ISUZU 4jb1 engine

[Johnstripacer]

Does anyone know if the ISUZU 4jb1 truck engine is the same as the 4jb1 in the bobcat 843B ?

 

[wateka]

I'm in the middle of rebuilding the 4JB1 in my 853 and I believe the truck engine is the same. The big difference seems to be whether the piston heads have a square or circle indentation on them. I believe the circle pistons are used in the generator (1800 rpm) version of the 4JB1 and the squares are used in the trucks and Bobcats (3000 rpm). I've been looking at buying a new motor out of China on Alibaba because my parts need includes a crankshaft, camshaft, and tappets along with everything else. The other big difference there (assuming you can get comfortable with your supplier) is whether the fuel injection pump on the new engine is rotary (Bosch VE, which is on the the Bobcat engine) or in-line. The fuel lines on an in-line pump do not look as if the would fit around the stock intake manifold. I also think the in-line pumps are governor limited to 1800 rpm because I've only seen them on engines sold by companies using them for generator applications.