Up Into Fourth
Posted 15 April 2014 - 04:07 PM
In David Vizard's "Tuning the A-Series Engine" book he suggests a mod to the water jacket at the pump to improve the water flow, especially in big bore engines .. and I was wondering if anyone had tried this?
I'm assuming he means to open up the gap between the block and the first cylinder bore slightly where the arrows are added and not just opening up the hole where the pump fits into/onto ??? The picture is pretty poor in the book.
TIA
One Carb Or Two?
Posted 15 April 2014 - 08:38 PM
I was looking at the same thing in one of Keith Calvers features in Mini mag, can't remember which issue, and it said what you're saying. Open up the gap between no1 cylinder and the block and not the actual opening on the outside of the block. I looked at my block the other night as it's sitting on the workmate in the garage partially stripped and the gap thats there is very small. I seem to remember him stating something about not opening it too much though as this can cause other problems. Will need to check that myself before I get the die grinder out! He also suggested blocking up the first four or six water holes in the top surface of the block, counting from the no1 cylinder end, this would cause the water to flow towards the other end of the block then back to the thermostat instead of straight from the pump up to the thermostat thus reducing the hot spot at the no4 cylinder end. Have you heard of this and are you going to try it?
Up Into Fourth
Posted 15 April 2014 - 10:28 PM
Camshaft & Stage Two Head
Posted 16 April 2014 - 02:53 AM
Not read that about blocking holes ... seems an odd idea to reduce the flow ...
I'll have a look at my block over the weekend and see what it looks like but re-reading Vizard it does seem to suggest just inside but does not mention how much should be removed.
It's not when you think about it - and it's why most domestic central heating systems run at very poor efficiency - because the installation engineers don't know how to properly balance the system.
The idea (with DCH systems) is to get a difference of 6C between flow and return on each radiator and the lock shield valve is used to obtain this. Any less difference in temp means that there is too much flow, and less and the radiator won't transfer it's rated output.
The engine (and the boiler) need to run hot - but there is a school of thought in the UK that we should "turn the boiler down" which is the worst advice you can get - the boiler needs to get the circ water as hot as you can without boiling for maximum efficient - let the room stat or thermostatic rad valves handle the room space temperature....
Obviously in a car there isn't much to balance save for plugging holes near the pump to increase flow to the furthest away pots, and of course the mini isn't a constant speed engine, and even more difficult still is that the heat output into the cooling system is varying all the time, so it's pretty impossible to balance unless you start forcing some constants.
A constant speed water pump would mean the you could achieve an even flow through the block and head.....but we don't have that so all this messing around may be fruitless 
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