Optimum water temperature

[Vince Caldicott]

I've recently had installed a 427 FE side oiler and have found that once the temperature reaches 80 degrees C. the main fan comes on and stays on until the car has parked and cooled down. Can anybody advise if this is normal and what is the optimum operating temperature for my engine. It has a competition cam and twin 675 cfm Holley's. Any advice would be appreciated.

[shep]

427s and 428s generate a lot of heat. With the 428 Fruas, you can just about keep the temperature under control at 70 mph on a cool day, but when you slow down for traffic it can fly off the gauge. We fitted an uprated aluminium radiator to keep the temp below 90C even at speed. That way with the biggest fan, or fans you can fit, it stands some chance of staying within boiling limits. Interestingly on my Frua, I made up an airdam which looked a bit like a Datsun 240Z, and it knocked 20C off the temperature straight away. I'll see if I can post a photo.

[Vince Caldicott]

Thanks for the reply. So it seems that what I'm experiencing is quite normal. The engine heats to 80 degrees, the big fan comes on and stays on, the temperature remains at 80 degrees. My concern was based on the engine that came out, it was a 428 FE and the big fan only came on in traffic and would go off once moving. I guess the power output was much less.

[Vince Caldicott]

quote:Originally posted by Vince Caldicott
   
Thanks for the reply. So it seems that what I'm experiencing is quite normal. The engine heats to 80 degrees, the big fan comes on and stays on, the temperature remains at 80 degrees. My concern was based on the engine that came out, it was a 428 FE and the big fan only came on in traffic and would go off once moving. I guess the power output was much less.
   

[Vince Caldicott]

quote:Originally posted by Vince Caldicott
   
Thanks for the reply. So it seems that what I'm experiencing is quite normal. The engine heats to 80 degrees, the big fan comes on and stays on, the temperature remains at 80 degrees. My concern was based on the engine that came out, it was a 428 FE and the big fan only came on in traffic and would go off once moving. I guess the power output was much less.
   

   Hi Shep, I wouldn't mind seeing a picture showing your air dam modification. Thanks. Vince

[nick Godridge]

I am sure you will be aware of this, but, just in case;-
   
   Kenlkowe do a range of Extreme high performance fans with built in shrouds, that shift a lot of air. You can find on their website
   (http://www.kenlowe.com/CoolingRetrofit.php) aat the bottom of the page, a very helpful product comparison chart which shows the dimensions and throughput for each model up to 17" o.d. This model shifts over 4000cfm, although,it does draw a lot of amps.
   
   Nick G

[Vince Caldicott]

Thanks Nick, that's a very useful link, I need to check to see what I currently have to see if it's feasable to fit a more powerful unit.

[rsk289]

Sorry, late reply to old thread, but anyway:
   
   I had a similar problem with my 289.  The fan doesn't need to come on at 80°C - the thermostat has barely opened (if at all) and there is a likelihood that the engine will run too cool.  You really want it to be running at a safe 90-95°C, especially if the system is pressurised.
   The problem you have is that the fan is coming on too early, and the hysteresis of the thermostatic fan switch probably won't switch off until something like 65°C, which it is unlikely to get to with the engine running.
   After extensive tests with bimetallic switches fitted inside the original Otter switch casing (tricky because of the 289's fan switch position in the lower hose water manifold), I have now managed to get my engine fan to come on at around 95°C.  It is capable of bringing the temp down to 80°C, so on the open road the fan goes off.  If sitting in traffic it will come back on again, but even in traffic the single 14" Spal is capable of cycling on and off.  This way on a typical run the engine is operating in the 80-95°C range, which is ideal.
   Running a motor too cool can cause wear.
   The bimetallic switches are extremely cheap, typically £2-3.
   Roger

[Vince Caldicott]

Hi Roger, sorry for the very late response to your post. I agree, I need to get the temperature up to around 90 to 95 degrees, my temperature sensor is mounted on the underside of the stainless pipe that comes off the header tank. It's a large brass hexagonal nut with 2 cables connected. It doesn't  appear to have any adjustment. Is this a standard sensor that I can replace?
   
