1hz 75 series advice

Submitted: Tuesday, Sep 17, 2002 at 00:00
ThreadID: 1997 Views:11074 Replies:6 FollowUps:3
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Hello All,

I have found some great topics on this board. I am on the verge of buying a 97 HZJ75 landcruiser. It is set up for mining use, complete with split rims and full-time 4wd on the front. It has the 1hz with 100000kms. It has a box on the back but nothing like the factory one. 1 ton full floating axle (no locker though). Like I said, it was intended for a gold mine, underground, but I have a chance to grab it. I am in Canada and these trucks are extremely rare, and tough to get for some reason.

Questions I have are:

the ATX turbo kit or similar - can the high compression ratio on the 1hz handle the turbo, any problems with head gasket failure from this extra boost?

the exhaust of choice down under seems to be at least 2" - 2.5" is this from an aftermarket header, who would make such a thing, or is it a custom build? straight pipe?

lifespan of the 1hz compared to the 3B or the 2H? Any better, or worse? in terms of kms. I have a 2h with 350,000 kms on it - front main bearing seal just starting to leak a bit. Is the block the same from the 1hz to the 2h? how about the injector pump on the 1hz, I have read a few problems - is this normal occurrence. If possible I would like to rack up similar mileage on the 1hz, with regular maintenance.

What about converting the front leafs to coils from a 78? series? is this possible physically? ie. is the front axle the same as 78? what would be needed for such a swap. I have a friend who has a 88 75 series with the 3b and he loves it, but it rides *very* rough. I guess a guy could order spring kit eh? Anybody have a ARB or the ironman spring kit on a 75 series? what are they like - an improvement? Who makes the better kit for ride comfort but heavy loads over long distance? serious offroad 4wd as a secondary use.

ok...thats enough for now.. thanx a bunch for any help. great forum.

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Reply By: Gray - Tuesday, Sep 17, 2002 at 00:00

Tuesday, Sep 17, 2002 at 00:00
Hi there, i can shine alittle light on your question/s. I've had 2 80s with the 1hz and a couple of mates have 75s one with & one without a turbo. With the turbo it's not uncommon for them to ware one and are very successful, but does opperate hotter (he tends to drive abit hard)
My 2 80s have had headers with a 2.5" exhaust, which improved power & economy. But turbo, better power economy not quite as good. He has a 3.0" exhaust with the turbo, most i think are fitted with a 2.5" system
and few i know of have a 3.0". As for the header my mates it's bolted straight up. For the longevity of 1hz, my 1st at 300 000km used 1lt of oil / 10 000km & still ran like a clock, the 2 75s use about 1lt / 5000km
1 has 165 000 the other has 230 000, i have seen 1 with 380 000km and still ran well. I think the key is, being well maintained
I would say the blocks would have to be different as the 2h the cam is in the block & 1hz is in the head.
The fuel pump ? I haven't heard of failures as such but have been prematurely worn out. Put down to poor quality fuel, I read an article a while back on european car makers wouldn't introduce certain models to Australia because of fuel pump failure due to the quality of the diesel. But by 2003 it should comply with the new standards. I've always used a fuel additive (redline RL2) it actually costs less / km overall than not using it.
Suspension being leafs it's a hard one to get a good compromise, my mates have ironman, empty horrid , fully loaded mmmm ok sort of !!
Someone may done a few experiments here. Hope i've helped good luck.
AnswerID: 6703

Follow Up By: Bob Y. - Tuesday, Sep 17, 2002 at 00:00

Tuesday, Sep 17, 2002 at 00:00
Would agree that 1HZ is different block to 2H. We run 2 or 3 79's here, and keep them for 3 to 4 years. personal vehicle is a 97 80 series 4 valve turbo with a 3" exhaust and it makes it a different vehicle. Worth the money, with improved economy. Don't know much about aftermarket turbos, but they do get hotter than the factory ones.
Would agree with regular maintenance for engine. As for the fuel pump, use GOOD, CLEAN fuel, change filters every 10k, don't, or at least, try not to run out of fuel, and don't use last 10% of fuel in each tank. The 1HZ pumps need plenty of fuel for both cooling and lubrication.
We had Lovells leaf springs on an HJ60, and they gave a good enough ride to stop the kids getting carsick. Catch you later...
FollowupID: 3005

