You could do away with the cap on the actual radiatior if you put one of these in the top hose:

We use these on Cobra’s because the radiator is laid down at about a 45deg angle.

Thanks its a good idea but i’m set on having it fixed on top of the carb manifold as its the highest point. The only place i could put that piece inline is at the rear of the heads and it would be on an angle. You would’nt think it would be such a hard bit to find in steel or brass.

Metal ones are cheap as chips brand new. You just need to find a race shop in the UK that would have them. DemonTweeks springs to mind.
You may even be able to get one donated & even fabricated specifically if you ask the right people. The idea is to aim high & start at the top. With that in mind I’d be calling around to McLaren, Lola, March & all the Formula 1 teams. Never be afraid to ask & the fact that this is a Spit should garantee that people wil fall over themselves to help.

Look here for a general idea:
http://store.summitracing.com/egnsearch.asp?Ntk=KeywordSearch&DDS=1&Ntt=Radiator+neck&searchinresults=false&N=+115&y=10&x=27

also:
http://www.jegs.com/webapp/wcs/stores/servlet/category_10001_10002_10129_-1_10109

This thing is about 10quid:

& thats billet, the others are even cheaper…

& when ya get totally desperate, theres a scrap yard near Mildenhall full of American cars that have radiators that resemble something from a Foden

Wait! Find a Commercial vehicle scrap yard & grab a smashed radiator from a wrecked big rig. Sorted!!

I’d still call McLaren tho……:cool:

Thanks for the info.:)

A second radiator cap?

I think you’d be better off with just one (on the manifold). With two radiator caps, one will always ‘lift’ first and ‘sods law’ says it wouldn’t be the one on the manifold where the air will tend to collect.

As long as your chosen cap will allow air/coolant to be sucked back into the system as the engine cools there should be no danger of the drum being crushed.

A simple air bleed valve will allow you to make sure that the drum is full of coolant before each ‘sortie’. I’ve used a bicycle tyre type valve (with metal housing) in the past.

Thankyou for that that a great idea. We’ll stick with one cap and have a airbleed valve on the tank. Having been to loads of scrap yards we cannot find a decent metal rad cap with fitting(ie top of an old rad) plenty of plastic ones so if someone has one it would be greatfully recieved.
Here are some pictures of the oil tank and fuel tank being fitted, its not finished so may look a big askew. Its a tight fit to say the least.:)

That looks as good a point as any without significantly altering the manifold.

The manifold will not really act like a header tank in this case as it should be filled with coolant (without an air pocket at the top) when the engine is running.

However it looks like a good point to purge air (and excess coolant) from the system (via a car radiator type cap) as the engine warms up and to draw coolant back in as the engine cools.

Do you know the total coolant capacity?

If that oil drum is full of coolant you should have something like 60 to 65 gallons in the system…and no air…which means something like 3 gallons will have to escape due to expansion (depending how hot the engine gets).

You will need an un-pressurised reservoir to catch this (connected to the ‘radiator’ cap by a hose) so that it can be sucked back in as the engine cools.

I would say it was important to have a cap that allows coolant (or at least air) to be drawn in as your 55 gallon drum could be crushed as the engine cools.

I would also put an air-bleed valve at the highest point of the drum as air will almost certainly collect there during engine runs.

Thanks for the advise will have a tank connected to the rad cap and give it a go she should be ready for a test in the next two weeks:diablo: . Watch this space.

Header tank

If I put a plate over the old outlet and weld a car header tank fitting and cap onto it I could use the carb manifold as the header tank? Would this work ? The old outlet is circled in read we have reversed the flow through the carb manifold and the arrows show the water flow direction. :confused: