'51 Build w/4bt Cummins

[kirsch11]

stinsonj, I put my truck on an S10 frame. My motor mounts landed exactly where the s10's did. Mine was a little high as well but had to cut the bottom of the cab to fit the transmission. I believe my driveshaft is 2.5" dia. I may have to cut the cab bottom a little more once I start towing with it. Here is the thread of my truck, https://67-72chevytrucks.com/vboard/...d.php?t=781360. I could post more pics of it if you want.

[stinsonj]

Can anyone describe how the cab mounts to the frame in the rear? I know there are shackles, for which i only have one for some reason, and I think there is some kind of rubber pad that goes between the frame and the cab itself, but I'm not sure. I currently have the cab mounted in the front with a kit I got online and the rear is sitting on the frame which puts the cab at a pretty good slope from front to back leading me to believe I'm missing something.

[kirsch11]

I believe there were two ways of mounting the cab in the rear. Some years had a single mount in the middle of the cab and some had mounts on the sides. Can't remember which years were which.

[nvrdone]

seems to me that the '47 & '48's had a single center mount. The '49's and newer had shackles from the frame rail to the cab.

[stinsonj]

Got the motor running last night fairly easily actually. Still need to build a battery box (going under the passenger floorboard) and wire everything up appropriately. Debating on what to do about cooling and think I’ve landed on trying the original radiator from the truck before doing a bunch of modifications to make a more modern radiator fit. Just not sure if the original will have enough cooling power or not
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[joedoh]

congrats on getting it running!

diesels have more efficiency than gas motors so cooling capacity usually requires less. I said usually because someone will be quick to correct me about specific applications like water to air intercooled turbo setups or two strokes or other things. your T in 4bt means you will have more cooling needed than a NA diesel, but still should be less. I cant say whether the stock rad will work though.

Originally Posted by nvrdone

seems to me that the '47 & '48's had a single center mount. The '49's and newer had shackles from the frame rail to the cab.

yes, although there are late 48s with the shackles, I have one. lots of late year changes in the first two years. if you have an in cab gas tank, you have shackles. if your gas tank is on the passenger frame with the filler in the bed, you have no shackles, its a center mount. your 51 will be shackles. no one repops shackles but they do repop the bushings, so you can rebuild them, i sold my extra shackles on ebay when I had some

[stinsonj]

Originally Posted by joedoh

congrats on getting it running!

diesels have more efficiency than gas motors so cooling capacity usually requires less. I said usually because someone will be quick to correct me about specific applications like water to air intercooled turbo setups or two strokes or other things. your T in 4bt means you will have more cooling needed than a NA diesel, but still should be less. I cant say whether the stock rad will work though.





yes, although there are late 48s with the shackles, I have one. lots of late year changes in the first two years. if you have an in cab gas tank, you have shackles. if your gas tank is on the passenger frame with the filler in the bed, you have no shackles, its a center mount. your 51 will be shackles. no one repops shackles but they do repop the bushings, so you can rebuild them, i sold my extra shackles on ebay when I had some

I really appreciate the info. I’ll have to start watching eBay for another shackle to make the pair.

Come to find out the stock radiator is full of holes (not much of a shocker) so I’ll probably just install a stock replacement that has a horsepower rating high enough to cover anything I would ever do to the 4BT. Ideally, I would like one that’s the same dimensions but has the inlet on the passenger side rather than in the center but I can make a center Inlet radiator work just fine.

Started installing the front fenders tonight. Wanted them in place before I started wiring so I have a better idea on how to route everything. Also didn’t mention before that the transmission is all installed. One of my big hurdles is installing a clutch and gas pedal. I already have the brake pedal installed via a power brake kit I bought awhile ago online, but don’t even know where to start with the other two pedals. May try and find something out of a mid 90’s Dodge Ram diesel to retrofit
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[lower50's]

Man I like what you are doing! The 4bt will be a great motor for the truck.
I don't have a 4bt but where my big diesel sits and how low I mounted my cab my driveshaft ended up above the floor boards so I have a huge trans tunnel.

[reg3]

Awesome build man! Loving all of the 4BT swaps that are happening right now. Mounting height looks great. I am in the same boat as you Lower50's, when i mounted by 4BT in my '48 I ended up having to cut a ton of the floor out to build a trans tunnel as well, rather do some extra cutting early on to get the engine/trans sitting higher than have to avoid speed bumps and potholes later on.

Keep the progress coming.

[stinsonj]

Been awhile since I've posted anything so here's an update:

Since this truck is my wife's, and I want it to be as safe as possible, I decided awhile back to have a local hot rod shop do some of the work on it that I wasn't comfortable doing. So, after waiting on a list for a few months, i was finally able to get it in to a shop.

-They ended up installing the steering linkage (I had issues with clearance around the starter)
-Install the entire brake system (swapped to hydroboost instead of the vacuum boost i originally had in it.
-Fabricate/Install gas and clutch pedal
-Build transmission hump
-Build and install driveshaft

They were able to do all of this over the course of about a month, which would have taken me 10x as long so all in all, I'm pretty happy with the work they did.

Since getting the truck back, we started working on wiring via a Painless Wiring harness. Been fairly simple so far and have since completed about 50% of the wiring, including getting the truck to start with a key for the first time.

I decided to go with a stock replacement fuel tank (behind the seat) just to limit fabrication, which was installed over the past few days. The cummins has a fuel return line so a bung needed to be added to the tank which i bought from Performance Online. Super easy install, took about 5 min. The fuel supply and return lines were both run and so far, no leaks which is nice.

