Build Isuzu 4BD1T Lexus LX450 (Land Cruiser) Build

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gerg said:
Ahh yeah, I can see how it would only take that happening once to sour your opinion. I've not really heard of breaking head bolts off. Wow that would suck. You must be super human to break them Doug. Shesh.
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Wheelingnoob said:
I have done it before, it sucks! Fortunatly I was able to get it out after a great deal of work.
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Yeah I'm an animal. I helped a mate out with the head on his Mazda diesel ute a few months back. Only snapped one off and it was a tiny 8mm which was next to the exhaust manifold so it was ideal rust temperature and it was getting water weeping in from the failed gasket. Rusted in tight and snapped off clean. Took about 2.5 hours to drill and chip it out then re-tap the hole. No way was it ever going to unscrew.

But because it was a bolt, the head came off easy. If it was a rusted in stud I don't know what I would have done.
 
On the topic of broken head bolts...I've slowly been helping my pops on his model T. We rebuilt it about twenty years ago and this summer it blew the head gasket because it was low on water. It has head bolts and we've broken three or four of them. Apparently metallurgy has improved since 1927 :-). Bummer is these bolts didn't break off flush with the deck. Now they are pins and we can't pick the head up far enough before contacting the body. Looks like we'll have to pull the whole engine trans now :-(

Sorry...not really on topic... But wanted to commiserate with ya a bit. Hope this week goes well for you and there's a clear smoking gun...
 
Well today I had a few hours to start taking the head off and got to it. Went well and 3 hours later the head was off.



Cylenders look good, the sleeves are not even polished and still have the dull coating on them engine deck looks good with no signs on HG leaking there.




I peeled the HG off the head and it was very clear where the issue was it was between cylender 2-3 and 3-4. You could clearly see on the HG and the head that it had been leaking a lot there. The HG was not damamged or missing anything it just seems it let combustion gasses in there and the cooling gournals in that area.

2-3


3-4


Head 2-3


Head 3-4





So at this stage the head is ready to go out and get crack checked (did not see any with my eye and a magnafying glass). Its also getting checked for flatness and decked if its out. And the valves are getting a full rebuild this time not just checked. Hope to have that back in a week if its not cracked.

None of my head bolts showed any signs of damamge or streching but I have new ones so will use them instead.

My turbo is pumping a fairly large volume of oil into the intercooler piping so its going out for a re-rebuild too.

I have a question about the burn patterns on my pistons. I thought the injectors and corasponding soot marks shoud be in the bowl of the pistions not on the lip of the bowl but im not sure I have never looked at one after its been run. Any input? To far retarded? Worried maybe that is why my cold starts where so hard at just 5c its smokie and cranky for the first few min. Again maybe this is due to the HG issue?? The change was very noticable it started great one day and then not good the next and has stayed that way.

Cyl 4


Cyl 3


Cyl 2


Cyl 1



Also one cylender seem to have a slightly shinny soot ring at the top of the sleeve almost like its using oil, all the others are dry or very very little. This is also the cylender that checked a bit lower than the others on a compression test a few weeks ago.

So today was a success, I found my smoking gun.
 
Great to finally have a cause for your woes.

The turbo leaking oil, I'd check the drain and crankcase pressure. As you know, turbos normally only leak significant oil when the pressure gets higher in the drain than behind the compressor wheel. But a dodgy seal is always a possibility too.

As I've mentioned before, I'd advance your timing until it starts nailing and then back it off until it smooths out. See how that compares your your current timing marks. The torch marks on the pistons do suggest retarded timing.
 
Great work. Any guess what the gasket didn't seal? Just non oem issue maybe?

Pumped you'll have it together and sorted
 
Pictures of the cylender liners showing the oily black build up on cylender 2. You can see on the others its much less. This cylender was the one that was slower to build pressure than the others whwn I did a compression test.



 
gerg said:
Looks bad, but good Jerms. Should we get the glass table out and some big emery paper and deck your head? I always wanted to do that. Glad to see it's an obvious fail rather than inconclusive.
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PMing you now.
 
gerg said:
Looks bad, but good Jerms. Should we get the glass table out and some big emery paper and deck your head? I always wanted to do that. Glad to see it's an obvious fail rather than inconclusive.
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How flat do you think a glass table would be after a few years? That stuff sags right?
 
Tonight I was able to get a water stone and a few lapping supplies. I also got a persicion straight edge to test the flatness of the head. I cleaned it with a solvent to get off all the old silicone gasket material and copper gasket. I checked it down to .001 and the feller did not go under it at all. So no warped head!! Some good news finally.

So I started at it with a lapping stone. I started off with a fairly dirty head surface, no damage just stains and what looks like fast cut on a head decking machine before I got the engine. I have been told by quite a few not to deck to head so im just going to lap it by hand and get the surface as smooth as I can get it.

Working at it...


After 20min..





After 40min..





That was all my arms could handle for the night.So far its going well. Im very slowly getting the machining texture off or down to a point it should not effect HG sealing.

I work through the weekend but plan to use a slab of glass and some lapping paper to get the final finish on it. Then its going out to get the valves done and checked for cracks. I cant see any with a close inspection so am hopfull.

Injectors are getting droped off to have the pop pressure checked so im not fighting the timming for no reason. My throught is maybe the pop pressure is to high causing the ignition event to be retarded causing the burn patern on the pistons, the hard starting cold and high EGT'S/boost issues. Well see what they find.
 
Dougal said:
That looks pretty sharp and clean. I'd happily bolt it up.
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Thanks, I'm happy with how well its cleaned up as well. No pitting and only a very slight mark in a couple spots from the fire ring. Ill hopfully finish it up tonight so its ready to go out and get the valves redone and checked for cracks.
 
Good progress... Is there a spec on how much the liners can protrude above the block deck? Any ideas on what caused the HG to not seal properly?
 
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