Articles on Completed Swaps

Uncle Douglas

Well-known member
Interesting. He kept his LT77 transmission.
And tiny clutch assembly, with small friction surface area, not ideal behind these engines. Wonder if this is the fellow that bolted a piece of plate steel to the cummins fly wheel to move the friction surface back and allow him to incorporate the rover pressure plate bolt pattern.
The second radiator behind the front skid plate due to insufficient cooling from the primary generic Summit sourced one means you can't off road the
truck as it will fill with mud/silt/dust and stop exchanging heat.

The radiator we had made drops engine temp 2 degree's per second that the fan ran. The ecu asks for cooling when it needs it via a switched ground for an electric fan. You can watch the coolant temp drop on the Murphy gauge.
In my opinion, if you have spent 9k on a brand new Cummins, your cooling system should be a topshelf solution, not a kludge.
 
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LR Max

Well-known member
Did a quick mpg conversion, which came out to 16~18 mpg (US miles and US Gallons). Either that seems low for a diesel or they were in the throttle the entire time. But it is a heavy truck with a giant brick on the roof (to extra brick the already brick front end) so there is that.
 

rocky

Well-known member
I'd be hoping for 23-26 mpg from the conversion. Is their result typical for this conversion?
 

Uncle Douglas

Well-known member
In a Jeep running 70-75 mph to trade shows the Cummins owned display truck consistently got high 20's.
Guessing this fellow did not switch to a 1.2 tcase since he kept the lt77 so he's turning 15% higher rpm than ideal.
Also keep in mind that the intercooler piping and exhaust system on a diesel plays a large role in how the engine breathes and that drives economy.

Since this guy did his own work, and judging by the rest of what we can see, I'm guessing he kludge'd it.
 
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MountainD

Well-known member
The cummins Disco was getting in the high teens, correct? It’d be interesting to hear real world mileage— I’m guessing 20 or below based on what I’ve heard so far, but I am interested as the 2.8 is on the table for my next build...but not at those levels. I’m hoping it’s considerably more...
 

LR Max

Well-known member
The Cummins test jeep was a late 90s TJ. So it has an AX-15 with a 0.79 over drive and a 1.1 transfer case. It could've had 3.07s or 4.10 gear ratios (depending if it was a 4 or 6 cyl initially).

But otherwise it was stock. Stock tire size and nothing else bolted onto it. Using the R2.8 gear calculator, with 3.07s, at 70 mph, it puts it near the top end on the "efficiency" range of the R2.8. So 3.07s make sense.

7555


Looking at that rig they built, here is what it looks like. Assuming retained pre-TDI LT77 and 1.4 Transfer case:

7556


So yeah, pulling an extra 1100 rpm to do the same as that TJ, and I'm sure its significantly heavier. Bump it up to 85 (pretty much the average speed needed to cross the country on any interstate without getting run over) then you are really pushing that engine at 3700 rpm. Of course it wouldn't be an old rover unless it was screaming along at 3,000 rpm.
 

defenderholty

Well-known member
Kind of hard to tell what's what with the article and its production. I don't spell all too well myself so I have something in common with the author. I saw another write-up on this vehicle and remember thinking that I would have done something different, though I can't remember what it was -might have been the lt77. End of ramble.. I am seriously considering one of these for mine but I really like the idea of no ECU on my 200.
 
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haru182

Member

I somehow managed to notice the interior on this truck and the fact that it was still rhd....but didn't notice it was a 2.8 swap when it was first listed. No mention of the trans/tc so I think it's safe to assume lt77 and 1.4.
 

Red90

Well-known member
It would be nice to see some unbiased reviews including things like accurate fuel consumption measurements. When people spent $20k+ on a swap, it is hard to remain unbiased.
 

Z.G

Well-known member

I somehow managed to notice the interior on this truck and the fact that it was still rhd....but didn't notice it was a 2.8 swap when it was first listed. No mention of the trans/tc so I think it's safe to assume lt77 and 1.4.
Haha! They offer a 12 year car loan to purchase it, yikes!
 

rocky

Well-known member
It would be nice to see some unbiased reviews including things like accurate fuel consumption measurements. When people spent $20k+ on a swap, it is hard to remain unbiased.
One things for sure. Its one of those things that if you do regret doing it after the fact, you won't admit it.
At some point the opportunity to drive a 90 with this conversion hopefully come my way. Certainly my fav 90 was powered by a 200tdi.
 
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