Reply By: rojac - Tuesday, Sep 17, 2002 at 00:00

Tuesday, Sep 17, 2002 at 00:00
Hi, I've a 90 75 ute with 190k , has regular maintenance and sees more offroad than on, 2x tanks, snorkel,toyo front & rear lockers, roadgrippers on splits, with ironman leafs matched to monroe shockies, extractors with 2.5" system with 1 box.
The motor 1hz uses no oil, the leafs are rated 25% over std, with approx 40-50 mm lift gives a firm and bouncy ride empty and a firm ride loaded, I reckon its rides ok, you got to take it for what it is, its no ferrari. The sytem gives me more torque and better economy than stock but not much more pwer but it is noisier. The splits are ok , tyres relatively cheap, good wear and grip,noisey, no punctures yet touch wood, have limitations in cornering and wet stopping on bitumen but as before you got to take it for what it is. Lockers are great but a bit slow to engage.Cant help you with the turbo but have a look at the gear box, see if its hard to put into 1st or reverse, if it is you might have either clutch hassles if your lucky or the start of gearbox probs like fork wear. dont know the cost of g/boxes over there but theyre not cheap here.
Apart from that a good reliable truck. Hope it helps.
AnswerID: 6711

Reply By: mudgutz - Tuesday, Sep 17, 2002 at 00:00

Tuesday, Sep 17, 2002 at 00:00
mmmm turbo on a 1hz some blokes say there good......i used to work for toyota and have seen many a 1hz with bottom end bearing problems from aftermarket turbos fitted to much boost so make up your own mind......the 2h block is definatly different to the 1hz.....1hz is overhead cam and develops approx 90 kw as compared to about 73 kw from a 2h....head on 1hz is alloy and 2h is cast 1hz will need a head generelly before the 2h if you must go the turbo go for a factory one they have lower boost and are designed for the 1hz...........my 75 has ironman springs and rancho shocks ...hard ride empty firm and bouncy take the kidney belt......but loaded for a trip approx 8oo kgs including fuel water and gear it is very good....the mining set up will/should be heavy heavy duty springs well they are here in oz so dont change the springs you will find them plenty heavy enough but put on some good shockies toyo shocks are crap......beware mine use equals hard work/ poor driving so yes i agree with above check the box and transfer case right out....look for whining at 70kms and up ....this will be lay shaft case hardening being shot means a tx case rebuild ouch$$$...and yes check to see how easily it goes into first/reverse and first to second if there notchy and hard to get could mean a box ouch$$$ again too also check for play in the rear diff also they are the three things mine vehicles suffer from here...as for fuel pumps well as above .....the quality of the fuel is everthing...get rid of the split rims put some wider tyres on 32x10.5x15s
are good the stock tyres will not stop it well on tar the 32s fit under with stock height and give you 1 inch anyway and about 4% lower revs on the highway with no need for flared guards..
AnswerID: 6721

Reply By: Derek - Wednesday, Sep 18, 2002 at 00:00

Wednesday, Sep 18, 2002 at 00:00
Hi Johnny. I've got to agree with most of what has been said above so I'll only add what is important. 1HZ's around here have a reputation for lasting foreverif you don't turbo them (even the factory turbo version had big end problems) Regular oil changes are the key to longevity. A guy I've just met is an engine reconditioner and he reckons they're notorious for breaking camshafts. This is new to me. I decided to fit extractors and a 2.5'' system instead of a turbo and couldn't be happier. I agree with the above comments on power, torque, economy and noise also. The blocks are different, as one is OHC and the other a push rod engine and fuel pump seals can be damaged if the pump is pre '95 and you run on the new fuel (it's the same fuel with less of some polluting chemical in it). I can't advise you on the spring change but it from what I've seen it looks near enough to impossible without compromising safety or your wallet. Good luck.
AnswerID: 6756

Follow Up By: Peter L - Wednesday, Sep 18, 2002 at 00:00

Wednesday, Sep 18, 2002 at 00:00
G-day Johnie,

As above for the 1HZ. Mine has 294K - no problems so far but has been serviced properly (by me!) and never reved too hard.

