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1 hour ago, trchris said:

Hi Rob 

the point I was trying to make was because of the cheaper fan units build quality they are less effective than a better built unit The one I originally used didn't in my opinion fill me with confidence of its effectiveness the Spal is smaller and only 80w yet provides a better flow through the radiator I suppose it comes down to money you pay for what you get. I agree there's no need for bigger more powerful fan units the same as large output alternators bigger is not always the solution

Chris

Hi Chris. 

Yes very true. My current fan is definitely over specification. But makes me feel happy. The usual classic car thing. Feeling happy that the car will survive even rare events :-) . Mind you the last 10CR we ran up mountain passes in unseasonably hot weather. I knew the fan would hand it if called upon!

Could also use it to dry any washing we had in the car:D

Tim

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Should also say I ran with the engine fan for many years, and have one on my triumph saloon. Work fantastically. 

Tim

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On 11/26/2020 at 12:16 PM, RogerH said:

Hi Folks,

mention was made last week or so about Radiator fans and what to buy.  Revotec, being the most expensive, were being queried as to whether they were worth it or not.

I don;t know about Revotec but I do know about cheap ebay sh*te.  About 5 years ago I fitted a 'good value for money' ebay wonder.

After about five years and 4 miles per year ( 20 ish miles) the heap of dung stopped working.  OK, it was cheap. But imagine if it was on a road going car - major upset.

Mine is similar t the one that Mike North removed a short while ago as it didn't push enough air through the rad.  12V  120W - steer clear.

I would like to thank the forum for raising this issue and killing my fan  :P

 

Roger

Roger 

This may inform, just a bit of fun in the garage, partly to justify the cost of the Revotec !!

 

 

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Hi all,

FWIW I have a TVR Vixen 2500 (TR6 engine) that I have mainly used for track days. 14 years ago I fitted two Yamaha bike fans picked up second hand on Ebay. They seem very efficient, reasonable cost, Japanese reliability, nice and light and pull 11.5A combined.

I did a track day at Zolder a good few years ago in a 40 deg C heat wave. Cars were dropping like flies, the Vixen kept going all day 80-85 deg C showing on the temp gauge! Ed.

20201127_222702.jpg

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On 11/26/2020 at 7:07 PM, Hamish said:

Hey that’s what I have the 220w 12” sucker ( ie fitted engine bay side of rad.) curved blades works for me. 
turn it on and watch the temp gauge drop. Bought feb 2018 fitted soon after. 
fitted to the rad with the plastic through rad spring loads ties. With small felt pads to space it from the rad. The type you can get in a pound shop for fitting to the bottom of chair legs. 

Good info Hamish, although changed fan type and bought a spal type, curved blades 12" puller probably much the same but £20 dearer!

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I junked the mechanical fan on my 4A over 40 years ago, at the same time dispensing with the hub extension to facilitate future changes of the thick TRactor fan belt. I fitted a Kenlowe 127L kit bought from an acquaintance who had purchased it to fit to his Rover saloon and then given up. The ducted fan is fitted as a 'pusher' in front of the rad and about 1/4" from the core. My experience has been much as RobH, the fan is only required when crawling in traffic for prolonged periods or perhaps climbing a long gradient in low gear stuck behind other vehicles. I prefer to anticipate such a situation and switch the fan on with the manual override before it cuts in automatically. As regards reliability the original motor is still going strong. Years ago I was very lucky to find another complete 127L kit in a box of bits under a table at a car boot. The vendor had no idea what it was and was happy with three quid! I carry the spare motor on board just in case. Over the years i have replaced the capillary sensor twice and the override switch once. I am aware that Kenlowe no longer supplies spares but alternatives are available if I should ever need.

Tim

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13 hours ago, North London Mike said:

Roger 

This may inform, just a bit of fun in the garage, partly to justify the cost of the Revotec !!

 

 

Hi Mike,

that is rather scientific for you. Well done.   

It shows how poor the flow is - assuming that high flow is good.  I would have thought a high flow would reduce the temp quicker thus having shorter on periods.

Talking about high and low flow rates I have just started writing a book about Hurricanes and Tornadoes. So far it is just a draught copy.

 

Roger

 

 

 

 

 

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Hi- I fitted a fan from a Vectra on a home made bracket in front of the radiator and soldered the temp. switch to the bottom radiator tank.

 Not been used in anger yet but appears to give a good flow of air.

Seems cheap and efficient so far.

cheers Neil

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3 minutes ago, Richard Pope said:

Pusher fans always cause turbulance and can be very inefficient. To avoided where possible.

But if they cool the engine adequately Richard, where is the problem?   

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I have tried a variety of fans over the years. The one fitted to my TR came off a Citroen CX2400 in about 1990. Sucks about 20 amps but blows a gale.

I wasted money on a cheap ebay 120 watt fan that I fitted to a Stag. I knew it wasn't going to work before I fitted it. The blades were long and thin with a pronounced curve across the chord.

The shape at the tips was such that the curve of the blade was pushing the air at the leading edge and pulling at the rear, the net effect being to absorb what feeble power it had without actually propelling any air through theradiator core.

