To Sleeve or Not to Sleeve? Replacing Cylinder Liners on a 4d56td Rebuild

ynwa · Post by **ynwa** » Mon Apr 24, 2017 1:26 pm

There weren't very many results for +cylinder +sleeve or +liner so here goes. Calling out all experienced engine re-builders.

Having shredded the keyway in my Crank recently (see viewtopic.php?f=6&t=18031 for reference), I'll be rebuilding this summer. This is possibly a silly question, but is this a 100%, 'while you're there' sort of thing, or could you measure the liners for wear (mic for ovulation) and if within spec, give them a hone and fit with new rings/pistons? I'm planning on leaving everything stock. No point in over-boring a great motor.

I'd probably just have a shop do this naturally. But would love to see an active Engine specific section for those of us that get in deep on occasion. :)

Share your thoughts!

Post by **Growlerbearnz** » Mon Apr 24, 2017 2:25 pm

It all comes down to how worn your bores and/or pistons are. If your pistons are fine but the bores are wrecked then a re-sleeve (and new rings) will do, if the pistons and bores are both damaged then you'd buy oversize pistons (Mitsubishi make them, so they intended the engines to be bored out a couple of times) and re-bore the existing sleeves.

I don't see the point in replacing the pistons *and* sleeves, except that it lets you keep the original bore size. Great for a concours competition, no real advantage otherwise. The sleeves are there so the engine can be rebuilt over and over again*, even beyond a couple of piston oversizes, as in the case of a commercial truck.

Just watch out for cheap rebuild kits- Turbo engines from the factory have different pistons and rings to non-turbo engines, but the rebuild kits all have the same type of piston and rings. I'd consider buying genuine Mitsubishi pistons and rings if you need them.

Hopefully you can find a replacement crankshaft which hasn't been reground: the crankshaft on turbo engines is nitrided, and most rebuilders don't bother re-nitriding the crank after grinding (since it only needs to last through the rebuild warranty period).

*also because the sleeves have more predictable metallurgy. Nothing worse than boring out a block only to discover there's a porous spot in the cylinder wall. Sleeves mean you don't have to scrap quite so many blocks.

ynwa · Post by **ynwa** » Wed Apr 26, 2017 7:30 am

Hey, thanks GB. Def not a lot of rebuild chatter on here. Apparently, the local shop can get new AM cranks for the 4d56. Pretty sure they are Hyundai. I'll take the block to a diesel shop and have them take a peek. I've treated it very nice since it arrived, but it wasn't treated well prior.

Post by **Growlerbearnz** » Wed Apr 26, 2017 11:04 pm

I recently looked into rebuilding my engine. To do it properly* would have cost about NZ$4000 for the block and crank. A new Hyundai D4BF costs about NZ$6500 which is uncomfortably more, but I've managed to justify it by telling myself it also comes with a new water-cooled turbo, injection pump, and injectors: easily NZ$2500 of value. I'm practically saving money!

*My definition of "properly" is a bit more involved than your average engine rebuilders.

TieMyShoe · Post by **TieMyShoe** » Thu Apr 27, 2017 1:16 pm

sleeves as a last resort, otherwise just bore it over slightly.

murdermitten · Post by **murdermitten** » Tue Jun 13, 2017 9:19 pm

Hi guys, I've been in the midst of a rebuild as well, and am looking for factory 4D56T pistons that are slightly overbored (.25).

I've been looking but cannot find them, have you found any leads?

Thanks,

Eric

Post by **Growlerbearnz** » Wed Jun 14, 2017 12:13 am

Where have you tried? Amayama.com list them at US$100 ea (genuine Mitsubishi, of course). oemmitsubishiparts.com might have better shipping rates to the US though.

What part number are you looking for? Epc-data says you need four of MD103313 (single piston and pin) plus one of MD103392 (ring set, enough for four pistons) http://mitsubishi.epc-data.com/delica_s ... 7855,7856/
and http://mitsubishi.epc-data.com/delica_s ... 9259,9260/

You've seen the "how to find parts" faq post, right? http://www.delica.ca/forum/viewtopic.php?f=16&t=17210

murdermitten · Post by **murdermitten** » Thu Jun 15, 2017 8:58 am

Thanks Growlerbeanz!

I've read that post, albeit a while ago before I got deep into the parts rebuild. I have been predominantly using Partsouq to look, then Amayama to buy (also my favorite resource).

