engine conversion

[farmer boy]

I got to thinking today and was just wondering if this would work. 1977 Dodge truck with 5 speed manual coupled to a 5.9 Cummins. I think the original engine is a 315?

 

[JDemaris]

I'm not sure I understand the question completely. You can put anything into anything with enough work. But - the Cummins uses a adapter to make it fit several types of transmissions e.g. the Gertrag or NV4500.
A 318 gas engine has a totally different bolt pattern, flywheel, etc.
There are many older Ramchargers, Chevy Blazers, Ford trucks, etc. with Cummins 5.9s and 3.9s - so it's been done, many times.

 

[farmer boy]

So all I would have to do is make up an adapter along with a few other things? Do they sell these adapters?

 

[JDemaris]

Yes, go to 4btswaps (dot) com and you'll get all the info you want.

Also cummins-conversion (dot) com

 

[Anonymous-0]

One big problem is the rpm difference of the original gas V8 VS the 5.9 diesel. you need to change the rear axle gearing unless you would be satisfied with 40-50 mph top speed.
when you say a 70's model with a 5 spd, I assume you are talking about a 50 series or larger truck ??

 

[farmer boy]

Not following what you mean by 50 series or larger. It's a 3500 1 ton.

 

[Anonymous-0]

Ok, I assumed wrong as to the size of the truck.
I was thinking with a 5 speed it had to be atleast a 50 or 500 series (1-1/2 ton) or larger truck.
I did not realize a mid 70's 1 ton was avalible with a 5 spd manual. If the 5 spd has an overdrive 5th and not lower than 4.11 rear axle, should be OK with the diesel.
Many times a diesel engine will not turn high enough rpm to work well in a machine geared for a gas engine that can turn 5000+ rpm.

 

[fixerupper]

A few years I thought about replacing the four speed manual with the five speed in my 79 Dodge 2500 360 but I was told the five speed from that era, if I could find one, was weak. You might want to think about that if you hook a Cummins to that tranny. Maybe the 3500 had a stronger version of the five speed? Jim

 

[farmer boy]

I thought about that before but not for this specific idea. WHat does a diesel spin at max rpm 3500rpm? Gas engines may be higher RPM's but they don't always use that higher RPM. In our GMC Sierra it will shift at 2000RPM normally but will shift alot higher if you got your foot on the pedal. That's an automatic but still. What I'm saying is if you were to put a diesel infront of it you should be okay except for torque issues.So if your a relaxed driver you should be okay with it.

 

[JDemaris]

Yes, RPMs are a problem, but there are many work-arounds. With HD fourspeeds, there'a a little overdrive box made by Ranger that goes ahead of the transmission. It is extremely rugged and - since it mounts between the orig. trans. and clutch housing - it works in all setups, 2WD and 4WD.

Also, many Dodges and GM 1/2 tons were available with four-speed manual overdrive transmissions - the A833 or NP833.

Also again - some older trucks are not geared all that bad to start with. I put a diesel into a 79 Blazer. It came OEM with a 305 gas engine, four-speed manual trans. and 3.08 axles. It was fine just as it was for a diesel transplant.

 

[buickanddeere]

Why sink thousands of $$$ and your time into a 30 year old truck? When for the same money you can purchase a newer factory diesel?

 

[farmer boy]

I don't own either truck but know where I could get a Cummins engine and the Dodge for probably under 1500. Just a thought. Will most likely never happen. On top of that the Dodge has a box with hydraulic dump.