Did they say why a 1HZ block cant be machined?
Custom HZJ79 from parts, built in the US! (1 Viewer)
- Thread starter yooper
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crushers
post ho
explain to me again why a crack 'way down low' resulted in poor compression or over heating?
now, machining the block can reduce the compression travel area causing interferrence between valves and pistons.
we experienced this on Todd's second engine rebuild.
the machine shop shaved the block to make it true, put in the new liners to factory specs and never bothered to inform both the machine shop and myself.
reassembled the engine and something just didn't sound right. days of trying this and that before pulling the brand new head to find all 4 exhaust valved had been kissing the pistons.
so, that is why you can't machine the top of the block.
does this help?
now, machining the block can reduce the compression travel area causing interferrence between valves and pistons.
we experienced this on Todd's second engine rebuild.
the machine shop shaved the block to make it true, put in the new liners to factory specs and never bothered to inform both the machine shop and myself.
reassembled the engine and something just didn't sound right. days of trying this and that before pulling the brand new head to find all 4 exhaust valved had been kissing the pistons.
so, that is why you can't machine the top of the block.
does this help?
yooper
SILVER Star
- Thread starter
- #644
Seriously? You were the first person to ask me why the block couldn't be machined. Interference is obviously a risk but should be avoidable. Unless you do it wrong.
The engine overheated because all the coolant got blown out through the overflow by combustion gases, which entered the coolant jacket under pressure through the crack in the cylinder wall. Does this help?
Last edited:
crushers
post ho
well, till this happened to Todds second engine i did not know the caution. the clearence is very minor so machining can be only really, really minimal.
we all learn. i had gassers milled in the past, hence the question when i asked it.
the coolant passage isn't that far down and you mention deep down crack, hence that question.
i can see my participation is an irritation to you, i will no longer comment on your thread.
bye
we all learn. i had gassers milled in the past, hence the question when i asked it.
the coolant passage isn't that far down and you mention deep down crack, hence that question.
i can see my participation is an irritation to you, i will no longer comment on your thread.
bye
semlin
curmudgeon
well first off your question about the crack and follow up comment about milling todd's engine seem to have nothing to do with each other. i read it several times and i have no idea what one has to do with the other.
and secondly, are you saying you milled todd's second engine recently after being told by yooper on this thread that you can't mill those engines, meaning you ignored yooper, or are you saying that you asked the question about milling here when you already knew the answer because you had already milled todd's engine.
either way, i can see how yooper might me "irritated" by that post.
I was told it is by design, and has do with with the fact that the pistons travel higher than the block surface. Which makes no sense to me, why would that matter? Two machinists and I think ENS told us that.
Ok ,maybe this is common on interference engines in general.
Im surprised a block could actually warp that much.The 1HZ block is a hefty lumpy of iron
Tapage
Club 4X4 Panamá
could you post a pic of .. I'm dying to see how bad it looks ..
How the heck did that happen?
Here's an idea. Maybe there was enough electrolysis from the coolant to eat the water jacket in that area, causing the metal to be thinner, which allowed the bore to crack to the jacket? Or is that portion of the cylinder bore open to the crankcase?
Only other time I've seen a diesel engine split like that is when this guy, ambulancechaser, built his 4BT as far as you can, no budget type of thing. At 80psi, the block split in half, looking like that inside the bore.
EDIT:
That new 1HZ block sure is pretty
Is the new block come with engine no?
yooper
SILVER Star
- Thread starter
- #655
How the heck did that happen?
Here's an idea. Maybe there was enough electrolysis from the coolant to eat the water jacket in that area, causing the metal to be thinner, which allowed the bore to crack to the jacket? Or is that portion of the cylinder bore open to the crankcase?
Only other time I've seen a diesel engine split like that is when this guy, ambulancechaser, built his 4BT as far as you can, no budget type of thing. At 80psi, the block split in half, looking like that inside the bore.
EDIT:
That new 1HZ block sure is pretty
It was a mine truck engine that was sold by the mine, basically for scrap. It had been abused for an unknown time. Proffitt's painted it and bolted it into my truck and bolted a turbo to it. In hindsight, when I asked them for compression numbers they changed the subject.
That portion of the cylinder is coolant jacketed. The coolant was being blown out through the radiator overflow. It was probably eroded from the coolant side, yes, and we also overbored the cylinders the maximum amount because the walls were scored.
NEVER EVER BUY A USED MINE TRUCK ENGINE.
The phenomenon you mention is actually from cavitation rather than electrolysis. Many diesels requires SCAs (supplemental coolant additives) be added to the coolant to avoid local "pinpoint" boiling or cavitation erosion--especially in designs that have wet liners rather than a regular design. The Ford Powerstroke comes to mind. Anyway, SCAs can vastly reduce the cavitation erosion which leads to premature failure.How the heck did that happen?
Here's an idea. Maybe there was enough electrolysis from the coolant to eat the water jacket in that area, causing the metal to be thinner, which allowed the bore to crack to the jacket? Or is that portion of the cylinder bore open to the crankcase?
Only other time I've seen a diesel engine split like that is when this guy, ambulancechaser, built his 4BT as far as you can, no budget type of thing. At 80psi, the block split in half, looking like that inside the bore.
EDIT:
That new 1HZ block sure is pretty
I have no idea whether this could have been an issue or route of failure in a 1HZ . . .
What's up?
yooper
SILVER Star
- Thread starter
- #660
It just keeps letting me down. The drivetrain is now nearly bulletproof but the steering, electrics, fuel supply, etc. gremlins are wearing me down. I still can't trust it to do a job for me in a pinch, and I would definitely not ever trust it to take my family on a long unsupported expedition, which is what a LandCruiser is for. I realized it was time when I got my 35 year old FJ40 out of winter storage, it started instantly, and I was relieved to be driving something rock solid reliable again for a change. I'm too old for this s***.
I'll post a for sale thread sometime in the next few weeks, need to get the tome of information together and take some photos, etc.
Not sure what the newb laughing above is about...
I'll post a for sale thread sometime in the next few weeks, need to get the tome of information together and take some photos, etc.
Not sure what the newb laughing above is about...
