52 replies to this topic

[jd lj]

Handheld digital anemometers are as cheap as dirt these days - http://www.ebay.com....P0AAOSw2x1XLVVb - and they're ideal for testing fan performance. Generally a good OEM clutch fan will shit all over electric, and from a great height.

A clutch type fan isn't going to help with a stationary vehicle sitting there idling is it? Correct me if I'm wrong.

[StephenSLR]

A clutch type fan isn't going to help with a stationary vehicle sitting there idling is it? Correct me if I'm wrong.

 

The clutch engages as soon as the temp. reaches a certain level, whether the vehicle is stationary or not.

 

 

From memory mine would always spin.

 

s

Edited by StephenSLR, 05 June 2016 - 07:19 PM.

[jd lj]

The clutch engages as soon as the temp. reaches a certain level, whether the vehicle is stationary or not. From memory mine would always spin.
s

Even so, at idle would it be spinning fast enough to pull more air flow than the original mechanical fan? Once the car is moving the fan performance is almost irrelevant isn't it? The problem is that the mechanical fan and I assume the clutch fan are only spinning slowly at idle which is when the air flow is low and needs to be compensated by the fan.

[jd lj]

I fitted a 14" High Flow Davies Craig to the front of my LJ's rad. Its a tight fit to mount up without cutting/shutting anything, i made a little shroud, it sits off the rad by about 30mm and mounts to the rad support panel (upper and lower). Highflow might be overkill, as it pumps out that much air the fins in the rad restrict the airflow to a point that its reflects back out the inlet side to the fan...
But anyway, it works really well. I fitted a thermo switch to an in-line rad top hose housing i bought off ebay. Looks quite tidy, an even tidier way to do it would be buy a new thermostat housing from rare-spares that has the thermo switch hole already taped in it and mount it there.
Beauty of the thermo fan is it gives alot more space in front of the engine to run any balancer etc you want. 

Rich, can you post a picture of your set up to show the clearances etc.

[StephenSLR]

Even so, at idle would it be spinning fast enough to pull more air flow than the original mechanical fan?

 

In my LX SL/R L32; the original fan is a clutch fan and I do remember it overheating once, after 10 minutes or so of driving after I did doughnuts in a park. lol I switched off the car and the engine seemed to be jumping around a little.

 

s

Edited by StephenSLR, 05 June 2016 - 07:28 PM.

[RallyRed]

regarding this ....just got to remember that all over the world, and in places a dam sight hotter than here....there are all sorts of p.o.s running around with daggy old mech. fans on them, and doing just fine, not to mention all those grossly overloaded trucks belting up mountain passes in India ( or where-ever).....all with mech fans.?

 

Electric where reqd for space etc IMHO

 

p.s. my track car runs an elect only...so not bagging them.

All just my  H.O.

[Shiney005]

My neighbor did that with his Nissan Patrol and put a plastic fan blade through the side of his battery.

Has the aftermarket industry come up with one that works with the car's computer yet? The one in my truck only starts working once it hits about 90C. It has an air powered clutch, but I can't see why this couldn't be electrically actuated. 

[yel327]

http://www.rarespare...product=2809822

http://www.rarespare...product=9945214

http://www.rarespare...product=7435372

http://www.rarespare...product=2818877

 

 

I am glad I found this topic. When I first started nutting out my engine build I was originally set on fitting AU thermo's. I know they are reasonably easy to fit but for me (and my engine a mild 304) I wanted something simple and more original looking. I've now decided that the clutch fan with shroud is the way to go and its interesting reading that this type of setup is potentially more effective at cooling than thermo fans. Does anyone have any photos of a square blade clutch fan fitted with a H-series 3 core radiator and the H-series shroud in an LH-LX? I have found some in this thread here but keen to see as many as I can find.

 

Torana engine to radiator and fan geometry isn't all that different to a Holden (avoid using H-series as this means HD-HZ and HK/T/G shrouds are very different to HQ-HZ).

 

You can't use WB to VS clutch fans with HQ-HZ V8 shrouds and 3-row (thick) radiator, you need the round blade HQ-HZ clutch fan with a HQ-HZ V8 shroud. What does work, and which I did with my HZ Overlander was to use a HQ-HZ 6cyl with A/C shroud - these use the same 3 row thick radiator. It was a VP 5litre (with longer 1978 onwards) water pump, square blade fan, 5 row HQ 350 radiator (same size as 3 row) and 6cyl fan shroud. You just have to get the fan sitting in the right spot which really means using the longer water pump (which also has a better bearing in it for the big fan). When you fit it all you need is the later water pump pulley and everything works. This is a far better setup than the short water pump with a fan spacer as it loads the small pump's bearing up too much.

