1HZ lovers look away -- 350 Chevypowered HZJ75 (1 Viewer)

[JungleBiker]

Devotees of the Toyota 1HZ engine may wish to look away…

So our little workshop here in PNG has this crusty old Land Cruiser HZJ75. Mid 1990’s vintage. Yeah, it’s rough, but a new one would cost us around US $40,000, and used ones are very hard to find since most people here tend to buy new and then simply drive them into the ground. In fact one of our customers just spent a lot of money on a nice looking used HZJ76 with an aftermarket turbo on it, only to discover that at some point in its life somebody bashed a hole in the oil pan, ran it out of oil, wrecked the main bearings and the crank and long story short, he’s spending US $8000 for a new long block. Let’s just say that here in PNG a second-hand LC worth having would cost almost as much as a new one. They are great vehicles and will last longer under the sorts of harsh conditions encountered here than most other vehicles will.

So anyway, the 1HZ engine in our shop truck was getting pretty tired—it had nearly half-a-million km on it and was getting harder and harder to start in the mornings (bear in mind that we are located just 6 degrees off the equator and in the highlands where we are located most of the time the temp is between 75F/23C and 85F/29C), but even so it was taking nearly a half hour just to get it started and the compression pressures were well below the manual’s minimum so clearly something needed to be done.

We considered rebuilding the original engine, our shop can do that sort of thing, but it’s very hard to find a good machine shop here that can do things like grind cranks, bore cylinders, line bore blocks, deck blocks, skim heads, any of that kind of thing is really hard to get done here. Also, parts are often very expensive, so when we weighed our options, we found that we could import a brand new 350 Chevy truck engine (5.7L V8 RPO L05, 210 hp/300 ft.lbs) from the US for less than we could rebuild the 1HZ.

In my opinion, (and it’s just an opinion), the 1HZ engine is seriously over rated. Before anybody starts writing to try to change my mind, let me just say, I do have lots of experience with 1HZ’s. It’s one of the most common engines to come through our shop. Overweight, underpowered, and they get lousy mileage to boot. About all they have going for them is their reliability, and even that is not significantly better than a great many other engines. Here in PNG they have the added advantage of the fact that diesel is a cheaper than gasoline/petrol and is more commonly available (meaning that in the middle of nowhere you can probably find somebody selling 5 litre jugs of diesel).

Nevertheless, we decided to go the Chevy route, just to see how bad it could possibly be. We ordered the adapter and engine mounts from Mark’s Adapters in Australia, the engine from JEG’s in the US. We liked the Mark’s Adapter because it keeps the trans in its original location and moves the engine forward a bit, which is good for keeping the HEI distributor away from the firewall and allows more air flow around the back of the engine.

In the process of planning out this build we spent a lot of time on MUD looking for similar conversions, but there weren’t many that were well documented. I’m hoping to change that with this thread. Let me just say at this point that the truck is pretty much done and drivable at this point (still needs a little bit of fine tuning), but over the next few days (as time permits) I’ll be putting up pics of the build so that when others go searching, they can find the info that we were looking for.

 

[JungleBiker]

Crap. No way to edit the title of the thread?

 

[Gus]

Even as somewhat of a Toyota purist I still enjoy seeing what can be done with these rigs. This sounds like a cool project, bring on the pics and details of the swap.

 

[61Mk+]

