Cooling a V8

Just for fun I bought a Buick 300 water pump - US$21 from Rockauto - by the time it got to me it was A$63, still VERY much cheaper than ERC2810 if you can find one. It has a flange on the end for a pulley and fan to mount on. From rear face to end of shaft 4-1/8";rear face to front of casting 3"; shaft dia is 5/8". There is 1-1/8" of shaft protruding from the casting. Only difference to our basic body is there is a drilled and tapped hole in the top face, with a plug screwed into it - looks like a tapered thread. Seems that 5/8 is a std shaft diameter, as its the same as the nose of an SD1 pump shaft, and the nose of ERC2810. Interested in the dimensions of ERC2810 with the viscous adapter removed - total depth from mounting face to end of shaft, and how much shaft protrudes out of the casting. My Disco viscous and fan is 2-3/8" thick, not counting the depth of the LH threaded female part which will screw onto the shaft. That gives insufficient clearance , so shaft would need to be shortened around 1/2". Still check the 17" dia would clear the top shroud. Only real problem is fitting a pulley to line up correctly. The availability of a 603936 would solve this problem, but havent been able to find a reference to one anywhere.
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PS - got an email from Rockauto - code for 5% discount (152818972140296872, goes in the 'how did you hear about us' box), inviting me to share it with anybody and everybody. I have bought quite a few 928 parts from them in closeouts over several years now.
 
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Another query. Got my radiator cleaned up and all leaky bits fixed. Had thought to fit a blind cap on the rad and the pressure cap on the overflow bottle - a cream plastic thing that looks original - it seems mounted properly. The cream bottle has a strange neck that wont take a pressure cap - looks like I will have to leave it with a pressure cap on the rad and have it suck back the overflow when it cools. Does this seem normal, or is the overflow bottle unusual? Different type of cap needed ? Bottle visible below.
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He standard and NADA water pump are the same. It is the fan mounting part that differs. It is only pressed onto the pump shaft and can be swapped for the viscous fan part if you can find one (I did exactly that when I got a new pump!) A lot of parts on the NADA are common to a number of other cars, both British and American. For example the dual circuit brake system is straight out of a Series 3 E-Type Jaguar, the electric window switches are Chevrolet Chevelle and the A/C pump is generic. I am pretty sure the parts needed for a viscous fan to be fitted can be found from another application if needed.
 
That looks like an expansion tank that would have a pressure cap, perhaps provide pics of the neck so we can see what is there.
To work by having a pressure cap on the rad that sucks back when it cools, the cap on the rad must be a double seal cap. This type of cap has one rubber seal in the normal place, and another that seals around the very top of the rad neck.
 
One hose from bottom of overflow tank goes to a nipple on the rad filler OUTSIDE the sealing face. The new cap is marked 'return type' or similar - I read this to mean it will allow a suck back from the overflow. The overflow tank has a soft rubber overflow tube from the side of its filler neck. will get a pic of the neck later.
 
Back again. On further checking I find - the new cap is marked 'Recovery System' and has the extra rubber seal just under the cap . The old cap does not have the extra rubber seal, and it will fit on the overflow bottle! So the extra rubber seal was the problem. Now have fitted the pressure cap on the overflow, and a plain blank cap on the radiator.
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I have connected the hose from the bottom of the pressure tank to the original overflow on the radiator, and then used a flat cap on the radiator. The outlet to the overflow tank is therefore within the pressurised system.
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The overflow tank is now under pressure so I have used the original pressure cap on that, noting the small rubber on the cap is sealing against the plastic in the tank at the lower end of the neck, not against the metal pressing at the top of the neck.

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The green tube is outside of the pressure zone and it just an overflow pipe going to ground, although if you ever get the coolant that high, you may have other problems :oops:
 
Quattro - this is the same as my arrangement now. If I have put too much coolant in the overflow tank it should get blown out on the first run up to temp, and then be stable. Might get a new flat cap for the rad filler neck to be sure it all seals in the right places.
 
I don't think it will work that way...any trapped air or vapour is going to push the coolant out of the overflow then you won't have anything there to suck back in when the engine cools....You really need to leave both caps off, fill the radiator, start the car and wait till the thermostat opens and sucks the water down then top up radiator till the coolant is flowing out the top row of pipes and starts coming out the filler. Then put the plain cap on it and wait till the water expands into the overflow tank. Then you can put the pressure cap on the overflow.
 
With the overflow feed from the rad going into the bottom of the overflow tank I dont think vapour or gas can push fluid out of the overflow. Take your point re the filling process though.
 
I have an expansion tank in 'Hazel' (Ser 1 V8). I filled the radiator up per the instructions - engine at about 1500rpm - then put the blank cap on. As soon as you drop the revs, the level rises into the expansion tank which I left the cap off whilst doing this. Unfortunately, my expansion tank is metal & therefore I can't see what the level is like.

I know it's been colder weather of late, but I'm sure the engine is running much cooler. One thing I do notice is that the heater works properly for the first time I can remember; presumably because there are fewer or no airlocks in the system :cool:
 
I found exactly the same. It forms effectively a one way valve which will burp out any air over time and because it'll only pull back water into the system as the coolant expands. One tip is to find the steepest street you car and park nose up and let it sit for a few minutes, this will help vent anything stuck in the system too.
 
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