4BT Thanksgiving! It RUNS!!

[JimmieD]

Giving much thanks here this day: the Town Wagon 4BT conversion is running!

Fired it up at about 1:00 p.m. today for the first time!!! It was tooth and nail right down to the finish line getting the fuel injection purged, primed and pumping. Made it to a friends for Thanksgiving day dinner by 2:00 p.m. I was running late, and wanted to see what it could do anyway but won't know for a while: the speedo head twisted off at about 95!

Runs very strong and the NV4500 is a dream compared to the notchy old NP435. I had to fab a clutch slave pushrod from a Grade 8 bolt and had no idea of correct dimensions so took my best guess. Came out Perfect!

New to diesels and the acceleration off idle is amazing with all that torque working for you. Very good bottom end and mid-range kicks in hard when the turbo spools up, revs strong to about 2,500. Top end is on the weak side but only compared to the bottom end power. I'm used to stepping down on the gas a little for the hills and mountains: ha ha don't have to bother with the diesel! This is going to be lots of fun.....

I have had 2 V8's in this same truck but with taller rear gears. Now with the Cummins and 4.1 rear I'd say it's stronger running than either of the gasser V8's. The last engine was a well built 360-3 with lots of trick parts but there's no comparison when it comes to raw torque at work.

2 things on the down side: NOISY AND LOTS OF VIBRATION! I haven't insulated anything so noise issues can be dealt with but the 4BT vibration will take some getting used to. Offhand I'd say I made a bad choice on engine isolators. I stuck in some old hard 440 rubber that I had laying around so at the least they need swapping for brand new. Anyways, it runs and drives and I'm giving thanks! Thanks to Gordon and all of you who contributed to the success of this project!

JimmieD

[Gordon Maney]

That is really neat. It will be interesting to see what you learn in the refinement of the noise and vibration.

Comparing apples to oranges, perhaps, but at the Iowa Rally I had the privilege of driving a 6BT conversion, WWII 6X6 based truck. It is fitted with a Power Wagon cab.

It is much quieter than my 2001 Cummins truck. Very impressive. He used a lot of sound deadening material in all parts of the cab, as I recall.

I suppose there may be inherent limitations in the 4-cylinder design with regard to vibration, but Bob's truck suggests to me that you could make enormous improvements.

If your engine is too rigidly connected to that big body shell, you have just created a gigantic speaker of sorts. Ignoring the mounts, simply lining the entire inside of the body, on all surfaces, with some of the new sound deadening materials would make a night and day difference.

A look at the mounts used in the delivery truck applications might yield useful information.

[JimmieD]

That is really neat. It will be interesting to see what you learn in the refinement of the noise and vibration.

Comparing apples to oranges, perhaps, but at the Iowa Rally I had the privilege of driving a 6BT conversion, WWII 6X6 based truck. It is fitted with a Power Wagon cab.

It is much quieter than my 2001 Cummins truck. Very impressive. He used a lot of sound deadening material in all parts of the cab, as I recall.

I suppose there may be inherent limitations in the 4-cylinder design with regard to vibration, but Bob's truck suggests to me that you could make enormous improvements.

If your engine is too rigidly connected to that big body shell, you have just created a gigantic speaker of sorts. Ignoring the mounts, simply lining the entire inside of the body, on all surfaces, with some of the new sound deadening materials would make a night and day difference.

A look at the mounts used in the delivery truck applications might yield useful information.

Hi Gordon! Yes, there is a problem with the basic design of the 4 cylinder Cummins in comparisons with the much smoother balance of 6BT. As suggested by Paul in NY, there is a possibility that my hard starting problem [air in injection pump etc.] may be contributing to the cyclic vibrations. Also circumstances: went low budget on the engine isolators, old, dried up 440BB parts. WRONG! Plus the fabricated crossmember uses hard LA360 isolators instead of the Cummins part. Further, the exhaust is clamped directly to that same crossmember, with no isolator of any kind. Still have much work to do....

Per your suggestion I may well redesign and fabricate new front motor mounts so I can use the Cummins 1100639 gel-rubber isolators, some beautiful pieces of work! BIG difference from solid rubber mounts.

