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Discussion Starter · #1 ·
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This is where it all started. I ended up with this truck through a complicated series of trades. The previous owners had installed a 250 straight six from a '70s Chevy pickup. The brake system had been gone through and updated to a dual master cylinder with power booster. The front end had new kingpins and bushings. I figured it would serve me well for hauling gravel and compost for our little acreage.

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I did a quick brush paint job (dents and all). For the next couple of years, I hauled a lot of gravel, compost, and trash, and the old truck did a great job. One thing I didn't like was that the 250 didn't have the torque that the old 235 would have had. I found an old Watson Brownlipe transmission and installed it. Now I could start out in 2nd gear using the low gear in the Brownie. Before that I had to slip the clutch to start out in 2nd.

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But the old engine was used when they installed it, and never ran as well as I thought it should. Plus they did a really crappy job putting it in there. This is when I decided I'd like to upgrade to a diesel, preferably a Detroit.

I put out a few feelers and a friend in Washington found me a little 3-53 from a fishing boat. The price was right and the deal was made.

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Discussion Starter · #2 ·
I had to do some work on the Detroit. The blower had gotten water in it and it froze and broke one of the impellers. Another blower was found in Wisconsin, and I installed it. Problem- now the engine would not turn. Pulled the blower off and realized the drive gears were different than the original ones. I swapped the gears and retimed them. Now it turned over. I took out the injectors and spun the engine with the starter until I had my oil pressure.

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I made a video of the first start and uploaded it to YouTube.

Next step- now I have to figure out how to get the diesel engine into the truck.
 

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The 3-53 may do OK for what you're doing but a 4-53 would probably have been better. The base 3-53 was only about 101 HP and 205 lb ft of torque. Probably less than your current six. Now if you had the 3-53T you'd have 131 HP and 317 lb ft of torque which might be a good bit better. The military used some 3-53 engines in the Gama Goat vehicles during the Vietnam war. It was rated at 56 MPH which was probably going down a 45 deg hill with a strong wind on the tail. LOL. There is a GM flywheel/clutch adapter for the Detroits.
 

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Discussion Starter · #5 ·
This engine was equipped with an SAE #4 bellhousing. I looked into getting a Gamma Goat setup, but the prices were through the roof. Phoenix makes an adapter for the #4 to fit the Chevy V8 bellhousing and flywheel. About $500 for the set. Not bad but after looking at their product I decided I could build my own adapters.

I started with some 3/8" plate steel, then did a lot of measuring to make sure I was drilling in the right places.

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Once that was figured out, I cut around the edges and cleaned them up so it looks like an adapter.

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A couple of the bolt holes couldn't use a regular bolt due to interference, so I used countersunk bolts for those places. You can see the two coming out to accept the Chevy bellhousing. They came in handy as they guided the engine into place as it was dropped in.
 

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Discussion Starter · #6 ·
Meanwhile, Otis and I were tearing down the truck and getting it ready for the new engine.

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Once the gas engine was out and the crappy mounts cut from the frame, I dropped in the diesel. It slid into place like it was made for the truck.

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The top two bolts needed the heads ground off on one side, which was cool because it kept the bolts from turning while I tightened the nuts.

I was even able to use the original clutch linkage.

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The engine fits like it was made for the truck. The left side left plenty of room for the steering box. I did have to move the engine a little to the right for oil filter clearance.

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The angle of the intake tube matches the slope of the inner fender.

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The front of the engine sat right over the original mount for the original engine.

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Discussion Starter · #7 ·
I took the front motor mount that was used in the cradle and modifed it to bolt to the front crossmember of the truck.

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Between the mount and the crossmember I used 1955-57 Chevy passenger front motor mount cushions.

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The remainder of the original front mount was used to make the two rear mounts.

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I drilled the rear mounts to fit the engine mount bosses on the bellhousing. Then drilled through the frame flange (I know, not the best thing to do but it should be okay. If I run into problems later I'll go in and reinforce it). I used the same cushions on the rear mounts ('55-'57 Chevy front mounts).

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With the engine bolted in, I turned my attention to getting things wired and plumbed. The original radiator worked with a little creative hose routing. The original fuel tank was drained and flushed out with diesel, the a return line was run back into the filler tube of the gas tank. The primary filter was mounted on the frame behind the right front tire.

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Discussion Starter · #10 · (Edited)
Question:
Nice work, looks like it was made for the job.:) What did you use to adapt the #4 flywheel to bolt up to the Chevy Flywheel? Thanks.:)

Answer:
I made an adapter from steel plate and 5" cold rolled steel. The Chevy flywheel bolts up to the adapter, I had to use a shim between the flywheel and adapter to get the exact depth for the clutch to work properly.

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Discussion Starter · #11 · (Edited)
Question:
Looking good. Nice that the blower is on the passenger's side. One thing I was wondering is the rotation of the engine. Marine engines came in both clockwise and counter clockwise.

Answer:
Rotation was one of my major concerns. Luckily this one was already set up for the correct direction. Changing the rotation on a Detroit is not a major problem though. It involves swapping some gears inside the front cover and changing the lines on the oil pump. Maybe one or two other things but it's no big deal.
 

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Discussion Starter · #12 ·
After I removed the marine exhaust system, the only manifold I could find that would work with the right side blower turned out to be one from a 6V-53. Even then I had to make a spacer to fit between the head and the manifold. Using parts from O'Reillys and Amazon I made an exhaust system that exits through the fender well, The muffler is tucked in under the cab and currently exits at the right rear corner of the cab. Plans are to make a straight stack with a rain cap when I get a chance.

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Discussion Starter · #13 ·
I've been driving the truck for a couple of months now and I'm really pleased with the way it all works. It has plenty of power to keep me happy, and I can get by with just using the main transmission if I want to. But it's more fun to use the Brownie as it gives me another gear between the main gears. The way the ratios work out it's best to just use direct and high because there isn't any difference from one gear's high to the next gear's low.

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As you can see, I swapped out the old 20 inch lock ring wheels for some 19.5 wheels from a GM motor home. Right now the only down side is that with the low rear end gears and the smaller tires, my top speed is not that great. I've located a motor home rear axle with 4:56 gears as opposed to the 6:17 that's in there now. But it has disc brakes, so I'm probably going to get the front axle as well.
 

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If you get the front axle, the tires will stick out of the fenders! Since you have a 2 ton front axle, you can use it as is, get front disc brake spindles/hubs off a ‘91 to ‘01 +/- GMC P-3500 HD truck, make or get made kingpin shims and bolt them on your axle. D-80 off front donor with disc brakes should also work, they come in different widths, though.

Ed in CO
 

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Hi Ed.

I see this as three point mount with two cushions on front mount. Have seen this setup used on older GMC 6V53 and 6-71 trucks.

My concern would have been the offset between engine and frame mounts. I would have remedy this by moving the left frame cushion right so it center lines with the engine.

Bob G in Virginia
 
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