   Thank you for your help.
   Vince

[rsk289]

Hi Vince - this may be different for the 427.  On a leafspring rack and pinion car, it is the temp gauge capillary tubing that goes to the top hose connector.  The electric fan thermoswitch is mounted in the bottom hose water manifold that passes through the chassis by the steering column (RHD) at lower right front.
   Sounds like you have a more conventional modern type of switch fitted at the top hose, which is OK as long is it will definitely be in coolant all the time.  They are not adjustable but if you google fan thermo switch you should find loads of different value switches with the same thread.  You need to check what fitting yours has - most seem to be M22 1.5, even for Rovers, TRs etc. so I'd think it's pretty standard.  I'm afraid I don't know what 427s would have had when new.
   I have a Spal US fan fitted now which runs something like 1800 cfm rated, but I don't know how that figure is arrived at.  It sucks a lot more air than the Kenlowe I had though, which struggled.

[Vince Caldicott]

Thanks Roger, I think I'll remove it and take it to a local car factors to see if they have one with an on temperature of 95 degrees and an off temperature of around 80 degrees as you suggested.
   Vince

[rsk289]

Probably want something like this:
   
   http://www.ebay.co.uk/itm/PEUGEOT-505-Temperature-Switch-Radiator-Fan-50110-New-/331979242003?fits=Car+Make%3APeugeot%7CModel%3A505&hash=item4d4b813a13:g:XP0AAOSw8gVX5HL7
   
   There are loads of different ratings.  A good list here:
   
   http://www.x-eng.co.uk/X-ThermData.asp
   
   You don't need the double ones, although I use one in my old Mustang which has twin fans, nice to have them coming on at different temps.
   
   Roger

[Vince Caldicott]

That looks exactly like mine, I will post the results once fitted, thanks Roger.

[rsk289]

Vince, it can be a pain sorting what temp range will work best, as you have a heat source you can't change (assuming ignition timing and mixture is correct) i.e. the engine, but can vary thermostat, fan effectiveness and fan thermo switch range.  In sorting both Mustang and Cobra I ended up trial-fitting a few of these switches until I got it right.
   I can only speak for the small-block Windsor.  According to Bill Carroll's Ford Cobra Guide of 1964, SAI swapped the factory thermostats for a 160°F (71°C) unit when they installed the 289 engines.  This seems very low, but it's what I have in my factory-correct 5-bolt 289 cooling system and it works well.  Basically, I think the cooling system in a 289 is so marginal that the thermostat opens early and the running temp is controlled entirely by the roadspeed, waterpump and electric fan.  Dan Case has given me invaluable help in water pump decisions and I have chosen to go with a stock, not high volume, water pump which does not cavitate at high rpm as it has fewer vanes on the impeller.  At Dan's suggestion (and in line with COB6029, the Haynes Museum car) I have also retained the mechanical fan on the water pump.
   My fan thermostat is set to turn on the fan at around 90°C and turn off again at around 75°C, which it does in general usage.  I have now achieved the point at which I can leave the car running with the bonnet closed and the fan will cycle on and off over a 30 minute period (the neigbours love me).  To get to this, I had to fit the most effective 'puller' Spal fan I could find in 14":
   
   http://www.jegs.com/i/SPAL/063/30102042/10002/-1
   
   - and this works very nicely, rated at 1864cfm.
   You may need a different temp rating switch as your fan switch is in the top hose, which will register earlier than the bottom hose (where the 289 switch is located).  Only trial and error will tell.
   Roger
   ps as intimated in shep's post above, effective ducting to ensure the air cannot get around the radiator anywhere is essential.

[Vince Caldicott]

Hi Roger, I can see that this isn't so black and white. My engine is producing over 600 hp which means it gets up to temperature quite quickly. I have a very large electric fan which keeps the engine at around 80 degrees which I feel isn't hot enough and will increase engine wear. I don't have a fan belt driven fan. I will try and replace the switch as previously mentioned and monitor the results, if that doesn't work I will try a different switch. I will look into what water pump I have as you say it may have some bearing on my engine temperature. Thanks for all your input.
   Vince.