Fan Timing

Hi Guys

Took my F for a quick spin, no more than 10 miles. The fan came on but didn't turn off once I was home and parked up.
After 15 mins of the engine being off the fan was still on. At that stage I disconnected the battery to stop the fan.
How long should the fan stay on for?

If it is the front radiator fan, it should go off with the ignition. If it is permanently running with ignition on then that is likely open circuit on the ECU water temp sensor. Either sensor has failed , become unplugged or has a broken wire.

If it is the engine bay fan it should time out after 8 minutes. But needs to be really hot back there to come on, we are talking a hot summers day and a high rev thrashing. If it is on normally, then failed eng bay temp sensor.

markvrs wrote:

If it is the front radiator fan, it should go off with the ignition. If it is permanently running with ignition on then that is likely open circuit on the ECU water temp sensor. Either sensor has failed , become unplugged or has a broken wire.

If it is the engine bay fan it should time out after 8 minutes. But needs to be really hot back there to come on, we are talking a hot summers day and a high rev thrashing. If it is on normally, then failed eng bay temp sensor.

The line: “hot summers day” is relative, the engine bay fan is active on mild summers days here in Oz, regardless of whether or not it has been thrashed or driven like Grand Ma on her way to the bowls club for bingo.

One project I was asked to look into was temperature monitoring on a Triumph Stag. The original V8 didn’t have a good reputation when it came to overheating, resulting in folk throwing it out & installing the Rover V8. These days with the focus on originality a Stag makes stronger money with the original & there are companies who have re-evaluated the cooling system, designed a more efficient radiator, twiddled here & there’s been great advances.
To assess before & after performance I sorted temperature monitoring in the send & return circuit on the radiator, water jacket etc & override switching on the retro fitted electric fan.
As I’ve mentioned on a number of occasions my trusty f acted as test bed for these items, thus I can override both fans, monitor when the fans kick in, see what the radiator circuit is up to (which with the radiator circuit we have is a useful adjunct), as well as check the water jacket temperature.
This last is not a convenient read out to check as it is still in the test rig in the boot!
M

In my experience Stags biggest problem was that bastard Lucas duel point distributor, the moving plates that the points were mounted on would get very loose, leaving the timing all over the place, resulting in overheating, I had a simple solution for this…..bin the shitty Lucas dissy and replace it with a Bosch dissy from a Ford Cleveland V8, I had to change the drive gear, using the one from the old Lucas dissy and drill it out to suit. The other thing I had to do was use 2 dissy clamps from a Holden red six engine as the Clevo dissy doesn’t have the slotted mounting flange.
This modification made the cars run so much better and so much more reliable.
The cooling system was pretty marginal on the things and I would always fit electric thermo fans, these days I’d be inclined to fit an electric water pump too as the internally mounted water pumps were bastards of things too!
Once properly sorted the Stag engine was pretty reliable.

I was only involved in the monitoring & logging. In comparison with what is available from China via eBay etc these days, design & build was a more exacting task. A decent data logger was an investment then & one can only marvel at the pscan for our cars & OBD readers in general to realise how rapidly technology has moved to a point where you can have access to data once the sole preserve of a main dealer. The bogo units available from China cost little more than the price of a couple of pints & a cigar.
As far as the engine was concerned it was never going to be a classic like the Rover (Buick) engine, it was little more than a couple of the 1500cc engines used in the Spitfire, according to some, others that the four pots were half of the V8.
Let’s hope Cobb’s can clarify as he has first hand knowledge.
M

It's quite incredible the rivalry that continued to exist between the sub brands within the British Leyland stable and how ultimately detrimental that thinking became: That not only Triumph had a whole series of engines that weren't available to the rest of the group* but they even persauded management to subvert budget to design and build their own V8 for the Stag which was after all a relatively small volume, niche up market sports car rather than adopt the tried and tested Rover 3.5 or launch with the straight six 2.5 from the Triumph saloons


* ok the Triumph 1.5 was admitedly used in the MG Midget

The rivalry between the Rover, Triumph & Jaguar was intense & even though they were under the same umbrella, they would each try to position themselves so their former competitor was the one under the ripped seam that was BL & they were the ones who were dripped on.
M

The Stag V8 was indeed based on 2 inline fours. I agree that it was insane to waste scare resources to develop, when they already had a lighter and better V8 of similar capacity within the group, especially when you consider the variations of the design.
The 2 F1 world championship winning Repco Brabham V8s were based on the Buick/Olsmobile versions of the RV8, proof enough that the basic design was quite capable of converting to a more modern OHC design, and there were also twin OHC versions.
Incidentally the Repco Brabham engine was designed, developed and made here in Melbourne, Australia by the renowned Phil Irvine, designer of the Vincent Black Shadow and Black Lightening engines as well as the Repco F5000 V8.

