Conclusive info on 4D56 head onto 4D55 block info?

[Balcorn80]

Do not do that! The clearances will be too small and the valves would probably hit the piston. The recesses in the piston are fairly deep, and the valves protrude several millimeters from the head. I would not recommend putting a protruding valve head on a flush valve motor

That's why I'm curious as to what 4d55 piston tops look like compares to later 4d56. I know my head is a protruding valve head. Because I could see that before install. What I do not know for sure is that the block was fro protruding valve head. Because I have not seen piston tops of either to verify.

I suspect that, with 600 miles on it, I am not running mismatched head and block. But would like to see piston pics to satisfy my curiosity...

[Balcorn80]

Pulled my head off. Discovered my problem. I used a gasket set for a 4d55t when input my motor together. The head gasket is .05mm thinner crushed than the 2 notch head gasket recommended by Mitsubishi for the 4d56t(but it IS appropriate for a non-turbo 4d56). The directional arrows in the top of the pistons were imprinted into the carbon on the underside of the head.

Problem solved.


So. For the record, you can get a protruding valve head and block off AliExpress and have them delivered in 7-8 days for $2200. All the parts for your 4d55 will bolt on and work fine. Just make sure to use a 4d56 head gasket.

Also, this same supplier has the protruding valve heads for the 4d55t available too. In case you don't want to buy new fuel injectors.

[dancinggecko]

That doesn't make a ton of sense. 0.05mm is less than 2 thousandths of an inch, you'd get more change in that just due to the expansion of parts with heat. The head bolts weren't over tight were they? Also didn't know there were different head gaskets for the 4d56 and 4d55

[Balcorn80]

Factory service manual lists 5 "grades" of head gaskets going in .05mm thicknesses. And in looking at various vendors I see parts listed for 4d55 and 4d56, but not 4d56t. Pics of these gaskets, like the one I first installed, have no holes or notches. Pics of 4d56t gaskets, like the ones shown in the FSM for 94+ show these marks. So, too, did the 4d56t gasket sent to me by the engine supplier.
When you have pistons that protrude slightly above the deck of the block and a head that for all intents and purposes is flat across the bottom with valves protruding, a few thou IS pretty critical.

[Balcorn80]

I do not believe it was over-torqued.the "kiss" marks were universal on all 4 pistons. I wish I had microcameras to have watched it all as it happened. Because it was a maddening 3 months. But swapping out the head gasket did it.

Got 29mpg across the first 150 miles to boot.

[camoit]

The reason they make different thickness gaskets is to compensate for machine work on the head and block. If you take off .001” then you need to add it back with the gasket

[Balcorn80]

Yep. And according the the factory service manual, the first 2 grades are appropriate for non-turbo and the latter 3 are appropriate for turbo'd motors. Machined heads\block or not.

[dancinggecko]

Huh, I guess we just hadn't machined enough of of my old one to need that. I'll have to keep an eye on that when we rebuild it

[Balcorn80]

The readily available online pdf of the 94+ service manual hives a very good description of measuring for which head gasket you need. I also found an excellent video on youtube by Ajusa(an import parts manufacturer) that shows a completed head gasket job, including measuring and head gasket selection. I do not know if it is as hyper-critical on a 4d55t(I believe cranks and stroke are biggest difference. Pistons are the same) as it is on the 56. And now, my motor is a 56 under the skin. I had to time my fuel injection pump to 4d56 specs too.

[dancinggecko]

Yeah, the 55 an 56 are basically the same except for stroke. They did tweak a few things here and there, the biggest things being the head had roller rockers and better cooling passages (supposedly), but pretty much anything that goes for one will translate to the other. What did you set your injection timing to? Depending on the source I've seen three or four different timing values, you might be able to advance the timing some and gain a little bit of throttle/turbo response and power

[Balcorn80]

I think it was .030 at 9*. Whatever the measurement was, it was at 9* instead of 5* like the 4d55 said.

I also scooted JUST a smidge advanced, for that mentioned extra throttle response.

