1hz custome coolingguy (1 Viewer)

[CamCald85]

Hello all my name is Cameron 1st time on here.

I've joined up because i need some help.

Here is the scenario 1 have a hzj75 series that I stripped to the chassy and completely overhauled ground up ( when my parter gets home I'll get her 2 show me how to put up pics ) I am a mechanic by trade and spent 90k and 5 years building this thing and hellow and behold she runs hot.

I'm sure you have all heard of a 1hz that runs hot and this would have been covered b4 but I assure u I have done everything and can't get a win.

Eng is rebored decked block milled slugs to reset deck height at .005 all turbo grade internals blueprinted ballenced simallar treatment to the head injectors set at 10 bar more crack off pressure and built the pump to suit ( slightly over fuelling but not enough to push temp ) passes tk test passes pressure test. Will b borrowing compression gauge this weekend can't c that being the problem though.

Oil cooler is spotless cooling system is spotless.

Brand new ( when eng was assembled 7000 Kay ago ) gmb water pump new thermostat and replaced it again with a genuine one after 1000 k just to b sure ( tested it to ) dayco fan hub band new then opened drained and replaced hub fluid just to sure ( pulling like a champion ) true flow fan
And a brand new oex radiater then pulled radiater out and had it flow tested all clean.

Wtf.

The problem seems to b ram air but with 7k of bulbar I'm not parting with it.

I have cooked up an idear f how to fix this.

Firstly have heard u can put a 79 series radiater will fit and is a bit bigger is this true if they are longer will it fowl on the steering dampener?

I assume I would also need the shrouding to match.
Will I need a different fan also.

Has anybody done this and how did it go.

Triden do a high flow thermostat 30% more so I might put one in.

Now the next idear would seem a bit crazy to most people but I'm a bit mad so here goes.

I want to put a second radiater behind the cab under the tray 38 mill core with the tanks left and right 3/4 in and out with 2 maridine 8 inch thermo fans 540 cfm each with a Davis Craig electric fan control system.

Quite simply a massive heater core.

Wanting to plumb the 2nd heat exchanger out of the heater lines.
Out of the block at the back through the core and back in to the out her heater line where it dumps the water in behind the thermostat.

I've done this on 2h eng up in the gulf and nt and it works but there is a floor in my dezine it works fine when ur in a hot climate all the time but I live in Roma qld where we get hot summer 45 deg Celsius plus and a cold winter -5 and here lies the problem the 2h I did this to went in to cold once
And it took 1hr to heat up and actually over heated because the eng was trying to run purely on the 2nd system and the thermostat did not open to let the primary system start working.

I have a few idears on how to fix this but it's tricky.

Am thinking about a 2nd thermostat just near the block on the feed to the 2nd core set a say 2 degre higher than the primary so the 2nd system only works when u really need it on a hot day at high speed and massive load.

Am thinking along the lines is an in line thermostat with a 3 mill hole drilled in it to allow a small amount of constant flow.

Now here is where it gets tricky a 3/4 in line thermostat would b no good because with 3/4 lines even when fully open u won't get full flow through the lines.

How big would I need to go b4 I would get the same flow through the lines when fully open as if it wasn't there?

I have thought about running the return back to the main radiater or back to the bottom hose so the main thermostat does all the controlling 4 me but am concerned about water flowin the wrong way hence stick with heater line return.

Unless there is some sort of electric temp control heater tap on the market that I don't know about?

There is more to this as well am wanting to put an electric booster pump on the feed side of the 2nd core to healp the main pump out but trying to figer out what flow rate I want head pressure and so is a bit of a nightmare.

So come on guys help me figer this out pls

 

[Loober]

I would start with an upgrade of the radiator first, mine was was running hot and had the stock radiator rebuilt with large passages and more fins/in and it did the trick.

Your other ideas are a bit extreme, an intercooler would be money/effort better spent and would serve the engine much better then a 2nd radiator. Just the logistics of routing 1.5" radiator hose to the back of the truck makes me cringe.

 

[divemedic]

Where are you located? Climate conditions?

You mentioned a bull bar, do you have large lights obstructing the flow?

Do you have an intercooler?

 

[GTSSportCoupe]

Have you tried servicing your viscous fan hub? Does your fan roar like a monster when the motor starts getting hot? If it's not making much noise it's not working properly. Put some new heavier silicone oil in the hub. On many of them you can adjust the turn on temp too. Don't use aftermarket ones; the Toyota ones are best. I've had lots of experience fighting heat, and the fan clutch is one of the most important things.

 

[RhinoRig]

Turbo? What's the exhaust look like? Have you checked the blinker fluid?

