Improving Air Flow to Radiator

madaboutled · Guru

Improving Air Flow to Radiator

reglynn · Guru

Is the motor home an auto

madaboutled · Guru

reglynn wrote:
Is the motor home an auto

Yep, but not your typical 2.5 Lt diesel... (see my signature below).

macka17 · Guru

Hey Zig.

If it has the usual Windsor. the rad is a combination.
Water and Transm fluid.

think about exchanging\selling it.
Buy a MANUAL Transm, 3 tube one.
with a separate Auto cooler to suit. separate to.

You'll get MUCH better(er) cooling to both.

Also coupla other little helpers..

Get an extra. Transm COOLER Rad or finned tube. and set it into Hyd line t'wee transm
and cooler. in the OUT of transm line side. As a secondary unit.

Will give waay more cooling again.

Another little item.
IF your trans "hunting" a bit cresting climbs?.
Think about a Torque Converter Lock up Switch.

There are several on Market. Cheaper than Wholesale Auto's. (near $500)
(I have theirs)
LOOK on NET Auto cooling and Lockups.
It's interesting.

That donk and transm. are NOT designed to drag your load all day.
They a Falcon donk. 351 a Fairlane.

Bagmaker · Senior Member

have you made a shroud to ensure all of the air coming through the radiator goes over the fans?

Ron-D · Guru

When I used to own a taxi many years ago when the cabs had overheating problems from memory ,a new radiator core fixed the problem, putting an extra fan on the radiator back then would have been useless...

Peter_n_Margaret · Guru

You may find that your fancy fan arrangement actually blocks a significant amount of air flow and the overheating will get worse unless it is running all of the time.
A higher capacity radiator core would be a much better solution.

Cheers,
Peter

macka17 · Guru

Std Ford.CORES .

WERE, as standard 2 core. The 351's had a 3 core.
We used to swap out for more flow.
BUT. I think with your load. Permanently on the back.
You'll need more.
a 3 cog Auto will possibly do a lot of "slipping" too.
Hence overheating it's core rad,
and reducing efficiency on ENGINE cooling part of a dual rad If anything.

If You Serious??..
Go to an Alumunium RAD, MFG.
We have one that exports Globally for performance 4wd's.
He'll tell you what and mfg it\them, for you..
Everything else is just a stopgap.

But splitting rad's IS first step. Specially if you thinking of going
North or Central.

patrol03 · Senior Member

You should be first looking at radiator efficiency. this can be achieved by a radiator that has an extra row of tubes together with extra cooling fins between the tubes. It is amazing what is out there when you investigate. An Auto Trans cooler could also be fitted into the return line after the radiator or ideally, by pass the radiator and use a high capacity cooler with a fan mounted in an appropriate position where the radiator will not be impaired. Might cost up to a grand but cheaper than cooked engine and trans.

Aus-Kiwi · Guru

I prefer ti use OEM fan and shrouds . These aftermarket fans donât. Pull enough air .Look at EL / AU Falcon or Commodore fan- Shrouds . The wider, thicker blades seems to pull more air through ., One other to consider is âexpansion tankâ. Had a few old diesels seems to overheat ! Added a larger header or expansion tank ., no issue . Fitting an under tray between radiator and engine helps pull air through big time . Check water pump is Not cavitating If final drive is much lower than designed for . If rpm is high ??

-- Edited by Aus-Kiwi on Thursday 16th of November 2017 06:32:07 PM

madaboutled · Guru

Unfortunately I'm stuck with using the stock transit radiator due to the space available. I've spoken to a few radiator places and all have said that an off the shelf 3 core for that size is not available unless I want to spend big bucks to have a custom one built.

That said, all have said the stock heavy duty radiator (which I've got) is a wide 2 core cross flow system and this should be OK if the air flow can be improved. Also most radiator places these days don't build them any more. I've been told I'd have to go to Brisbane or Sydney to get one custom build.

The shroud I've built covers the whole core area and the new fans are more than double the CFM capacity of the 3 original fans. It also has a thin rubber seal on the edges that contact the core, (not seen in the photos below) I added the rubber so it not metal on metal and also help prevent the fans sucking air from outside of the outer edges. This will hopefully force the air to come through as much of the core as possible. The original fans only covered 60% of the core area and there was some large areas that were totally blocked by the brackets holding the original fans. Where as the new shroud covers 100% of the core with about 75% of the core area covered directly by the fans.

Also should note that I do also have a secondary Auto Trans Cooler that's suited to V8's.

The old system was OK and it's never really been a problem, I've just had to take a few breaks going up steep ranges where I'm going slow cause of the vehicle in front. With the fans rebuild I'm also putting each fan on its own temp sender and setting one of them to come on earlier. I'm also adding an over-ride switch on the dash to enable me to turn the fans on before they are needed, IE going up ranges. Travelling over 70 Kph there's sufficient air flow without the fans. So, these changes should improve things.

