V8 auto & oil coolers

[Tom1809]

Hi chaps.

Need some advice on my v8 auto conversion. Both radiator and auto bog brush cooler was beyond use from the donor vehicle so scrapped original plan and gone to plan b.

I have sourced a new military 2.5 petrol rad. Which now leaves engine oil cooler and auto box cooler to source, position and pipe up.

I will be honest I have no real idea on how much cooling is needed for these and I wasn't able to work out a area of size to make a decision myself. The truck will be used n green lanes and winch challenges so would be working hard and need extra cooling at a guess.

I have been looking at goodridge fluid coolers. I have not ,measured the width of the wings as I'm not sure if challenge wings from north off road will allow a larger arear in between one and another. But here is the link to the ones I've been looking at.

http://89.206.185.119/extra/file/g-cool_book[3].pdf

I was thinking of using the 37mm x 7 or 14 plates, and making a frame bit like the tdi ones to add some brackets on to mount like this ( please excuse the rather crude drawings still learning the app)

and running pipe work either down the front and under the radiator, or around the sides of the radiator but don't know till i get me wings. However My only concern is mounting in front is going to cause problems with air flow to the radiator and possible getting blocked with mud etc. I will be using a viscose fan and not electric as I have had bad experiences with them.

The other question I have is, with the v8 would bonnet vents be a good idea to help with engine bay temps whist using at slow speeds?

Cheers

Tom

[zardos]

Hmm cannot understand the diagram, some labels would help and a hint to the orientation to the diagram, I assume that it is looking from the front?

As for how much cooling is required that is a difficult question.

I can tell you that using a small donut oil to water cooler is ok for the oil in a 3.9 v8 90 which is used for winch challenges and a standard 3.5 v8 rad is ok with twin electric fans as well.

The whole engine bay and bonnet does get hot and I do have some small vents on the rolled sides of the bonnet.

Mine is a manual so cannot say about transmission cooling from experience.

I also have North Offroad Challenge wings, so if you want pictures just ask.

For any cooling needs ask Think Auto they have always been very helpful and are very knowledgeable about cooling.

[Tom1809]

Thanks zardos, sorry about the pictures it doesn't show text unless I physically print it off. Looking from the front, oil cooler on the left and auto box cooler on the right, brackets from top and bottom to hold them securely. And the pipes either going around the side of the radiator if there is room or they will go under the radiator. If that make sense. So if a small oil to water donut cooler is sufficient then it saves a lot of hassle for me. Just the auto box to worry about then, and cheers for the link.

If you could that would be great, I am just after a front picture so I can see how tight eeverything is in between the wings

Thanks

Tom

[yella 90]

is the 2.5 rad going to be man enough to cool the v8 ?

autobox wise

ive got a 30 row oil cooler with a 9" leccy fan attatched to it which keeps it all in shape no matter how hard its worked

the last thing you want to be doing is cooking your auto

[mickeyw]

The under bonnet heat in a V8 Defender can be considerable, I know this

Now I know that when my lecky fans come on the heat tends to be blown out of the bottom of the engine bay. This is very noticable when I get in or out of the truck.

When driving off road, this route of exit is invariably blocked by mud and water, especially if you happened to be well bogged. I seem to recall Nige (HfH) mentioning that he felt having vents in the bonnet weren't the most effective way of losing heat. I believe he still has tdi style air intake vent grilles fitted to left and right wing sides. This would be a good exit route for underbonnet heat blown by the fan, one day I shall get round to fitting mine

As for the rad, I'm using a turbo D unit, that has built in engine oil cooler. My auto box uses just the standard bog brush cooler, but I have never tried to monitor its operating temp to know how effective this setup is. That said, the box seems to work OK.

A couple of years ago I had my rad recored, and having seen how they assemble everything I reckon I could have had them use a RRC left hand end casing that includes a through-the-water transmission oil cooler, instead of the original item. This would have effectively provided the same transmission cooling as an auto Rangey.

[zardos]

Some pictures

[zardos]

Some more pictures

The radiator is mounted in the standard bottom mounts on the front cross member and is a 3.5V8 90 rad, and is 765mm wide.

You could probably get the standard 3.9v8 auto disco rad in there which is just slightly wider from memory and this has twin oil to water coolers in the end of the rad.

Hope that helps.

[Team Idris]

I can't see anything other than a full width V8 rad cooling him, but hell, it might work? I know my 3.5 kicks out loads of heat, but its on carbs. I know I couldn't do it.

