Archived Message
Smaller water pump pulley
Have read with interest the postings regarding the fitting of a big bore thermostat. I fitted one a year or so ago. Not sure if its impact is noticeable. The manual override switch for the fan however is and likewise I can see the impact of a smaller pump pulley ( the pump rotates faster). What I seem to have missed is the source of the smaller pulley.Can someone help please.
Peter Ferguson
22/07/2012 @  21:10
Under topic: RV8
 
Archived Reply(ies) received for this Message
Smaller water pump pulley
The pulley is available from V8 Tuner http://www.v8tuner.co.uk/product.php?id=216
Geoff King
23/07/2012 @  20:48
 
Smaller water pump pulley
Geoff,
I have today received an email from Paul at V8 tuner to tell me that the small water pump pulley is no longer available, or not from him anyway. Can you tell me what the diameter of your pulley is please?, and have you any thoughts on where else it may be available? I shall now start trolling through the internet.
Graham Cornford
23/07/2012 @  21:00
 
Smaller water pump pulley
Peter,
Rimmer Bros have the small pulley Part No 602582A. I have ordered one and as I write, they have only 6 left.
Graham Cornford
23/07/2012 @  22:21
 
Smaller water pump pulley
Peter,
Just a thought, the pulley 602582A fits the MGB GT V8 and has 3 holes to attach it. Not sure if it fits the RV8, you will have to check that, although looking at an illustration of the RV8 pump it does have 3 holes also.
Graham Cornford
23/07/2012 @  23:23
 
Smaller water pump pulley
Thanks Graham
Peter Ferguson
24/07/2012 @  04:54
 
Smaller water pump pulley
I must admit not quite fathoming why this change is necessary, Peter. Did you have overheatng problems or header tank blowback?
Fitting a larger thermostat is questionable on the RV8 because the water pump coupled with the fan and radiator should cope. The MGB V8 may well be different, however. My son even had a standard MGRV8 in Tokio and I can tell you it's very very hot there in the summer months coupled with a 70-80% humidity. My only change was to have a fan run-on relay built in by Bosch so that when I stop after a hot run, the fan will cut in and out once or twice to keep the coolant temp. at a sensible level.
Peter Garton
24/07/2012 @  19:39
 
Smaller water pump pulley
Peter.
I am not sure it is necessary. Just part of a package of measures to keep the temperature down when running slowly in traffic. Like having a larger radiator, a lower temperature rated switch for the fan and my most recent mod, a manual switch for the fan. All give a better chance of keeping the modified temp gauge from going beyond 100 degrees C.
A smaller pulley to speed the rotation of the pump when you most need it seems a good idea. Against all this concern, in the days before I modified the temperature gauge I was more than happy with the nice steady reading!
Peter Ferguson
25/07/2012 @  05:22
 
Smaller water pump pulley
For the BGT V8, loss of coolant due to local boiling at engine switch off can be simply reduced to a negligible level by a minor wiring change. I fitted an additional fuse to feed the fans and fan relay direct from the battery feed at the fuse box. This is normal practice on more modern cars. It means that the fans may continue to run if they are running at the time of switch off or may even strike up after the engine has stopped. Although the pump is not running there will be a small amount of circulation due to thermo-syphon action which, with the radiator contents effectively cooled by the fans, is enough to ensure local boiling in the block does not occur and loss of coolant at switch off is prevented.
Bob Owen
25/07/2012 @  05:29
 
Smaller water pump pulley
I find with my V8, which has a manual override switch on the cooling fans, that on stopping after travelling in traffic on a hot day, I turn off the ignition and then (if the temperature gauge is showing above say 5pm on the dial) I then turn the ignition back on to set the fans running again. After about three minutes I start the engine up to set the water pump going and it pumps the cooled coolant in the radiator around the system and the gauge falls. It is sometimes necessary to repeat that three times but at least then the car is not left very hot.

