Cooling a V8

cobraboy

Well-Known Member
OK I have read various threads on uprating the cooling of a stock V8 car but an still wondering which way to go on fans.
I have installed a header tank and also a recovery bottle so the header is always full and higher than the engine.
The fan choice is one area I still cannot nail down.
I dislike putting electric fans in front of radiators, I would much rather have one behind in a proper cowl. I have had to lean my radiator back a little to clear the bonnet structure so have even less room than normal so cannot fit one behind.
I read that the export to Aus models used a 13 blade plastic fan on a viscous coupling, is this setup available ?
It must surely be a compact unit to fit.
The only other way I can think of doing it is to take off the water pump, fit a blanking plate and have a remote electric pump but that is getting more and more complicated.
Or am I stuck with a front mounted fan ?
BTW I have the stock steel fan at the moment.

Whadya think.
 
Hi Mark.
The NADA / Aus / air con set up is the best factory set up with a cowling fitted as well.
Problem is getting the correct water pump which has been NLS for years.
I am not sure if you could adapt a standard pump to take the viscous unit as I have not tried as yet.
I know you don't like the thought of electric fans but I did fit one to my friends v8 a few years ago keeping the factory metal fan and adding a 3 core rad ( can now get uprated 2 core ) and had not had any cooling issues.
Some of the overheating I think is caused by heat not escaping from under bonnet area when in traffic hence why the NADA bonnet was vented.
Clive.
 
Hey Clive
The space behind my rad to the mounting face of the WP is 6.5" tight, I know the SD1 viscous set up is 8" so that wont fit. I hear what you are saying regarding heat in the engine bay and think that the engine mounted fan does help in that regard as it is always running.
If I could get a lightweight fan onto the P6 pump with a viscous coupling with clearance then it would be the ideal outcome.
 
OK I have read various threads on uprating the cooling of a stock V8 car but an still wondering which way to go on fans.
I have installed a header tank and also a recovery bottle so the header is always full and higher than the engine.
The fan choice is one area I still cannot nail down.
I dislike putting electric fans in front of radiators, I would much rather have one behind in a proper cowl. I have had to lean my radiator back a little to clear the bonnet structure so have even less room than normal so cannot fit one behind.
I read that the export to Aus models used a 13 blade plastic fan on a viscous coupling, is this setup available ?
It must surely be a compact unit to fit.
The only other way I can think of doing it is to take off the water pump, fit a blanking plate and have a remote electric pump but that is getting more and more complicated.
Or am I stuck with a front mounted fan ?
BTW I have the stock steel fan at the moment.

Whadya think.

I think you like to make life very complicated for yourself. Sat in traffic for an hour last week at over 30 degrees didn't skip a beat. 16" Spals do the business!

My next step is to make a simple timer ne555 circuit for the speedo so when the vehicle stops the fan ticks over at super-low speed regards of temperature to circulate air.
 
I think you like to make life very complicated for yourself.

Really ?
I just don't want to throw on a fan in front of a rad !



My next step is to make a simple timer ne555 circuit for the speedo so when the vehicle stops the fan ticks over at super-low speed regards of temperature to circulate air.

Hmmm .....................................
 
I think you like to make life very complicated for yourself. QUOTE]

I am afraid that you have read that one wrong.
Sure I can throw on a big fan in front of the rad, but the proper way to do it is to have the fan/s behind the rad in a cowl and that is the option I am exploring.
You have now realised realised the need to keep air moving through the engine bay whilst the vehicle is stationary and this has led you to add a layer of complexity to your install with more wiring, timers etc etc .
I like simple elegant solutions that work, and a short coupled viscous fan would fit that bill nicely. I only threw in the electric water pump scenario as a curved ball.
 
It's already wired as it has an electronic speedo for the ZF so it has a magnetic pick-up on the prop. The current system has been tested up to 36 degrees and is fine.

Even if I could put it behind I wouldn't do this as the extra spanner room (now redundant cowl is removed ) is really useful. Yes I know its a less efficient solution technically.
 
Before you get all the Visco parts (and in which condition), why not using an E-fan. I like Peter´s way and have also installed a Spal (but 350 mm) in front of the rad, now having all clear between rad and engine. But, why not using a sucking fan between engine and rad. The fan is running also with engine off until the thermoswith says ok. I have read the chapter in Des Hammils book about the cooling system. It´s interesting, as he is very focussed on a good degassing system. The header tank connected in a P6 can only work as a overflow bottle and this will not cure it in his opinion and my top rad hose looks exactly like the nightmare Des describes (it makes a loop up over the rad, so always has air).
You said, you installed a header tank and a recovery bottle, what does this mean ?
 