Have been told by a diesel pump technician that the rotary pumps don't like too much suction, and that the factory filters don't filter fine enough.
He suggests using TWO of the CAV type filter assemblies - much finer filtration and having two means reduced suction effort (and therefor wear) for the pump. The CAVs also have a glass bowl so water/dirt is immediately obvious.

Qustion for Derek - What brand extractors & details of the exhaust/muffler/resonator please.

I'm curious about your comments regarding big ends as I'm not aware of problems with the 1HZ. The factory turbo'd motors were NOT 1HZs but they did have problems with bearing shells in the erly 12 valve motors.

FollowupID: 3029

Follow Up By: Derek - Friday, Sep 20, 2002 at 00:00

Friday, Sep 20, 2002 at 00:00
G'day Peter. My extractors are Motivator brand, the muffler is a Murcury brand and the piping is 2.5 inch. There is only one muffler mounted about half way down the car. The engine revs more freely and has become much more 'flexible' making it nippier around town. Whilst I think the acceleration has only marginally improved, the torque has improved greatly and I can hold an extra gear on highway hills. This is one modification I recomend anyone should do if they have reservations about fitting a turbo. I also agree with one of the comments in an above posting, that is, if you simply fit a turbo you PROBABLY won't have any troubles. If you start screwing up the boost or fiddling with the fuel pump then you'll get the power but risk an engine failure. A friend of mine has the 1HZ-T and through a data base similar to this, read about the supposed problems 1HZ-T were having. He decided to pull his big ends and mains and sure enough they were corroded out. The shells looked very much like the bark of a scribbly gum. This to me indicates corrosion rather than a mechanical break down of the babbit metal due to the increased pressures imposed by the turbo. You said that the turbo version of the 1HZ is a different engine. I thought they were the same engine except for the head and some other minor non-visual changes. Could you please clarify this? Also, it only takes a few failures in any product, and suddenly the rumour mill is saying such and such are notorious for this or that when in fact the failures probably account for only .5% of all the vehicles sold. Anyway that's my 2 bobs worth-catch you later.
FollowupID: 3051

Reply By: Peter L - Friday, Sep 20, 2002 at 00:00

Friday, Sep 20, 2002 at 00:00
G-day Derek, Thanks for the exhaust info. Re: Factory Turbos on the 80 series 1990 to 1995 were the HD-T motor(2 Valves/cyl). After 95 was the HD-FT where "F" stands for Four(valves/cylinder) The 1HZ was never turbo'd by the factory - it is indirect injection whereas the HD-T & HD-FT are direct injection. The widespread bigend problems are with the factory turbo'd motor and occurr as a result of faulty b/e bearing shells.
If anyone has one of these factory turbo'd motors which has not had the shells replaced they should have it done IMMEDIATELY. Decent shells were used from 1996 I think - check with Toyota. As for the 1HZ with aftermarket turbo there were very few with b/e problems, and as you suggest excessive boost/fuel was generally the cause.
AnswerID: 6803

Reply By: johnnycanuck - Saturday, Sep 21, 2002 at 00:00

Saturday, Sep 21, 2002 at 00:00
Thanks everybody. Good information. The alloy head is a bit of a worry, as to replace if ever needed, it here would be major cash $$ providing I could even get one. I am still debating spending a lot of money (25,000 Can Dollars) on this truck, or spending less on another 86 - 87 era LC Hj 60 wagon, and do some work on it - OME springs for one. They are an amazing vehicle. Existing one frame is totally shot (rust), and starting to die a slow death. See the room-thing is a major consideration. I know the hzj is a great truck, but it is just a cab and box (tray?). BUT it is a 1997! (almost new in my books) To try and get a hj wagon, they are 15 years old, and even then they hold their value pretty good - I would have to lay out 15,000 to get a decent one. Not whining, but why Toyota doesnt sell newer models of diesels here in canada is absolute horse shyte. A bonus of living in Oz I guess. Thaks again for the great reviews and information. Out of curiousty how much for a set of those extractors for 1hz. ? Happy wheeling!
AnswerID: 6807

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