Hello JungleBiker,

I am one of the fans (perhaps the term 'freak' may be more appropriate) of the 1HZ, so i welcome someone else's opinions on them; otherwise i may be chronically blinded to its faults. Overweight, fuel pig, low power: okay, thanks for the heads-up, 'cause my bias gets in the way.
I have, however, made my decision for my engine, and 1HZ it is. Reliability isn't the only issue for me, there is also parts availability around the globe.
Having said that, i am of the opinion that GM's 350 V8 is God's own V8: it is lighter as you say, it is blessed with a simplicity that is heaven-sent, and it is fantastically reliable. One can also find huge numbers of parts as well as after-market tuners to make that engine provide more power/torque/efficiency/what do you want? than possibly anything else available; it has, after all, been in production since the 1950's: i do not know of another engine that can claim the same. I do speak from a North American perspective, so i find it hard to believe you'd get all those advantages in Papua New Guinea.
Whatever, much as i love LandCruisers, i don't see the point in keeping them factory original if one wants them as daily drivers, or for any practical use that does not involve concours or museums. Just because it was factory doesn't necessarily mean the factory got it right. So your approach works, to my mind: get the best components available to you, for your purposes, in your area, and put them to use. And if you get complaints about your having ruined the originality of a lovely LandCruiser, remind them that you need to use the damn thing, not display it.
Best wishes, Sir.

 

[JungleBiker]

Parts list:


12568758 GM Goodwrench 350 87-95 For 1987-1995 Chevy/GMC trucks with 350 vin code "K" engine up to 7200 GVRW

The RPO - L05 engine was found in the following vehicles:

1987 Chevrolet Pickup (RV1,2)

1987 GMC Pickup (RV1,2)

1987 GMC Suburban (RV1,2)

1987 - 1991 GMC Suburban (RV1)

1988 - 1995 Chevrolet Pickup (CK1,2)

1988 - 1995 GMC Pickup (CK1,2)

1988 - 1995 Chevrolet Tahoe (CK1,2)

1988 - 1995 GMC Suburban (CK1,2)

1987 - 1994 Chevrolet Van (G1,2,3)

1987 - 1994 GMC Van (G1,2,3)

1995 Chevrolet Van (G2,3)

1995 GMC Van (G2,3)

1405 Edelbrock manual choke 600CFM carburettor

2104 Edelbrock intake manifold

40002 Jegs HEI distributor

10159409 Chevrolet Performance Intake Manifold Gaskets 1987-95 Chevy 305/350 TBI

R900 Racing Power Company (RPC) Ram’s Horn Exhaust Manifold (ther emight have been a better choice of exhaust manifold, but we made these work without too much trouble.)

3 bolt 2.5” collector gasket exhaust manifold

45658 Dorman starter bolts 4 5/8”

9608E AC Delco spark plug wires

DL3510MS Duralast Starter

CWP-520HD Duralast water pump fits many GM 80’s v8 long pump clockwise rotation(serpentine belt engines will have counter clockwise water pumps)

6029 Duralast power steering pump

300-122 Dorman power steering pump pulley

82581 Dorman Power steering pump cap

E71129 Dayco lower power steering hose

FRA-159 Pioneer flexplate 168-tooth (one hole gets enlarged to fit adapter)

81432 Compressor works theremostat housing

CR45TS AC Delco spark plugs

Z40 Ryco oil filter (short style) GM v8s cars (Ryco is an Aussie company and it's easy for us to get Ryco filters, though we did order a box of NAPA Gold filters from the US)

FIL1061 Napa Gold oil filter (tall style) on GM 1-ton trucks

91039608 Speedway motors 3-groove crankshaft pulley

Summit 2-groove water pump pulley

A212CW AC Delco air filter (AC filter fits better than other brands it can cross-reference to)

1969 Chevy Chevelle 396

R2195TBK RPC air cleaner lid

R2148BBK RPC air cleaner base

82800 Jegs crankshaft bolt

23605 Jegs oil filter adapter · 1968-00 Small Block Chevy

MFK915HD Mark’s Adapter mount kit

MFK1060CLS168 Mark’s Adapter engine to transmission

 

[Tapage]

looking forward on your build .. I see a lot of Chevotas here .. and not entering in the debate if the 1HZ worth it's reputation or not .. I always thought, NA diesel it's just half engine.