I found replacing the radiator last year after nearly 37 years, replacing the Otter switch and replacing the pressure cap on the expansion tank made a major improvement to the cooling. Fitting a manual override means you feel you have better control over the timing of the fans coming on so you can anticipate a build up of heat - for example as you come off a major road and wind your way through traffic.
Victor Smith
25/07/2012 @  05:52
 
Smaller water pump pulley
Victor wrote "I found replacing the radiator last year after nearly 37 years, replacing the Otter switch and replacing the pressure cap on the expansion tank made a major improvement to the cooling."

See, now this is precisely why I get the right hump about the commonly held notion that V8's are prone to overheating.
For some reason rubber bumper cars seem to have an even worse reputation, presumably because the smaller grille vents allow less air through to the rad and so these cars will not tolerate neglect as well as the more common chrome nose cars.

Bluntly, a V8 with a cooling system in GOOD condition (irrespective of what's mounted on the nose and tail of the car) with all the right bits fitted in the right order (i.e. you don't forget something stupid like ensuring the thermostat is fitted with the jiggle valve at 12oclock) will NOT overheat!!!

You just can't expect components to go on indefinitely. If you neglect your tyres they will eventually become bald and pop. If you neglect your suspension the car will handle like a jelly and start steering from the back axle under load and if you neglect your cooling system it will (surprise, surprise) overheat.

The first thing I did to my car when I got it home after giving it a bath was to dump the coolant, strip the rad out and replace everything rubber I found.
Even when the fan relay burnt out earlier in the year on a hot day the car still didn't overheat in the heavy traffic despite being one of those rubber nosed cars with the "bad" reputation?

MG got it right at the factory. No need to mess around with it.
Heck, even my pal's factory V8 fitted with a supercharger from a Sherman tank (yes really) and Nitrous oxide still runs the factory style cooling system with no overheating issues. I'd bet my house that engine generates more heat than a stock example!

Sorry if this comes across as me having a grump folks, but in truth I am. It's SO simple to get this one right. I mean, If an oaf like me can work it out...
JC Moulds
25/07/2012 @  07:17
 
Smaller water pump pulley
I'm inclined to agree with Mr. Moulds since this concurs with my input to your theme, Peter. The RV8 runs perfectly well in Australia which is also jolly hot in the summer months and, as mentioned, all over Japan where they were mainly exported. All one has to do is to make sure that the relevant bits and pieces in the engine bay are actually functioning properly such as your radiator (no sludge deposits at the bottom), the water pump is ok, the fan belt also plus no air locks in the system itself and your thermostat which, as I understand it, you've already replaced.
Peter Garton
25/07/2012 @  14:23
 
Smaller water pump pulley
I have just received the water pump pulley from Rimmer Bros and part Number 602582A which I was told was a smaller Diameter pulley is exactly the same diameter as the original. It is however nicely polished, but it will be going back. My search will continue, but I would like to know from Geoff the diameter of his pulley please.

I must apologise for the incorrect information on my posting, but I was informed that it was of a smaller diameter, and would fit the MGB GT V8 pump
Graham Cornford
27/07/2012 @  05:12
 
Smaller water pump pulley
Graham,

Ive just measured the OD of my alloy pulley at exactly 6.
Geoff King
27/07/2012 @  23:54
 
Smaller water pump pulley
Another interesting discussion. The 6 inch dia pulley will increase pump speed by 14.5%, so assuming the same increase in coolant flow of 14.5%, and all other conditions remain constant then the coolant temperature rise across the engine will be reduced by 13%. So for a temperature rise with a wide open thermostat of say 10deg F with a standard pulley the water oulet temp will be reduced by 1.3deg F, hardly likely to be visible on the gauge or to make a significant change in the time taken for the fans to stop running. Of more concern is the fact that at high engine speeds the pump might begin to cavitate but more importantly the power to drive the pump is permanently raised for what is a very small reduction in coolant outlet temp.
Tony Lake
30/07/2012 @  23:28
 
