HELP! Me spend my money wisely – 12HT

[Billyfj7312ht]

I am about to embark on the “mechanical” side of my build and knowing nothing about motors I was hoping some members could point me in the right direction to get the most out of my $$.

I purchased a 1989 12HT 24V motor from a HJ61 with 235k , I saw a video of it running a couple of days before it was removed. It is now in my FJ73.

My intentions are to have a 3” dump pipe and exhaust and a front mount? Intercooler. I will be using the vehicle for moderate 4WDing and Med-long road KM.
Question: Before I move forward i would like to know what you guys would consider the minimum to make this engine safe and reliable, considering the access I have now?
*gaskets ? *bearings? *tests? Not including add ons and visual cleanup.

Thanks

 

[Oldtoy74]

While you got room to move, replace water pump, thermostat, hoses, flush and check radiator, I would replace as many gaskets as possible, ensure to replace front & rear crank seals at least, if your not confident mechanically get someone to rebuild turbo, and then then tune your boost and fuel mixture, adjust the valves clearances, get injectors tested and rebuilt or serviced if required, you will love the 12ht, it's great donk

 

[Locked79]

Triple turbo. Oh yeah








Hmmmmm. Maybe not so wise.

 

[absalom]

I have the 1-HDT and the 12HT still makes my pants tight.

 

[ozcrusier]

I would recommend doing a comp test and if all is well have it dyno tuned then add a couple gauges for boost and temp.

 

[Sooke]

You are going to love it! pre-turbo temp gauge a must if you plan on increasing boost and or pull a load. Easily installed after build is complete. Enjoy....

 

[Tapage]

boost, pyro and oil pressure gauges are basic IMHO .. also replace as many hoses/belts as possible, not only coz it's easier now, but also coz you don't know if are going to be available tomorrow ..

 

[REDREEFER]

Hey there Billy, nice project BTW, that will be one nice 73!

I have included a pic of a problem area with both the 2H and the 12HT......this pic shows the gasket area at the top of the timing gear case that cannot be seen with the water pump in place. Just about every 2H or 12ht that I've had anything to do with has either had this gasket blown out or is starting to blow out. If yours is severe I would recommend going to the effort of replacing the gasket with a new one. Or at the very least a thorough inspection at the time of water pump change.

Others have already mentioned some great points but I would add the removal of the rocker shaft for carful inspection for any wear.or damage to the rocker contact faces as well as the valve steam tops. The valve rocker arms on a solid lifter motor do take a beating over time and can wear quite badly when they are not regularly adjusted.

I wish you luck with the build!

Rob

 

[Billyfj7312ht]

Much appreciated everyone. I have started a list and will post the final "to do" list before I start.
Because I want to be able to do my own servicing and track side trouble shooting I have decided to use a guy I know (retired mechanic) to help........well I will help him really, once I have a direction to take and purchase the parts required. That way I learn as I go along.

Thanks @REDREEFER for your in depth post that is handy information.

 

[Billyfj7312ht]

I have started stripping the externals of the engine this week and Al has worked a game plan out as we've gone along.
I'm at the point of ordering parts which will take a few days to get in. I will post list and photos soon.
While I'm waiting I'm going to give the block,brackets and some pulleys etc a bit of a spruce up with a clean and paint.
One item is the bell housing plate to engine.
I am hoping someone could tell me if there is a problem with using the auto one I got with the engine ? I have the manual H55F now.
It has an inspection/access flap so you can make some adjustments/tighten bolts for the auto I think?
Should I silicone the original plastic flap in or rivet something over the hole???
Thanks

 

[roma042987]

nothing wrong with using that plate. check my 60 fix up thread in my signature of the refresh I did on my 12ht before dropping it in...you may want to do more than replace seals

 

[Billyfj7312ht]

@roma042987 Just read your thread, great build thankyou.

I noticed your inspection port has not been pressed out. Would you say I can just silicone the existing plastic inspection panel back in or should I rivet a neatly trimmed aluminium piece in its spot before painting? Just worried about sh!t getting in..

We have inspected the crankshaft, top end and lower bearings and Al is of the opinion that the motor is in great condition so I am rolling the dice on this and just doing what is needed.

I must consider the whole build………. and my wife’s sanity.
I still have a long way to go with this build and my train of thought is the motor has not done too many KM, Al’s seen the wear and his attitude for the internals is if it ain’t broken don’t fix it. After this build I will know a lot more about the 12HT and if it fails I will fix it. I won’t have lost any money, only time.

Stage 1 of motor freshen up:

· Front and rear crankshaft seals

· Rear crankshaft housing gasket

· Exhaust manifold gasket set

· Turbo return line gasket

· Valve cover gasket

· Side cover gaskets x 2

· Water pump to housing gasket

· Water pump to block gasket

· Thermostat upper gasket

· Thermostat lower gasket

· Ring exhaust pipe to manifold gasket

· Belt set

· Transfer case lever boot and retainer/seal

· Throw out bearing boot

90% are genuine parts and will post photos and part no’s when all in. The non genuine are japan non gen because they are viton seals not EPDM. I have to sleeve the crankshaft pulley centre because of a scratch but this is in stage 2 with other stuff like pressing some bearings out of pulleys and looking close at the viscous clutch fan etc. The aim is to get as far as I can before handing it over to a diesel specialist to test and inspect injectors and tune/fit what I can not.

 

[TLC Norway]

sounds good. I'd also install pre turbo egt probe, boost gauge and a mechanical oil pressure sender.
Do you have a build thread for the project? Looks like a good cruiser in the making!

 

[Billyfj7312ht]

sounds good. I'd also install pre turbo egt probe, boost gauge and a mechanical oil pressure sender.
Do you have a build thread for the project? Looks like a good cruiser in the making!

Thanks TLC. You can find my build thread here

So I have pulled most brackets,pulleys,pipes, manifold and turbo off. Cleaned the removed brackets etc on a bench wire wheel.
Cleaned the block with some degreaser and a small stiff brush.....HEAPS of times. Then some fine paper and solvents.

Painted block in just a standard industrial enamel.

 

[Billyfj7312ht]

I had to scrape some black foam from the motor?

 

[Billyfj7312ht]

I'm a bit disappointed in my supplier (internet store). Some gaskets were not labelled toyota and some seals were non genuine.
He tells me not every product has a separate label. I only went with this supplier because I wanted genuine so I ended up giving him the non genuine seals back and because of time restraints replaced them with non genuine seals from a local bearing shop I have dealt with for 20 years. I have just received a EPC CD that comes with detailed diagrams (which I need) in the mail so this should solve this problem.
I replaced every bolt,nut and washer I could

Al hard at work...

 

[ozcrusier]

She looking clean mate.

 

[Dougal]

Looking at that 12HT and comparing to an Isuzu 4BD1T, you'd swear the Toyota and Isuzu engineers were drinking buddies sharing drawings.

 

[TLC Norway]

Niiice!

 

[doug720]

Looking at that 12HT and comparing to an Isuzu 4BD1T, you'd swear the Toyota and Isuzu engineers were drinking buddies sharing drawings.

Funny, I was thinking the same thing. So many parts and design look like they could almost bolt on my 4BD2!

Nice looking swap. You will be happy you went through all this work every time you open the hood...Bonnet!