V8 Pulley sizes and identification

RogerD · Post by **RogerD** » Sat Sep 13, 2014 5:02 pm

Hi all, I've got a Westfield V8 and it runs a bit hot (don't they all?!). Motorway settles at 80 with the electic fan on all the time. Never goes any lower. A roads = 90, traffic = 100. Heavy stand still traffic in summer = 110.

Apparently I've no stat installed, and I've noticed my stat bypass hose goes to my header tank, which seems wrong if no stat is installed as that means hot water going stright back through the system bypassing the rad. I clamped that pipe but it made no noticeable difference. I assume as it's a small pipe it gets ignored, with the water going through the main rad pipe?

When I bought the car the prev owner mentioned I had "performance" pullies and that perhaps my water pump pulley was too large and it could do with shrinking to speed up the pump. Looking at it it is clearly bigger than the crank pulley.

You can't really see the crank pulley but you can see how large the water pump pulley is.

I was thinking of trying a smaller one but can't for the life of me tell what I actually have and where to get different sizes? It has been suggested I have TVR Power pullies but I can't find the site, and a site that sound similar has none like mine (Poly v?). Any suggestions. I've read that normally you have about a 1:1 ratio on RV8's - water pulley to crank pulley ratio?

Backgound: the engine is reported to be 4.3l but I'm told that can't be true as only TVRs have 4.3l size. I have dyno prints for 250bhp & 250 torque peake at 6000rpm. Drives wondefully to 6k. Only hesitates if she gets to 110 in traffic. Have to get her to 105 or below to get everything right again.

Oh - also - my fan temp sensor is on the input side of my rad (top). (I assume the water pump sucks water from the rad bottom into the engine). I've read that it's better placed on the rad output as that's the temp you are interested in? Kind of academic though as my fan is on pretty much all the time and can't get the engine below 100ish at stand still.

DaveEFI · Post by **DaveEFI** » Sat Sep 13, 2014 6:31 pm

If you need a fan running on the motorway there's something very wrong with the airflow through the rad.

Normal running temperature for an injection engine is 88C. Removing the thermostat won't help reduce temperatures higher than this - it may actually make things worse. Obviously in slow moving traffic or at rest the temperature may well go higher - that's where you need an efficient fan or fans. Many electric ones simply don't shift enough air.

Ian Anderson · Post by **Ian Anderson** » Sat Sep 13, 2014 8:25 pm

Do you have a cockpit heater fitted?
If so how is it plumbed?

My guess probably not fitted and the flow and return are looped together.

If so this is the bypass so the water avoids the radiator.

Ian

RogerD · Post by **RogerD** » Sat Sep 13, 2014 8:25 pm

My Kenlowe stat is clearly set below 80 degrees as it's switch off point, hence the fan runs on the motorway. I have no doubt the fan is contributing nothing at those speeds.

At motorway speeds it won't drop below 80, but if you say the normal running speed is 88 (I'm carbed but I guess it is similar) then that's no surprise.

I've got an inline stat switch ready to install, to replace the Kenlowe (which is faulty and sticks both on and off) that is 95/86 so that should be more appropriate.

RogerD · Post by **RogerD** » Sat Sep 13, 2014 8:28 pm

No heater - this is the current plumbing:

(The small black rectangles off the manifold and water pump represent blocked off pipes)

I'll check for the absence of a thermostat when I take things apart soon, but I'm fairly certain I was given the correct information. The rad pipes get warm/hot instantly. If there is a stat it doesn't do anything!

RogerD · Post by **RogerD** » Sat Sep 13, 2014 8:42 pm

Here are some pics that might better explain than my drawing. I'm fairly new to RV8's.

ChrisJC · Post by **ChrisJC** » Sun Sep 14, 2014 8:27 am

What a mess!
In my opinion:
'e' should be 't'd into the bottom hose (which I suppose it already does)
I am confused about what 'd' is, but that pipe should go into the top hose.
'b' is fine
'n' should go to 'g' (as it is the heater circuit)
'k' should go to 'f' (as it is the thermostat bypass)
'b' to the rad top is correct - it is just a bleed. Maybe the carb manifold has one as well, certainly the SU manifold had a small bleed.

Chris.

RogerD · Post by **RogerD** » Sun Sep 14, 2014 11:31 am

D is the thermostat housing bypass output, well, that's what assume it is. A small pipe that comes out of the stat housing under the main rad output.

If I put n to g would I not be taking hot water from the manifold and putting it straight back into the pump, and therefore engine, bypassing the rad?

I thought k was the secondary manifold output allowing for mounting the manifold either way round, and is hence already covered by the use of n?

I thought n was the main manifold output not the stat bypass, that is d?