And adding a donut oil cooler will add even more heat load to the rad water.

Engine bay heat seems to be worse on V8 than 4 pot because two exhaust manifolds are heating the space. On the 4pot there's only one manifold, so hot air can escape on the other side of the engine over the rocker box. I considered a sucking bonnet fan, as the fuel was boiling in my carbs after an hours winch challenge. We believed we could never get ahead of the manifolds heat output. So I fitted a blower fan right over the carbs, which sorted him out. But I'm rear-rad, so engine air flow really was restricted!

I wouldn't think there is enough gearbox oil flow to shift the heat from stalling the torque for a long period, as its small bore pipe. So my best guess was a 16 row intercal cooler, about 6" wide with 235 between the fittings. It lives in the passenger side footwell, blowing out into the wing space, with a 7" spal fan. It avoids the mud there.

Engine oil cooler was also a 16row intercal/mocal/oxford style cooler with 5/8" bsp fittings. Fitted in my Comp days, it was also in the footwell and kicked out enough heat to act as a cab heater. But it's just been removed to make way for the dry sump tank. I believe oil temp will be okay on winch challenge, which is short bursts of power ??? (Now carrying more oil to act as heat buffer)

Thats where I am with it

It did cross my mind that it got hotter in mud pits, as it blocked the air out of the bottom of the truck. So what if I ran a fluid pipe so low it sat in the mud?

[Tom1809]

I'm not sure if it's man enough or not, I got it cheap enough so it's not to much of a loss if it isn't. It's similar height to the disco v8, same thickness but about 2" shorter but doesnt have a internal oil cooler so li guess less heat load.

So really for both oil and autobox I'm looking at a 28 plate 37mm x 241mm x 249 mm size cooler With a 9" fan, positioned some where but in front of the radiator to avoid mud. Can't put it in the foot wells unfortunately so some where in the engine bay.

[iomlt]

doesnt mention which v8 your running. so at a guess. i would remove the engine oil cooler and concentrate on water cooling. use the 2.5 rad and splash / spend high on some very decent fans twin fans keep an eye on temp and if your struggling get a bigger (V8 90) rad. then buy a oil cooler for the gearbox from whitbred or someone and put this either infront or behind the rad and make sure your push or pull fans pull air through both rads. I know Malcom at whit bred has it behind his rad (to stop it getting blocked with carp) and uses push fans and he has had no problem at all so connot see you having any neither.

I run with twin fans sucking through my rad with the auto box cooler on the outside and seems to work very well on my 3.9 see pic from when i was building the truck

then i have two big kenlows on the inside "sucking" air through.. .

[iomlt]

or somethin like this for your gearbox? http://www.summitracing.com/parts/BMM-70298/?rtype=10&mitem=1&page=1

[Tom1809]

Sorry i forgot about that bit. I'm running a 3.9 serpentine with megasquirt, I was planning on running the standard viscous? You wouldn't recommend this then? I'm still new to the whole winch challenge thing and want to try and make the right choice first time as I don't have much money to throw around making to many mistakes, obviously I will tweak and change things after my first couple of events and the truck will evolve with me no doubtly.

[iomlt]

standard viscous fan... work well when in good order but in water and the likes could cause problems, in theory they shouldnt. so ifffffffff your keeping a viscous and i presume you have the cowing still in there too??? you MIGHT be able to fit a oil cooler like mine behind the rad and let the viscous pull the air through.. i would say when the viscous is working hard it will pull enought air through.. at a guess.

the summit racing opion is a cost. but you could hide that at the rear (if your truck cab) or somewhere under the bonnet out the way. i would personally got for this one http://www.summitracing.com/parts/DER-13700/ and buy the optional inline thermostat control.

this will easily sort it out for you and you wouldnt need to worry about it. but it comes at a cost.

there are other options out there i believe devon use Lamanova Coolers.. which might also be a option. as this cools the oils system using the water from the rad.....

so many options..... life eh!

[Tom1809]

Yes there is so may options to choose from i really don't know which way to go with it and need to start ordering things so I can starting organising where things are going to go an what else I need.

That actually seems reasonable fron the states considering I'm thinking of using two of these http://www.merlinmotorsport.co.uk/p17012/GOODRIDGE-G-COOL-28-ROW-OIL-COOLER/product_info.html?osCsid=eaf585438ef60fa3cdc52f8d8a538a57

Another thought going back to team idris he has a radiator in the back. I wonder if the oil cooler and auto box cooler can be fitted in front where the rad would be, with there own electric fans, and then run a radiator at the back of the truck, I suppose the problem then is getting enough air to flow through it and would be a long pipe run, so would have to use a inline water pump and also stat, however would allow winch to sit slightly further in and could get a better approach angle?

