1HZ and 1HD-T camshaft compatibility

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Joined
May 4, 2014
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Costa Rica
Hi guys, I am currently rebuilding my 1HDT motor and my camshaft had a bad wear (water or bad lubrication maybe), I decided to buy a used camshaft and then found that it had a light wear as well:

aMoaRF1.png

My mechanic said its better to not take the risk.

So I decided to get my money back and start looking again for another 1HDT camshaft.
I was not able to find another one, and the new one costs $1600 here in Costa Rica.
After digging around, I found a 1HZ camshaft like new, so I took mine (1HDT) and measured both.

*Keep in mind that the 1HDT and 1HZ camshafts have different parts numbers (13501-17020 & 13501-17010)*

Surprisingly the 1HZ camshaft is 1mm bigger than the 1HDT (why? dont know! I suspect because Toyota needed to supply power from somewhere if there is no Turbo), I used a digital caliper and measured the Base circle and lobe lift.
My mechanic said that this is not a problem at all if the head (valves and everything) is calibrated with it and actually might gain some power.

This is something I wanted to read somewhere on the Internet, but it does not exist! So here is is for everyone else, hope it helps you guys!
 
I think it's common to see a more aggressive camshaft in a naturally aspirated motor, though I haven't seen this swap done on the 1HD-T before.

I know with my Audi 2.7T it's very common to swap in camshafts from the naturally aspirated 2.8 for this reason.
 
There's a FB group called "1hz, 1hd/t/ft/fte modification's & upgrades" where I've seen it mentioned, can't remember the results though. Mostly Aussie's on there, and they've been messing with these engine longer than anyone.
 
There is a thread on here somewhere that discusses the differences in timing and overlap between the 2 also. Not sure if anyone ended up trying to swap one over.
 
Someone posted a chart in a thread here fairly recently showing camshaft lift, lift timing and valve opening duration for a few Toyota diesel engines. I'm stuffed if I can find it now!

The NA variants all had earlier opening valves, and longer duration than the turbo'd versions. Timing was quite different from one engine series to another.

Be interesting to here the results if you go that way.
 
Hope for the best! I will post if I feel anything different with the 1hz camshaft, let's see how it goes...
I am expecting to end the rebuild this year or the first week of January.
 
I put a 3L camshaft in my 2LTE. It had similar differences as the 1HZ and 1HDT would. The 3L is normally aspirated. The camshaft has more lift and duration than the 2LTE on. I liked the difference a lot. Maybe very slightly less low torque, but really nice improvement in mid to high rpm power.

Here are the specs for the 1HDT and 1HZ camshafts:

1hd_power-jpg.1353496

1hz_power-jpg.1353497
 
Oh, and from the manual, the differences in lift are as follows:

1HZ Intake lobe measures: 55.1 typical
1HDT Intake lobe measures: 54.45 typical

1HZ and 1HDT Exh lobe both measures: 55.95 typical

So basically, the lift difference is on the intake only and is about 0.65mm more with the 1HZ cam. And from the specs above, the 1HZ has 7 degrees more duration on the intake, but the exhaust is the same.

I say give it a try.... :)
 
Done recently in Qld by well known diesel performance workshop not much in it but yeah looks like the HZ shaft out performed the HD unit...still I wonder why Toyota made the difference in cams and not used the same in both engines?
 
worth the hassle .. maybe not .. but since you are there and you need a replacement, do it and let us know how it goes ..
 
I put a 3L camshaft in my 2LTE. It had similar differences as the 1HZ and 1HDT would. The 3L is normally aspirated. The camshaft has more lift and duration than the 2LTE on. I liked the difference a lot. Maybe very slightly less low torque, but really nice improvement in mid to high rpm power.
FWIW a friend of mine did the same swap and noticed almost nothing. Considered it a waste of time/money. YMMV.

If you need a new cam and you're in there anyway I'd go for it. Otherwise, not so sure.
 
FWIW a friend of mine did the same swap and noticed almost nothing. Considered it a waste of time/money. YMMV.

If you need a new cam and you're in there anyway I'd go for it. Otherwise, not so sure.

Might have to do with how much air he's trying to shove into the engine? I'm running about 19psi (post intercooler). Maybe the differences are more noticeable with higher boost...not sure.

But yeah, I'd agree it's not the best bang for buck mod. As you say, if you need a cam anyhow, it's not going to hurt.
 
Might have to do with how much air he's trying to shove into the engine? I'm running about 19psi (post intercooler). Maybe the differences are more noticeable with higher boost...not sure.

But yeah, I'd agree it's not the best bang for buck mod. As you say, if you need a cam anyhow, it's not going to hurt.

I think the same... And as Greivis posted the difference of 1HP between the 2 camshafts, I think that if you push the engine with some boost, intercooler and diesel, the differente of HP will increase between the 2 camshafts.
 
Update...
2 Years running the 1HZ cam on the 1HDT motor, still running like a champ.
 
Update...
2 Years running the 1HZ cam on the 1HDT motor, still running like a champ.
I'd be interested to know how mcuh boost you are running and if you did any "aftermarket" mods. Was thinking about this and the google brought this thread up. I have a 1hdt in my hzj77 and am getting a bit carried away with parts and all.
 
I ended up swapping the engine for a 6BT, the 1HDT could not fill up my power needs.
 

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