New owner of a 84 turbo diesel pickup - I'd appreciate any advice from forum members. Truck has engine trouble and will probably need a rebuild or a replacement. How much better an engine is the 4d56 than the 4d55? Or, put another way, is a 4d55 worth the cost of rebuilding or replacing? Another alternative: are there any other engines out there that might fit easily into this truck? Thanks for any thoughts....

I'm pretty sure that the engines you have in your part of the world are the same as what we have here in NZ. In that case, if you can get hold of a 4D56T, it is a way better option than the 4D55. Apart from the engine size (2300 vs 2500cc) the 4D56 has a number of better/improved features over the 55. The 56 has a better tubro/wastegate assembly than the 55, as well as a better designed head (although they are interchangeable). If you can get a Post-91 4D56 (Gen II), then it's even better, as they have roller rockers as well as an increase in HP over the earlier 56. The 56 will bolt up to the 55 trans as well, and the mounts are the same.

Hope that helps!

Actaully, that's the problem. We DIDN'T get the 4D56 in anything over here.

There were two or three years of Mitsubishi, Toyota, Mazda, and other compact Japanese trucks and a couple years of Toyota Camry Corolla and the like... That was all back in the early/mid 1980's...

Now, to get anything diesel powered, you have to go up to a Ford F250 or larger. Or something like the Isuzu Elf (NPR) type truck...

Thanks, Chris_Rob. I've come across several mentions of owners of this truck wanting to upgrade to the 56 because of lack of power. Your assessment is looking like another nail in the old 55's coffin...

What do you know about differences between the injector pumps in the two engines? I heard that the 56 uses a computer-controlled pump?

Incidentally, it is true that the 56 was never sold here in the States, but that doesn't mean they can't be had...

True that. I wish there was a better price than the $2100 that "JDMenginescorp" on eBay wants.

A.) That's more than I payed for the truck to begin with.
B.) They can't tell me anything about the particular engine that they're selling other than what Wikipedia says about it... No year or model it came out of. No known mileage either. Compression and leakdown numbers? Forget about it.
C.) They're not local.. Even if they pay shipping, with all of the above, I don't know what shape it's in. What if I have to return it because it's a pile.

I have an importer looking for an enigne. He's local and I trust him.

The 56 has a mechanical fuelpump like the 55 up to the year 2000, then it has 114hp with a fuelpump similar to the 4m40 and then again in 2005 or 2006 it goes CDI. Still the post '91 engines have at some point a lot of wires going into it and around it, like my '96 but I haven't got any clear answares on what they are. All the pumps are based on a Bosch VE design and the gen II's all have Zexel fuel pumps.