Where I was getting tripped up was that the Partsouq parts guide did not specify overbore size so I was getting nervous (or I was reading it wrong), but the ebc-data site is much much clearer there, so I think I'm good. It hurts that they're that expensive, but I'd rather se OEM and (hopefully) never tear the engine apart again.

Going to order these up as well as my crank bearings and hopefully be on my way to a moving vehicle again. Thank you again for your guidance!

Eric

Post by **Growlerbearnz** » Thu Jun 15, 2017 2:00 pm

There used to be a website that had the diagrams like Partsouq, but the year-by-year part listings of epc-data. Of course it's gone now. *sigh*. I'll look at updating the process in the parts-finding post.

$100 for a quality, forged piston really isn't bad. The ones in my Mini were $165 each and they're *tiny*.

murdermitten · Post by **murdermitten** » Fri Jun 16, 2017 1:13 pm

Okay, oversized pistons and undersized crank bearings ordered!

Sorry to basically hijack your build thread, but what is the concern about machining the crankshaft, is a milled crank that is not "re-nitrided" going to fail spectacularly?

Last question for the day, do I need new head bolts for reassembly (due to the previous ones stretching)?

Thanks again guys.

Post by **Growlerbearnz** » Fri Jun 16, 2017 2:36 pm

The crank shouldn't fail spectacularly, it just won't last as long as a nitrided one- the journals will pick up scratches and wear much faster than they should.

The bolts in our engines aren't the one-use type ("torque to yield bolts") so don't technically have to be replaced every time (despite Mitsubishi saying "always use new bolts". Though if yours are original they might have corrosion and fatigue, so a new set won't hurt.

murdermitten · Post by **murdermitten** » Thu Jun 29, 2017 4:53 pm

Thanks Growlerbeanz.

Additional update, Amayama contacted me and refunded my money on the pistons, the 0.25 oversize pistons and rings are no longer in production (though they were listed as available when I ordered). :(

I've reached out to them to see of .50 is available but I am getting nervous.

Also my engine rebuilder did not seem to think the crank was nitrided, he said it would have more of a grey cast to it, I can send a photo next week when I go back.

murdermitten · Post by **murdermitten** » Wed Jul 19, 2017 10:32 am

Hello everyone-

So, parts arrived yesterday, .50 overbore pistons rings etc. Took it to the shop and got some bad news...something is not making sense. I've ordered parts for the engine from Amayama, double checked against the PartSouq site, but the piston head is a completely different shape. Also the replacement head I've ordered has a smaller combustion chamber diameter, so now there is a concern that either the engine is not the correct one, or that the parts are not correct. That and the valve seat recession is different...so everything feels out of whack at the moment.

Pictures below show help tell the story.

What do you guys think? Did I basically get an engine that is not, in fact, from a 1991 Delica? Or is it just that there have been changes and updates over the years and these replacement parts are in fact going to work (I doubt it...)

Any help or input is appreciated :)

ynwa · Post by **ynwa** » Wed Jul 19, 2017 1:47 pm

murdermitten wrote: Sorry to basically hijack your build thread, but what is the concern about machining the crankshaft, is a milled crank that is not "re-nitrided" going to fail spectacularly?

Totally helpful addition to this thread. I mangled my keyway so I have to buy a new crank when it finally comes out. But I'm leaning towards just a small clean up overbore but finding the right pistons could be a real issue when things aren't stock anymore...

Cheers!

Post by **Growlerbearnz** » Wed Jul 19, 2017 2:45 pm

murdermitten wrote:the piston head is a completely different shape. Also the replacement head I've ordered has a smaller combustion chamber diameter,

Righto. Your new piston is a pre-'93 piston for use with a pre-'93 protruding valve head. The old piston is a post-'93 piston, for use with a recessed (also called flush) valve head. That old piston is not out of a '91 engine. If it was pulled from a '91 Delica, it's not the original engine.

Though you might get away with it after all: you'll have to install a valve to check, but it looks like the new head is a protruding valve head which is correct for your new pistons. (The precombustion chamber port is large and square. Recessed valve heads have a smaller, more rounded PCC port). I hope it came with valves though, recessed and protruding valves are not interchangeable (they're different lengths) so you can't use the valves from your old head.

Check out this post in the TRL: http://www.delica.ca/forum/viewtopic.php?f=94&t=17332