headlamp vacuum system

[rjaxe]

Lotex,
Check that the non return valve is functioning. Similar problem occurred to my car which had previously been fine,traced it to the NRV malfunctioning.

[Frank Howard]

The Elan was introduced, the headlamp system was generally considered a joke by the motoring enthusiasts of the day ? and even today when being discussed generally gets a rueful shake of the head by non-Lotus enthusiasts.

Brian,

This comes as news to me. It's my understanding that developing the headlight system was one of the last engineering challenges that Chapman and Hickman faced on the Elan. And the fact that Chapman and/or Hickman designed the front cross member to double as a vacuum tank is even more evidence of genius. If you look at other sports cars from 1963, you will be hard pressed to find one with disappearing headlights, especialy at the price point of an Elan.

If non-Lotus enthusiasts ruefully shake their heads, this is just confirmation that non-Lotus enthusiasts don't know much about Lotus. I use my car as my daily driver and my original vacuum system works perfectly. If yours didn't before you replaced it, there was probably something wrong with it, that's all.

Sorry, I get a little testy when someone criticizes Chapman for his engineering capabilities.

[bcmc33]

Frank,

My vacuum system also worked ?perfectly?, but having been in automotive design and development for over 30 years, it still remains embedded in my retired brain that continuous improvement is the key to success. I wonder who said that at one of our youthful seminars???????

If I gave the impression that the vacuum system was not an elegant solution to address a problem that only existed in one part of the world ? then I apologise. The system was elegant in that it was very quickly implemented to get the car through Federal regulations ? if it wasn?t for that requirement, the 26R would have remained the better looking and more cost effective norm.
I?m sure it was never the intention that the Elan should be the first production car with disappearing headlights ? to obtain Federal approval was definitely an after-thought, and a panic to comply. And of course, Lotus even had to ?cheat? to achieve this (by raising the body at the front by 1?).

I still maintain that an electric lifter design is a better engineering concept, and would have been adopted very quickly by CABC if the motors had been readily available at the time.

I feel sure that all the modifications I have done, or about to do to my car, would have had CABC approval ? even if they do offend the purists.


And by the way, the only criticism I ever had of CABC was to demand (sorry, persuade) Jim Clark drive in a Formula 2 race 1968.



Brian Clarke
(1972 Sprint)

[ppnelan]

I think you'll find the Elan was designed with pop-up headlights to make a lower front wing line and to meet British safety laws, not to pass US laws! And the pop-up design pre-dates the 26R...
However, the raised front suspension WAS 'created' to help pass Federal laws...

Matthew

[andyhodg]

Lotex

I had a similar problem in my +2. It was finally traced to cracks in the front crossmember where the wishbones attach. (its a Spyder service exchange chassis) Now all welded up (by Spyder) and working perfectly. Before fing the cracks I also replaced a corroded actuator. They can rust badly on the underside where they are bolted to the bottom of the nosecone.

Good luck

Andy

[Frank Howard]

The system was elegant in that it was very quickly implemented to get the car through Federal regulations ? if it wasn?t for that requirement, the 26R would have remained the better looking and more cost effective norm.

Brian,

Then again, they could have met the Federal regulations as well as saved some money, going without headlight covers and winding up with it looking more like the Europa.

[Frank Howard]

I still maintain that an electric lifter design is a better engineering concept, and would have been adopted very quickly by CABC if the motors had been readily available at the time.

Brian,

No argument here as Chapman did adopt electric lifter designs once motors became readily available. Just look at the Esprit, the Eclat, the Excel, and the "new" Elite. I just can't see fixing something that isn't broken. (Unless it interfers with a nose mounted radiator.)

[Frank Howard]

And by the way, the only criticism I ever had of CABC was to demand (sorry, persuade) Jim Clark drive in a Formula 2 race 1968.

I'm still pissed at him for making Jochen Rindt drive the 72 at Monza in 1970 when he was begging to drive the 49.

[bcmc33]

On second thoughts, I guess us Europeans were somewhat pissed-off with Chapman when Ronnie Peterson was always made to pull over to let Mario Andretti win the Formula 1 championship in 1978.


Brian Clarke
(1972 Sprint)

[robcall]

I still maintain that an electric lifter design is a better engineering concept, and would have been adopted very quickly by CABC if the motors had been readily available at the time.

Brian,

No argument here as Chapman did adopt electric lifter designs once motors became readily available. Just look at the Esprit, the Eclat, the Excel, and the "new" Elite. I just can't see fixing something that isn't broken. (Unless it interfers with a nose mounted radiator.)

