Head Gasket replacement for LJ78 (1 Viewer)

GTSSportCoupe

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The pitting is common when the heads on these have been cracked for a while and driven that way. It's from the coolant/water that leaks into the cylinder while the motor is running. Some say the water mixes with diesel exhaust and creates sulphiric acid or something like that which then eats at the cylinder walls. As ugly as it looks, you might be fine to run it as it is. As long as the pitting does not extend down to where the rings travel. In fact, every 2LTE short block I've seen apart has at least some of that pitting from when the first gen head cracked. If your compression was good (easy clean starting) before you took the motor apart, then you're probably good to go. It's depressing, I know.
 
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The pitting is common when the heads on these have been cracked for a while and driven that way. It's from the coolant/water that leaks into the cylinder while the motor is running. Some say the water mixes with diesel exhaust and creates sulphiric acid or something like that which then eats at the cylinder walls. As ugly as it looks, you might be fine to run it as it is. As long as the pitting does not extend down to where the rings travel. In fact, every 2LTE short block I've seen apart has at least some of that pitting from when the first gen head cracked. If your compression was good (easy clean starting) before you took the motor apart, then you're probably good to go. It's depressing, I know.
The pitting is above the the piston rings. So, should I just replace the head, and not worry about the block?
 
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That sucks man, my cylinder head was cracked in between every single valve as well. Replaced the head and I was good to go again. I don’t recall pitting in the top of the cylinders though.
 

GTSSportCoupe

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The pitting is above the the piston rings. So, should I just replace the head, and not worry about the block?

Did you ever have a compression test done? How did it start in colder weather? If compression was fine, you could probably leave the bottom end alone.

Can you get some better pictures of the pitting in each cylinder and post them here?
 
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There is pitting in 1 cylinder only. other 3 are clean. Please see the attached pix. Please zoom as needed to get a closer look. Thanks for the help 👍🏻

cylinder pitting no zoom.jpg
 

GTSSportCoupe

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Can you comment on how it started/ran before the cylinder head problem? That is what is most important. Or compression numbers if you had a test done.

The piston in cylinder one is at TDC in your picture, so I can't see the cylinder wall at all. Can you take a picture like this (but of the cylinders with the damage?)

SAM_0216.jpg
 
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Can you comment on how it started/ran before the cylinder head problem? That is what is most important. Or compression numbers if you had a test done.

The piston in cylinder one is at TDC in your picture, so I can't see the cylinder wall at all. Can you take a picture like this (but of the cylinders with the damage?)

View attachment 2108264
After the pre-HEAT, the cruiser always started on first turn. No misfires or rough idling. It's all original with all the emissions in place. Opened and cleaned the intake. It was clean already. 3 cylinder surfaces have no pitting. Sorry, I did not take pix of all cylinders, and I am out of town currently. I felt it had a difficult time accelerating to 40mph (slow on 1st and 2nd, 3rd onwards is good) but after that it was all good. Based on comments from other owners, it seems the slow acceleration is normal. My other car is a BMW, so, it's all in expectations. Then suddenly, over heating began. The reservoir coolant will begin to bubble in less than 10 min....perhaps 5 min. The only coolant leak was from the reservoir overflow. During a start after a overheating episode, the cruiser will start on first turn, it misfires and rough idles for Around a minute. Heavy white smoke during the rough idle. Then back to normal, smooth until it begins to overheat. Thank you
 

GTSSportCoupe

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Sounds to me like the bottom end is fine. As horrible as it looks, I think you're good to continue using it. Throw a new updated cylinder head on there and keep on truck'in.

Misfire and rough idle after the head completely cracked is most likely from coolant entering the cylinders in a much greater volume than it had been initially.
 
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Sounds to me like the bottom end is fine. As horrible as it looks, I think you're good to continue using it. Throw a new updated cylinder head on there and keep on truck'in.

Misfire and rough idle after the head completely cracked is most likely from coolant entering the cylinders in a much greater volume than it had been initially.
I ordered a head. Patiently waiting for its arrival.
 
