LDT Head Gasket swap. How many shop hours?

[M543A2]

We had a multifuel head gasket, not the late type, blow at the back of the block. We found that earlier motors do not have a cooling passage at the back of the block like the the later ones do. The ones without this extra passage, when checked with an IR temperature checker, heat up really fast in the area at the back of the block shortly after start-up, staying that way until the whole engine temperature normalizes. This is why we consider it to be very important to have the engine temperature come up before putting any heavy loads on it. Our thought is that this hot spot can cause uneven shifting of the head/engine block interface at the gasket when it heats up before the rest of the engine, possibly contributing to blown gaskets there.
Regards Martin

 

[Tototex]

After watching some youtube videos of the spring compression tools, it doesn't look so bad. I'll pick up a tool and keep on working.

So for the valves, I need to remove the springs, clips, and pull those rods out. Sound about right?

Than I just need to remove the fuel lines, exhaust, and intake, than the head should pull off.

Than I just need to find a good machine shop! Hopefully no more surprises.

 

[Tototex]

Alright, someone just told me I can leave the valves and springs in. The head will come off with those still attached and the machine shop will remove them and do the valve job... that makes this much simpler. Thank you for that clarification!

 

[Tototex]

If I am only getting one of my two heads shaved, should I get the valve job on that one head or leave it alone?

I imagine only getting a valve job on one head could be an issue. I wasn't planning on taking the second head off since the gasket was just redone on that one a few months ago.

 

[gimpyrobb]

I would, but thats just me. As old as the motor is, I believe it to be a good practice.

 

[clinto]

There's no way I'd go that far and not do both.

 

[MG2936]

At 39000 on the overhaul my rear head gasget started leaking antifreeze. None in the oil but a lot on the firewall. I replaced it with the old style head gasget for the simple reason I didn't know there was an improved model. The engine was running fine so I didn't touch the valves, and I certainly didn't take off the front head.....those things are heavy. 10,000 miles later everything is still good to go.

 

[fsearls92]

Might as well do it since you already are going to have it torn down. The few extra bucks will give you reassurance you did it correctly.

 

[brianp454]

I always let my truck warm up for a bit before taking off. With the exception of when it was shut off for a short time, such as to drop books off at the library.

Do you have a pic of the cooling passage and lack of a cooling passage?

I think I've seen your truck. One of my childhood buddies lives in your neck of the woods and I recall seeing in on my last visit while driving around. Small world!

We had a multifuel head gasket, not the late type, blow at the back of the block. We found that earlier motors do not have a cooling passage at the back of the block like the the later ones do. The ones without this extra passage, when checked with an IR temperature checker, heat up really fast in the area at the back of the block shortly after start-up, staying that way until the whole engine temperature normalizes. This is why we consider it to be very important to have the engine temperature come up before putting any heavy loads on it. Our thought is that this hot spot can cause uneven shifting of the head/engine block interface at the gasket when it heats up before the rest of the engine, possibly contributing to blown gaskets there.
Regards Martin

 

[Tototex]

I've been toying with the idea of redoing the back head as well but my mechanic keeps saying "If its not broke, don't fix it." It seems crazy to have it this torn down and to just leave it alone.

Plus I know these heads can only be shaved down so much and the back head was just redone a few months ago. Shaving it again may cause an issue?

Do I need to pull the injectors out of the head? Or do I just disconnect the two fuel lines and leave the injectors in the head? I took off one of the injector bolts and saw a spring inside. I hope I didn't screw anything up. Put that bolt back on and figured I shouldn't be in there.

Finally, any ideas how to get the head bolts off from under the injectors? I was thinking a straight extension might work if I just leave it plugged in loosely. That or I need to weld some kind of S bar extension.

 

[porkysplace]

1916267]I've been toying with the idea of redoing the back head as well but my mechanic keeps saying "If its not broke, don't fix it."[/COLOR] It seems crazy to have it this torn down and to just leave it alone.

Plus I know these heads can only be shaved down so much and the back head was just redone a few months ago. Shaving it again may cause an issue?