In addition I changed the design of the truck body/chassis. It is now much more of a monocoque structure with new frames and braces welded in to reinforce the chassis/cab/floors areas. I used square tubing and heavy steel plate, like .020, for floors, welded or bolted to that new framing. That means that harmonics have a huge tuning fork assembly as you describe, plus not all of the metalwork is finished and tight. Will be throwig down some temporary rebond carpet padding and carpet for the short haul, then Dynomat and more serious insulative products as time permits.

I would say that these problems are peculiar to my truck and how I built it and that they can be fairly easily solved with a bit of re-engineering. I simply did not have time or even resources. The snow is coming tomorrow so I JUST made it! We'll be under several feet until next May!!

Gordon, I could not and would not have done this great and highly satisfying conversion without you, your website and the fine guys here! THANKS!!! Thanks everyone!

JimmieD

[MoparNorm]

Congrats! Bro!
There is deffinitely a need for the proper mounts, I must have missed the details of what you were using in your earlier notes...or I was brain dead (the more likely answer!) That vibration will not only make you irritable but it will slowly self destruct all of the bolted connections...by unbolting them... if you can swing it change them now, or if you think it will make the trip, do it in the tropical clime of Piute...= )
MN

[JimmieD]

I did some tidying up today per your and Gordon's advice! plugged a few holes and then found that I had gotten in too big a hurry and forgot to install cab mount bolts behind the seats: DUUuuuhhh! Loosened exhaust pipe and stuffed a piece of Zook Rupture Gasket [ha haha] into space where pipe bolts hard to crossmember to eiminate telegraphing of exhaust harmonics. These few things made a big difference.

But: with the truck idling outside it rattles stuff on the walls inside the house ha haha! We're on tufa and volcanic float so it's like a skin on a bongo drum.

Still have some starting problems but getting the bugs worked out. Yea, snow coming tomorrow big time so Baja sounds like a much better idea.... :~ )

[JimmieD]

Phase I complete!

Okay, I'll try to post a pic of the installed 4BT in the '67 Town Wagon. Not the sharpest stick in the bundle here, but I'll try. This is NOT the finished project, just a step in the journey. Sorry about the ugly patch panel on firewall...

[yosemitesamiam]

Okay, I'll try to post a pic of the installed 4BT in the '67 Town Wagon. Not the sharpest stick in the bundle here, but I'll try. This is NOT the finished project, just a step in the journey. Sorry about the ugly patch panel on firewall...

don't know how I missed this thread...awesome man!!! Glad to see it is running for you. That is one major accomplishment man!!!!

talk to you soon, and enjoy the snow!

[JimmieD]

Thanks, Sam! Snow is about a week away. Already got hit a few times but the big stuff is coming....

[yosemitesamiam]

Thanks, Sam! Snow is about a week away. Already got hit a few times but the big stuff is coming....

Yeah, we have had our share of snow here in Colorado for sure!!! Had a cold snap that lasted a week, sub zero weather at night, evening and morning...warmed all the way to 10 during the day. Crazy!!!

I want to get started on a project, but I'm really either going to have to wait until we have our own place (no way our neighbors would stand for a project in the yard, front yard small, back yard not fenced)...or get something that is running and throw some paint on it...

Well, enjoy that ride in the snow! It should be fun!!!!

Sam

[Jake]

Congrats Jimmie,
Nice job on the conversion, it must be a real triumph the first time it runs down the road under the powerfull sound of the diesel engine.
You deserve all the help you may have recieved from this forum becouse you are always quick to help everone else with thiere progects.
Cudos!!

[JimmieD]

Thanks, guys!

[Ugg013]

Yo Jimmie:

CONGRATS! So, you'll be here in Uggville by New Years Eve right? HA!

Later
Ugg

[JimmieD]

I can try, what year ya got in mind?

[Ugg013]

Last. Don't know if there'll be an Uggville anymore this one.

Later
Ugg

[p14175]

I haven't been to this site in a while so belated congrats on getting the 4BT operational!

I read your comments about noise and vibration. Yes, those are part of the charm of the Cummins 4BT.

For vibration, we had good luck with using the Dodge Cummins engine mounts and drilling a few holes in them. That will dampen the vibration considerably. And best of all, the Dodge engine mounts are really cheap.

Noise is another issue. We have been using QuietCar with success on our IH Scout 4BT and a 1st gen Dodge Cummins 4x4. I like it because it isn't flammable and can used inside or outside.