1HZ rebuild difficulty? (1 Viewer)

[TSnider]

Hey guys, I know these are built as an industrial engine. I'm curious how difficult the rebuild process is. I have heard of rebuilt engine issues in Toyotas over the years but those were US spec petrol engines not really built to take the same abuse. I cant imagine there is any rocket science to them, but just curious. How tight are tolerances on these bad boys?

I have experience rebuilding old John Deere engines.
Curious if these 1HZ engines have issues with rebuilds. Considering importing a 78 in a few years when the 1999 coil spring trucks qualify for it, and I would for sure want a rebuild from the get go due to personal preference, even though I know a lot of people go with the "if it aint broke dont fix it".

Thanks

 

[divemedic]

Well, I know my limitations and I know the HZ needs some special tooling. Something about shims for valve adjustments; I might be off base on that.

I consider my self fairly handy but I’ve learned my limitations as the years pass. I kinda mark it up as, if I have to ask I probably shouldn’t.

 

[TSnider]

Im a diesel fleet mechanic by trade, but I repair slopped together older Mack and Cummins engines mostly. I've never done in depth work to any of my Toyotas, because I have never needed to. I'm not of the caliber of a master tech, but been around big diesels for years.

Special tooling is something I was certainly curious about. I am also not in a situation where I have to do it myself, I am happy to pay someone who is very familiar with these. Reliability is key, so if paying someone else is required for that I'm okay with it. Just trying to learn a bit about them.

 

[simonliew]

hi I have rebuilt couple of 1HZ and 2 1HDT,it’s not a big deal,I get the machine shop to machine the block usually with 0.025 oversized pistons and sleeves and they put the crank n pistons in the block,and I assembly the rest ,the valves adjustment is not hard to do,the machine shop can do them for you or you can buy the little valve adjustment tool to push to shim cup down so you can change the different thickness shims for valve clearance, it’s time consuming but not hard,you can measure the clearance and the shim thickness you have and then order the shims or order few different thickness shims,a shop manual will help ....

 

[roscoFJ73]

I know these are built as an industrial engine

Built the same as any other engine.

 

[FJBen]

No rocket science here. Just old diesels with certain specs to go by.