Aus-Kiwi · Guru

Btw if thereâs no barrier between the larger and smaller fans ? The big fans may pull air through the smaller ? Are they pulling air behind radiator or in front ? If the latter ? They will be restricting air . You could add another radiator off the heater hoses ? Midmount it behind cabin ? Using metal pipes to assist in extra cooling . Double check total ignition timing ?? It could be over advancing ?? Or mark harmonic balancer timing at say 35* rev to 3000 rpm and check with timing light ? To check max advance ., Make sure you have correct thermostat. Cooler is ok .

madaboutled · Guru

Aus-Kiwi wrote:
Btw if thereâs no barrier between the larger and smaller fans ? The big fans may pull air through the smaller ? Are they pulling air behind radiator or in front ? If the latter ? They will be restricting air . You could add another radiator off the heater hoses ? Midmount it behind cabin ? Using metal pipes to assist in extra cooling . Double check total ignition timing ?? It could be over advancing ?? Or mark harmonic balancer timing at say 35* rev to 3000 rpm and check with timing light ? To check max advance ., Make sure you have correct thermostat. Cooler is ok .

The fans are on the engine side so pulling air. With the old fans The large fan didn't have a shroud and was mounted to the RHS, the 2 smaller fans were on the LHS (one on the bottom & one on top. Between the large & small fans WAS a pressed metal bracket that was about 100mm wide and it just blocked the airflow. The radiator places I've been to all have said "if you could get rid of that bracket....."

Timing & Carby mixtures where both done on a Dyno last year. Timing is still good but carby is running a bit rich, I'm putting in an Oxygen sensor & gauge next week to help sort the carby out.

Aus-Kiwi · Guru

Need a wide band o2 sensor . Try a piece of paper on fans to check air flow or direction . With out a baffle between the large and small fans ? You may have issues ? Fans pull a few amps too . Early alternators where only 50 amp . Is it a Windsor or Cleveland ? Thermostat , top hose on block or inlet ? .

swamp · Senior Member

Hi
Overheating issues gotta luv them.
Falls into a number of areas
At idle or close to it
While driving above 40kph high load

Generally in theory why big fans are fitted is to cover up for having a slightly small radiator or lack of air flow over core size
At speed its always core size in 99% cases
It was common that all EURO machinery had very small radiators coming into AUST. Actually some Kubotas Tractors still have radiators increased in size b4 being sold .
Air flow can be restricted by front body work --inlet air
Radiator shrouds can restrict high speed air flow --- outlet air
The air outlet shroud needs to have air outlet rubber flaps ,they open under high speed allowing max air flow

Mechanical viscous hub fans do the best job at moving air

WRV · Member

had a ZD fairlane years ago with a 302 windsor, always overheating, had a custom made 5core radiator, eventually sold it, years later talking to a new friend that raced cars with 302 windsor, said the biggest problem is most people get rid of the shroud for the fan, he said this was crucial for efficient cooling

Aus-Kiwi · Guru

I have 750 hp 302 twin turbo Windsor as my daily driver.. I has a 4 core radiator and std EL Falcon fans and shroud.. Trust me you need more radiator !! If anything LARGER than Falcon / Fairlaine as its under load.. Another option is to fit an electric pump and install another radiator in the rear with elect fan ... The option would be way cheaper than engine repairs.. Save you some grief, heart ach !!!

madaboutled · Guru

OK the only times I've had issues is on very steep ranges or in heavy traffic where we're going less than 60kpm. The problem has been identified as an air flow issue at reduced speed, as the water temp rises then the fans would have to deal with the increase in temp and the loss of air flow from speed.

The pic below shows the original fans, as you can see there are several areas not serviced by the fans and the bracket in-between blocks a good portion of the radiator. Additionally the small fans that are more motor area than fan area. Before removing the old fans I tested them putting a piece of paper on the front of the radiator. The paper would hold anywhere the fan blades were directly under. So as you can see there's lots of core area that totally relies on airflow coming through when moving.

I fitted the new fans and shroud last week..... What a difference!.

With the paper test it sticks to all areas of the core including into the corners. I even tried a small piece of paper right in the corner, sticks like S@%* to a blanket.

I realise that when the fan's aren't spinning there could be some air flow restriction, but it should be far less than the original set up. I've also added a pilot light on the dash that will tell me when the fans are running. Additionally, I've added an override switch so I can turn on the fans manually when in traffic or before we hit hills. In this way I can get the fans going before the thermostat triggers them so the water temp won't rise .

I haven't road tested it under extremes as yet, but I can already see a vast improvement. At idle when the fans are triggered by the thermostat, there is about a 40 to 50% decrease in the time it takes to cool to the point the fans turn off. On a long slow drive at 50 KPH there seems to be sufficient airflow to maintain temp without the fans, so that in itself is another huge improvement. I'm looking forward to taking it up to Dorrigo in a few weeks for a test run.

Joda · Senior Member

Consider electric water pump, higher water flow plus less load on engine, also can set pump to come on with override switch on dash plus everything Macka said,

Aus-Kiwi · Guru

Does it have a heater ? A simple cooling aid is to extend the hose behind cabine . With cooler / radiator of some sort ? Even a air conditioning heat exchanger ? In series with heater . When it gets to point of kicking down before it gets too hot !! Turn the heater on . The extra coolant should be enough to cool for short busts . Even if itâs just the extra coolant ?? Yes the top section of the fan above radiator should be sealed !!