The Stag engine was an OHC engine, but quite heavy in comparison, with it’s iron block, in fact the Rover V8 was only @ 18 lb heavier that the inline 4 version of the Triumph engine used in the TR7. There was of course the 16 valve version of the Triupmh inline 4, the Spint, and there were even proposals to use the Sprint heads on the Stag V8, this might’ve improved the performance of the Stag, which wasn’t really a sports car , more of a nice GT with a removable roof.Having said that they gave the Stag a loverly exhaust note.

Triumph themselves ended up, using the Rover V8 in the TR8 anyway!

The rivalry within the[strike]Playland[/strike] Leyland Group was as mentioned, extreme, Upper management wanted Jaguar to drop the XK inline 6 in favour of the Rover V8, so when Jaguar were designing their XJ40 range to replace the old series 3 XJ6 and XJ12 range the designed the engine bay too narrow to use the Rover V8 engine the result was they had to keep the old XJ12 in production alongside the new XJ40 series XJ6 for some years and then eventually had to redesign the XJ40 platform to widen the engine bay to accommodate the V12 engine.
Playland’s upper management would’ve been better off not indulging in their divide an conquer method of running the group and encouraging a more cooperative approach between the companies within the group and spending money on developing designs properly, instead of leaving the customer to bare the cost of development.
But what else would you expect from a bunch of stupid, politically appointed bean counters who wouldn’t know a car if it bit them on the arse!

My word you managed to squeeze in an awful lot interesting stuff there, especially the bits about Phil Irvine. My dad & he were both Fellows of the Institution of Mechanical Engineers & although they knew each other I can’t say how well.
The Repco engines were very competitive for a time & then they slipped under my radar; they could still be.
There is a time band across which I have great affection, where engines were designed by inspired engineers, many of who cut their teeth during the war & took those skills forward.
BRM was a case in point. Started post war & picking up on prewar ERA designs, Raymond Mays, Tony Rudd & Harry Mundy (who was a friend of dads) produced remarkable results from, at times, underfunded work. The 1.5ltr V16 was & still is a remarkable piece of engineering in all respects, had the formula not changed & development continued it could have become a landmark engine.
It is still made, all be it in odd ones & it’s now finding that reliability original lacking, due to that formula change.
And not a computer in sight or a calculator; slide rules ruled.
OK.
M

Phil was a clever old bugger, he figured when the new 3litre formula came into effect for the 1966 season everyone would have new unproven and complicated engine designs, he chose reliability over performance, working on the idea that in order to finish 1st….1st you must finish, by the time everyone had workable reliable engines they’d bagged 2 world championships.
After that though the more sophisticated engines such as the Ford Cosworth DFVs and Ferrari flat 12s etc took over.
Oddly enough the very successful Repco Holden F5000 engine was challenged by another engine based on the Rover V8 Leyland Australia built a large car called the P76 the V8 versions had a 4.4litre engine based on the Rover V8, this engine had a longer stroke higher block deck height larger diameter crankshaft journals etc. this was the basis for another F5000 engine with the help from Repco not many were built but it did achieve some success.

Under the F5000 rules the engines had to be based on a production V8 block and have pushrod actuated valves trains, so yet again the light weight nature of the design was used to great advantage, as there weren’t any other production pushrod V8s about!

I have one of the 4.4 litre P76 V8 engines sitting on my engine stand, my intention is to shove it much modified form into my Triumph TR7…… that oughta liven things up a bit!

On the BRM V16…… I had the soundtrack of a BRM V16 going through its paces on a vinyl record……….what an amazing sound…an unholy shrieking scream! I dunno what happened to that record.

Was the P76 ever a plentiful sight in Australia. They really should have tried selling it here.