Cummins + Allison - Value Added?

b. rock · 09-13-2019, 09:59 AM

Test drove a van a couple nights ago that had a 6.7 cummins + allison swap. I have a decent handle on what the rest of the van is worth, but what I'm trying to wrap my brain around is how to value the drivetrain. It was done by a shop that specializes in doing these conversions for trucks, and they did a pretty solid job. Everything on the dash works, the wiring is pretty clean, and all the metal work (mount/exhuast/etc) is clean. The biggest piece missing is the a/c and was about to check for the compressor when it started downpouring/hailing. EGR and DPF are deleted, turbo replaced with a fixed vane borg warner, so the usual suspects for the 6.7 have already been fixed. I will say that the engine fit in there surprisingly well, looked like there was access to most everything without too much grief.

Thoughts on how much that would add to a van? Sometimes engine swaps really don't get you any value over a stock vehicle in similar condition, sometimes it adds a fair amount. Can't get a pulse on which one this is so any input would be appreciated. Thanks

carringb · 09-13-2019, 10:16 AM

Cummins swaps always command a premium, no matter what they are installed in. If you want a diesel E-series, this is the way to go IMO.

I would however take the emissions delete into consideration with the price. This means it could never be registered in CA, and other states are likely to implement testing in the future, since the small number of owners deleting their rigs are responsible for such a disproportionate share of noxious emissions. And keep in mind that some cities in CO already do require diesel emissions testing.

They probably used the Dodge A/C compressor, which is garbage. But even if they didn't bother, I wouldn't consider missing A/C a show-stopper. There's good electric compressor options, just need enough alternator capacity to power it, but then you can have engine-off A/C for a short time, depending on your battery bank. I would however factor that into the price as well.

**BroncoHauler** · 09-13-2019, 10:19 AM

A lot of it depends on your ability, or someone else's ability, to actually perform work on the van and keep it running. I've had a number of highly mo0dified vehicles, and it does reduce the number of competent mechanics who can address issues.

I think there are a lot of positives to the conversion you're looking at, but there are some downsides as well. As far as a financial value, I'm not really sure there is an upside IMO.

Herb

b. rock · 09-13-2019, 02:44 PM

Yes - I'm aware of the impacts for resale as far as emissions go. I'm guessing it would be next to impossible to add the DPF system back in, especially not in a vehicle not originally designed for it. I personally don't care because my county doesn't have emissions, but the majority of the front range does.

I've had swapped vehicles before. Some done well, some not so much. This one is done fairly well. I'm of the newer generation of people that work on cars so I like having a modern ecu to plug into. However you have a valid point on the # of mechanics that would touch it. Even going to the parts store would be a treat - engine from a Ram, transmission from a GM3500, front axle from a F350, rear axle from an E350.

It drives quite nicely and that torque is just unreal. I'm thinking 15-20 mpgs on the highway are certainly reasonable based on what the truck guys get, which is somewhere around 50-100% better than the V10 is currently getting. It's a bit quieter and smoother than some of the Ford V8 diesel's I've been around as well.

SMB123 · 09-13-2019, 04:23 PM

Value - I'd value it at the same year Powerstroke; maybe a bit higher for the fabled 6.0 years. They have an outstanding combination that probably cost way more in both time and money than they will ever get back. They may still be on the "crown jewels" phase of what they have and not be willing to part for less than all in cost. Also, how many miles on the chassis and engine/trans?

carringb · 09-13-2019, 08:07 PM

Quote:

Originally Posted by b. rock

It drives quite nicely and that torque is just unreal. I'm thinking 15-20 mpgs on the highway are certainly reasonable based on what the truck guys get, which is somewhere around 50-100% better than the V10 is currently getting.

You won't get 20 without hyper-miling. Diesel truck forums have this uncanny ability to turn fuel economy into another d--- measuring contest, and somehow everybody's downhill with a tailwind best case magically turns into their average.

25% better than a V10, everything being equal, is far more realistic.

If you're trying to justify this rig on potential fuel savings, it isn't going to happen. If you want torque at low RPMs, without the potential nightmare of owning a 6.0, then this is good rig to consider.

IMO, doing a full "bulletproofing" runs 8-10k, and I'd happily pay at least that much to drive a Cummins conversion instead. Probably more. But not without a very thorough checkup on the entire conversion. And I'd want to see the history of the donor motor as well.

One more thing to consider... The 6.7L will exceed the torque ratings of the Allison 1000 unless torque management is used. So good tuning is essential to keep things intact.

mgmetalworks · 09-13-2019, 08:50 PM

Quote:

Originally Posted by carringb

Diesel truck forums have this uncanny ability to turn fuel economy into another d--- measuring contest, and somehow everybody's downhill with a tailwind best case magically turns into their average.

Van forums too!

Quote:

Originally Posted by carringb

If you're trying to justify this rig on potential fuel savings, it isn't going to happen.

Exactly right!

Quote:

Originally Posted by carringb

One more thing to consider... The 6.7L will exceed the torque ratings of the Allison 1000 unless torque management is used. So good tuning is essential to keep things intact.

Also consider that pretty much everything about the Allison is more expensive than other transmissions. An "oops" moment of layin' into it a little too hard can ruin several paychecks.

In all of my experience getting my Cummins/Allison swap finished in the van, I've learned that there is a lot of misinformation out there when it comes to tuning this combination. Your buddy's cousin's neighbor who changed shift timing once in his Duramax with EFI Live is not going to understand how to tune the 6.7L and Allison trans correctly. Don't let anyone touch anything in the calibrations unless you know that they have the knowledge and proven experience.

Aside from that, if it's a clean swap and it runs/drives well... I'd have no reservations about it. I love the Cummins/Allison combo. Drives better than any diesel van I've been in.

b. rock · 09-16-2019, 11:18 AM

Thanks folks. I did start my van hunt with a diesel initially in mind, but the 6.0 and 7.3 eventually got nixed for different reasons. Think I'm going to try and bring this thing home. Bringing it back by the shop that did the conversion to confirm a few things including tune, intake air heaters, and a couple other small things.

On that note...anyone want a 60k mile '05 EB XLT V10 from SoCal with a camburg lift and bumper? I'll get a FS ad going shortly.