How many different 8.3 liter cummins blocks are there?

[98G]

Is the block for our M939a2 trucks the same as used in a 325 HP 8.3 in a motorhome from the late 90's?

Yes, I searched. Yes, I called Cummins. Yes, I called several parts places to ask for numbers. No answers forthcoming.

Old bad block motor number is 45383673. New block part number is 3971411. New block serial number is 3968602.

 

[patracy]

I can't answer specifically. But I can give a generalized answer. I have been through a few 5.9 Cummins over the years. The blocks are pretty much the same in regards to things "bolting on". With that said, there's variances within them. I dealt with a "cracked 53 block" on my dodge. I ended up swapping the parts over to a "STORM" block. The part numbers and casting numbers were different. But the internals swapped without a problem.

Cummins uses control numbers as well to determine a package. But often times they use related parts from the same family of engine. The difference typically comes in the fueling specifications of an engine.

I'm going to make a educated guess here. The late 90's is when Cummins was using the VP44 as a stop gap for EFI. I know the 8.3 had offerings of this just like the 5.9 did. If it's a VP44 pump'ed engine, don't expect it to be a easy swap. You'll need to ECM, harness, and throttle pedal at the very least to use it. Now, that said, if it's the mechanical pump, then yes, you likely could get it to work. Just in any case expect to have to deal with sending unit changes, plumbing variances, and linkage fabrication/changes.

 

[98G]

I've got a guy with a bad 8.3 liter block in his motorhome. He says the entire engine is just rebuilt with all good components and assembly errors ruined the block. He wants to use everything off his motor to build one of my NOS bare blocks.

Before we go shipping big heavy things accross the country, I want to be sure that this is viable...

I strongly suspect that there are not huge differences between blocks.

Thanks for your reply. This helps.

 

[Suprman]

Call cummins tech support give them his engine serial number and your block part number they are very helpful. I don't know about pulling and reusing sleeves.

 

[98G]

Call cummins tech support give them his engine serial number and your block part number they are very helpful. I don't know about pulling and reusing sleeves.

I did. They couldn't give me a definitive answer either way : "it should work, but compare them side by side."

 

[Suprman]

I would be brave and go for it then. With the Skytrak 5.9 engines the older ones use rotary ve style pumps and different injectors. Newer ones use the bosch inline style like our a2 trucks 8.3. I believe there are 3 main variants from the late 80s to now. I don't know if the blocks are actually different or it's just different heads.

 

[Bandit02]

The 5.9 used first the VE, then P7100, then VP44 then retired with the CP3 (common rail) pumps. The VE/P7100 were 12 valve heads and the VP44/CP3 was a 24 valve design. You can bolt a 24v head onto a 12v block or mount a P7100 onto a 24v engine and have the holy grail of Cummins engines.

The only thing I remember different between blocks was how the early ones (P7100) style has their fuel systems hooked up. The common rail ones have different intake plates for mounting the fuel rail and etc. I do know one difference is new ISC/8.3 have casted into their blocks are the mounting hardware for a ECM on the left hand side. I believe the heads are slightly different for the different valve covers, the early ones were narrow and the new ones are full face because of the CCV.

I'm 99% sure the blocks are all the same on the older ones.

 

[patracy]

The 5.9 used first the VE, then P7100, then VP44 then retired with the CP3 (common rail) pumps. The VE/P7100 were 12 valve heads and the VP44/CP3 was a 24 valve design. You can bolt a 24v head onto a 12v block or mount a P7100 onto a 24v engine and have the holy grail of Cummins engines.

The only thing I remember different between blocks was how the early ones (P7100) style has their fuel systems hooked up. The common rail ones have different intake plates for mounting the fuel rail and etc. I do know one difference is new ISC/8.3 have casted into their blocks are the mounting hardware for a ECM on the left hand side. I believe the heads are slightly different for the different valve covers, the early ones were narrow and the new ones are full face because of the CCV.

I'm 99% sure the blocks are all the same on the older ones.

Yes, you could bolt a 24V head on a 12V block, but you need to change pistons as well since injector placement changes and would affect spray pattern. Injector lines are completely different from all the variations as well. The timing covers are different as well due to the various pumps.

But with all of that said, the base blocks accepted all the various parts. Again, it's an apples to oranges comparison. But given how Cummins operates, it's a pretty safe bet.