My second thought it's about the V8 .. If I'm were a V8 it's coming my Cruiser way, must be a very powerful beautiful sound V8 .. like an LQ9 or those pretty healthy LS3

 

[JungleBiker]

We went with the L05 engine because we wanted the 300 ft. lbs. of torque. On paper it looks like this:

--the 1HZ has about 120 hp at 3600 rpm and 210 ft. lbs. torque at 2300 rpm
--the L05 350 we got has 210 hp at 4000 rpm (around 205 at 3600, which is where the 1HZ peak is), and 300 ft. lbs. of torque at 2800 rpm (around 275-280 at 2300 rpm, which is where the 1HZ peaks).
--At around idle speed (the dyno chart I have starts at 800 rpm's) the 350 has 240 ft. lbs., which is well up from the 1HZ's 210 ft. lbs. peak. --Even with a turbo and an intercooler on a 1HZ--which will set you back more than AUD $3000--you only get 317 ft. lbs., which is only 17 more than the L05.

But all this aside, our reason for changing to the V8 was not because we wanted more power, but because it really was cheaper for us to put the V8 than it was to rebuild the 1HZ. As for parts availability that somebody mentioned earlier--it's true that you'll find no GM dealers in PNG, however, even getting Toyota parts is a total pain in the butt, in spite of the fact that Toyota has better than 75% of the market share in PNG. Locally, Toyota just isn't interested in helping fix their vehicles, they would much rather sell you a new one. Admittedly, as I mentioned earlier, most new Toyotas here are simply driven into the ground and have relatively short lives, on average I'd say a Land Cruiser lives maybe 10 years and then it's complete junk. Not because Toyota didn't build a good truck, but because vehicle maintenance is simply not practiced here. So as a result, even for locally sourced vehicles, we end up having to get our parts from overseas. And believe me, getting parts for a General Export Toyota from the US or Australia is tough. It will actually be much easier to get Chevy parts from the US than it is to get General Export Market Toyota parts from anywhere.

I agree that an LQ9 or an LS3 would sound cool, but we were shooting for simplicity, (no computers) and practicality, which in our context means as few electronics as possible. This will be a daily use work truck in PNG and needs to be simple.

 

[JungleBiker]

Slow going on the pics--internet speed from here is pretty bad.

 

[JungleBiker]

Here is the truck we started with:

 

[Tapage]

so you are going carburated on your V8 ..?

 

[JungleBiker]

Yup. We went with an Edelbrock 1405, (600 CFM, 4 bbl, mechanical secondaries, manual choke) it's a remanufactured one that cost a lot less than a new one and so far we've got no complaints. We also went with a simple HEI, all self-contained, no external computers. Outside of the ones inside the distributor, the only sensors on our whole engine are the sending units for the water temperature and oil pressure, and those are old school gauges--the only wires going to them are the ones that power the backlights.

Tried to upload a bunch of pics last night, but my internet connection gave up on me, (that's life in a developing nation) will try again later.

 

[JungleBiker]

For the curious, here's a pic of a pretty typical day in our shop; we see a lot of Land Cruisers:

At one time the organisation I work for had three of these HZJ75 utes, a black one, a white one and grey one. The white one was the oldest, but had the fewest miles on it. They were hard miles though, as that truck got used mostly for driving out in the bush. Anyway, we retired it and stripped it down for parts to support the black one and the grey one:

As this thread unfolds, you'll see bits and pieces of this white truck popping up here and there.

 

[JungleBiker]

Here's our engine:

Never mind that fan clutch--we discovered that with minimal modification a NOS Mitsubishi fan clutch we had laying around the shop actually fit on the Chevy, but we felt that it was too long to actually use, so we took it back off.

