The V8 Owners Forum -

Ive just fitted an MGB V8 Rad to my Kitcarwith an RV8.
Now, other than the main feed and return pipes there is a small pipe by the side of the top feed pipe.
Is this simply to run to an expansion tank? and will that suffice?

Yep
Thats the connection for the expansion pipe.
You can use any tank really as long as its big enough. You can use an MGB V8 expansion tank or any of the SD1 tanks as they are matched to the 3500.
If you are stuck for space you could even get one made by allysport or Serck to suit.
If you are using the MGB V8 rad then you will need a tank with a rad cap fitted.

Thanks for that !!

I am looking to convert my system to closed with an expansion tank. Rover V8 in MK2 Cortina. How large would you say is large enough. Julian

The SD1 expansion tank is quite small - maybe 1 litre?

Chris.

The MGB V8 exp tank is about a pint on the 3500.
As a rule of thumb you would expect about 1/23rd of the total cooling system volume to expand into the tank at around 80 degrees C at atmospheric pressure. So a pint or a litre is more than enough. You only need to make sure that from cold, the whole system is filled and there is a bit in the exp tank cover the dip tube. Normally about 1/3 full in the exp tank from cold is good.

julian.jay wrote:I am looking to convert my system to closed with an expansion tank. Rover V8 in MK2 Cortina. How large would you say is large enough. Julian

Just a personal view, I use a total loss system on my Cortina, Just to save space,, it starts to get a bit tight in there,

Sorry to be dim but what is a total loss system. I guess it is not one where all of the water has leaked out - (I had one of those on a kit car !!)

Julian

I guess it is not one where all of the water has leaked out

That would be a dead loss system

Total loss usually is interpreted as anything that comes out is lost and cannot be recovered.

Most production cars run a contained loss system with either a pressurised on unpressurised expansion bottle in which the contained loss is kept until is is sucked back in.

Dave

As long as the expansion pipe is connected between the rad and the EXP tank and the pipe is full of water , and the EXP tank has a bit of fluid in it to cover the bottom of the dip tube you could mount it remotely if you wanted to. You could even fit it in the boot.

My expansion tank is a long way below the top hose (from where it gets it's feed), and once primed up, it works fine.

Chris.

ChrisJC wrote:The SD1 expansion tank is quite small - maybe 1 litre?

Chris.

My SD1 motor has about a litre expansion tank volume, in a tall slim shape, and the level goes up a couple of inches from cold to fully hot. Maybe 25% of the volume of the expansion tank.