Next on the list is to figure out how to hook up the throttle cable. It will take a bit of engineering to come up with a solution but nothing I can't handle. Once that is done, I will bleed the brakes and clutch then it will be time for its first, albeit short, test drive (radiator is not installed yet).

[dsraven]

um, no pics, didnt happen. haha.
nice when things come together, especially when it meand you can start it with a key. even better when you can make it drive and stop. gonna be a big day.

[dsraven]

good thinking with the hydroboost, no vac pump that way and hydroboost works so well.

[stinsonj]

Limited work being done on the truck due to just being busy with other stuff but I did get it driving! What I did to make the throttle work is a bit hokey but works surprisingly well. I essentially took a piece of 2" pipe that was pre-bent into 180 degrees, made a bracket, and routed the cable thru the pipe back towards the firewall and hooked it up to the throttle linkage. Not something I'm super proud of but it works for now.

I also bled the brakes and the new clutch slave cylinder I had to buy before taking it for its first, albeit short (no radiator yet) test drive which went swimmingly.

After the test drive, I worked on plumbing the turbo to the intake (not going to install an intercooler yet) and was able to find a pre-bent pipe that fit up ok. The bends were perfect but the ends were odd diameters so I had to use some reducers to mate it up to the 2.5" turbo and intake. An air filter was also installed which was much easier.

Next will be a radiator whenever I feel like dropping some more money into the project.

Ill post some pictures tomorrow likely.

[joedoh]

outstanding!

[stinsonj]

Here are some updated pictures as promised.

[lower50's]

looking good! keep plugging away.

[stinsonj]

Insane that it's been 10 years since we started this project.

We moved back to Oregon and have been working on the truck here intermittently. It now has all of the body work on and has been in its first parade this past July 4th! We trailered it to town for the parade but halfway there, my trailer got a flat. So I unloaded the truck and drove it, down a highway, about 5 miles to get to the parade. My wife followed since it isn't registered but it drove surprisingly well.

Don't mind the ugly wheels, there are just temporary until we get some smoothies on it.

[6DoF]

nothing as motivational as being forced to push it and doing better than expected!

plan to play with the motor at all? i have some good ideas

[stinsonj]

Ya, I haven't done much research but I would like to get the power up at some point. First step would be an intercooler I would think.

What are your ideas?

[6DoF]

lots of potential obviously, what's your plan for the truck? mostly hooning vs mostly family ice cream night are probably different builds. you've got the p-pump already too, so huge win there.

for sure an intercooler would be high on my list no matter the plans. and you really can't go too big.

did you do the nv4500 5th gear nut fix?

as spendy as they are, a Fluidampr is worth the money. after putting one on my daily, i immediately ordered one for the '55.

i buy basically all my cummins hot rod stuff from Power Driven Diesel. never the cheapest, but great service, they are always willing to talk thru your build ideas n needs, and the parts are always quality. plus they often have good sales if you can wait for em.

fuel delivery:
i'm a huge fan of the DIY hot rod mechanical lift pump. will support a lot of HP, that injection pump loves the higher PSI and available flow, etc also a dirty cheap upgrade and will outlast any electric. i ditched the screen for an inline 100micron filter from amazon. i also ditched all the banjo fittings for AN hoses.

https://www.youtube.com/watch?v=NtLskWH4ALQ
https://www.youtube.com/watch?v=KtXdks8i-eM

Injection pump:
- gov springs, get the 4k from PDD and never look back. the extra RPM before the pump defuels makes it 1000x more drivable.
- MAC rack plug ... not just more fuel available, but you are tuning over a larger throttle range
- AFC max travel kit with spring for what psi you are shooting for
- cut the AFC foot (instruction in the max travel kit from PDD)
- Delete the fuel plate

boost:
- boost elbow if sticking with single wastegate'd turbo ... spool is gooood
- the factory single turbo shouldn't be able to put out enough PSI before it makes more heat than boost for the engine to care ... probably like 30-35psi. i run 45 on all stock 6bt long block.

i don't see how re-torquing the head bolts a little higher hurts anything. i did mine until i can build a new engine to play stupid games with, but can't remember the number. but if you can spend the money, get studs. cheap insurance against accidentally doing stupid things. if i can get these rocker stands machined next week at work, i'd trade ya some machined ones for your stockers and then just machine those.

you can do all the pump and wastegate tuning with stock injectors and see if that's enough. all that is pretty cheap relative to the next steps ... $10 says you'll want more! hehe. PDD's powerjet injectors are as good as they claim and do run that much cleaner.

after that it's turbo's and head gasket upgrades, etc

[stinsonj]

Dang man, sounds like you have it figured out! I really appreciate all the info and guidance. The only reason it's not intercooled at the moment is because I just wanted to get it driving and plumbing in an intercooler seemed like a task I didn't want to tackle at the time. I need someone like you local to come over and give me some pointers in person!

I honestly don't know if there has been any work done on the transmission. I remember reading something about the 5th gear nut fix back when I was looking for transmissions but never got around to checking to see if it was completed or not.

[6DoF]

[6DoF]

also timing, lots of vids on re-timing a ppump. i'd run 19-20deg on even stock builds. some say you need special tools, but i 3d printed a template to mark degree increments on the balancer and use a harbor freight 2-bolt puller on the pump gear.

killer dowel pin fix? really easy to change the pump timing if already in there with the cover off.