Piston pitting

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Jan 25, 2020
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Hi, first time posting on here. Figured it would be a good place to find advice. I have a 1990 hzj77. I’m having to replace the head gasket and found some putting on one of the pistons. I’d like to know if the experts out there think it’s merits piston replacement as well or if it’s no big deal. Thanks!
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Hi mate
The piston has had something bouncing around inside to cause that damage. Hard to tell but looks like some water damage in one of those cylinders. The head looks like it has cracks time for a replacement. I would pull the the pistons looking for broken rings also. I think it’s time for a rebuild or maybe a hone with new pistons if money is tight.
 

Gengis

 
 
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what made you think it was the head gasket? Syntoms for a cracked head are similar??

How many km's/miles on the engine??

George
 

roscoFJ73

 
 
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Welcome to the forum

I think it might be overheating. Last time I seen a 1 HZ piston that swallowed a metal washer, it left dents that shape in the soft piston top.
The cylinder head looks like the surface of a meteor after its passed through the atmosphere.
Someone had a HZJ77 on here a few years back that was pumping coolant out with the exhaust, I wonder if its the same one.
There is probably a cheap patch up but I wouldnt trust anything less than a full rebuild, but obviously it needs more examination.

How many klms has it done?
 

GTSSportCoupe

2LTE abuser
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Almost all the 2LTE motors with cracked heads I've seen look exactly like that. The longer they're run with cracks, the worse the pitting is. It's from water erosion. So yeah, that motor was probably overheated repeatedly at some point in it's life until the cylinder head cracked.

As long as the pitting does not extend in the bore to where the rings are, the motors can still run ok (with a new head of course). However the cylinder bores in yours do NOT look good. Looks like water sat in them and rusted them. This will cause hard starting and blow by (low compression). My 2LTE cylinders had the same damage, and I decided to replace the short block entirely; it was a vast improvement.

Here are some pictures of a cracked head 2LTE for example: Builds - 1992 LJ78 build/refresh
 
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Thanks for the replies! The engine only had 227K km’s on it. The head does have cracks, it’s pretty screwed. It seemed to be running fine but I noticed some oil and coolant leaking from the back of the engine. It was hard to see where it was coming from but knew the head had to come off at least. I’m just hoping I can salvage the block at this point. Just got real expensive. Hopefully can get the block sleeved, there is some pretty bad putting around the top of a few cylinders. I’m having a hard time finding a replacement block too, if I need it.

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Think I might as well do a 1hd-t conversion at this point. Depending on the block I’d even consider the Cummins R2.8. Be great if some one has already done that before.
 

SNLC

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In my honest opinion your money would be better spent swapping in a 1HDT or 1HDFT vs dumping thousand into the 1HZ.

Cost wise, I have gotten good 1HDTs for $5k and FTs for $6500. Yes it will cost more to swap in but it is money well spent and in the end you will get way more for the truck if you sell it.

Cheers
 

SNLC

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Think I might as well do a 1hd-t conversion at this point. Depending on the block I’d even consider the Cummins R2.8. Be great if some one has already done that before.
You are welcome to give us a call at the shop. We are very familiar with 1HZ, 1HDT and FT as well as the R2.8.

Cheers
 
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Anyone know where I can get a fair price for 1hdt injection pump and injectors? Incidentally, I’m also looking to sell a slightly used 1hz block and head. 😅
 

GTSSportCoupe

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how likely is this type of damage from too lean a mixture?
Not likely at all. That damage is 100% from water leaking in from a cracked cylinder head. Also, you're getting diesel/gasoline engine theory mixed up. Lean AFRs in a diesel make for COLD combustion temps, rich AFRs in a diesel make for HOT combustion temps.

So in order for AFR's to damage a diesel, they need to be very rich. An easy sign of this is tons of black smoke out the exhaust. And lots of power, LOL. Also, high combustion temp damage usually leads to cracked/melted pistons and/or cracked pre-combustion chambers. Looks totally different than the problem your engine has.

Anyone know where I can get a fair price for 1hdt injection pump and injectors? Incidentally, I’m also looking to sell a slightly used 1hz block and head. 😅
Did you find a 1HDT to swap in?
 
Joined
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Not likely at all. That damage is 100% from water leaking in from a cracked cylinder head. Also, you're getting diesel/gasoline engine theory mixed up. Lean AFRs in a diesel make for COLD combustion temps, rich AFRs in a diesel make for HOT combustion temps.

So in order for AFR's to damage a diesel, they need to be very rich. An easy sign of this is tons of black smoke out the exhaust. And lots of power, LOL. Also, high combustion temp damage usually leads to cracked/melted pistons and/or cracked pre-combustion chambers. Looks totally different than the problem your engine has.



Did you find a 1HDT to swap in?
Thanks for the info. I have found a block that supposedly been machined and the cylinders have not been bored, just waiting on a bit more info. There’s a company in AU that will sell a complete 1hdt head with cams and valves etc that seems like a good price. Claims to be genuine Toyota parts. 1HD-T COMPLETE Genuine cylinder head kit for Toyota Landcruiser Assembled
 
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If the AFR mix was causing it (which I doubt it is), it would be even across all cylinders. Yours only has it on 3 cylinders. It must have been bad for a long time because I have not seen that on a 1HZ before.
That’s a good point, glad to know it wasn’t me.
 
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