Thermodyne Engine Dead

[DRUMMER35501]

Hey guys, I am starting work on a B61 with the END 673 and the TRD67 2 stick and have found out that the engine is going to have to be built and I also have transmission problems. I am considering changing engine and transmission. Is there an engine and transmission that I could swap will limited problems and what kind of problems would there be. I was told that a 300 with a 9 or 10 speed would bolt up with no problems. Is that true? Thanks in advance for the help.

[JAW]

I've got an E75, 1947 with a 510 ci Thermodyne, and I've got the same problem, we blew our engine last Saturday. If you have any suggestions on what I can do, please send me a private message or post here.

Thanks,

JAW

[Rob]

Hey guys, I am starting work on a B61 with the END 673 and the TRD67 2 stick and have found out that the engine is going to have to be built and I also have transmission problems. I am considering changing engine and transmission. Is there an engine and transmission that I could swap will limited problems and what kind of problems would there be. I was told that a 300 with a 9 or 10 speed would bolt up with no problems. Is that true? Thanks in advance for the help.

Most any of the 672 cubic inch Mack engines will fit in there without a lot of trouble. My recomendation would be to upgrade to a later engine such as a 237 Mack and a different transmission also. The TRD-67 will not stand up to torque rise of the newer engines unless a "feather touch" on the accelerator is used. This is assuming the truck is "worked". Parts are very near non existent for that series of transmission also. If you decide to use a Fuller transmission, the flywheel housing will have the correct mounts as Fuller transmissions do not serve for the rear engine mount as the Mack transmissions do. The Mack transmission mounts to frame brackets that are bolted to the truck frame, and Fuller transmissions mount to the flywheel housing, and the flywheel housing is connected to the frame of the truck via mounting brackets. The starter location with the later style flywheel housing damn near necessitates removing the left fender and liner to change also as the position is just under the driver's feet. Having the small duplex transmission, (TRD-67) may require a driveline switch to larger size but I'm not sure. Most of the B series trucks with the END-673 engine used a 1710 series, (full round) style driveline measuring just over six inches across the yokes.

I had installed a ENDT-676 engine into my 57 B-61 with an RTO-910 transmission behind, and did not like the power combination. The engine was never in it's operational torque band and always running out of gear. Don't get me wrong, it ran perfect, just not suited for my application at the time.

Of course with any change, there will be modifications to the truck. Just be sure you have enough cooling capacity through the radiator to cool the beast.

Rob