12h-t freshen up and swap

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mcguirejohnson

mcguirejohnson

10 Year
Joined
Oct 16, 2011
Threads
58
Messages
1,353
Location
Colorado
Hey there,

I have a thread over in the 60 series section, but I figured that I should start one over here for the diesel related stuff.

I am swapping a JDM spec 12h-t into my 87 FJ60 and yesterday I began the madness. So far everything is looking good, green coolant out of the water pump, OEM filters and belts. I got the motor stripped to the long block and then got the head off. I am going to check later today and make sure that everything is within spec using the FSM but so far it is all looking good.

I am hoping to just have to clean and reseal the motor in preparation to the swap using OEM gaskets.

The only issue that I can see so far is my injector tips seemed to be a little gummed up with carbon so I am going to get them tested and then act accordingly. Anyone know of a place here in the states that sells rebuilt or rebuild kits for these?

Pics will follow shortly. I will update as a go along!


-McGuire
 
Pics from yesterday, nothing interesting yet:
ImageUploadedByIH8MUD Forum1437227043.588521.webp

ImageUploadedByIH8MUD Forum1437227071.386783.webp

ImageUploadedByIH8MUD Forum1437227084.141907.webp

ImageUploadedByIH8MUD Forum1437227141.470868.webp


Swap candidate:
ImageUploadedByIH8MUD Forum1437227166.764260.webp
 
I have a few general questions for those tuning in.

Would it be wise to install a fresh set of rings and give the cylinder walls a fresh hone since I have it torn down this far?

Also what is a good way to give the injectors a good clean? There is evidence of carbon build up on the tips (I will take picture for reference if needed). The #6 cylinder looked wet compared to the rest so I am thinking that injector might not have a proper spray pattern. After researching a bit on the web it seems that getting replacement injectors here in the states would be rather difficult.
 
Unless you are boring the cylinders and installing oversize pistons I would not hone the cylinder walls. It will increase your piston to wall clearance and could cause some piston slap when cold. You could potentially pull the pistons and check your ring gaps and maybe replace your oil control rings if you wanted to get crazy with it.
 
roma042987 said:
Unless you are boring the cylinders and installing oversize pistons I would not hone the cylinder walls. It will increase your piston to wall clearance and could cause some piston slap when cold. You could potentially pull the pistons and check your ring gaps and maybe replace your oil control rings if you wanted to get crazy with it.
Click to expand...

Next step is to check the clearances. I didn't think about how it would make the ring to cylinder wall clearance greater.. The only reason that I was throwing the idea out there is because there is a small amount of surface rust on the cylinder walls. I put some marvel mystery oil on the walls to make sure that it doesn't continue.
 
You will need to strip this engine right down, there 30 years old and they don't run for ever, valves need reseating, valve stem seals, head plain, rings, bearings, full gasket set, new turbo CHRA, block chemically cleaned, new welsh plugs, etc. The one item you don't rebuild will be the item that will fail? then injectors rebuilt, IP service.

You can buy a full rebuild kit with new pistons, sleeves etc, for around $1,200 to $1,400 AUD, I enjoy rebuilding 12ht's and have now started another rebuild for another project.

IMG_1368.webp


IMG_1366.webp
 
watrob said:
You will need to strip this engine right down, there 30 years old and they don't run for ever, valves need reseating, valve stem seals, head plain, rings, bearings, full gasket set, new turbo CHRA, block chemically cleaned, new welsh plugs, etc. The one item you don't rebuild will be the item that will fail? then injectors rebuilt, IP service.

You can buy a full rebuild kit with new pistons, sleeves etc, for around $1,200 to $1,400 AUD, I enjoy rebuilding 12ht's and have now started another rebuild for another project.

View attachment 1109146

View attachment 1109147
Click to expand...

Hang on give me a second to wipe up my drool...

Okay I'm good. That motor is a piece of art man.

I completely understand where you are coming from stating that it is a 30 year old motor and it should be gone through. The problem is, I have a hard time justifying doing a full rebuild when everything is within spec according to the FSM. The motor has fairly low miles (150,000 ish) or 260,000km and before I took it apart there were little to no leaks at all.

I believe in the saying that "if it's not broke, then don't fix it" and honestly I think that it will serve me another 250,000 km before I need to completely overhaul. It will happen eventually, but just not at the moment.

I will be replacing things like the water pump, thermostat, main gaskets, etc., etc.
 
watrob said:
Looking at the oil residual in the turbo you have got blow-by or the CHRA needs replacing? how much oil is in the ventilation hose that goes from the rocker cover to the inlet housing?
Click to expand...

The only oil that I could see on the turbo side was what is seen in the picture. The ventilation hose seemed dry. What is the CHRA?
 
watrob said:
CHRA, a complete internal for your turbo housing.
View attachment 1110093
Click to expand...

Ah thanks for the pic. Ya I think I am just going to get a turbo seal kit off of eBay and save up for one of those g-turbos before I dump money into this one. Later down the line of course.
 
If the oil in that turbo is from the bush on the turbo spindle you would be far better off getting a new CHRA for $180. Its no use pulling the old CHRA apart if the shaft is warn. You need to check if there is any side ways movement in that CHRA.

Once you put the turbo back on the 12HT its a big job trying to get if off the engine while its in the vehicle, also you are talking about striping down the CHRA and replacing the oil bush and seals, how are you going to rebalance the CHRA? the CHRA's parts are machine balance up to 150,000 revs, the completed assembled CHRA is then rebalanced and the nut on the end is then shaved, this is done to see if there are any harmonics at high revs of the assembled CHRA.

So just pulling it apart and putting it back together may make it worse?
 
Good luck with this swap. I've got a 12H-T in my 60, best mod ever! I just had the head gasket replaced, did the whole head.
It hadn't failed, just a preemptive strike on a small seam leak. I'll follow along as see what you learn. J
 
I'll be following along to see what unfolds too? I am on the same thoughts as McGuir and cruiserpilot, hopefully just doing gaskets and some minor repairs. If I get the all clear after my diesel mechanics diagnosis I will leave it till something fails and then do a major rebuild later.
I would love to do what watrob has done ( its a piece of art and a credit to him) but it is way above my knowledge so I would have to pay someone big $$$$$$ when I could get another 3 - 5 or more years out of it as is.
 
watrob said:
View attachment 1109146

View attachment 1109147
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I just want to say that I really, REALLY want to win the lottery for the sole purpose of contracting you to build me an engine like this!

Also, I too will be watching this thread to wee the final result. I have been toying with the idea of rebuilding my turbo because of an oil leak in the area. If I do have to take it off, I might as well rebuild it! Lol
 
Hey, where are you sourcing your gasket kit from? You are going to use Toyota head gasket on this aren't you?
Are you doing any work to the head?
When I did my head gasket I have only slightly over 200,000 K on my motor and it was in perfect running order.
Like yours it had not failed, but I still did the full valve, guide, seal, deck of the head. My guy also was very
adamant about using only Toyota gaskets.
 
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