Do I need to pull the injectors out of the head? Or do I just disconnect the two fuel lines and leave the injectors in the head? I took off one of the injector bolts and saw a spring inside. I hope I didn't screw anything up. Put that bolt back on and figured I shouldn't be in there.

Finally, any ideas how to get the head bolts off from under the injectors? I was thinking a straight extension might work if I just leave it plugged in loosely. That or I need to weld some kind of S bar extension.

Sounds like your mechanic is looking for "job security" when you take it back in a few months to do the rear head .

 

[gimpyrobb]

NO you don't NEED to pull the injectors, just be careful setting the head down so you don't rest it on the injector tips, lay it on its side. I made a wrench to get those head nuts off, another guy here in town told me an oxygen sensor wrench from horrible freight worked wonderfully.

 

[jacklegjim]

If you are going to have the head machined the injectors will need to be removed.
The injector tips stick out of the block side of the head. There are a few post on here
that show you how to build a wrench to remove the lower head nuts. I made a
wrench from a cut down boxed end wrench and welded a socket to the cut end.

 

[rustystud]

NO you don't NEED to pull the injectors, just be careful setting the head down so you don't rest it on the injector tips, lay it on its side. I made a wrench to get those head nuts off, another guy here in town told me an oxygen sensor wrench from horrible freight worked wonderfully.

An Oxygen Sensor wrench makes a lot of sense !

 

[Tototex]

I looked at the offset Oxygen Sensor wrenches. They look like they would work just fine and they are cheap as well. Under $10 most places online.

I am either going to buy one of those or make the device below I found on SS. Just cut a 7/8 socket in half and weld onto a piece of metal. Doesn't get much simpler than that and it wont break!



Also, I got my injectors off after calling the local motor pool to get some instruction. Just had to detach both fuel lines, remove both bolts on the bracket holding the injector in place, and it pulls right out. Some of the brass washers stayed in the head though. They will probably just fall out when I tip the head over after pulling it out. Not sure how else to get them out.

Now its just these 3 head bolts under the injectors and the head is off!

 

[Tototex]

Well, here is my fabrication.



It worked great. Just cut a socket in half with an angle grinder and then welded it to a flat piece of metal, than ground down the end that has the socket.

Pulled off my front head and it looked great. Gasket looked practically new. Both the block and head were a nice shiny silver. It must be the back head that is leaking. This is most concerning since I know the back head was shaved and given a new gasket by a competent mechanic about 100 miles ago. What would cause another failure? Cracked head? Warped block? Im pulling that head off tomorrow and taking it in to the machine shop. Will keep you guys posted.

 

[Tototex]

Welp, the issue was in the rear head. Got the rear head off and there were obvious leaks from each of the pistons to the antifreeze. The 3 bolts under the injectors were not torqued. I was able to unscrew one of them with just my hand. So there is the cause.



Machine shop checked both heads and told me they are flat and the valves aren't leaking. They recommended I just clean them up and put them back on, just dont forget to torque the head bolts.

The mechanic who changed the previous gasket for me figures he must have forgot to torque those and has offered to pay me my hours for swapping the gasket myself. He is a good guy and mistakes happen.

My brand new gaskets came in the mail and the box was folded in half. Would you guys use these or recommend returning them? You can see where the piston ring on the gasket is pulled away from the gasket material because of the bend. Makes me nervous.

 

[Wildchild467]

I feel like I could swap head gaskets in about 8-10 hours. I have gotten pretty good at it.

 

[gimpyrobb]

Nope! I wouldn't use them.

There is a torque sequence for putting the heads back on, Make sure you use it and you won't miss any of the nuts. Now you have to find out if you have a thick deck motor or not- that will let you know which torque settings to go by.

Look on the block, just above/behind the alt. If there is a TD cast in the block, you use the higher torque value.

 

[rustystud]

My brand new gaskets came in the mail and the box was folded in half. Would you guys use these or recommend returning them? You can see where the piston ring on the gasket is pulled away from the gasket material because of the bend. Makes me nervous.

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Just like Gimpyrobb said, "Don't use them !" . Send them back and "Demand" a refund !