[dancinggecko]

Yeah, I think that is what I found when I put the 56 in mine. I bumped timing way up, I think closer to 2* or 3*, but then again I am running an 83 pump. I haven't gutted one of the later pumps to see if there is anything different to their innards from the older ones, they may do better at milder timing. Now you've got me curious to see what cam plate is in the later 56 pumps, lol

[Balcorn80]

Mine is a pump from the 85(I think was actually built in 84) DieselKiki (before zexel) pump that I had rebuilt at Diesel Injection Service in portland. The only cold weather provision is a high idle pull cable. Rudimentary as heck.

[Balcorn80]

Actually now I'm curious about my pump.
The head from my 4d55 has the larger injectors than my 4d56 head. And I have a tc05-10a turbo, which I understood were on earlier. When I took my pump to be rebuilt they ran the numbers and said it looked like it was originally an N\A motor's pump with a turbo top half(diaphragm and such) put on. So they rebuilt the pump and set it up according to turbo specs. Anyone know a good place to run the numbers off pumps?

[Balcorn80]

Also: more head info, because I have it and I'm hear for information. Both gleaning and sharing.

There is some sort of aftermarket cylinder head part number system that a lot of chinese manufacturers use. I do not know where it originates. But I know this, in regards to "our" motors: 908611 is for protruding valve large fuel injectors, or 4d55t motors. 908612 is 4d56 protruding valve head with smaller injectors. 908613 is 4f56\d4bf smaller injector recessed valve head. You can search those numbers on eBay or AliEx and find the head you may be looking for. Also, AliEx has generic 4d56 injector sets for pretty cheap if you want to move on up to 4d56. Granted, they likely aren't rebuild able. But when a set is the cost of a single I jector rebuild, well...

[dancinggecko]

Hmm, that's interesting. The large injectors were only used on the early 4D55 motors, never on the 4D56. They went to the smaller style of injectors starting in 84 and used those up until the switch to common rail direct injection on the newer 4D56.
With the injectors they are completely rebuildable, we redid the ones on mine a few years ago. You can get new nozzles from Scheid Diesel, once you get those it's just a matter of getting the injectors shimmed to pop at the correct pressure

[Balcorn80]

Yeah the large injector heads were only for 4d55.
If the 4d55s went to smaller inje tors and wastegates turbos after 84... That must mean the motor I pulled from my 85 must have been an 83.

[Balcorn80]

Yeah the large injector heads were only for 4d55.
If the 4d55s went to smaller inje tors and wastegates turbos after 84... That must mean the motor I pulled from my 85 must have been an 83.

[Balcorn80]

Holy double post, batman!

[weelsey]

Hi thank you all for sharing It's great to have found the diffinative info on the heads. I'd thought to chime in in part because I'm told I need to stop lurking and post to maintain my status, but I'm looking for advice, too.

And it looks as if this thread contains a lot of diesel knowledgeable ones.

I'm in the position of owning (3) delica 4d56t and (2) 4d55t (one ford one dodge) engines (plus one or is it two mazda/perkins 2.2l ford diesels).
1990 delica I recently cooked by idling without coolant until shut down boo hoo after years of investment in the engine with anticipation for to build 4x4 diesel mini-truck. 1992 4d56t x2, one with bad motor run dry of oil, one project van needing turbo oil seals so as to not run-away.

now I'm recovering from trek to get rebuilt short block and spare 4d55 and a whole jumble of Ranger's and their accompanying bits.

Was the '83 4d55 with larger injector bores also the one with larger pump head/plunger? IIRC, it was here I read that the diesel kiki had preceded the zexel on the mitsubishi. My '83 2.2l Ranger NA diesel kiki uses larger injectors which makes me wonder the pump head size.

