The V8 Owners Forum -

Maybe someone can help me here: I got an JE Developments 4.5 V8 (dry sump, Cosworth pistons, Carillo rods, big valves head, no T-stat, twin radiator setup...) in a historic formula car.
The PO had lately an electric water pump installed. I just reworked the heads (head gasket was shot) but the engine is still overheating - I have just let it idling for 10 minutes or so.
I checked the plumbing and found out that the eletric water pump sucks coolant out of the expansion bottle. The bottle is connected to the heads (see picture), but the feed of the waterpump is the top fitting on the tank. That can't be right. It will suck out a lot of air, when the expansion tank is not filled completely.
Now my question: is it possible or bad for the engine to have the waterflow reversed: in my case sucking it from where the water pump was and feeding it back again in to the engine in the head via the tank? I changed the plumbing and it gives me a nice coolant flow without air. But do I miss something here? The 2 radiators are way below the engine.
Thanks for any help here?

The water pump should pull coolant from the bottom (cool part) of the radiator, and push it into the engine.
The standard mechanical pump pushes coolant into the engine, the top engine coolant outlet from the heads goes into the top of the rad.
Why would you want to reverse this? This is all done because heat rises. To go the other way you are working against this.

Thanks, you are correct. I do not want to reverse the coolant flow, but I see no other possibility without major changes in the expansion bottle. I cannot pull coolant from the bottle without air (even when I add the connection in the lower part of the tank) - there is still air above the coolant level , I am sure some air will be pulled in. I would need to redesign the coolant tank and add an real expansion tank, but on a formula car the space is very restricted.
I know when the coolant flow is reversed it will work against the physical characteristics, but as long as the flow of the electrical pump is high enough I hope to be on the safe side

On your swirl-header tank the top port should be the inlet, and the bottom port should be the outlet.
e.g:
https://www.merlinmotorsport.co.uk/know ... ce-car-323

If you try and use it the other way round you are defeating the whole benefit of having the swirl tank so might as well not have it, and just connect the heads outlet upto the radiator top hose, and have a header tank else where.

Reversing the cooling system you will be feeding the hot water from the top of the rads into the engine!

Thanks! The 2 radiators I have do not have upper or lower ports - the ports are on each on the top of the fairly inclinend radiators. I now changed the direction of the flow of coolant so now the upper port of the swirl header tank is the return line from the radiators. So I am feeding the cooled down water into the heads, right?

If you need to use electric pump you could always look at one of these
Which will keep water flowing the normal way

http://forum.britishv8.org/read.php?11,51112

Ian

Thanks Ian,
very nice pump, but it won't work either - it would also draw the coolant with the air from the swirl tank. The only way I see which works is to pull coolant out of the block (where the waterpump normally sits) and back in to the engine via swivel tank and the heads.

Eugen

According to this it seems reverse flow coolant system would work:

http://prod.lv2014.gener8cms.net/index. ... verse-flow

oh, yes, this sounds good! Thanks for the link!