MD head

[Brad Motheral]

Picked up this head a few years ago from machine shop. Off a TD6. Customer never came back to pick up. Fully reconditioned. I never looked at it much. Just tucked it away.

Got it out to put on a SMD I have and noticed this brass plug blocking off large, injector side water passage between cyls 1 and 2. You can see there was some pinning done around it, probably to fix a crack. My question is: Is this an unfinished fix of the crack around the water port? Was it a homemade way to redirect coolant flow? Should I drill it out? This tractor still had the restrictor plates on all 4 of the large coolant passages going into the block so I'm not sure if I should leave restrictor out of that hole and use the rest? Has anyone else ever seen this?

Thanks, Brad

 

[560Dennis]

Thats loc and stitch repaired. Acceptable repair for cracks in cast iron .
Suggest this, I would have a machine run a low pressure air test to be sure there are no leaks from your description , I think it need to test it
before you put it on .

 

[Brad Motheral]

Yes. I know what the repair is. I've had lots of heads lock and stitched. Or pinned. It's the brass plug in the water port that's confusing me. Not sure why it was put in there. Wondering if I should drill it out or leave it the way it is.

 

[redforlife]

I'd backtrack to the machine shop that
it came from, and ask them.
If something needed to be drilled out
or removed, I'm really puzzled by why
the machine shop didn't do it them
self. That would kind of make the head
job not completed and not ready for
installation. Be kind of like sending
it out the door without putting one of
the exhaust valves in it. Wouldn't
it???

 

[560Dennis]

Flow of coolant blocking by brass not to good of idea if the block has matching port , what do you think ?
Hot spot Id say .

 

[Brad Motheral]

Ya. It doesn't make sense to me either. I was just wondering if it was a shop fix to redirect coolant towards the back of the head. There are other smaller ports nearby for flow to possibly make up for it..? The restrictor plates in the 3rd photo are supposed to go in the large coolant ports anyways. Maybe they thought this worked even better????? I think no matter what, I should at least drill that plug out to the same size as the orifice in the restrictor plates.

 

[Janicholson]

It might be an incomplete repair. the plug being used to allow the drilling of the stitches closest to the hole. I would likely
drill all but a ring of it out. or remove it and use a die grinder to smooth out the protruding stitch bumps. Jim

 

[rustred]

what i am wondering is how thick it is? and what are those other 3 plugs for on the bench? sure appears like that head never got finished. i
am presuming the plug should ahve been removed then the head run on a milling machine, as there looks to be scatches on the surface. looks
like it needs .010 removed. they might have just stuck it aside once the customer abandoned it. that is usually the case, or the custmer
could have even told them too much cant afford that. myself i would not remove the whole plug , just drill it 3/4 of it out. not going to
hurt a thing on an engine not worked hard for hrs. on end. and a bit more ,... the head should be stored on a cardboard, to prevent
scratching the surface once its machined. just pulling the head on a metal bench will scratch it.

 

[D Slater]

Can't tell you much for certain since IH made so many changes related to the heads. Does show some heads used two plugs made of brass or stainless steel one inch diameter. Think you have smaller diameter hole. Does the head have a casting number near number one injector? Only head I have to look at off engine is a later number than a MD and some holes are different from the pictures. Can't find any plugs in that head.

 

[redforlife]

A guy once told me that the back cylinder would get less coolant circulation because of the nature of where it's at. I never really thought about it before, myself. But it does stand to reason. The inflo coolant has to travel through the block without going through the head water jackets to get to the back cylinder. Then it has to travel through the head past all the other water jackets to get back out the outflow. So, in my opinion, a water jacket plugged off at number 2 cylinder, would only increase water flow to the back of engine. I don't think that would be a bad thing myself. I don't think it would make the area around #2 run any hotter than around what #4 would normally be.

 

[the tractor vet]

Now ya got me scratching my head , Ya know how long it has been since i have had a head of one of them old engines . I sold my 450 D WAY back like 73 or 74 and the last 450 D we took down was in 1980 that belongs to a close friend and we found a cracked block with crack in two cylinders . Back then he did not have the money to repair it nor afford a used engine . It is still in pieces . I could go lok at that head tomorrow as it is setting on the pallet where we stacked it back them . while i was doing the T/A and clutch on his 966 last week he made mention that before i check out he would like to get it back running again . Use to be around here we had a few M D's thru 450 D's . Three of us had 450 D's . My one friend and i farmed together with two 450 D's back then we pulled two 4x14 540 semi mounts .

 

[Brad Motheral]

I would like to remove it completely but I don't want to compromise the stitching.

 

[Brad Motheral]

I really hope you don't think I would drag a head across ANYTHING without protecting the surface.

 

[Brad Motheral]

I'm pretty sure that's why they put the restrictor plugs in initially as well. They were trying to get more coolant flow to the back of the head and block.

 

[Brad Motheral]

Head is a 260869r4. Has a Y casting
date(1953).

 

[rustred]

it was not meant that way,.... its just a bit of info for anyone. i have seen people do this. lots of people read these posts. and also for example just stick in the back of a pickup.

 

[D Slater]

Have that head number but don't remember how head gasket surface looks. Did find when head 260898R4 was replaced by 260898R5 that two core openings being between 1 and 2 and 3 and 4 at bottom face of pre cup side of head, 1.000 to 1.003 by 5/32 deep were eliminated. Later replacement head 277098R1 is what I have off engine and after checking it doesn't show the bronze plugs expansion plug 256659R1 or steel number 172545 being used on those heads. Found the 277098R1 on late MD through 450 as a replacement head, but was original equipment on most or all 450. Shows plugs used on D-264 engines until later half of 1956.

This post was edited by D Slater on 03/06/2022 at 06:42 pm.

 

[560Dennis]

Never seem that md head design , does the head gasket (left side) have those restrictions ?
Looks like left is blocked off for more heat .
Not answering your question but just want to understanding md coolant (diesel ) system .

 

[D Slater]

looked some more at two cylinder heads 277098R1 removed from D-264 engines. Head gasket 53436DE was used, with restriction for the 4 holes you show four of in picture made in gasket. Hole you have plug in was wide open on those. Does your head gasket have a number?