1978 HJ45 Troubleshooting help needed (1 Viewer)

Joined
Oct 24, 2017
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Hey troops,

I really need some help from the experts. I'm an engineer and have run through every permutation I can think of to fix this rig. Now it's driving me crazy.

I have been slowly restoring my 1978 LHD HJ45 with the 12Vdc H Diesel motor in it over the past 3 years. Unknown mileage, import from Columbia. As you can see from the pics, I have a lot of time and $$ invested in making it look and run great again.

I've replaced the injectors and glow plugs and both of these items are working great now. I've adjusted the valves per the manual with the engine warm. It starts right up after a 20 sec morning glow but smokes black a lot, runs very rough and does not want to accelerate without loading up really bad and smoking black even more. If I drive it around and force it to accellerate while all black smoke pours out, eventually it clears up some and the smoke decreases substantially except at full throttle. It does not have much power though. I live at 6800ft and tried adjusting the HAC for max fuel just before smoking too bad and it helps, but creates even less power. I have installed a Wilson switch and am using 10V glow plugs so I can do a manual glow whenever I want. If I glow after start, it helps clear up the idle but when I let off it loads back up again. Engine shakes quite a bit.

Earlier, I replaced the pneumatic governor diaphragm and tested that it held vacuum. I've bled the fuel system countless times per the manual, new air filter, new oil and filter, new fuel filter, fuel lines and cleaned fuel pump screen along with new coolant, hoses, thermostat and cap. New valve cover gasket, oil cap, new intake, venturi and exhaust gaskets. I used all OEM part$$.

I pulled the radiator cap off when I started it yesterday and sure enough, I had bubbly and frothy new coolant. So, I figure head gasket must be shot. Before pulling the head and going through all those motions, I did a compression test this AM via a diesel compression tester through the glow plug holes.

Here are my conditions of the test. Cold engine(likely would be higher warm but just wanted a baseline), 70 degF air temp. Here are the results, tested twice and averaged results(they were within 2 psi)

Cyl - first fill - final fill
1 - 179 - 330
2 - 162 - 318
3 - 160 - 302
4 - 163 - 300
5 - 170 - 318
6 - 180 - 320

The H service manual says 421 PSI new, 284 PSI limit and 28 PSI difference. Clearly the motor is worn and the overall numbers are low, but still within spec. The difference of 30 PSI between One and Four concerns me. I was honestly expecting to see much worse since the coolant is so bubbly.

With these compression numbers, what should I check next? I do not have a leakdown tester unfortunately. I'm really frustrated and do not know what to try next or where the blowby into the coolant could be coming from.

The oil did not have coolant in it and the coolant did not have oil in it so they are not mixing.

I know putting $$ into the H is not ideal but that is what I have and 2H motors don't exactly grow on trees in the states.

Help please, suggestions/tips greatly appreciated.

Thanks,

Mark

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Joined
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Black smoke usually indicates too much diesel (white smoke is timing/combustion temperature and blue Smoke means burning oil).

Next test would be to remove the oil filler cap and see how much blow by is occurring... it’s hard to describe but there should be a little bit of air/exhaust coming out. Say around the same amount you normally breath out during a normal breath.

If there is a lot more coming out under fairly high pressure it indicates either worn rings or valves not seating correctly.

If blowby is acceptable it could be the injection pump needing an overhaul/rebuilding, might be injecting far too much diesel.

You said the coolant was fresh but frothy, any signs of oil? Frothy doesn’t explicitly mean a blown head gasket.

So from here you can either rebuild the engine (they are actually really easy to rebuild). You’ll be up for say $1200-1800 in machining costs and between $1000-2000 in parts depending what needs doing.

Tearing the engine down won’t cost you much (apart from time and tools) and give you a better idea of what needs doing.

That said, that’s a really nice rig you’ve got there. Not sure what your skill level is but there are lots of good diesel swaps kicking around. A 12HT should bolt straight in although harder and expensive to find, a 1HZ will fit although that might require a custom bellhousing or mods to make the H150 fit, or there are some cost effective merc deisels floating around.

The H is a reliable engine but I would personally rather spend money on something a little more modern/powerful.

Cheers
 
Joined
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Adelaide, South Australia
Frustrating for you.

Have you ever run the engine with the exhaust manifold off. I'm curious if you've just got an issue with a single cylinder or not and its difficult to tell with the manifold on. With the manifold off you can see the exhaust from each individual cylinder. It can provide a lot of insight. The frothy coolant is concerning though.

Take some videos and post if you get a chance.
 
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Good tip on checking with exhaust manifold off. I will try that next.
 

RufusTheDufus

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Sounds like you're going through some of the same troubles I went through with the H that I had in my Troopy a while back.

I had an intermittent head gasket leak. The only way I was able to diagnose it was using a chemical tester kit for the cooling system. You can do a search here in the forum for the brand. There are different versions for gasoline and diesel engines. They detect the presence of combustion gases in the coolant. You could have a bad head gasket, or a cracked head. The H heads are known for cracking.

