1HDT Engine Rebuild

[mountaincruiser]

Hey Guys -

I'm in the process of having my 1HDT for an HDJ81 rebuilt. The rebuilder wants to bore 040 (1mm). Can only get 020 oversize pistons and rings. 040 pistons do not exist - so he wants to have them custom cast in the States for mucho $$.

After some research, I can't find one example of anyone going 1mm oversize on a 1HDT rebuild. If no one makes them for this engine, is this plausible?

Only the #6 cylinder had low compression due to a broken ring. The rest were good, head pressure tested good and this engine has 114,000 kms - no roll-back, etc. Crazy or what

The engine has been in the shop for over 3 months now. At this stage, should I finish the rebuild at this shop, request a refund and take it to another shop or just swap? Any insight would be much appreciated.

 

[lshobie]

Sounds like an idiot to me.

 

[Deny]

I'm no mechanic, but what I would do is go down there take a look at that Cylinder wall of #6, if it is OK, just get him to slap in a new ring and be done with it, will probably last for ever like that anyway.

 

[mountaincruiser]

Sounds like an idiot to me.

One more thing, before I brought it in to the shop, I pulled the head and had a look with a friends dad who is a heavy diesel mechanic. He said the walls still had descent cross hatching and I probably just neaded seals. There was no visible scoring.

 

[mountaincruiser]

I'm no mechanic, but what I would do is go down there take a look at that Cylinder wall of #6, if it is OK, just get him to slap in a new ring and be done with it, will probably last for ever like that anyway.

Thanks Deny - I would, but I'm at work for the next 2 weeks in a camp. So I can only deal with the guy on the phone for now. Part of the problem. I should have some pic's of the block with the head off. How do you post pic's?

 

[Tapage]

.40 .. ! damn .. if it's necesaary why not just a sleeve and back to facotry size .. ?

 

[roscoFJ73]

.40 .. ! damn .. if it's necesaary why not just a sleeve and back to facotry size .. ?

x2 It sounds like he doesn't know what hes doing. A 114000 klms is very little for these. I have a 1HZ block with 140000 klms in my shed and the bores are like new.

See if he can show you with micrometer the out of spec cylinder
Number 6 may have had a valve problem.

Did it have any blow by?

 

[mountaincruiser]

.40 .. ! damn .. if it's necesaary why not just a sleeve and back to facotry size .. ?

Thanks Tapage. Exactly - if only the #6 cylinder could possibly be scored from the broken ring, why not just oversize and sleeve that one cylinder back to spec? The other 5 wouldn't need anything other than rings. Is this right? I'm no machinist, but your suggestion makes sense.

He's been in buisiness since the 80's and I was reffered to him by a Toyota mechanic who does diesels. I don't want to argue with the guy unless theres definitely a red flag.

Do you guys think this is reason enough not to trust the rebuilders ability?

 

[mountaincruiser]

x2 It sounds like he doesn't know what hes doing. A 114000 klms is very little for these. I have a 1HZ block with 140000 klms in my shed and the bores are like new.

See if he can show you with micrometer the out of spec cylinder
Number 6 may have had a valve problem.

Did it have any blow by?

Hey Rosco -
serious blow-by. I thought it was the turbo seals--> replaced it with new OEM (cracked housing due to heat)-->then had excessive crank pressure -->compression tested-->#6 low, other 5 fine.

 

[roscoFJ73]

You should tell him to wait until you are back in town,and then go down and have a look for yourself.
Any scoring causing bad blow by will be plainly visible.

Do you guys think this is reason enough not to trust the rebuilders ability?

I never heard of engine rebuilders in australia doing it this way and these engines are really common here,almost like small block chevs in north america.

I had a 1HZ rebuilt a few years back and the engine rebuilder said that putting a sleeve(or jacket as we call them) was so easy he wouldnt even charge extra if it needed doing on my block.

 

[sailor]

Maybe your mechanic wants you to help pay down his credit line? There are a bunch of JDM specialists in BC, a few are HDJ81 specialists. Maybe a consult with one of them is in order?

 

[mountaincruiser]

I never heard of engine rebuilders in australia doing it this way and these engines are really common here,almost like small block chevs in north america.

Rosco - I think this is THE problem. Spoke with an oldtimer heavy equip mechanic at work today, and he said that the broken #6 ring could have caused this kind of damage, for sure. I thought I had a good look down the the cylinder - but never popped it out.

The Mechanic at work also said that if this was a Chev he would've bored it 040, because oversize pistons are really common for 350's. It makes sense to me now that he really was trying to do a descent job - only to find that the parts aren't available for a 1HDT. I think thats why the machine shops in OZ oversize & "jacket" the cylinders from the get go. They KNOW this.

I just saw a movie that sums it up "I have bad luck & s*** luck, and my bad luck just ran out".

So I called him tonight with renewed trust and he's sleeving ("jacketing") 3 of the cylinders and boring 020 (0.5mm) over. The jackets are 1/8" thick.

Food for thought - said he re-measured the tolerances because he doesn't like to sleeve 2 cylinders side by side? Only jacketing every other one which matches what he needs because of wall thickness and "warpage" with the sleeves? The mechanic at work said it made sense. I'm lost. Oz mechanics must know better if its common to do all cylinders, I guess.