Smaller water pump pulley
I cannot agree with J C Moulds that the standard factory V8 is adequately cooled. In the late 70s/early 80s I did much work on the cooling of mainframe computers and by experimentation learnt a great deal about back pressure and the resistance of various shapes to speedy airflow - hence my early comments on moving badges behind the overriders and the oil cooler down below the valance(as practised by the factory for the R/B models). My prime reason for fitting RV8 manifolds to Harvest Gold 1904 was to improve the airflow which it certainly did, but in hot days in Italian traffic jams etc the guage would still rise to around "2-o-clock" or even worse, and I would be scared to switch off in case the overheated engine would not restart! Victor introduced me to a number of Australian members at Silverstone one year and they had all had major overheating problems with factory V8s, their solution being to fit radiators which were around 5" longer i.e.,almost to the bottom edge of the front valance thus catching the airflow through the two large slots in the valance. So, whilst I agree that an original car in perfect condition might cope with the mild temperatures experienced in England, our older cars, even if in perfect condition with rebuilt or new engines/radiators/water pumps etc just will not cope with hot ambient temperatures of 30C etc without overheating in traffic jams i.e., in real life.
Gordon Hesketh-Jones
31/07/2012 @  17:16
 
Smaller water pump pulley
I've gained the impression on this particular thread that we are mixing the two V8s up nicely. Our friend Peter Ferguson commenced the discussion and it is quite clear to me that he's referring to the RV8. The last comments from Gordon refer to the V8 and for the unitiated this could be a little confusing. Clive does have a modified radiator in his list which I suppose could solve many problems resulting from a defective unit but as far as I can gather, also fom Australia, is that the RV8 should run without overheating and I can only suggest reading the information on this theme in the RV8 workshop notes.
As Webmaster has suggested, this could be condensed down to a final note listing all the possible causes and their rectification separated clearly out into the two categories V8 and RV8.
Peter Garton
31/07/2012 @  22:54
 
Smaller water pump pulley
I think it is important to distinguish between getting hot and overheating. My proposition is that getting hot, which all V8s experience in summer in slow moving traffic, is normal. Quite usual with low forward speed so little ram air and some pretty inefficient unshrouded pusher fans doing their best to get coolant temp down. I would say it is a non-damaging event, the engine copes well because it occurs at low load. I am not aware of failures that occur as a result of what I would call a normal hot coolant cycle where all the components in the cooling system combine to bring the temp back down quite quickly before the cycle starts again.
Overheating infers working outside the usual coolant temperature range for long enough that damage will result if the event is allowed to continue. Probably involves quite high engine loads and typically could be prompted by a hose failure leading to low coolant level or a drive belt failure that causes the coolant pump to stop.
I think it would be good to have some feedback on overheating incidents that have resulted in engine damage or catastrophic failure with a description of the circumstances.
Tony Lake
02/08/2012 @  06:08
 
Smaller water pump pulley
I recall a trip to the UK in our RV8. I drove all the way from Germany to Swavesey and had the EPAS from the MGOC workshops fitted into the RV8.
We then drove back to Germany and landed in a massive jam just outside Cambridge on the Motorway. Stop and go but mainly stop and crawling. The airconditioning was fully on because of the very hot conditions at that time. Anyway, I can report that my RV8 did not at any time overheat even though we were hardly moving, and, as I've mentioned, the airconditioning was fully on all the time. We then drove all the way back along Autobahns to Germany through France, Belgiumand Germany in very hot contitions again with the aircontitioning fully on. There was no sign of any overheating. The crux of this thread is that providing the RV8 engine components are looked after and function properly, the engine in the RV8 will not overheat.
Peter Garton
02/08/2012 @  15:00
 
Smaller water pump pulley
Peter,

Is your temperature gauge still being driven by the ECU or has it been modified to indicate the real temperature? And does the RV8 have a gauge with H & C, blue & red or degrees?

Im curious to know what temperature is considered normal and what is overheating, Ive seen 2 oclock and 5pm mentioned but I wonder what the temperature is in Celsius or even Fahrenheit?
Geoff King
03/08/2012 @  04:39
 
Smaller water pump pulley
My guage is still as it was from the production line, Jeoff. I read about the "gauge is lying RV8 note" but feel I have no cause or justification in changing anything since I don't have problems.The temp. guage needle points to 12 o clock normally which I strongly suspect is identical or similar to the Rover 75 guage arrangement. This is an ambient running temp. of roughly midway between 80C-100C
Peter Garton
03/08/2012 @  16:46
 
Smaller water pump pulley
Peter,

Very wise to change nothing; the ECU will control the temperature gauge to read normal in all but the most extreme conditions, just like any other modern car, that is why the RV8 doesnt overheat in Australia or Japan or any other country. And is why the GTV8 overheats when its stopped at traffic lights for a few minutes; the gauge isnt controlled by an ECU but is measuring engine temperature.