As an aside-the Elite/Eclat had two vacuum reservoirs-one for the headlamps and one for heater flap actuators.(one in each footwell panel).
The headlamps went electric from ?1980 with the introduction of the 2.2l engine.
The vacuum heater flaps were carried through into the later Excel and did not go electric until 1986

So someone at Lotus saw merit to the vacuum system

[peterako]

Hi Lotex,

How are you?

Could be:

- Faulty one way valve at the inlet manifold. This would allow the vacuum from the light pod leave when the engine revs are up

and/or

- Leaky crossmember....will do the same.

I have bypassed the crossmember and put in a homemade vacuum reserve as I found the crossmember was leaking (only holding enough reserve for about 30 mins). Now my lights stay down more or less indefinitely (> 2 weeks).

I also added a second one way valve away from the inlet manifold as some posters suggest that at certain revs the valve on teh manifold can resonate and leak back.

Take care,
Peter 1973 +2S 103/5

[Rob_LaMoreaux]

When the Elan was designed electric operation of the headlamps was possible, but really heavy. Today the electric actuators are really light, so it is a different story. The Elan system is an elegant solution when all the parts are right, but as with any vaccuum system, especially one that old, it is easy for the parts to leak. My car has sat for a month now (gas tank leak) and the headlights are only half up. They have never started to rise while driving WOT, but then I re-did everything in the system since the car came to me with ugly fixed headlights. Well, I take that back, they did rise on their own once, but I replaced the plastic vacuum tube with copper after the header melted the plastic.

I don't remember the Elan being raised for headlight height, it should not need it since even an early car had 24 inches (this has been lowered to 22 inches in the US) from the ground to the centerline of the headlights. I thought that was just the Europa.

The rope solution seems nice and cheap, but my experience is rope eventually falls apart in the elements. It does remind me of the SAAB Sonnet method of a twist handle and gearing which was simple and effective.

Anyway for Umberto, electric operation would probably be the easiest and least expensive. The original actuators are getting hard to find, and the headlight switch (especially failsafe version) is really really hard to find (I got really lucky with ebay - wrong description, right part, near me, so cheap). Modern motor door lock units (not solenoid ones) may work, although a Corvette C5 or early Mazda MX-5 Miata headlight actuator may also work, but may be harder to adapt. The GM headlight actuators for the Firebird, Fiero, and C4 Corvette are fairly easy to find in the US and they have torque sensing turnoff built in so you don't have to worry about a limit switch. I am not sure about other units, especially since most of the cars that had them also had a switch to leave the headlights up to prevent the motor from burning out when the car was covered with ice.

Rob

[RobL7/Elan]

Hi All,
A couple of items that have been mentioned in previous discussions of this topic would do well to be mentioned here. 1. Install a new one way, or "check" valve' down line from the original. This valve should have a "cracking pressure" (opening pressure) of at least 3Lb. The original valve seems to fail as is is heated and cooled countless times over the years, resulting in the internal spring loosing tension and the ball not seating in its seat. This allows vacuum to leak back to the manifold when its vacuum pressure drops under throttle opening. The original valve has threads that fit the manifold though, and keeping it in place and inserting a new valve just downline works well. If this is done, and there are no other leaks down line, the light should stay up (or down as the case may be) even on open throttle conditions. Leaking cross members, vacuum pods,(or pod diaphragms), leaking accuators switch are all common areas to check. I sealed the diaphragms with bicycle tube sealant, which works well considering the cost of new pods. With these fixes my S2 ligts stay up on all driving conditions.

Rob
65 S2, 96 Caterham

[SADLOTUS]

Hi all.

Continuing this post I also have a question.

Today I started the car and after fixing exhaust leaks turned my attention to the headlights - S4 non failsafe - Both pods will go up but only three quarters of the way!

Individually they'll go fully up and be hard to push down showing that there's good vacuum in the pods, there's good suction from the manifold, I've tried different valves and cleaned and adjusted the actuating levers/rods, but, linked together they wont go fully up, even if I force them up they both immediatly droop. Push one up and the other will drop. I'm running out of ideas.....suggestions please.

[andrewdmoore]

A quick and very very cheap way of checking the non return valve is to go to a supplier of fishtanks - dont laugh just yet. The pipe that passes air into a fishtank has a non return valve in it to stop water going up into the pump. This valve cost me 79p and my headlights pop up and down just fine.

Regards, Andrew