 

[coldtaco]

Start with a longer radiator. My turbo 2H would run hot at hwy speeds, I did everything I could think of, even got a new core installed using the factory upper and lower caps. Did nothing. I got one of those high flow thermostats, nothing, flushed with cleaner multiple times, nothing. So I finally got a custom alum radiator built from PWR in Australia, had it lengthened 2" on the bottom and changed the intake some (not a problem with the HZ) I even put thicker silicon fluid in the fan hub to no results. The new radiator did the trick. I just used the stock fan shroud so the bottom 2" of the radiator are not covered by the fan shroud. And I live in AK where the peak summer tems are in the mid 70's F. So, try a larger rad first, and also do the silicone replacement on the fan hub.

 

[roscoFJ73]

Firstly have heard u can put a 79 series radiater will fit and is a bit bigger is this true if they are longer will it fowl on the steering dampener?

I assume I would also need the shrouding to match.
Will I need a different fan also.

The HDJ79/78 is the biggest radiator . The stock 1HZ radiator is the same volume as the old one, it has a different part number to the 1HD FTE radiator .
I have heard of others using the HDJ7* radiator on a 75 series. I think its an inch longer in the lower tank area. Go into a caryard and measure it up or ask an ebay seller for the dimensions, but I don't think you'll have a problem.
The rule of radiators is for the fan to cover 70% of the radiator core

IMO ,you are probably best stopping right there and converting it back to stock and see if it runs cool, rather than throwing more money into it.
The danger here is that the more you add onto the engine, the more it complicates finding the original problem.
With all those mods ,it could be combo of things causing it.

In all honesty, you should have looked for good 1HD T

 

[CamCald85]

Not turboed yet built 4 one though exhaust is 2 .5 inch guys read the post fan hub is new and pulled down and refilled with Toyota fluid pulling hard 5 post bull bar with big mesh like I said ram air is the problem spotties out atm 2 increase air flow not enough though and at $7,000 for the bar it's staying.

In Australia ambient temp as I said swings from 45 deg Celsius above to -5 below.

I wanna run a 3/4 line from heater feed to 2nd heat exchanger back in to heater return a second thermostat will b needed due to a cold winter fluid dynamics is deamon I need help with with a second system and no thermostat will result in running to cold in winter thus wearing the bores out to return to bottom radiater hoze u run the risk of water running the wrong way so heater return it is

 

[renago]

14 years ago I have bought a brand new 78 HZ1 .
Used it in the Sahara desert in deep summer , fully loaded for 10 years.
Stock .
NEVER EVER over heating , not even heating .
Before going into wild makeup solution , I would strongly recommend to check out the engine , fuel injection system , and cooling system.
HZ1 does NOT heat up.
The engines that do is because they are not correctly regulated or there is some flaws in the system .

Bye Renago

 

[CamCald85]

Yea in hindsight I should have put a 1hdft in hard to come buy and very expensive approx 10k for a second handy then u have to rebuild it spent 8 k on 1hz internals and should give me close to a million Kay's it not heavy modified just a really well built good Pistons rings rods blue printed and ballenced rebored decked and so on injection is slightly tweaked.

Colling system is stock but brand new aftermarket parts.


Already tried the local wreckers and the bloke there is a bit well let's call it special.

Very difficult to deal with wouldn't let me borrow a stuffed one to c if it will fit wouldn't let me measure it or compare fans or shrouding or anything so I walked out .

Parts supplier tells me the 79 is 50 mill longer.

Am going to talk 2 radiater specialist tomorrow and bust out measuring tape radiater upgrade first then if no good second heat exchanger still working on second thermostat idear

 

[CamCald85]

RAM AIR is the problem people for those of u who don't know air flow is 1/3 of your cooling at speeds over 80 klmh the fan almost becomes irrelevant and you become reliant on ram air ITS NOT THE FAN HUB a bigger radiater means more capacity goin go down the dimple tube road thus slowing the water down holing it longer gettin it cool b4 re entry.

Has anybody put a 79 radiater in and did it clear the stering dampener are the fans different.

Let's start by seeing what we can get in there.

As for wild make up idears open your mind these Utes in Western Australia in temps of 50 degrees Celsius brand new ran hot we started taking bonnets off removing air con to get them to run cool fine in a mine but not 4 me second radiater works I've done it but where I live we get both extremes and would prefer auto water control rather than taps thus idiot proof in all weather conditions.

The wagons where fine they where wider in the font and had good air flow.

Now I know my bull bar is the problem but the arear I work in hitting Roos at 120 k that weigh 100kg is the norm hell I cleaned up 5 the out her morning and hitting cows at 800 kg at 120 Kay is pretty normal around here so like I said the bar stays

Your arb or Tjm bar wount last a week here.

