Keepin Your Cool With Alloy

[diby_2000]

Have read and read threads on uz swaps onto hilux/surf etc.

Nearly everyone seems to have problems with kepping these monsters cool!

Just want to clarify what i THINK i have read.

With a large alloy (maybe double or tripple pass) radiator and the biggest thermo fan possible, u should be able to keep a uz cool under ALL surcumstances including soft sand.

I'm really keen on this swap but dont realy want to put vents in the bonnet or run an external radiator. I may be able to suffer a relocated a/c condensor if i have to but i would have a tranny cooler up front also.

Please tell me if i'm dreaming or if this is possible.

Any other info i need to know?

 

[1uzvl]

I think alot of the probs come from (and this includes 253/308 installs in these things) the fact the motors are so big and hav little chance of getting the hot air out of the engine bay.

We have often made rads for 75 series diesel chev engine conversion and have found the all the scoops,lifted bonnets ,tripple pass rads have never made big differences.Saying that we have never done anything in ally,which would work better again.

 

[Zuffen]

Thicker radiators are not the answer.

The rear half of the radiator is getting hot air off the front half of the radiator. Think about it.

The real answer is fitting the largest square foot (or square metre) radiator so more air can flow through it.

If I were doing this I would cut openings in the rad support to allow a larger radiator to be installed and still get air.

I would then block any opening in front of the radiator through which air can escape before going through the matrix.

Then I would make sure I had good fans with a good shroud and lastly make sure the hot air could get out of the engine bay.

 

[v8toy1]

im doin a conversion at the mo and from what i learnt and been told if u have to bigger capasity radiator the water pump etc cant handle the volumne of coolant and push it around quick enough therfore the coolant doesnt really move around the block/radiator at the right rate and it either stays hot or to cold. the other thing i learnt was with shrouds it's pretty obvious u need one i got a 12'' electric fan and the shroud it sits on is about 20 to 30mm away from the core so it draws air from the whole surface and not just where the fan is i moved my down to about 10 to 15mm away from core but that is about as close as u wanna go.
As with mine i got a dual bypass so it goes in the top and comes out the top but that was mainly due to the fact of where the inlet/outlets are on the engine mine was a 2.8 deisel dualcab lux the radiator i got built was ally dual bypass same dimensions as deisel radiator with a eletric 12'' fan and shroud in between the engine and radiator hope this helps oh and i still got aircon condensor in original postion

 

[Mattmannz]

Have you got any pics of your setup V8Toy?

I can't see how I could get a radiator in between the motor and the radiator, there isn't enough space.

Cheers
Matt.

 

[bansheebuzz]

i am using a deisel radiator in my rn85. temp rarely gets above 85deg but in traffic it will, i have twin 12 inch fans pushing that switch on at 95deg, they have no problem keeping the motor cool. Condenser for the a/c is under the tray

 

[v8toy1]

Have you got any pics of your setup V8Toy?

I can't see how I could get a radiator in between the motor and the radiator, there isn't enough space.

Cheers
Matt.

i will do soon but to get it all in the engine is about 5mm of firewall and i recessed radiator under support panel about 10mm the rad pretty much sits flush against the condensor i also got rid of the fan drive pulley and hub and i am getting a shorter belt to fit(obviously kept the idler pulley though) the agp between the engine and rad is about 15mm i could get more out of it by redesighning the support panel and movin condensor closer to grill but at the moment i just want to get it done so i can take it up north where i live now i'll try and get pics on here but parents only got dial up and it takes ages i'll see how i go i''ll do it tomorrow

 

[webbie]

I think alot of the probs come from (and this includes 253/308 installs in these things) the fact the motors are so big and hav little chance of getting the hot air out of the engine bay.

I have rang several 'alloy' radiator places and this is exactly what they said. He said that although he wanted to sell his product, it wasn't really going to fix my/our (Lexus-Hilux/Surf combos).

Things which I have done (which most also recommend/ask) is:
Space rear of bonnet to let hot air out.
No bull bar
No spotties in front
Removed splash guards from inner guards.
Have installed 15" * 12" trans cooler
Run the std diesel 3 core (after pro flush out)
Run 2 * 11" thermo as pushers with shroud that has 100% of air going through top 70% of radiator.

The only time that I have run in to troubles is about 12km of soft sand with a fully loaded (I mean fully loaded, could not even fit another 6pack if we tried). Just means that you have to pull over for a beer and let it cool.

It's fine for road and off-road driving, just have to keep on eye on it on the soft stuff.

Cheers.

 

[Mattmannz]

You can't run a shroud when you use pusher fans as you will actually restrict airflow.

The shroud on pullers actually increases airflow because you are condensing it and forcing it through the fans and you are starting with a large opening and working down to a small opening so you take a lot of airflow and run it through the fans.

With pushers if you use a shroud you restrict the air intake significantly as the only intake is now the surface area of the fans.

Each fan should have a small shroud to concentrate it's airflow over the radiator however the radiator face cannot be covered like it would be with puller fans.

Matt.

 

[webbie]

With pushers if you use a shroud you restrict the air intake significantly as the only intake is now the surface area of the fans

I was pretty lucky that this wasn't the case, only really lost the little bit between the bottom of the 2 fans.

This is also my mounting method, as i wasn't really keen with plastic things through the radiator.

Cheers.