Cummins NHRS engines in Mack chassis
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By 45LMSWM - 7 Years Ago
I have a 1953 Mack that was originally equipped with a Cummins NHRBS-600. At some point, the original engine failed and was replaced with a naturally aspirated Cummins.

I have a Cummins NHRS-6-BI that I am planning to use in place of the original engine, which came out of a LeTourneau scraper. I have the correct fan drive parts for use in my Mack, but I would like to know if there are any other differences in the front drive components that I need to change over. For one, the crankshaft dampener on the NHRS-6-BI is HUGE. Looks like nothing I have ever seen.

Does anyone have any pics of what the front of one of these engines should look like in a Mack, or in any truck application for that matter?

Any help would be greatly appreciated.


By jhancock - 7 Years Ago
Maybe try Red Smith 860-573-8017 for some info.

By Aaron - 7 Years Ago
There may be a lot of changes to make from a construction to automotive engine, front cover may be one, the flywheel housing may be another, compressor if it doesn't have one, the ballancer shouldn't be a problem, timing could be another. If you had a serial # Glenn might be able to trace it or at least a CPL on it.
By wayne graham - 7 Years Ago
Also if it came out of const equipment it probably has a push fan which will have to be changed. I have no idea which balancers could be run on that engine or for which application. Like Aaron said perhaps Glenn or one of the guys could run some numbers. I think Dan Cornett has one of these in his Hi Binder. Wayne
By Jeeperscreepers - 7 Years Ago
John, Wayne is correct. I have two of them, HRBB-600's, in my trucks. I don't have any pictures of the engines that show much but if you're not in a great hurry, I'll take some Friday and try to post them. One engine has a PT pump and the other has a double disc pump.
By 45LMSWM - 7 Years Ago
Thank you for the replies. I have the correct flywheel housing, flywheel, and fan drive set up to use this engine in the Mack. Engine also came equipped with a compressor as the Letourneau scraper had air brakes.

I think most of the differences are in the front cover/accesory drive. I will try and get the serial numbers off the engine over the weekend.