Engine/Transmission (1994 - 1998) New Member - what should I look for?

[BrianJohnson]

Ok - so I'm the NewB here. Although I'm not new to the diesel world. Owned several GM's over the years. I will always have GM's, but I'm looking at repowering a 72 truck with Cummins power. So please bare with me as my experience is all GM, so that's all I have to compare to.



So here's what I need to know.



What do I look for?



I am thinking a 12v, but I'm not sure what is considered 'good parts' and what is 'bad parts'. In the GM world, there were specific engine blocks to start a build up from. Is it the same in the Cummins world? I would consider a 24v for the better air flow of the extra valves, but I do not want electronic injection on my old truck.



Once an engine is found, is there anything specific to look for problem wise? Cracks, etc?



I guess what I'm looking for is a good place to start my search. What to look for and what to avoid.



Thanks in advance for your time,

Brian

 

[HeavyHauler]

Brian - welcome to the TDR!



As far as "bad" blocks, do a search on "53 blocks" and you'll have all the info you need. Some people have had these crack and others have hundreds of thousands of miles on them with no problems.



If I was doing a Cummins conversion, I would go with a manual motor, that being the 12 valve made from 94 - 98. You can make a lot of cheap power on a 12 valve compared to the electronically controlled 24 valve.



The 24 valve engine have very weak lift pumps (you'll learn about that) and this problem can be avoided by going with a 12V. I'm sure there would be a lot less wiring and confusion going with the 12V also.



Also, look through the Cummins/Diesel Conversions forum for more information about repowering. And if it's air flow that you're worried about, you can always swap a 24V head on your 12V engine.



Good luck!

 

[Joe G.]

I don't think the air flow for the 24 valve head is any better as far as power is concerned. the 12 valve has a MUCH better fuel system. It's mechanical and really moves fuel. Some of the 24 valve guys have installed a 12 valve P7100 injection pump on their 24 valve engines to get the extra horsepower available with it. The best is the engine used in the non-California manual transmission '96 to early '98 trucks because of the injection pump version used on them.



One thing that should be done is the KDP blocking fix for the 12 valve and some of the 24 valve engines. Other than that there are no problems for any of the 12 valve engines.