I would love to put a fan between the engine and the rad but have only 40mm in front of the waterpump pulley and the rad. I have installed a brass header tank from another BL car on to the RH inner wing, this is plumbed with an 8mm hose from the radiator filler neck overflow stub, there is now a blank cap on the radiator and a pressure cap on the header tank.
The over flow from the header tank goes to a recovery bottle next to it allowing the header to overflow and recuperate on cooling down.
My top hose is fairly flat.
I agree that there is no flow through the header tank to purge air, the only way to do this is to make a T fitting to go in the top hose at the highest point and take a pipe to the header tank then have a return from the header tank into a T in the heater return just before the water pump.
I am looking at making up a viscous set up to fit the front of the P6 water pump pulley as I have an old pump and pulley I can play with.
And yes as I said I can just throw on a big fan in front of the rad and be done with it................. but where is the fun in that ;)
 
I am looking at making up a viscous set up to fit the front of the P6 water pump pulley as I have an old pump and pulley I can play with.
And yes as I said I can just throw on a big fan in front of the rad and be done with it................. but where is the fun in that ;)

It sounds something like what i did, fabricate an adaptor that fits between the standard water pump and a Land Rover V8 or TDi viscous and big plastic fan.
 
The factory viscous set up also uses a much smaller drive pulley and different length Belt.
This makes the 13 blade fan turn faster at idle speed.
Clive.
 
Hey guys thanks for all the help on this. I did contact the guy with the P6B viscous coupling to ask if it fitted the std waterpump or had its own dedicated pump, I did not get a response.
So....... from the junk pile I have turned up a viscous coupling and fan on an SD1 waterpump :) and have set about making it fit the P6 pump. I have also figured out how to shorten the std P6 pulley.
This will give me two irons in the fire, I can fit the modded SD1 viscous fan setup on a P6 pump with a shortened pulley or I can fit a shortened P6 pulley and then fit twin electric fans on a cowl at the rear of the rad.
As the SD1 viscous version will cost sweet fa I will go this route first because quality twin fans plus a controller will not be cheap and with the viscous I get air movement through the engine bay when stationary.
I will take some pics of the conversion and add later.

Mark
 
Hi, That viscous coupling won't fit on a std P6b pump because there's no threaded stud sticking out for it.

Colin
 
Here is my attempt at a P6 viscous fan mount.
Warm the existing pulley and remove from shaft, mount in lathe.
IMG_0487.JPG
Turn outside of pulley until it is parallel at the end diameter and not tapered.
IMG_0488.JPG
Part off at approx 27mm from front face.
IMG_0489.JPG
Clearance the inside to go over the water pump snout.
IMG_0490.JPG
The other part of the pulley I turned down to leave it around an inch or so long, it does not matter, but the inside is bored parallel for around 12mm at the small end.
IMG_0491.JPG
The reason for the parallel boring is so that the parts can fit together one inside the other, this creates an adjustable pulley that you can fine tune to set up the water pump pulley to match up with the crank pulley. I made them so that I had to heat up the ring part to go over the nose section and have a shrink fit.
IMG_0492.JPG
Together trued up in the lathe and awaiting tacking together for belt and braces.
IMG_0493.JPG
Backside
IMG_0494.JPG
The viscous mount, removed from the SD1 shaft and turned down ready to press on the P6 shaft.
IMG_0486.JPG
As it will all sit on the P6 shaft

Measurements are a guide only, puts the fan @ 10mm closer to the rad than the current set up.
 
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Nice job!
Building a shroud around the fan makes the fans work much more efficient and therefore will create better cooling
Peter
 
Nice work. Off topic, what's that green sports car with the yellow snout in the background of the second photo?
 
Nice work. Off topic, what's that green sports car with the yellow snout in the background of the second photo?
Something I cobble together at work, Aston DBR1 recreation, that one, alloy body Aston 6 cyl. Bespoke builds from scratch.
Three of ours at Snetterton
Snetterton test day 3.jpg
Prescott hill climb
AO0X0908.JPG
 
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