I have a few pumps, including a 4d56t in pieces which I could investigate the cam plate on if that's still of interest to anyone, as well as I think 3 4d55 pumps with the wax motor cold start advance clap-trap - Man, I'd like some with the simple cable pull! - Seems most of the 4d56T from delica's from Japan have no mechanical cold start timing advance and the pump in pieces is one I began to adapt with VW TD pump cold start lever acting directly by screw or cam on the timing piston so as not to have to machine out the hole on the housing for the cam ring business. So there's that

An overheated well oiled engine might still live again with a new head. I want to get the most out of all this stuff. I guess I've established that all of these mitsubishis are protruding valve being pre-'96.

I can put a 4d55 head on a protruding valve 4d56 block using a 55 head gasket but my compression ratio will have gone up.

Can I put 56 roller rockers and cam on a 55 head?

I can put a 56 turbo manifold on a 55 head

both the 4d55t and 4d56t pre-intercooler were rated at 86hp, the 55 with more volumetric efficiency. So what happens with this reverse sequential head swap?

The spare '55 head, the only dodge element, can make my van go again. I think the rebuilt '55 block goes in the 4x4 Ranger instead of a '56, since the delica motor needs some machining for fastening in. But I'd like v-belts....

I would get some quality head gasket perhaps in a thicker variety for the reverse swap?

[weelsey]

Mine is a pump from the 85(I think was actually built in 84) DieselKiki (before zexel) pump that I had rebuilt at Diesel Injection Service in portland. The only cold weather provision is a high idle pull cable. Rudimentary as heck.

If it looked like it had a timing advance function but also accomplished a fast idle at the same time. This is a diesel kiki from early 80s and is probably more desirable then the wax motor apparatus, or even the VW piston direct mechanism I'm trying to build

[weelsey]

The large injectors were only used on the early 4D55 motors, never on the 4D56.

dancinggecko, do you have part numbers for those larger injectors you could share here?

[dancinggecko]

Ok, so there's a lot going on here. For starters, I sadly do not have the part number for the injectors. Your best bet would be to try and find a set online or send them to a diesel service shop to get rebuilt if you have a set. Just search based on the engine year.
The 83 model injection pumps were made by Zexel, and the 84 and newer pumps were made by Diesel Kiki. They are identical except for the AFC on the top of the pump. The 83 ones had a screw on the top that allows for easier adjustment of the AFC, which is what controls how much more fuel is delivered based on boost. The diesel kiki pumps can be adjusted as well, it just takes removing the cap off of the AFC. Otherwise the pumps are the same. Cam plates are the same, head/plunger size is the same, and so on. Depending on the year the castings of the pump cases may be different depending on if there were some pump mounted accessories available, but that's about it.
I have not measured to see if a set of roller rockers and the cam from a 4d56 would fit on a 4d55 head. They might, but I don't know.
I also wouldn't hedge my bets on the injectors being the same between the Perkins diesel and the Mitsubishi. Those are two completely different designs by two different companies. Same with the injection pumps. They may both be Bosch designed VE pumps, but they will be configured differently depending on the motor.

[weelsey]

There certainly is, Dancingecko. Ah, yes. The Mazda pump without boost reference (though with aneroid) will be unique. I wondered if the big injectors in the early Mitsubishi were the same body style as my Mazda s2 because, well, they are bigger too. I've gained some familiarity with nozzle options for these.
THanks for the suggestion I'll see if those numbers can be found online. believe it or not the little crush and shoulder washers are easier for me to find.
Another difference in configuration on the older diesel kiki is the cable actuated cold start advance/high idle mechanism:
I've seen the two styles of the pump tops and wondered. but what is it about the '83 pump size that makes it desirable by some? Bigger, plunger/head?
I did a little digging and learned Diesel kiki became Zexel in 1990 or so.
I'll be keen to learn if anyone as put the older heads on the 56 block. I did read somewhere perhaps 4x4wire.com that the 56 cam and rocker assembly fit right in there on the 55 head. And the updated oil pump might need to be scavenged from a 56 for the 55.

[gustycrosswinds]

C. Trouble shoots the glow plug system and finds that the 6v relay is completely toasted not activating. The wires appear to be getting super hot going into it. He will be wiring a manual set up tomorrow.

Do you happen to have a schematic or diagram of the wiring for a manual glow plug setup? thanks