Heavy Duty Radiator

rocky

NAS-ROW Addict
I looked at Ron Davis for a V8 radiator but got the nearest thing to a blank star you can get over the phone.
I was spending tons of time in Greenville SC but could never lay my hands on an old V8 unit to take to them. https://www.griffinrad.com/index.php


So I did the crazy thing and went Allisport. One issue there is that 3.9 NAS radiators have a straight upper connection, Early v8 have an elbow that they use.

It just seems crazy to ship in a radiator but I did.
 

Angus

Well-known member
I've had an Allisport radiator in my 3.9 for about 3 years. No issues and great cooling, but I made sure I had rubber pads on the bottom mounting pegs. Was not happy with the steel on aluminum mounts.
 

evilfij

Well-known member
Are you sure it’s the radiator and not a fan issue? Low speed beach driving would make me thing it’s an air flow issue.
Or head gaskets or leaking cap or leak or thermostat or water pump or air bubble etc.

I have the aluminium one from RN on my LWB and the gauge never budges so I suspect something else, probably the fan clutch is weak/bad.
 

MountainD

Technical Excellence Contributor
Also depends on fans. Engine driven or electric? Sometimes beach driving is high rev, low speed. Some E fans are not up for it t. Workin Mech and then focus goes to other components.
 

DPdotCOM

Member
Are you sure it’s the radiator and not a fan issue? Low speed beach driving would make me thing it’s an air flow issue.
I've got a dual fan revotec electric fan setup. It appears both are working. But no shroud.

 

DPdotCOM

Member
Or head gaskets or leaking cap or leak or thermostat or water pump or air bubble etc.

I have the aluminium one from RN on my LWB and the gauge never budges so I suspect something else, probably the fan clutch is weak/bad.
ok, clearly i should do some more digging. sorta hard to diagnose/solve for bc it holds temp nicely in normal conditions, but maybe I'll just put in a new thermostat and try to bleed the system regardless, then see if i can't find someplace to replicate sand driving since I'm done with the beach for the season.
 

evilfij

Well-known member
I would strongly consider running a mechanical fan with a clutch if you have a V8. But that’s just me.
 

DPdotCOM

Member
I would strongly consider running a mechanical fan with a clutch if you have a V8. But that’s just me.
Wouldn't a mechanical fan actually move LESS air when we're talking about slow-ish sand wheeling? The revs aren't TOO low, but we're still talking 2500 RPM to 3000RPM, not like, 4500RPM track time in a TR6.
 

evilfij

Well-known member
Wouldn't a mechanical fan actually move LESS air when we're talking about slow-ish sand wheeling? The revs aren't TOO low, but we're still talking 2500 RPM to 3000RPM, not like, 4500RPM track time in a TR6.
My personal experience is that the mechanical fan with the proper shroud moves more air than any electric fan set up. That highway speed rpm mechanical fans work great. At track speed a lot of air is being pushed through the rad by just going fast.
 

1of40

Well-known member
overheating at low speed tends to be the viscous fan.
That's been my experience as well. What turned out to be a simple solution for me is running a toggle switch to the AC condenser fan(or you could run an efan if you dont have AC). I've only needed to use is on long steep grades. This summer I had my 90 in all over the Alpine Loop passes, some as high as 14K. I just toggled it on and watched the temp drop a couple degrees and stay steady in the high 190's-low 2's.
 

MountainD

Technical Excellence Contributor
My personal experience is that the mechanical fan with the proper shroud moves more air than any electric fan set up. That highway speed rpm mechanical fans work great. At track speed a lot of air is being pushed through the rad by just going fast.
My experience as well.
 

DPdotCOM

Member
That's been my experience as well. What turned out to be a simple solution for me is running a toggle switch to the AC condenser fan(or you could run an efan if you dont have AC). I've only needed to use is on long steep grades. This summer I had my 90 in all over the Alpine Loop passes, some as high as 14K. I just toggled it on and watched the temp drop a couple degrees and stay steady in the high 190's-low 2's.
So are you advocating for a secondary fan? or just that electric fans are good because they run irrespective of engine speed?
 

MountainD

Technical Excellence Contributor
AC should have a secondary fan. For when the clutch on mechanical fan (or engine coolant switch for e-fan) isn't up to temp to engage, but AC still needs cooling.

I will add that this is what new cars do, whether they have mechanical or e-fan.

Also, for those that say 40-50HP is killed by mechanical fan, that is not true. It is typically in the 3-10 HP minus what the e-fan pulls. The higher the amperage of the e-fan, the more HP it pulls from (nothing is for free).

And this isn't a debate on the energy efficiencies of HP or mileage. It is pretty universally understood that e-fans win that. It is about cooling. And the second I have to slow down because I can't keep up with the cooling demands is the second the debate ends for me. I want solid cooling and I want that at all times. Stopping on a long incline to cool sucks. Trying to build momentum back up (particularly with a manual diesel), it is tricky on the clutch. You HAVE to feather the clutch just to build turbo pressure and take off when you are on the 10%+ grades (trust me, that is a lot). And it won't thank you.