[iomlt]

you wouldnt need a inline water pump at all. the current water pump is more than man enough... If you can put the rad and cooler in the back then yes you will have more room. or....... if your running 100" why not move engine and box back? so many options.. make your mind up and run with it..

[iomlt]

you wouldnt need a inline water pump at all. the current water pump is more than man enough... If you can put the rad and cooler in the back then yes you will have more room. or....... if your running 100" why not move engine and box back? so many options.. make your mind up and run with it..

[iomlt]

On and for that price of the oil cooler i'd be buying the one from summit racing...... http://www.summitracing.com/parts/DER-13700/ includes fan and all you do is buy a £10 inline fan thermostat and bingo you have a controlled fan oil cooler that comes on and off at the perfect temperature. I'm actually nearly talking myself into buying it cuz it sounds soo good. where as currently i dont know really whats going on with my gearbox oil. i hope to think if anything its over cooled........ when dropping the oil it looks ok... but who really know without fitting a temp guage to the sump..... i will do that to see how effective my cooling currently is. I just think if its good enough for whitbred then it should be good enough for me.

[Tom1809]

Ok so better off putting rad in the back, that's no biggy and I'll run the pips through the cab hopefully some extra warmth in the depths of winter although they would have to be boxed in. Auto box wouldn't be so hard to get to the back I suppose but the oil cooler would be one hell of a run to make but never know any things achievable when well thought out.

I wish it kept the disco chassis I got the axles from and the box and engine, was really solid but didn't want to go down the route of sva/Iva checks so still with the standard 90 chassis, considering raising the spring mounts to lower cog like richard chassis do on there 100" comp chassis.

So now got a better idea of what I need now, just hope I finally get my pay packet this month so I can get moving with it some more. Thank you very much for your advice.

Tom

[iomlt]

I wouldn't put pipes through cab as a truck cab and V8 is so warm already! Make sure your heater and the screen vents are in perfect order and steam becomes your best friend!

The way I have tried to build my truck is trying to keep things as simple as possible. The more electrical goodies you have the more chance of problems can occur.

I hope I have given you some more ideas but I'm sure more professional advice will be along soon.

[Team Idris]

Here are the water hoses sneaking up the leaft hand chassis leg;

Rear rad frpm front;

Rear Rad from rear;

Rear fan runs all the time. Half speed for this and that, full speed for challenge. The two front fans are on thermostat

[Tom1809]

Thanks chaps,

What size pipe you run up the side of the chassis leg team idris? 35mm ally?

I have never had a v8 so Its still the unknown, the 200 tdi was well pathetic at heating the cab so I assumed it was going to marginally better. There goes my plan of welding up the front flap to stop water ingress, new seals and making sure proper shut I get a small water fall if I go bonnet deep inside the cab

Thanks

[Team Idris]

38mm steel exhaust pipe thats been in about 15 years. The inside looks better than the outside due to antifreeze

Ideally it would be under the floor where it could do more cooling, but it's nice and safe inside. The crinkles are from bending with a gas welder.

[Tom1809]

Ah didn't see the crinkles, well that's cheaper than alloy so can get on with that before everything else goes on

[Tanuki]

Personally, I like oil/water heat-exchangers for both engine- and transmission-cooling, coupled to a big water-radiator up-front.

That way you can get the engine-oil and transmission up to proper temperature (100-105 Centigrade) quickly from a cold-start by sharing coolant-heat with them, then only when bulk-coolant temp is 95 centgrade or above does the thermostat open and the radiator come into service.

Hot is efficient; hot promotes both low fuel-consumption and long-life. It's also worth noting that if you're fitting a thermoswitch to activate an electric fan on the main radiator, this should go in the radiator *outlet* not the inlet.

Run with 50% antifreeze and a 15PSI pressure cap on the radiator and you can happily go for days with the sensor in the top-hose to the radiator reading 115 degrees - thats what we used to aim for on the late-1970s Escort RS2000 rally-cars.

[Team Idris]

"if you're fitting a thermoswitch to activate an electric fan on the main radiator, this should go in the radiator *outlet* not the inlet."

I'll have to ask for an explanation I think neither works well.