3406 3zJ/7fb rebuild

Boys I will be honest I have ran some #### hot B models. Watch the gauges and I have never melted a piston. The wider rod of a C model is all hype in my honest opinion. I have covered many miles in a 85 400hp 7fb at 1950 rpm all night at 85 to 90k with a cow bus behind me. My stoutest stock combo was a 5YG which was a 460 peec. We put a 4MG pump on it and a borg turbo...it would hang with most. Thing about a B is timing and overhead set including bridge adjustment.

 

Well the cylinder kits cost the same either way. So the nozzles will be the extra expense. Just remember nozzles have to match pistons and a C pump will push B nozzles but a B wont push C nozzles very long. All that said I have a good friend that has a mostly stock 3ZJ with a 15 over and 3.55's on tall 24's....thing is a legend around home. Nothing wrong with a 3ZJ when they right

 

Turns out the engine in need of a rebuild is a 3ZJ as well.

Came out of a 1992 Peterbilt.

Good to know these B models are great pullers when set up right.

The engine that’s currently occupying the frame space in the 1992 pulls a 5 axle b-train with authority. Better than the 1998 475 hp 6TS 3406E I’m driving right now.

Except it likes to drink it’s fuel....

 

Yes.

 

The 1992 with the 3ZJ I was told used to have 24.5 rubber which allowed it to go up to 80 mph. Not sure if it’s capable of that with a loaded trailer. More likely while empty.

It was swapped out to 22.5 rubber but still the same gearing.

With a loaded trailer, it gets to 65 pretty good but then falls off after.

The 87 Pete gets to 75 mph with a loaded trailer but it’s not as fast at get up and go as the 92. So likely the governor in the 92’s pump is limiting fuel at so many rpms.

 

Both use the 100-7408 or 20R-7546 camshaft. As you noted, difference will be piston cooling jets.