it doesn't mean they couldn't come after you.

Breathless5.9 · Dec 13, 2021

300bhp/ton said:
It's all a bit vague, the radically altered vehicle regs: https://www.gov.uk/vehicle-registration/radically-altered-vehicles
And largely self cert, but it doesn't mean they couldn't come after you.

View attachment 254530

I'm on 9... nothing to pursue...

1998 defender Cummins swap

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