19 replies to this topic

[andyjmapex]

Hi guys,

 

can you shed some light on why my rad isn't functioning 100%?

 

New engine build in its first steps of running:

 

Eaton 45 supercharger,

12g940 head + decomp (temp solution)

metro cam

standard everything else.

 

Right - due to me making the bits for the supercharged bolt on myself, there has been a move around with the radiator. Its is now bolted to the inner wing and moved down an inch in order for me to fit an electric fan in as the standard plastic fan didnt fit with my charger belt.

 

anyway, the car will run just past normal operating temp (approx 110 deg C) and then blow coolant from the rad cap (i mean alot). I have replaced the cap with a sealing one and fitted an expansion tank, however now it just empties the radiator and overflows the bottle.

 

I BELIEVE the problem to be that the radiator is too low now and the water is pumping out of the cap before it can go through the top hose. If you look dead on the thermostat is higher than the cap - would this cause these problems? If i fabricate a new thermostat housing to bring the top hose to horizontal would this help do you think?

 

take a look at photos!

 

Regs

Andy

 

 photo 1.jpg   38.43K   39 downloads

 photo 3.jpg   35.03K   35 downloads

 photo 2.jpg   39.83K   42 downloads

 

 

[Tupers]

I think you're going to keep running inot the same issue unless you move the filling point of the radiator up. A Metro thermostat housing comes out flat but I still wouldn't count it it being low enough once water's flowing through the system. 

 

Every other blow through system I've seen has used a standard fan and kept the rad in the standard position, could you not space the fan away from the belt?

[andyjmapex]

metro housing isnt a bad shout, i may give that a go.

 

Ive never been a fan (pardon the pun) of the plastic one and the electric one seems to work better so I'd like to keep it ideally! I may see what else i can to do get the rad lifted up a bit more.

[Dusky]

Nice rad to standard location and fit a 4 blade metal fan.

[Steve G]

Could you fit an expansion bottle somewhere a bit higher up ? At least then you would have enough coolant in the system.

[andyjmapex]

ive also heard a bigger expansion tank may be needed (im using a half litre jar)

 

going to make sure there is not an air pocket in the top hose too today - then move the bottle higher up too as you said

[Gr4h4m]

Are you running a 2 core rad? Or is it a standard, if it's standard I'm not sure it would matter if you put in on the roof or even the moon , is always going the struggle.

[carbon]

You can have the expansion tank / filling point at a much lower level than the thermostat housing. But for this set-up to work you really need the Metro themostat housing with the small bore take-off pipe. 1100/1300s used a similar set-up, the radiator cap had no pressure release, the vented cap was on the expansion tank about 2 foot lower than the top of the rad.

 

This small pipe allows the air which collects at the highest point in the cooling system to be forced out into the expansion tank. As long as this pipe is connected into the base of the expansion tank it will draw water back in when it cools down.

 

The expansion tank must be capable of taking system pressure - typically 15psi. Half litre is a bit on the small side, but this depends on the total volume of water in your cooling system.

 

Also if you get a second-hand Metro thermostat housing to try this out make sure this small pipeway is clear - I have had one occasion when this 'furred up' over time, and when this happens you get a lot of pressure building up in the cooling system...

[andyjmapex]

It is a standard rad, wit no heat matrix plumbed in. so i have a large amount of water not in the system and an old rad!

 

do the metro housings have the same top hose diameter?

 

my problem is that the water is spilling out of either the expansion tank when fitted (or the rad cap when not) at "normal" operating temp. 

Edited by andyjmapex, 15 September 2014 - 07:37 PM.

[cal844]

Change the thermostast?!

[andyjmapex]

no thermostat in there! I'm running an electric fan with electric thermostat so no need!

[Tupers]

Have you got a blanking sleeve in there? Clicky

[cal844]

Cant be that, im out of ideas :/

[andyjmapex]

never seen them blanking sleeves before! is it needed?! thinking about it, it had classic head gasket symtoms. going to try the checks tomorow - it seems to be blowing air in the cooling system...

[Cooperman]

It may well be that the electric fan is quite simply not shifting sufficient volume of cool air through the radiator. Electric fans are constant speed, whilst engine-driven fans shift air in direct proportion to engine revs.

Electric fans are really intended for front mounted fans where the speed determines the volume of air going through the rad and the electric fan is just an auxiliary fan for low speed/heavy traffic conditions. Really an electric fan is not suitable for your application.

In most higher output Minis the electric fan is just to augment the metal one, assuming a 6-blade export fan is fitted (this is the best available).