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My '76 4BT 620


zerickk

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Hey, I just joined Ratsun today to start a build thread of this 1976 620 I bought a few months ago (Oct '11). I picked it up in Brooks off Kijiji for $250. The engine and transmission were already removed. It came with a bunch of extras including an extra transmission, rear end and cowl,

 

My plan is to clean it up and paint it satin black with gloss black lettering on the tailgate and gloss black wheels. I took a while to decide on what engine I wanted to use until a friend suggested a Cummins 4BT. I'm pretty sure nobody has ever done this swap before, but if anyone has any info on one that has, i'd love to see it!

 

So here is what the truck looked like the day I picked it up..

sFvEE.jpg

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First thing I did was strip off the doors and fenders to get a look at the rust

 

kmOVD.jpg

 

The doors are pretty good with the exception of the bottoms of the skins

 

orRwc.jpg

 

The fenders look okay in this pic, but they have loads of bondo over rust

 

zuHVO.jpg

 

 

The truck has obviously been repainted by someone which was helpful in saving me time in areas such as rust repair

 

Rust free new floor

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Here are some pics of the extras i have

 

Transmission

f9ddo.jpg

 

Rear end, another transmission, block, head

1cTwe.jpg

egJpD.jpg

 

Since I have this in my garage in the city and not on my farm, I decided to start on the body over the winter. Then I can look into the engine in the spring. I`ll have to get some size measurements and think about mounting, weight on suspension, etc.

 

Sanding...finding bondo

HmyPb.jpg

 

De-hooked, hammered out tons of small dents, light bondo for the rest

d1AKM.jpg

 

Looking good with some primer. Still need to do the bottom of the box

M39NY.jpg

 

Passenger side

nv5zE.jpg

 

Sanded down and de-hooked

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Driver`s side still needing work

QFvoi.jpg

 

Shot of the interior. The dash is in decent shape.

eSpeU.jpg

 

Awaiting an engine

XngIn.jpg

 

My small mess of a workspace

fGNaM.jpg

 

I`m currently doing more body work on the passenger side of the box. I`ll post pics as it progresses.

 

If anyone knows of a place I can get some new front fenders, or some originals in good condition that would be great!

 

Check out my youtube channel!

http://www.youtube.com/milomoviemakers

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Have done any mesureing on the 4BT and the 620 engine compartment?? Those motors are extremely large, and very tall too. I worked with the install of one in a FJ60 Landcruiser. Took a stock six cylinder out of it and the 4BT was a snug fit. Then the truck had to have several inches of suspension lift to get the front differential away from the oil pan. Extremely tall motors. And extremely noisy to drive too.

 

Good Luck, take lots of pics.

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Have done any mesureing on the 4BT and the 620 engine compartment?? Those motors are extremely large, and very tall too. I worked with the install of one in a FJ60 Landcruiser. Took a stock six cylinder out of it and the 4BT was a snug fit. Then the truck had to have several inches of suspension lift to get the front differential away from the oil pan. Extremely tall motors. And extremely noisy to drive too.

 

Good Luck, take lots of pics.

 

I haven`t looked too far into the engine swap yet, but i know it`s going to most likely need a load of firewall, hood and mounting work. I`m also worried about the weight of them.

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would you be willing to take a measurement of the total height of that RR tire? That is an original spare, Curious to its actual height?

 

Weight of the 4BT should be of major concern also. Those are an iron block/head. And along with that motor, a very large radiator is needed to cool them.

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Engine Name: Cummins B3.9L/4BT

 

Applications: Chevrolet Step Vans, Commercial applications

 

Configuration: Inline 4-cylinder diesel

 

Displacement:3.9L, 239 cubic inches

 

Bore: 4.02 inches

 

Stroke: 4.72 inches

 

Compression Ratio: 17.5:1

 

Aspiration: Turbocharged, non-intercooled

 

Engine Weight: 745 - 782 lbs

 

Oil Capacity: 10 quarts

 

Horsepower: 105 hp @ 2,300 RPM *

 

Torque: 265 lb-ft @ 1,600 RPM *

 

GVWR: 16,000 lbs

 

Take note of that engine weight, then figure at least another 200#'s of retrofit. reinforcement, and massive radiator addons~

Then there's how long the front end will hold up~ figuratively and literally.... Just sayin~

Not tryin to be a doubting Thomas here~ just want to make sure you approach this with both eyes open. If you can make it work, I've heard of diesel tuners that can coax double the torque out of the 4BT with little more than pump massaging and turbo tweaking.....

Let the pics begin~!

