4D55 and 4D56 heads the same?

[Rattlenbang]

Doing some digging, and it seems the only difference between the two engines was the stroke, accounting for the 2.3 and 2.5 displacement difference. Why is this important? They put the 2.3 in Dodge ram 50 trucks in the 80s and parts for those vehicles are still available locally. I just want to know if anyone has used 4D55 parts in their 4D56 block?

If so, Felpro gasket set HS9084PT1 Engine Cylinder Head Gasket Set has all the gaskets and seals for a head swap for less than $100.00

Nathaniel

[mararmeisto]

According to the wikipages (http://en.wikipedia.org/wiki/Mitsubishi ... ngine#4G55) the 4D55 is the earlier model and the follow on is the 4D56. Looks like the first is valved and the second is fuel injected, but I don't know if that means the heads will be different.

Given the age of the Delicas (post-'86) I suspect a lot of the mechanics that have been servicing these are more familiar with the 4D56 than the older version of the engine. That being said, maybe one of them could chime in...

[yojimbo]

Both engines have valves, and being diesels, both engines have fuel injection.

The bore and stroke = the same head gasket is a good guess, although sometimes different thickness gaskets are used to adjust the compression, and as stated in the other thread, some heads had flush valves and some had sticking out valves, which may again indicate a difference in head gasket thickness possibly for compression purposes. It would be handy to do a part number check. I havent used it but I remember someone using a Mitsu part lookerupper, might have been this, but I'm not on a windows box to check right now:

http://www.dsmtuners.com/forums/frequen ... c-p-s.html

[Growlerbearnz]

4D55 heads use a different style of injector, with a much larger thread where it screws into the head. The flow rates and opening pressure are the same though, so you can fit a 4D55 head and injectors to a 4D56 engine with no issues. Everything else- gaskets, mounting points, rocker cover- is identical.

Here's a picture of my new 4D55 head, and below it the old 4D56, showing the difference in injectors.

4D55.6.jpg (132.5 KiB) Viewed 4571 times