Thus crazy make up ideas is solution to keep bar to protect car and run cool.

 

[divemedic]

I'm going to give you race car guy advice given this is an air flow issue.

Seal the shrouds so that doesn't escape from around the radiator.

If you added hood risers, aftermarket scoops take them off. If you removed any plastics from/around the engine bay, put them back. Especially the hood cowl and plastic skid plate under the radiator. These bits are imperative to maintaining pressure sections in and around the engine bay. Very smart people designed the car so that the air entering the engine bay wants to get sucked out. Part of that is all the plastics.

If you have oil/trans coolers in front of the radiator try to relocate them.

Consider getting an aluminum radiator made.

Regardless, your completely nessesary 5 post bullbar is effecting the air pressure dynamics of you car. Normally the front of a car is seperated into three primary pressure zones. The front, being the bumper, valences, lights, and radiators. The middle, being the engine bay. The back being the firewall.

When driving the air hitting the front of your car compresses creating a high pressure zone. Air doesn't like to be compressed so it finds an escape route. The radiator is the escape route you want it to take. The shrouds are in place to feed air that direction. When air passes into the engine bay it lowers in pressure so it wants to naturally stay there. But the fire wall prevents this. There are plastic/rubber seals around the hood, inner fenders, etcetera... which creates another high pressure zone (air hitting the firewall plus heating up as it stagnates in the bay. The low pressure zone under the car "sucks" that air out.

Basically your 5-poster bar has killed that harmoney. Especially if the bar extends above and below the front of the car. A huge high-pressure zone now exists and air bleeds around the cooling system as a result. I would recommend you try using cardboard taped around the bar, basically extending the fenders and hood to meet the edges of your bar. If your over-heating is resolved you know exactly what your issue is.

 

[renago]

Aerodynamics is fine and I fully agree with Divemedic , but ...
pls be aware that HZ1 engine is used in Africa to run electric generators , not for days , or weeks but for months ,
without stopping ,
OK they have a thicker radiator , but the first issue is that the motor must not HEAT UP.
I think that the problem you have is not a POOR radiator , but a motor that heats up .
you don't solve that with a bigger radiator , you only post pone the full blow .
especially if you want to use it in the out back .
as a matter of curiosity what EGT do you get ?

Ciao Renago

 

[coldtaco]

engine too tight?

 

[renago]

What do you mean with "engine too tight"
low tolerance ?

 

[roscoFJ73]

Yes, tolerance to low. Increased friction, but I think after 7000klms that would have sorted itself out.

It could be something like this

 

[CamCald85]

Yes the eng is to tight still I can feel it was terrible on 1st start up,is getting better though compression is a tad high which will push temp a tad my bar is very similar to the one shown except 3 mill steel with the bumper arear bigger to accomodate winch very good advise on air flow already made 8 mill conveyer belt flaps for inside guard and somehow between 3 wrecker yards in brissbane got the plastics to go on side of rad and made 8 mill lifting blocks between bonnet and hinge to decreese positive eng bay pressure.

This all helped but not enough.

Just got off phone to rad specialist interesting call apparently I'm not the only one having trouble with this radiater people have been fitting this rad having trouble then taking there old one in to get recored problem goes away.

He tells me he can get a far superior core to suit a 79 series rad for a better price than a 75 ( higher turn over ) .

So will it fit if the core is 50 mill longer will it fowl on steering dampner also will the bottom hoze need to changed to a 79 shrouding is easy enough to buy and would like 2 avoid plastic tanks come on guys some one must have tried this.

 

[HomerOz]

G'Day Fella's,

Welcome on board CamCald85.
You have come to the right place for great advice mate, there a handy and generous bunch on here.

Cam, the only thing I can think of, is instead of buying a new "Triden do a high flow thermostat", just remove the current T/stat (and run it without a T/stat) for a while and see if that changes anything?
This will give you uninhibited coolant flow thru the system, which is one way of confirming the T/stat situation and may be a potential solution.

Hope that helps

D'oh!
Homer

 

[divemedic]

and made 8 mill lifting blocks between bonnet and hinge to decreese positive eng bay pressure

.

Get rid of the hood risers. They cause a venturi effect at the gap causing turbulence and consequentially cause air to stagnate in the engine bay.

 

[roscoFJ73]

So will it fit if the core is 50 mill longer will it fowl on steering dampner

Cant you just measure the clearance underneath your radiator? The damper is not even underneath the radiator, its about 80mm behind and the bottom radiator hose clears it by 70mm, on my HZJ75. Took me 5 seconds to have look