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It looks like these fellas have you on the right track. I looked in to this til I realized how much I'd have to do to the front suspension and how overly light it'd be over the back. The 4bt is just shy of 500 lbs heavier then the stock l20b. Plus as mentioned is way taller, wider, and longer then the l20b. Not saying it couldn't be done but it would take a TON of work and I dont figure it would end up being worth your time and effort.

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It looks like these fellas have you on the right track. I looked in to this til I realized how much I'd have to do to the front suspension and how overly light it'd be over the back. The 4bt is just shy of 500 lbs heavier then the stock l20b. Plus as mentioned is way taller, wider, and longer then the l20b. Not saying it couldn't be done but it would take a TON of work and I dont figure it would end up being worth your time and effort.

 

All that for 105 horsepower? Seems like a better idea would be a hot L20b. If you really want a diesel,isn't there a smaller one available? Something from a VW or Mercedes? Good luck!

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Yes in the 70s, 80s, and 90s there have been many smaller four cylinder diesels used by datsun, mazda, ford, chevy, dodge, mitsubishi, toyota, isuzu, bmw, and vw. The real trick is finding one. They were pretty uncommon back then and even more so now. I haven't yet looked at the mercedes diesel for measurements, but those exist too. if you want something more modern you could also look in to the diesel out of a mahindra tractor or something similar to that. Make sure you do some research on the longevity and reliability of which ever you choose to use. Most of them seem to be hard to find parts for. The ford one I believe I remember reading was bad about busting head gaskets. ....i also know mitsubishi,

Isuzu, bmw, vw, and a couple others still make a 4 cyc diesel for some cars and delivery trucks.

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Guest kamakazi620

All that for 105 horsepower? Seems like a better idea would be a hot L20b. If you really want a diesel,isn't there a smaller one available? Something from a VW or Mercedes? Good luck!

And 265 ft lbs of TORQUE!!!!!!!!! Be lucky to get 100-120 ft lbs out of a l20b

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would you be willing to take a measurement of the total height of that RR tire? That is an original spare, Curious to its actual height?

 

Weight of the 4BT should be of major concern also. Those are an iron block/head. And along with that motor, a very large radiator is needed to cool them.

 

Total height is 25.5 inches

tARzw.jpg

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Okay, so I decided to look into how the 4BT will fit after all the replies I received.

6jinQ.jpg

 

I went ahead and measured, and the engine is definitely taller than I had imagined (or the truck is shorter). I was thinking maybe 6 inches out the top of the hood, but here are some pics showing the height from the crossmember.

 

Lenght, 30.6 from the firewall to my finger.... could be done with extensive firewall mods

HDd1Y.jpg

 

Width, 24.6 inches to my finger. Not too bad

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Height, 37.7 inches is about the height of this straight edge....

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So, it looks like the 4BT is out of the question, as It would require lifting the truck to be reasonable, and I want to have a stock/mildly lowered stance.

 

Anyone know of any diesels that have decent aftermarket performance parts availability?

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Alright guys, I've been browsing around engine swaps a bunch now and I think I found a replacement I like. It's nothing new as it's been done a few times, but it looks pretty simple and would keep the weight down and increase performance. I'm thinking an SR20DET. Commonly available,good parts availability, good power, really not much bad I can think of.

 

What do you guys think?

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I think that is a much better option for you and will have a better after market parts selection. Its light weight and will easily fit the engine bay with little modification.

 

I told you i'd done the research and the 4bt was all around too big and too heavy. Now we have pics to prove it as I didnt take pics when I did my measurements.

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I think that is a much better option for you and will have a better after market parts selection. Itd light weight and will easily fit the engine bay with little modification.

 

I told you i'd done the research and the 4bt was all around too big and too heavy. Now we have pics to prove it as I didnt take pics when I did my measurements.

 

Thanks for the input! I think even if it did fit, the SR20 will be more fun due to the power differences and better handling with loads less weight.

 

It would be pretty awesome to see done with the engine sticking out that far though lol

 

Ps. Is there a way to change the thread name now?

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Guest kamakazi620

Thanks for the input! I think even if it did fit, the SR20 will be more fun due to the power differences and better handling with loads less weight.

 

It would be pretty awesome to see done with the engine sticking out that far though lol

 

Ps. Is there a way to change the thread name now?

I say you do the SD25 swap and put a Turbo on it!!! http://www.vanagondiesel.com/

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Anyone know of any diesels that have decent aftermarket performance parts availability?

 

 

 

Mercedes inline 5 om602 or similar with a bigger turbo will give you 200+hp and 300+ft/lb of torque

They don't start to wear out till about 800,000 miles and the parts are cheap.

Mechanical injection.

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