I am a heat "power user". I live at altitude (3% less cooling per 1000' elevation approx), plus I tow at altitude. I need a bit of cooling and I don't want to second guess my heat generation. I am currently converting back my R2.8 to mechanical fan for this exact reason. I had similar issues with e-fan on my Rover V8's. Mechanical reigns supreme for cooling. I'm fine in the winter, just the 100° summer temps which is the exact time I head up to the mountains to camp with the trailer.
 
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doktorno

Active member
I ordered an Allisport and it arrived damaged, but was not caught by installing shop. Sent back to Allisport on my dime to get repairs made at my expense. Allisport admitted receipt but lost the radiator in the shop and would then not return emails. Wish I had ordered from Ron Davis or RN....
 

evilfij

Well-known member
The rover V8 was designed to work with a mechanical fan. I am not sure if you have a 93/94 or 95 LWB 4.2 but I would fit a mechanical fan (with fan clutch) and correct shroud and that should fix your overheating issues. When they get warm the mechanical fan moves a ton of air. Not sure an electric fan can match it.
 
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jymmiejamz

Founding Member
Callsign: KN4JHI
My experience is that both genuine and aftermarket fan clutches and radiators are inadequate quality. If you could get an original factory quake radiator and fan clutch there would be no issues. I’ve tried all different brands of radiators and fan clutches and the one thing that consistently fixes running hot at low speeds is installing good quality electric fans. I’ve also had enough issues with genuine, aftermarket, and recored genuine, that I just go all out and install Ron Davis radiators with electric fans for all V8 Defenders.

Fwiw, in my NAS d90 that had a very high compression 4.6 With ac and a 4 core radiator, it always ran hot in summertime nyc traffic until I fitted the rovers north electric fan kit. And those fans are a joke compared to the SPAL fans that come with a Ron Davis Radiator.

In a world with good quality parts, a mechanical fan is much better at cooling, but that’s not the world we live in.
 

DPdotCOM

Member
This is maybe a dumb question, maybe valid - but do mechanical fans move more air due to size? or the nature of spinning at roughly engine RPMs?

AC should have a secondary fan. For when the clutch on mechanical fan (or engine coolant switch for e-fan) isn't up to temp to engage, but AC still needs cooling.

No AC in my case, so just the one rad. But others in this thread likely do.

The rover V8 was designed to work with a mechanical fan. I am not sure if you have a 93/94 or 95 LWB 4.2 but I would fit a mechanical fan (with fan clutch) and correct shroud and that should fix your overheating issues. When they get warm the mechanical fan moves a ton of air. Not sure an electric fan can match it.

This is in an 83 110, but it has a freshly rebuilt 4.2 in it (done by The Wedge Shop). It is the original water pump, so that could be something worth changing for sure. but alas the RRC fan shroud won't work for me, and the original engine bay and mechanical fan didn't have a shroud.

Fwiw, in my NAS d90 that had a very high compression 4.6 With ac and a 4 core radiator, it always ran hot in summertime nyc traffic until I fitted the rovers north electric fan kit. And those fans are a joke compared to the SPAL fans that come with a Ron Davis Radiator.

My setup is that same RN one.
 

evilfij

Well-known member
My experience is that both genuine and aftermarket fan clutches and radiators are inadequate quality. If you could get an original factory quake radiator and fan clutch there would be no issues. I’ve tried all different brands of radiators and fan clutches and the one thing that consistently fixes running hot at low speeds is installing good quality electric fans. I’ve also had enough issues with genuine, aftermarket, and recored genuine, that I just go all out and install Ron Davis radiators with electric fans for all V8 Defenders.

Fwiw, in my NAS d90 that had a very high compression 4.6 With ac and a 4 core radiator, it always ran hot in summertime nyc traffic until I fitted the rovers north electric fan kit. And those fans are a joke compared to the SPAL fans that come with a Ron Davis Radiator.

In a world with good quality parts, a mechanical fan is much better at cooling, but that’s not the world we live in.
Interesting. I still have the original radiator but aftermarket fan clutch (which frankly I think is overly aggressive) and can sit and idle at 95 degrees and flog doing 95mph (I have a disco/RRC cold start chip) and the gauge does not move on my my 90 (I also deleted the oil cooler, but I am not sure that makes much of a difference). Running 0w40 mobil one. The only time I had temp rise above the usual was when the fan clutch was shot. It moved a little above normal and I want into panic mode. I also don’t have AC which probably helps.
 

Angus

Well-known member
I have an Allisport radiator with the original fan, clutch, and shroud on a 3.9. I am running an 82 degree thermostat (if I remember correctly). The temp moves to about a needle's width below the midpoint on the gauge, and does not move, regardless of what I do. I run a radiator muff in the winter or it would never warm up and not provide any heat. Overall, not sure I could make it any cooler.
 
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