It found its way into the bin pretty quickly and was replaced with a 2 speed 14 inch kenlowe which was very impressive by comparison. I subsequently fitted the same type of fan to 2 more of my Triumphs, shame you can't get them any more!

Neil

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On 11/28/2020 at 4:45 PM, RobH said:

But if they cool the engine adequately Richard, where is the problem?   

They could be on a lot of the time and may not cool enough in very hot conditions. The blades churn the incoming air up and a lot of the cooling air is in effect blown away from the radiator quite significantly reducing the air going through the rad. You may be surprised how much aitr is stopped by the churned air. As my other car is a se7en I've had a lot of experience here as often se7ens use a pusher fan and these are on all the time. The aim of proper cooling from my notes on this are:

  • Maximum cooling is gained by slowing down the air supply in front of the radiator. To do this, add ducting from front openings to the radiator surface to try and make the inlet cross-sectional area smaller than radiator surface area so by adding ducting to direct all air through to radiator’s surface without gaps, air is slowed down. I.e. Fast air through inlets is now slowed as the ducting increases cross-sectional area. (Same logic as a aeroplane wing.)
  • Slow air takes much more heat from core than fast flowing air as it has more time to heat up (unless too slow and does not move,I guess).
  • Fans should be sucking and not blowing because you do not want airflow turbulence, you want smooth airflow at low speed. A blowing fan not only gets in the way of airflow but will blow air in all directions and what goes through the radiator core will go through with significant turbulence. A sucking fan will suck air through the core smoothly.
  • You should also have plenty of room for the hot air after the radiator (and sucking fan) to escape the engine area.

Please ignore the attached image. I cannt seem to get rid of it and there is no cancel post button.

image.png

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Nope. If you read my original post you will see I only have to turn the fan on very occasionally when stopped in traffic and when I do it works just fine.  

Who cares what the efficiency is like if it works?

Edited by RobH
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Mounting my Spal 12" fan with ties around the rad may work well,  but I decided to weld a couple of bars across the rad with bolts countersunk and welded into the bars to support the rad, also gets it close to the rad. It gives some peace of mind that the rad isn't going to fail with the weight of the fan hanging from the core tubes.

 

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P1080199.jpg

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9 minutes ago, pfenlon said:

Mounting my Spal 12" fan with ties around the rad may work well,  but I decided to weld a couple of bars across the rad with bolts countersunk and welded into the bars to support the rad, also gets it close to the rad. It gives some peace of mind that the rad isn't going to fail with the weight of the fan hanging from the core tubes.

 

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Have you removed the long crank extension that holds the original fan?   On a side screen if you do not do that the starter dog bolt chews the electric fan shroud or cover..  If you still have the original extension you may have to move the electric fan assembly upwards on the radiator.

Cheers

Peter W

Edited by BlueTR3A-5EKT
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I don't see much discussion of shrouds or cowls here. The fan is just creating a pressure differential across the rad core. In most of the installation pics there's clearly loads of pressure leakage around the fan, or areas of the core not benefiting from the fan. On my crusty old 1967 Silver Shadow with a 4 blade metal fan I had overheating in standing traffic, by fitting the plastic shroud off a later car so the old fan didn't leak pressure at the periphery and get that pressure applied to the whole core under the shroud then my overheating problem is gone - fan is the same old one, but it's effectiveness is transformed. I would say a shroud is more beneficial than hurricane force fans.

Edited by ctc77965o
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1 hour ago, BlueTR3A-5EKT said:

Have you removed the long crank extension that holds the original fan?   On a side screen if you do not do that the starter dog bolt chews the electric fan shroud or cover..  If you still have the original extension you may have to move the electric fan assembly upwards on the radiator.

Cheers

Peter W

Got the thin belt conversion Peter.

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2 hours ago, ctc77965o said:

I don't see much discussion of shrouds or cowls here. The fan is just creating a pressure differential across the rad core. In most of the installation pics there's clearly loads of pressure leakage around the fan, or areas of the core not benefiting from the fan. On my crusty old 1967 Silver Shadow with a 4 blade metal fan I had overheating in standing traffic, by fitting the plastic shroud off a later car so the old fan didn't leak pressure at the periphery and get that pressure applied to the whole core under the shroud then my overheating problem is gone - fan is the same old one, but it's effectiveness is transformed. I would say a shroud is more beneficial than hurricane force fans.

Thats very true just made this effort for a  Tenner, not pretty but will do the job

 

P1080201.jpg

P1080202.jpg

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3 hours ago, ctc77965o said:

I don't see much discussion of shrouds or cowls here. The fan is just creating a pressure differential across the rad core. In most of the installation pics there's clearly loads of pressure leakage around the fan, or areas of the core not benefiting from the fan. On my crusty old 1967 Silver Shadow with a 4 blade metal fan I had overheating in standing traffic, by fitting the plastic shroud off a later car so the old fan didn't leak pressure at the periphery and get that pressure applied to the whole core under the shroud then my overheating problem is gone - fan is the same old one, but it's effectiveness is transformed. I would say a shroud is more beneficial than hurricane force fans.

Does the Silver Shadow have a viscous coupling between pump and fan?   My memory says the Shadow fan is more like a propeller!

Peter W

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