Any advice welcome. I never plumbed this engine. I'd also like to lose one of the pipes to the header as I have a new ally header with one less pipe..

ChrisJC · Post by **ChrisJC** » Sun Sep 14, 2014 1:03 pm

So do K, D and J all come from the front of the inlet manifold? If so, what is K?

Is it that small piece coming out of the carb body itself? If so, I don't think that's part of the cooling system at all.

So then, the picture starts to make some sense:
I think I can see the thinking......
D is the thermostat bypass. Normally it goes straight into F. But it is connected via the header tank. Probably OK.
N is the hot water feed to the heater. Normally goes via the matrix to G. If you don't have a heater, you could probably blank it off, but it looks like the water is being taken into the radiator.

I think therefore it might work fine.

Is it just that your radiator is too small?, have you tried measuring bottom hose temperature?

Chris.

RogerD · Post by **RogerD** » Sun Sep 14, 2014 8:41 pm

D and J come from the front of the head. This, as I understand , is the water outlet after it's travelled all through the engine. If you look at the 3rd pic from the bottom, on the left, J is the big fat pipe going left to the rad. D is the pipe swirling round it and running across the bottom of the screen to the right (back to the header tank)

K, comes out of the inlet manifold (Offey manifold) - on the same pic it's on the left of the carb. Blanked with a bolt.

N - comes out of the Offey manifold on the right on the same pic, and doubles back to join J. As I understand, water from the head also flows into the manifold and this allows it to be also extracted from the rear of the head, offering more even water distribution - else it would skip the rear of the head? I could blank it off but then I'd lose that advantage...

I've attached a labelled photo.

So I reckon, I can connect D (stat bypass) to the water pump, say, at "g" and therefore free up a pipe going to the header. It'll feed hot water straight back into the engine, as I have no stat installed. I'm wondering , with no stat, whether I'm better to just blank it off. I can't see the point of it with no stat..... Or perhaps I do connect it to "g" so in case a stat is installed in the future at least it'll work. I'm not crazy about having hot water fed back directly in the engine all the time though. The pipe is a lot smaller than the J - rad pipe so perhaps it's not utilised much? it gets bloody hot quickly though.

My rad is as big as it can be in a Westie. It's a deep job, and fits snug.

I've ordered an IR thermometer off the web so I can see what temp the water is coming out of the rad. Will know by mid week...

ChrisJC · Post by **ChrisJC** » Sun Sep 14, 2014 8:54 pm

Yup.
D & J (& N in fact) are hot water outlets from the engine.
The circulation in these is from the water pump rearwards through the block, up into the heads at the back, then forwards through the heads to the front, then up into the inlet manifold next to the 'stat.
From there, it can come out of J & D. It also travels backwards again through the inlet manifold to N.
It doesn't exit the heads at the rear - the inlet manifold effectively blanks it off.
You are right, with no stat, there's no point in D. However, you should really have a stat, If everything is working properly, there's no reason not to have one.....
I think I would try to get as close to a factory system as I could, and work from there.....

Chris.

RogerD · Post by **RogerD** » Sun Sep 14, 2014 8:59 pm

Thanks Chris - much appreciated - good to clear up the basics. I'll grab a stat in the next couple of days and install it. I gather the restriction might actually help.

I guess I just grab any RV8 stat? Really have no idea what model my engine is.

SuperV8 · Post by **SuperV8** » Mon Sep 15, 2014 7:59 am

The stats are sold at different opening temperatures. There are many debates about the 'correct' open temp. I would just get one which opens at the 'factory' temp for your engine. Obviously your fan on temp must be higher than the stat open temp!

Make sure there is a small vent/hole in the stat and that this is positioned at the top. If no vent just drill a small (2-3mm) hole in the flange to help system bleeding.

If there is no stat then maybe the previous owner took it out to (incorrectly) help with an previous overheating problem?

Tom.

RogerD · Post by **RogerD** » Mon Sep 15, 2014 9:19 am

Excellent, thanks.

I think I'll get an 82 degree stat. 88 Seems too high.

My electric inline fan switch switch will use a 95/86 insert, so when the fan gets to ease off at 86, an 88 stat will fight it whereas an 82 stat will "keep out of the way". Sound right?

I've heard of people removing stats to increase flow, but there also seems to be a lot of people who say you need the resistance to control the flow and that removing a stat really serves no purpose at all.

DaveEFI · Post by **DaveEFI** » Mon Sep 15, 2014 9:52 am

Cooling systems are all designed to run with a thermostat. If anyone is tempted to remove it due to overheating it means there is something else wrong with the system. A bit like fitting a new battery when the alternator isn't charging.