Thread: 4BD1T rebuild

4BD1's do wear out.......

Yes the crankshaft in the 4BD1T is nitrided - this produces a very hard case and also increases the fatigue strength.

Isuzu say it cant be reground. I can't see why it couldn't be re-heat treated after grinding, but there is a possibility that it could distort during heat treatment (nitriding isn't as prone to this as most other heat treatment processes, because temps are lower, and although reasonably dimensionally stable they can grow a little).

To remove and fit the liners you will need a puller - see pics









Edit: pic from here - and I couldn't find any larger pics

My crank has done three rebuilds and hasn't needed to be ground yet. I would avoid it if possible. They are extremely hard and would take extreme punishment before showing any wear.

Cam wear will show up externally as your tappet adjusters moving a lot. IIRC they use roller followers so the lobes only wear if the rollers crap out. It happened once to the 4BC2 truck we have but it was a very cheap fix ($130 to get the cam built up and reground).

Thanks for the replies guys,
The followers in this engine aren't roller ones,can anyone confirm if the factory turbo engines should have roller followers?
Just got back from the engine machine shop that I normally use,he said the cam and followers are shot.
The crank measured up OK but has light scoring from lack of oil changes,he will find out if they can just be linished so standard bearings can still be used.
A word of warning,never ever buy an engine that has been owned by a scrap metal guy.Total lack of maintenance and bodgy repairs give you the s....
Eric

Originally Posted by THE 109

Thanks for the replies guys,
The followers in this engine aren't roller ones,can anyone confirm if the factory turbo engines should have roller followers?
....
Eric

No roller followers in my factory turbo 4BD1T.

Hey Eric
We used a similar puller as Bush65's to remove the liners when we did the rebuild, also used a similar method to refit (a mate of our's has all the gear for rebuilding isuzu's), our crank didn't need any work aswell...

Good luck with the build.

P.s we still have to find out about those alternators......

TIM.