 

[JungleBiker]

Here's the Mark's Adapter going on--to me this seems like kind of a weird, non-intuitive arrangement, but it's in the truck and working now, and seems perfectly okay:

stop! Selfie time:

 

[JungleBiker]

Oil system primed:

Ready for breaking in the camshaft--the engine stand is one that was originally made for running in Continental TSIO-520 engines for Cessna 206 aircraft, but we modified it for the Chevy, since the guys who used to use have switched to turbine powered aircraft and didn't need it anymore:

My co-worker, Ben (he's also on MUD but I forget his handle on here--he shows up in the background of a lot of these pictures and in truth he did most of the work on this project, I just helped out here and there, and perhaps more importantly I was the boss who approved the Chevy conversion), anyway, among many many other things, Ben built this instrument panel for the run-up stand--the aircraft throttle was a nice touch:

Breaking in the cam--there was a miss in the engine at this point that took us a little while to figure out--turned out to be a timing issue, but I suspect that the open exhaust manifolds didn't help either--certainly once we got the timing right it smoothed out and just got smoother once we got a complete exhaust system on it:

HAd to remove the original engine mounts to install the ones from Mark's:

Trial fitting. At this point we discovered that those nice looking motor mounts from Mark's didn't actually fit! This was probably the biggest surprise/curve ball that we experienced during the conversion. The engine sat way too high in the frame and in fact when Ben experimentally tried fitting the prop shafts/drive shafts he found that they simply wouldn't line up. Kudos to Ben for even thinking to try that, I admit I might not have thought to try that:

Once we had the engine lowered to where the driveshafts actually would line up properly, about 1-2 inches of the engine mounts were hanging off of the bottom of the frame. Clearly that wasn't going to work, thankfully we are also a fabrication shop, so we just modified them to work. Here's one in the process of being modified, you can see the original mount with our new gussets welded to the outside of it, later the bits of the original mount that hung off of the bottom were trimmed off:

And here's what it looked like finished--we tried to keep the slotted holes that Mark's had engineered into the mount at the same angle that Mark's intended, though I have seen others here on MUD who have taken different approaches:

 

[JungleBiker]

Then came the exhaust. Ugh. Would you believe that we could find no supplier of exhaust pipe here in PNG? Our options were:
--to spend a ton of money having some shipped in from the US or AUS by DHL (that'd still take a month to get here)
--get them cheaper if we had them shipped here by sea freight but then it'd take 3-4 months to get here, OR
--chop up a piece of 2.5" straight pipe that we had and make bends out of it. Ugly? YOU BET! But it will do for now. There are maybe half a dozen of these really hideous bends in the system, and yes, I could have made them nicer looking, but at this point in the project we were just wanting to get the truck done, since we need it running for work:

Since we had 2 complete HZJ75 exhaust systems in good condition, we were also able to salvage a lot of bends from those. On the right side we only had to get from the manifold to the already existing exhaust pipe that runs outside the frame under the right side door:

Starter can still be removed without having to remove the exhaust, same is true of the front rear spring pins:

But on the left side we ended up using our "spare" exhaust system (salvaged from the white ute) to try to make a mirror image of the right side. We even went ahead and engineered in those goofy rubber dampener things that Toyota seems to be so fond of. I mean, why not? We had them, the right side had one, may as well build one into the left side, too:

Was there a better way to route the exhaust? Probably. But this is what we came up with and what we figure will work for us.

So it's basically dual exhaust all the way back to the back of the cab. At that point I made this Y pipe, and went ahead and built in the flange so that we would have a place to be able to take it apart. The finished exhaust can be separated into 5 or 6 big pieces, with 2 or 3 bolt flanges at all the joints:

Unfortunately I screwed up in one of my measurements and ended up with this funny little jog that I'm not real happy with, though honestly I don't think it's a problem, it just bugs me:

We stuck with the original 1HZ muffler, it is HUGE and so we figured it'd probably be alright. Turns out it works just fine, we were all very surprised by how quiet it is, especially considering how noisy the old 1HZ was.