If you're able to drive it I would recommend a course (or two) of Auto-RX. Or if you can find the quicker acting GM ring cleaner kit you could give that a try. (The GM kit is hard to find these days.)

I eventually gave up on the H. I foolishly put a turbo on mine. It ran great for a while. But it got to the point I couldn't keep a head gasket in it. My HJ45 had a sex change and is now BJ45.
 

RufusTheDufus

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BTW, I have a spare head gasket for the H somewhere in my garage. I had a few custom made. I'm happy to send one to you for the cost of postage. I'll never need them.
 

ceylonfj40nut

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Besides blow by on valves, also check your throttle butterfly valve is operating as it should. Is the air filter clean? You are definitely at higher altitude. Do you need to adjust for this per FSM? Have you cracked open each injector feed line at the injector and cranked it to see if diesel flows?

I have a whole slew of H parts that I got with a HJ45 my son and I are restoring. Let me know if you need something. I might have it.

Really great looking rig. Love the wood bed and green combo. Love the wheels.
 
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Rosco: I just replaced my injectors with rebuilt ones from Hi-Tech Diesel in Kilburn AU (Hi Tech Diesel Injection - Diesel Fuel Injection) They use new nozels and use a pop tester to set opening pressure per spec. before shipping them.

Ceylon: I have fuel at each injector and have replaced/checked all those items well. Thanks for the offer on parts, will let you know. Thanks for the compliment, hundreds of hours invested in this rig...

Rufus: thanks, I read about all your challenges in your posts as well. One thought I forgot about, when I first bought the HJ45 a glow plug broke off in the head while removing it. I had a machine shop/mechanic shop take the head off and laser drill out the broken plug. I provided a top end AJ-USA Headgasket to them for re-assembly as well as the factory manual. I checked and it looks like from 1973-1977 Aug the H used a head with a Tear Drop shaped oil supply port and then from 1977 Sept to 1981 they switched to an OVAL shaped oil supply port.

I don't know when my motor was manufactured so I assumed the later design with the Oval port since mine was a 1978. If mine was actually the earlier Tear Drop design, would this mismatch shape around that back side of the head cause what I am experiencing? What head gasket years do you have? Does anyone know if there were any other differences between the early and later H heads?
 
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ceylonfj40nut

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I am not sure if this will help. This is the OEM full engine gasket kit I have for an H engine. It has a good picture of the headgasket.

My son’s HJ45 is a 1978.

I also have a rebuilt head. Not sure if the port side matches what you are referring to.

We are going the 2HT route. H parts are going to be sold.

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Interesting. It looks like this is the later style head gasket with the OVAL port. Top left corner of your gasket picture. Please set these aside for me in case my head is cracked. I ordered the head gasket leak test chemical/kit Rufus mentioned this morning so will hopefully know soon. Where did you source a 2HT from?
 

ceylonfj40nut

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2HTs are built. My son who is 13 is getting his first engine rebuild. We tore down a 2H, putting all new wear Parts in from Engines Australia, Alfin pistons (used on the 12HT). We are going to install a AXT turbo kit. Run it at mild boost.

Someone has inquired about the head and other parts but has not committed yet. Let me ask and I will let you know.

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Rosco: I just replaced my injectors with rebuilt ones from Hi-Tech Diesel in Kilburn AU (Hi Tech Diesel Injection - Diesel Fuel Injection) They use new nozels and use a pop tester to set opening pressure per spec. before shipping them.

Yes, Im aware of how they are rebuilt, but have they done it correctly?
I cant think of what else would be causing huge amounts of black smoke, you obvioulsy dont have a blocked air supply.
I dont have any experience with diesels at 6800ft, but I thought they would have run better than that.
Whats its like at sea level?
 

ceylonfj40nut

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We have an annual event SAS in Ouray Colorado where we trail ride well above 10,000ft ASL. Many diesel cruisers. None adjust their engines for altitude. Very little if any black smoke. Usual cause is too much fuel, too little air, both, poor compression leading to poor combustion. Did you check you intake throttle butterfly valve for position issues?
 
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The intake butterfly appears to be operating correctly from what I can tell. I replaced the accelerator cable and adjusted it per the manual. It is in it's most closed position at idle and goes wide open with the accelerator pedal to the floor. I have a slight slack in cable at idle. Do any seals go bad on the butterfly shaft that could cause a vacuum leak? Any other ways to test it?
 
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ceylonfj40nut

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Looks like it is working well. No gaskets on butterfly valve. If slack of cable at idle caused your issue, it should clear up when you floor it.
 

ceylonfj40nut

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I went through your description one more time. You mentioned when you used the glow plugs after a start, it clears up the idle some. Only thing the glow plugs do is add heat. Only other way a Diesel engine create heat is compression. Leads me to think it’s your lower compression numbers. They are within the low end of spec. Has the engine ever run well? What happens when you glow as you accelerate?
 
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It ran OK once warmed up but still lower power and a lot of sputtering. Will have to try glowing while accelerating. If I glow while revving parked, it seems to help a bit but not much.

BTW: I am reading your Old Landy post. Very interesting read.
 

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