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Any progress?
Thanks for keeping me moving forward. I ordered the head with cam installed etc. It came from Melbourne, AU to Cincinnati, via customs in Los Angeles in 18 hours....wow. DHL delivered 1of2 boxes, with the head bolts, and gaskets last Wed. After many escalations, and an email to the DHL CEO (he responded), the head was delivered yesterday. The installation work will begin tonight.

One of the head dowels is bent. Its about a 1/3 of an inch tall. Do I need a replacement dowel or is it just used to make it easy for the installer to line up the gasket and head correctly?
 
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Well, sorry for the delays, but happy that you are moving forward again - best of luck! I hope all goes well for you.
Regarding the question about the bent head dowels - sorry, I am over my head on that question. Maybe one of the smarter guys on the board will chime in.
 

GTSSportCoupe

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I'd take that dowel and some pictures of your block to your closest automotive machine shop, and ask them what you should do. Maybe they can give you a new one, and instructions on how to press it into the block with engine in truck.

Having done a couple cylinder head jobs on these motors before, here is my advice for the job.

The head gasket is a multi-layer steel design. They're awesome, BUT they need perfectly clean/flat block deck and cylinder head. So, you need to clean the surface of your block really really well. I used a gasket scraper tool and went through many razor blades. You really need to take your time and do a good job. Use a vacuum to suck up the debris as you work. Scotch brite pads work well for a final scrub after scraping; but you have to be careful not to get the abrasive into the cylinder bores, or oil drain ports.

Blow out all the head bolt holes with compressed air. Rinse them with brake clean, and blow them out again. Spray a bit of lubricating oil in there, and chase them with a tap. Repeat the rinse/clean/blow.

When you install the head, make sure the crank pulley is at 0 degrees, and the cam shaft is at 0 degrees, otherwise the valves might hit a piston as you life the head onto the block.

Make sure to follow the factory manual to a 't' with installation of the head and head bolts. Add a bit of engine oil to the threads of each head bolt, and under the head of the bolts. This will help lubricate them and give better torque consistency when you install them. Follow the torque procedure carefully: torque in the right order, and multiple passes.

Take the time to clean all your parts well. Especially clean the intake manifold. It's also a good time to block off or completely remove your EGR system. I also recommend removing the throttle plates in the throttle body; lots of info on this in the various LJ78 build threads.

While your coolant is drained, you could also get your radiator checked or even re-cored. Go with at least a 2.25" core thickness. I also recommend going to Evans coolant if you really want to protect that shiny new head indefinitely.
 

FJBen

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Great advise, however I would stay completely away from scotch brite pads IMO.

I would also replace any coolant hoses, flush the block, heater core and a new water pump. Good time to test the fan clutch as well. Get that cooling system in shape :cool:
 
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Great advise, however I would stay completely away from scotch brite pads IMO.

I would also replace any coolant hoses, flush the block, heater core and a new water pump. Good time to test the fan clutch as well. Get that cooling system in shape :cool:
I got a new water pump, timing belt kit, a new fan clutch. The Intake is very clean already. The radiator was cleaned before, and it was also checked by a radiator shop. New hoses and drive belts. Thank you
 
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The new head is installed, the Cruiser is on the road again 👍🏻 I drove it around 30 miles today, in traffic and at highway speeds. The temp gauge is constant at around 4/10ths. The engine is smoother and quieter than it was before (I could be imagining 🤪). Pl let me know if you need the part#s of everything that was replaced. I got a complete head from Australia (unpack, and bolt on) for US$1000. Thanks for you help and guidance
 
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The new head is installed, the Cruiser is on the road again 👍🏻 I drove it around 30 miles today, in traffic and at highway speeds. The temp gauge is constant at around 4/10ths. The engine is smoother and quieter than it was before (I could be imagining 🤪). Pl let me know if you need the part#s of everything that was replaced. I got a complete head from Australia (unpack, and bolt on) for US$1000. Thanks for you help and guidance
 

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