 

Finding a cyl A/C fan shroud will be your hassle, but I'd do basic measurements and then go to Rare Spares and measure the four in the links above - the HQ with 350 one goes close from memory (sorry about links at the top but this site has very limited functionality with modern versions of Explorer). Note also that the HK one and the HQ-HZ V8 one are shown upside down. With a HQ-HZ it is actually reasonably easy to convert the HQ-HZ radiator support to the same as WB and use a WB crossflow radiator and shroud, but Torana lots more work.

 

I've never had success with electric fans on iron headed SBC's in HQ-HZ, but viscous fan and shroud work perfectly even on a 3 row radiator. Never tried AU fans though or those with a decent shroud.
 

[jd lj]

Thanks for sharing your photos Rich. What is the thermo fan actually mounted on to, the radiator or the support panel?

[LC-GTR-1969]

Im not gunna offer a whole heap to the conversation, except that in my experience, a well designed cooling system seems to do very well with electric fans only.

 

Thats not to say I disagree (or agree) that clutch fans are better than mechanical fans which are better than electric fans yada yada, just that whatever does the job with the best reliability and the least fuss gets my vote, and in my case it was twin thermos. Works a treat for me. 

 

Just my limited 2c

[StephenSLR]

a well designed cooling system

 

Keep in mind there's more to your cooling system than just fans. Your water pump impeller has eroded vanes or your water jackets are blocked, your engine won't circulate the water properly. The thermostat has to be working correctly and opening all the way too. The right size radiator for your engine also helps, a common mod prior to elec. fans was changing from twin core to triple core and that was enough for most that went 350 Chev.

 

Exactly. Once you have a part or system that works adequately, there's no point at all in changing it to something else, even if that something else is "better".

 

I believe the trend to switch to electric at first was 'the buzz' regarding the horsepower gains, so if you're fussy about chasing that extra horse or two then you may want to upgrade but you're correct; for regular driving, the factory setup is usually adequate.

 

s

Edited by StephenSLR, 07 June 2016 - 08:39 AM.

[LC-GTR-1969]

Keep in mind there's more to your cooling system than just fans. Your water pump impeller has eroded vanes or your water jackets are blocked, your engine won't circulate the water properly. The thermostat has to be working correctly and opening all the way too. The right size radiator for your engine also helps, a common mod prior to elec. fans was changing from twin core to triple core and that was enough for most that went 350 Chev.

Exactly my point, in a well designed system most fan setups will do the job. The issue is many are not well designed and crutch a secondary cooling issue with a bigger bloody fan. Even still if it works, meh...

[toryman76]

Torana engine to radiator and fan geometry isn't all that different to a Holden (avoid using H-series as this means HD-HZ and HK/T/G shrouds are very different to HQ-HZ).

 

You can't use WB to VS clutch fans with HQ-HZ V8 shrouds and 3-row (thick) radiator, you need the round blade HQ-HZ clutch fan with a HQ-HZ V8 shroud.
 

 

Thanks for the tip, had no idea there were that many different types of shrouds. What exactly doesn't fit with the WB-VS clutch fan with the HQ-HZ V8 shroud and a 3-row radiator? I have just fitted the radiator this afternoon and threw the fan on real quick and I can't see any reason why it shouldn't work except for maybe bonnet clearance?

 

 

[StephenSLR]

Don't the HQ rads have the inlet/outlet hoses on the other side? I recall a friend had to swap them over, then again, he had a Chev in it.

 

s

Edited by StephenSLR, 24 June 2016 - 08:19 PM.

[toryman76]

Chevy radiators have them on the opposite side.

[yel327]

Thanks for the tip, had no idea there were that many different types of shrouds. What exactly doesn't fit with the WB-VS clutch fan with the HQ-HZ V8 shroud and a 3-row radiator? I have just fitted the radiator this afternoon and threw the fan on real quick and I can't see any reason why it shouldn't work except for maybe bonnet clearance?

The square front of the blades foul on the curve of the shroud, you need HQ to HZ blades.

Chevy radiators have them on the opposite side.

Actually 253/308 are the odd one out, SBC and 6cyl are on the same side.

[gtrboyy]

Read somewhere not good to use clutchfan on high stall convertor cars or maybe it's waterpump not so good either noticed lots of built 355's gone electric w/pump.

 

Mine seems to work fine but does have 4500 stally

 

Wht revs does the clutchfan cut out?