 

[roscoFJ73]

I'm lost. Oz mechanics must know better if its common to do all cylinders, I guess.

I dont understand why he is going to sleeve the other cylinders.
I would have thought the best way would be to fit a sleeve on number 6 and give the others a light hone and rebuild.
I also wouldnt be surprised if there waS a 40 thou oversized piston out here somewhere.
The guy Ive used in the past has sold his business and retired so I no longer have anyone to ask these questions

 

[9180ltd]

I work in the heavy equip industry and although am not an engine specialist i have done my fair share of industrial rebuilds. From what i have been taught and heard if you are going to boar or go oversize you do ALL the same. Any other method will cause an unbalance, think about your volume-metric differences. And as far as re sleeving these i think since the 1hdt is a dry sleeve(not meant to be "just replaced") it would be very expensive to do and where are you going to source the sleeve? this is much different from a wet sleeve engine where the sleeves just push out. I may be wrong as i have been before , just voicing my .02 as i have never heard of intentionally having different sized boars in an engine in the 8 years i have been doing it.

 

[9180ltd]

BTW, sounds like your engine possibly saw some extremely excessive heat (cracked turbo) make sure that when the IP was rebuilt it was re-set to factory settings, not whatever it was at when it arrived at the rebuilders desk.

 

[mountaincruiser]

I work in the heavy equip industry and although am not an engine specialist i have done my fair share of industrial rebuilds. From what i have been taught and heard if you are going to boar or go oversize you do ALL the same. Any other method will cause an unbalance, think about your volume-metric differences. And as far as re sleeving these i think since the 1hdt is a dry sleeve(not meant to be "just replaced") it would be very expensive to do and where are you going to source the sleeve? this is much different from a wet sleeve engine where the sleeves just push out. I may be wrong as i have been before , just voicing my .02 as i have never heard of intentionally having different sized boars in an engine in the 8 years i have been doing it.

From the machinsts measurements, 2 cylinders need to be bored 030 & 040 over due to scoring. These 2 will be oversized extra to accept a sleeve with 1/8" wall thickness. Then all cylinders will be bored 020. The end result will be all cylinders oversized 020 (0.5mm).

The guy definitely knows what he's doing and the mechanic at work confirmed this. I haven't seen the damage - but he seems like a straight-shooter who has been doing this for 35 years.

Boring 040 over with matching oversized pistons & rings is the optimum solution from what I've read. You just can't get them for this engine - even in Japan.


In case anyones interested, I found a cool article on cylinder sleeves:
Engine Blocks & Cylinder Sleeves: Engine Builder
If you read down near the end, you can see why sleeving has its drawbacks. What he meant by not sleeving two cylinders side-by-side is explained too for cast blocks. All engines aren't equal due to cylinder cooling. Interesting stuff. I'm sure theres alot more to consider way beyond me.

Thanks for the help guys. I hope no one else down the road has to search this.

 

[lowenbrau]

Geoff Walsh is selling sleeves for $5 each. I don't know why you wouldn't swap them all and bring the engine back to factory.

 

[prado t]

Geoff Walsh is selling sleeves for $5 each. I don't know why you wouldn't swap them all and bring the engine back to factory.

Exactly , get your motor away from that MANIAC , ship it down here and get it sleeved. A couple of years back, I seen a 12H-t at a machine shop getting the machining done for sleeving.
It is better to have the stock bore size IMOP,

 

[canadian bum]

I don't see why the other cylinders would require machining just honing. And if you get it sleeved on #6 back to stock spec you will be fine. I'm a HET and will be rebuilding my own 1HD-T in the near future. But my engine lost the #4 connecting rod bearing.

 

[9180ltd]

Wow there are a lot of different opinions here of what is proper. I guess mine is also just that ,.....an opinion. BALANCE in an engine is extremely (as is equal volumetric efficiencies) critical to longevity. So lets see what has been tabled and how it relates; opinion #1 hone it, rings and gaskets and away you go, your done. Problem #1 now you have new rings, probably brought compression up a bit but still have a dead cyl.SIDE NOTE; i went back to my binders from school and this is called a RE_SEAL not a REBUILD, and the reseal only relates if you can achieve at least maximum allowances. Time WELL WASTED. Option #2 hone 5 and sleeve the 6th. Problem #2 5 possible close to factory but not factory cyl's and one perfect hole.....may i remind you these engines have con rod issues, how do you think thats gonna pan out in the future after you just spent 2-4g to "not quiet do it right" Option#3 (most expensive now,... but cheapest long term ; Bring all 6 to same specs=balance and longevity.
I understand most people who are commenting here have not been faced with this particular dilemma so its easier to say "well id do this" ..... im sure ppl would put much more thought into the situation when their personal visa bill is at stake. In short if you want to keep the truck do it right, keep in mind how much it has cost (in time as well) to get you to this point. Do you want to roll the dice in possibly doing this again? The vast majority of people go through life never facing this, feel like being the one that has to face it twice on the same truck? Never mind the possible drivability issues you may face cutting corners on such an important section of your engine.
Im sure ill get blasted for this but im just trying to get across how much better off you will be doing this job right , .....right now even if it costs you an extra g-note. As i said every one has an opinion and this is mine. Good luck with your decision however you make it . After all you are, as I in possession of a truly legendary machine.