 

[JungleBiker]

GEtting closer! And wow, look how much of that ratty old white ute made it on to the black truck:

I really like the old style grille better and happily it was in better shape than the original one. While we were working on it, we went ahead and replaced the cab mounts, since some of the cab mounts needed repair, it worked out for us to make up our patches out of 8mm steel, in effect giving us an 8mm body lift kit. The whole truck looks somehow "happier" now, certainly it is standing up higher in the front, maybe because it just lost 200 pounds switching from the 1HZ to the 350? Or maybe it's just all the white body panels:

Here is the best thing about the Mark's adapter, and the whole reason why we went that way instead of with a bell housing adapter. The Mark's adapter leaves the transmission and transfer case in their original locations (obvious advantages there), and moves the engine farther forward than a bell housing adapter would. As a result, there is plenty of space between the distributor and the firewall (pay no attention tot he wiring in this pic, it's all sort of temporary and is improving all the time):

I made up a bracket that adapted the original HZJ75 throttle cable and throttle cable mount to the 350. I also made up a way to mount the LC cable to the Edelbrock carb by cutting up a broken motorcycle front brake lever (cable operated brake) and using the part that the brake cable used to fit into to mount the end of the HZJ75 throttle cable. The return spring was too stiff at first, I ended up having to lengthen the anchor point:

Somehow in the process of making this bracket, I goofed again--I set everything up just so so that there would be a correct amount of slack in the cable, but somehow when I installed it all I ended up with too much slack, like an inch too much(!). Then I tried to take up the slack by adding this stiff little spring to the pedal end of the cable, (admittedly not one of my better ideas):

Anyway, that didn't work, it made the throttle feel really weird, so I took it back out and then discovered that I had enough adjustment in the cable to take out most of the slack anyway.

Top radiator hose is 2 parts NOS Hiace hose and 1 part NOS Mitsubishi L300 hose, with a custom made jag/barb fitting between them (that I made). Bottom hose is a Chevy hose of some sort. For now we are using a 2 core radiator, but that may change--we need to fine tune the cooling system--we don't know what the fan came from, but it was one we had laying around the shop and it fit. It's too far from the radiator though and at first we were running it without a shroud--it worked fine as long as you were moving--as soon as you stopped the temp would start to climb. So we put the original 1HZ fan shroud in, even though it doesn't really line up with the fan--the fan is smaller diameter than the HZJ75 fan was, but it still makes a significant difference--I was surprised at how much difference it made--I mean, I know fan shrouds make a difference, I was just surprised that this bad combination of ill-fitting fan and shroud makes as much difference as it does.

Eventually we will probably end up going to a better radiator either a 3 core aluminum/aluminium one or a 4 core brass/copper one. For now the 2 core is working, but it's just a stop gap.

And I think that's all the pics I have right now.

 

[JungleBiker]

So we've only just gotten this truck to a state where we can drive it--in fact we only drove it for the first time last weekend. But so far I have to say that it's a big difference from the original engine. It's so quiet, smooth, and powerful. 2 of us can have a conversation in the cab while driving without having to raise our voices at all, which wasn't true with the old engine (bear in mind that the original sound deadening mats--it it ever had any--are long gone from this truck). 2nd gear starts are easy (general export trucks have 4:11 gears, are they all that way?) All in all it seems like a huge improvement, and so far we've not found any thing that the diesel was able to do that the 350 isn't able to do just as well if not better. Once it's through break-in we'll do some off-road stuff with it and see what it's like, but seeing as how we went with a fairly low hp/high torque version of the 350 (a truck engine), I think it's going to be alright. I promise to let you know, though.

Oh, by the way--if you do this conversion yourself, be sure to plug the original diesel return line--we forgot to and as a result when we went down a hill on our first test drive, gasoline started pouring out of the old return line and then wouldn't stop when we got to level ground because of siphon effect. Thankfully it was a really short drive and we didn't spill much.

 

[clintnz]

Great writeup! Nothing improves a Landcruiser quite like a petrol V8

Cheers
Clint

 

[decoco]

we will need videos.