Cummins Diesel swaps.....Who has done them. Looking for advice.

[Chevy3+3]

I have been through the build threads and no one seems to ever finish a project or are they are still in progress. I have some simple questions I hope some of you can answer. Someday I would love to do a Cummins swap but don't want to jump in not being prepared or educated.

My truck: 88' Chevy V30 4x4 CC Dually

Current drivetrain: 454, TH400, NP205

My questions:

1. What is the difference in the 1st & 2nd Gen 12 valve Cummins engines?

2. Which would be a better choice?

3. Which manual transmission would be the easiest to swap in. I would love a Manual tranny but would think a little more work would be required (clutch pedal, clutch master cylinder, etc.).

4. If I were to use an auto tranny what would be my best option with simplicity and dependability in mind.

5. Are body lifts usually required for firewall or tranny clearance (depending on tranny)?

6. Can I utilize my factory radiator support and radiator? Or are mods definatley necessary in this area?

7. Are there any prefab or factory built mounts or crossmembers for these types of conversions?

Thanks to any and info. I just hate going into a project like this halfa## because corners usually tend to get cut at that point. If I decide to tackle this project I want it to fit well and be dependable.

[JustTom]

Cut and paste your entire post here-

http://www.4btswaps.com/forum/forumd....9-Conversions

More info there on that subject than any where else.

Some say it's easier to put a Square body on a Power Wagon frame than swap everything.

Tom

[andrewmp6]

For a crossmember http://tndieselpower.com/ has one but his site is acting funny.The other company is http://www.autoworldmt.com/Page_11.html on the trans you could use a gm one like a turbo 400 or 4l80e with a adapter or use a dodge trans.If you want some builds to look at http://67-72chevytrucks.com/vboard/f...play.php?f=240

[84chevyguyid]

I am in the middle of an 86 crew cab cummins swap. I am working on it as time and money permits and after a year and a half I have the chassis ready to set the cab on for the last time, probably be finished next winter. Big differences between first and second gen 12 valves are injection pumps and intercooled or not. Motor mounts are different on them also. People seem to like the "P" pumped motors more as far as turning up the power. I used a motor from a bus and have had to scrounge up a lot of little pieces so my advise would get a running truck to use for the swap, that way you end up with all the things, trans included, that will make the swap easier. You can sell off whats left over and recoup some funds. I wanted an automatic and was initially thinking of running a 4l80e but ended up with an 06 allison 6 speed instead. More money but I think it will be lots better in the end. I massaged the firewall with a bfh to get a little better clearance on the back of the motor. I wanted the motor back as far as possible to give me more room to run the stock fan on the front. My crew started out as a 2 wheel drive and had the short trans hump and I cut it out and found a bolt in 4x4 hump and got the trans to fit without a body lift. I am lifting the truck a few inches to give me more clearance between the oil pan to front diff. I also want to run 33 to 34 inch tall tires too. There is lots of good reading on the subject on the 4bt web site. There is also some great posts in the diesel conversion section on here. You can buy mounts and that saves lots of time. I chose to build my own so I could accommodate the truck air compressor setup that came with the bus motor. I am running air bags front and rear and want a reliable onboard air system to go with the auto ride height valves and want to be able to blow up tires on the bikes, 4 wheelers, ect. My goal is having a nice daily driver/tow vehicle that can knock out 20 mpg and have 800 ft lbs of torque, with a nice ride. Here is a pic of the beast in the beginning

Mike

[84chevyguyid]

Here's why it fits in with the rest of the fleet

[Chevy3+3]

Lol. Yes it does fit. I will try and get a pic or 2 of my truck in a little while.

[Edahall]

Originally Posted by Chevy3+3

1. What is the difference in the 1st & 2nd Gen 12 valve Cummins engines?

1st Gen 12 valve - same block but VE pump which maxes out at about 400 hp. They're also quieter.

2nd Gen 12 valve - P-pump which can support up to around 1200 hp. Expect to pay $1000 extra for this engine.

Originally Posted by Chevy3+3

2. Which would be a better choice?

Both are good choices. If you want to go over 400 hp for winning races or making high dyno numbers, you obviously would want to choose the 2nd Gen 12 valve. If you want low rpm pulling power, there is little differece between the 2 engines.

Originally Posted by Chevy3+3

3. Which manual transmission would be the easiest to swap in. I would love a Manual tranny but would think a little more work would be required (clutch pedal, clutch master cylinder, etc.).

Easiest manual transmission to swap would be one of the manual transmissions offered in the Dodge truck such as the Getrag, NV4500, NV5600 or G56. The manual transmission is very much worth the effort if you know how to shift. They're much better at putting the power down to the ground than an automatic. They also tend to be more reliable especially with a Cummins.

Originally Posted by Chevy3+3

4. If I were to use an auto tranny what would be my best option with simplicity and dependability in mind.

Unfortunately, automatic transmissions and dependability especially behind a Cummins don't go together. These engines eat automatic transmissions because of the power they create at low rpm's.