Ignorance is bliss or paranoia.
Geoff King
03/08/2012 @  21:26
 
Smaller water pump pulley
Just to add my two pennyworth. My GTV8 has what is basically an RV8 engine complete with the EFi. It has a capillary gauge calibrated in degrees F and if stuck in traffic I will regularly see the needle registering over 210 degrees before the fans claw it back down. But with a 15 psi cap and ForLife coolant it isn't anywhere near boiling, so by definition it isn't overheating.
Mike Howlett
04/08/2012 @  06:31
 
Smaller water pump pulley
An interesting piece of data. The design objective at MG to provide coolant operating capability from minus 31 deg F low or cold temp up to 264 deg F high or hot temp is clearly achieved at sea level using a 15 psi pressure cap. Why would the designer call the high temperature overheating? Wouldn't instil much confidence in customers. Now if I were a Hillman Imp, Triumph Stag or Rover SD1 2.6L owner of the period I could definitely identify with overheating as would MGF K series owners of a later period. These engines didn't just overheat, they fried and then seized or else dismantled their cylinder head gaskets without so much as an explanation. Not the kind of experience V8 owners have to suffer in spite of the concerns about getting hot in summer in slow moving traffic. The V8 in all its guises is still a pretty tough engine.
Tony Lake
06/08/2012 @  05:06
 
Smaller water pump pulley
Today with a temp of only 97Deg F, I used the car for the first time with the new Big Bore Thermostat, 82C/180F.
Once warmed up on the highway, the temp gauge sat below normal, in fact just to the left of the 'M' of 'Made in UK' on the bottom of the gauge. Slower in town, it was just the same. At traffic lights there was no noticeable rise in the needle after a minutes wait and the fans did not come on.

Once home I let the car cool down for 2 hours with the engine in the sun and the rear of the car in the shade. The front wing temp was 147Deg F and the rear was 98Deg F. I started up and let it tick over at just shy of 1000 rpm with the bonnet down. When the fans eventually came on, I took the following temps with a digital thermometer, one without a laser pointer, right up against the measured item. Top hose, 177Deg F, Top of Rad, 108 to 116Deg F, Bottom hose, 172Deg F. I then let the car idle for a further 20 minutes with the bonnet shut and the temp gauge needle exactly dissected the 'N'. The fans stayed on all the time.
I turned the engine off and the fans ran on for a further 8 minutes. During this heat soak time the gauge rose to just above 'UK' of 'Made in UK'. I took further temps. Top hose 179Deg, Top of Rad 103 to 106Deg F, Bottom hose 106Deg F.

You have to bear in mind that I have an aluminium rad and Forlife coolant, but the car appears to me to run significantly cooler and when left for a long tick over, the needle would previously have gone well past the 'N'.

Time will tell by driving the car more, but my very un-scientific test leads me to the conclusion that an MGB GT V8, whose owner believes, that it runs hot, will run much cooler with the investment of 12.48UKP, and the driver will be less steamed up over it as well. In short, a good investment, which has been stated previously.
Graham Cornford
10/08/2012 @  07:37
 
Smaller water pump pulley
Following Tony Lake's contribution to this thread on 1st August saying "I think it is important to distinguish between getting hot and overheating. My proposition is that getting hot, which all V8s experience in summer in slow moving traffic, is normal." Tony has contributed a useful V8NOTE455 on cooling, what is so hot it could be regarded as overheating and the importance of a correctly pressurised cooling system. You can see V8NOTE455 at: http://www.v8register.net/subpages/V8det.htm#455
V8 Webmaster
14/08/2012 @  18:00
 
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