Lotus Elan and Lotus Elan Plus 2 Forums

Can anyone tell me how to confirm which way round the brass headlamp vacuum valve should be fitted?

They usually have an arrow on them but if you want to be 100% sure pull the rubber hose off the Inlet and suck the pipe..... if you can draw air through it then it's the correct way round but if it locks up and opens when blown down the hose then obviously it's the wrong way round. If it works both sucking and blowing then it's faulty.

Where did you find a brass vacuum valve? Here in the US they are all plastic and can't be installed in the engine bay as they might melt.

I purchased a one way valve a few years ago from a known parts dealer in Crediton, and was sent a Norgren brass part that looks just like the one on the photo

http://store.norgren.com/uk/en/list/val ... urn-valves

http://cdn.norgren.com/pdf/en_5_10_370_S_52x_S_531.pdf

it does not look original, but has worked fine so far (during installation I made sure of correct operation by blowing/sucking through it so that air would go towards the manifold only, from the vacuum tank which is to hold a reserve of vacuum).

Thanks!

I would be a bit careful with those non return valves.
My car came with them when i bought it and
they look very much like yours and they were not intended for use in a car.
The rubber seals "melted" after a while.
I think the petrol fumes dissolved them.

Just my experience.

Jens

Daugaard wrote:I would be a bit careful with those non return valves.
My car came with them when i bought it and
they look very much like yours and they were not intended for use in a car.
The rubber seals "melted" after a while.
I think the petrol fumes dissolved them.

Just my experience.

Jens

that model seems to have a nitrile seal, and if installed correctly it should get mostly air (vacuum drawn from manifold, then air coming from behind the dash)... I'll check if I can get an original one working at some point, but have postponed that as non urgent so far...

nb: I have installed mine almost like the one on the photo above, that is thermally (and vibrations) isolated from the head (was a bit suspicious myself upon receiving it, so opted for a non original yet safer installation location)...

I was supplied one by Fibreglass Services, unmarked, and it has jammed shut at least once and I no longer trust it. I hope to fit a T-piece with built-in valve, which I believe Sue Miller still sells, as the original lasted 30 years.