Originally Posted by Chevy3+3

5. Are body lifts usually required for firewall or tranny clearance (depending on tranny)?

No, not even on the NV5600. The NV5600 is a tight fit in my Suburban but it did fit in there without any body lifts.

Originally Posted by Chevy3+3

6. Can I utilize my factory radiator support and radiator? Or are mods definitely necessary in this area?

Yes, as long as you have a 4 core or 3 core radiator which I know were used on Chevy diesel pickups.

Originally Posted by Chevy3+3

7. Are there any prefab or factory built mounts or crossmembers for these types of conversions?

Yes, or you can make your own. You can also use the engine mounts from the Dodge truck.

That said, I encourage you to do the swap. I'm very happy with the swap on my Suburban and I use it at my daily driver because of this. With the gas engine, 14 mpg was typical but with the Cummins 26 mpg is more typical.

[Chevy3+3]

Thanks! If & when I do the swap I will most likely use a manual tranny. Do you know what the main differences are between the trannys you mentioned? I prefer to use my transfer case to keep the passenger side drop on driveshaft.

Originally Posted by Edahall

1st Gen 12 valve - same block but VE pump which maxes out at about 400 hp. They're also quieter.

2nd Gen 12 valve - P-pump which can support up to around 1200 hp. Expect to pay $1000 extra for this engine.



Both are good choices. If you want to go over 400 hp for winning races or making high dyno numbers, you obviously would want to choose the 2nd Gen 12 valve. If you want low rpm pulling power, there is little differece between the 2 engines.



Easiest manual transmission to swap would be one of the manual transmissions offered in the Dodge truck such as the Getrag, NV4500, NV5600 or G56. The manual transmission is very much worth the effort if you know how to shift. They're much better at putting the power down to the ground than an automatic. They also tend to be more reliable especially with a Cummins.



Unfortunately, automatic transmissions and dependability especially behind a Cummins don't go together. These engines eat automatic transmissions because of the power they create at low rpm's.



No, not even on the NV5600. The NV5600 is a tight fit in my Suburban but it did fit in there without any body lifts.



Yes, as long as you have a 4 core or 3 core radiator which I know were used on Chevy diesel pickups.



Yes, or you can make your own. You can also use the engine mounts from the Dodge truck.

That said, I encourage you to do the swap. I'm very happy with the swap on my Suburban and I use it at my daily driver because of this. With the gas engine, 14 mpg was typical but with the Cummins 26 mpg is more typical.

[Edahall]

Originally Posted by Chevy3+3

Thanks! If & when I do the swap I will most likely use a manual tranny. Do you know what the main differences are between the trannys you mentioned? I prefer to use my transfer case to keep the passenger side drop on driveshaft.

Getrag - 5 speed, sensitive to oil levels
NV4500 - 5 speed, 5th gear is weak, needs expensive oil or synchros can be damaged.
NV5600 - 6 speed, cast iron case, hard to find parts, heavy
G56 - 6 speed

I believe you can use your transfer case on all of these transmissions. My preference would be the NV5600 or G56. Having that extra gear is very nice.

[Ford Assassin]

Digging up an old thread....

Originally Posted by Edahall

The NV5600 is a tight fit in my Suburban but it did fit in there without any body lifts.

What clutch master cylinder did you use? Doing a Cummins/NV4500 swap.

Thanks!!

[v30crewcab]

I use a stock dodge master and slave, with an adapter to use it on the 85-up hydro pedals. you can also use the older manual pedals, and get a clutch bracket out of a 89-93 dodge truck and bolt it to the side of the chevy manual pedal setup.

[Ford Assassin]

Originally Posted by v30crewcab

I use a stock dodge master and slave, with an adapter to use it on the 85-up hydro pedals. you can also use the older manual pedals, and get a clutch bracket out of a 89-93 dodge truck and bolt it to the side of the chevy manual pedal setup.

I have the 85+ hydro pedal setup already. Where did you get the adapter?

[v30crewcab]

I machined the adapter myself. an easier way is to use a 90's ford master cylinder, with a wedge spacer. had that on my truck for awhile.

[Ford Assassin]

Originally Posted by v30crewcab

I machined the adapter myself. an easier way is to use a 90's ford master cylinder, with a wedge spacer. had that on my truck for awhile.

Still got the wedge adapter? Wanna sell it?

[v30crewcab]

I think I might. I'll have to look in the shop tomorrow.

[Ford Assassin]

Originally Posted by v30crewcab

I think I might. I'll have to look in the shop tomorrow.

Cool. I really appreciate it.

I read elsewhere about using a 94 Ford F350 clutch master cylinder, so I ordered one at O'Reilly's and will be here tomorrow.

[Ford Assassin]

The 94 Ford....the bolt holes are at 12 and 6....

[Ford Assassin]

I ended up using a stock GM clutch master cylinder and a slave from a NV5600 (smaller diameter piston vs the NV4500). Works great on my NV4500 with a South Bend 425HP kit for over 2 years now.