Show whole topic Jul 25, 2011 10:41 am
Julian Offline
Member
Registered since: Dec 04, 2007
Location: Belgium


Subject: Re: M45 Cooling Improvments
Hi Collin,
Great point you are making here! And this refers to every single "classic car" engine I have ever seen. The cooling circulation / coolant distribution is poor to say the least! The mods you recommend are certainly worth doing to the rear of the block on the 4.5 Meadows, as it is almost always 5 and 6 cyls that seize first if they are going to do. This must point to poor circulation around this area at the very least. We have measured this and found it true. V12s suffer on the front right bank to a very severe extent, and when you take even a little look you can see exactly why!

People fitting modern thermostats should read this VERY carefully. In an ideal world we would like to run our engines as hot as possible in order to make as much use of the heat produced by our combustion, and get that heat to act on expanding gasses and making power and not heating water! Fantastic modern cooling systems can do this quite well and we find some engines running at a design temp of 100+ degrees. However, if you are running your old pre-war engine at a happy 70 degrees C, you may find that on very poor cooling systems in some blocks like the V12 Lagonda, that some of your cylinders have water surrounding them at 95+ degrees C ! ! ! ! ! you therefore are not far away from a problem if you hit any situation that causes your water temp to increase! Although you may not even realise it as you think your water is "only" at 75 or 80 degrees as your gauge is telling you.

In any Lagonda other than a V12 you will be running at about 50 to 60 degrees in normal conditions with a good pump and clean radiator with shutters open. My advice is to let it be, it is rare for such low mileage engines to be harmed by too little engine temperature, but VERY common for them to overheat cylinders for seemingly no apparent reason! (the reason is actually very apparent once you are aware of the poor coolant circulation in various engines)
The V12 is another fish all together and needs extreme care if damage is not to be encountered! We are thinking about making a "cooling kit" for the V12 to help the situation. Hope we find time soon!

One thing to be careful about though is making things worse and not better! unless you are sure where the "new" water is actually going and able to measure this accurately (we are regularly surprised when testing that "theories" often don't work quite as well as we or others thought they would) then best leave it alone and just rely on a good clean Lagonda radiator to keep things on your gauge at about 60 degrees as ALL Lagondas with water pumps can do with the exception of said V12s, unless your radiator is not working to it's full capacity.

Good luck and enjoy your sunny days!
Julian