Lotus Elan and Lotus Elan Plus 2 Forums

pauljones915 wrote:With reference to Bills statement, non return valve between the manifold and T piece, Does any one have a picture of what this looks like? My manifold take off NOW goes direct to the T piece. There is to my knowledge NOTHING in the entire system that isnt just a pipe,less the light switch itself. Am I missing a bit?

It could be that your NRV is like the one shown below which in my car was located in the short section of rubber hose between the manifold and the nylon pipe which runs to the crossmember T piece and not immediately obvious. This one was gummed-up and not working but after a good soak in petrol it now seems to work OK.

Thanks all.

I can honestly say I dont have a non return valve fitted,but I do remember a box of bits in the boot when I got it back from the garage. When I get home next week Ill post a pic up of the bits I think may be part of the system and we will see then.

However,the point then is,do I buy a new one and be done with it.In that case where do they come from and is there anything special I need to look for?

Thanks all,Paul

RD has them, (Plastic). They work fine but the brass one would look better

James

In truth I don't think I've got a non-return valve myself in my system. I'm fairly sure there used to be one but it vanished on one of the maintenance/tune-up jobs done for me over the years,

I'd like to get hold of one myself, because they serve another very useful purpose. Since they pass stuff (air) only FROM the reservoir TO the carbs, they will discourage, or stop any petrol vapour from going the other way into the crossmember reservoir. The latter is a hazard if any welding has to be done on or near the crossmember.


If my lathe was still working, I'd be tempted to make a nice shiny brass one.

.....or just fit a VW inline type, I have one in my S2.

billwill wrote:If my lathe was still working, I'd be tempted to make a nice shiny brass one.

Would that be that lathe you were selling a year or two ago that operated with pedals and rumour has it that Fred Flintstone turned up his cart wheels on it
.....edit...actually I think you were giving it away

As per the one in the pic, sold to me my Matty a few years ago...

http://store.norgren.com/uk/en/detail/s ... urn-valves
or
http://uk.rs-online.com/web/p/pneumatic ... s/0722564/

or just go to P.Matty

Jeremy

types26/36 wrote:

billwill wrote:If my lathe was still working, I'd be tempted to make a nice shiny brass one.

Would that be that lathe you were selling a year or two ago that operated with pedals and rumour has it that Fred Flintstone turned up his cart wheels on it
.....edit...actually I think you were giving it away

Heh, Heh.. Not Fred Flintstone technology, it is Fred Dibnah technology! Flat drivebands from overhead pulleys.



It's still here looking for a new owner who will love it, but I disconnected part of it in anticipation of it being collected 2 years ago, but that Railway Group changed their mind at the last minute due to an illness of their leader.

http://www.datahighways.net/support/top ... orum_id=29

We would let it go, but not free, we would want a price just above the scrap metal price, to discourage scrapping it.

I've had a look today and my vacuum T-piece has a bulge in it on the carb side. This is almost certainly a built in non return valve.

Needs a thorough clean and check though.




Not the best place to put a non-return valve, I reckon, as petrol vapour might condense in the tube and run down to this valve & is more likely to get into the reservoir that way. So I think I will obtain an inline valve and insert it in the tube as near to the carbs as practical.

I thought this may help. This is the fitting on my manifold that has one pipe going to the servo - the downward facing one - and the other coming straight out through a non return valve - connecting to the T piece - and is very easily cleaned if anything should go awry. The T piece is just that on the front chassis member with no valves or anything else around.................

Hi all and just a quick update.

Drove her with the head lights up last night.Well not exactley "up", here goes. With the system connected as per the diagram posted I had so little vacum that the pods were not able to raise further than an inch or so. So I connected the take off direct to left light which is joined with the crossover to the right. As you can probably guess,as soon as the engines is on then the pods raise.The left is slightly stiff so is held ok ish but the right dances up an down quite a bit.Makes the lights almost ineffective,and when it was rewired the sparky used the micro switches in such away that when the pods are low enougth they will cut out. Good for night driving I dont think. Anyway,by wedging in a small surport i have a right pod that is reasonably ok but the left will still lower with a loss of vacum,like going up a steep Dorset hill,then cut out.

Got home but not with the best lights available, so from this Im thinking i have definately got a leak somewhere if not then several places.Hopefully not the frame leaking.Ill find what bit i think is a nrv and post up for you all to see,if it isnt then ill just have to buy one.I may be inclined to have a tank made so i know it has no leaks in it.

Whats the general ideas from the lotus world guys?

Paul

pauljones915 wrote:I had so little vacum that the pods were not able to raise further than an inch or so. So I connected the take off direct to left light which is joined with the crossover to the right. As you can probably guess,as soon as the engines is on then the pods raise.The left is slightly stiff so is held ok ish but the right dances up an down quite a bit.

pauljones915 wrote:Got home but not with the best lights available, so from this Im thinking i have definately got a leak somewhere if not then several places.Hopefully not the frame leaking.Ill find what bit i think is a nrv and post up for you all to see,if it isnt then ill just have to buy one.I may be inclined to have a tank made so i know it has no leaks in it.

Without an NRV your lights will never stay up - leaks or no leaks - so that's the first thing to eliminate. If you do have an NRV fitted somewhere that you haven't yet found I would suspect it's not working. Remove it and check it by simply blowing through it - it should pass air in one direction and not in the other (sorry if that's bl**din' obvious). If it's U/S or you find you definitely don't have one fitted then you need to fit a new one. Only then, if your lights still don't raise fully and stay up, can you be sure that you have leak(s) somewhere in your system. I wouldn't go spending on a replacement reservoir until you have eliminated all other possibilities.

I am kind of surprised that this topic is still active. I don't seem to have issues but then again I did away with the switches that Lotus used to ground the relays and just hard ground them so if the light switch is on then the head lamps are too. If I forget to turn off the lamps then I deserve a flat battery (and yes its happened). I see hose clamps on vacuum junctions, they look like fuel line too. I use vacuum tubing, 1/4 inch and 5/16 inch depending on which side of the Tee and its been in place for 16 years and still no issues. These photos are of the Sows Ear chassis that I am currently building and I don't know if it will work or not yet, the Vacuum switch was just pulled out of a box and installed in the dash, once the engine runs I'll get back and trouble shoot as necessary. This build is being done with what was culled out of the last 4 to 6 builds, parts are just there to be there so there is a complete system there to start with to test. I have seen the Lotus supplied vacuum elbows on the vacuum switch leak like sand. be real in what you expect from the parts that are 40 plus years old, they were never designed to last that long so everything must be scrutinized and checked. I forgot to say, I invested about $4 in the black vacuum tubing. Yes I am a big spender...

Gary

There's a topic somewhere on this forum with photos, on how to clean & repair the push-pull control valve for the vacuum. I.e the knob on the dashboard for raising & lowering the headlight pods.

That's the most likely source of leaks, other that the actuator-pods in the front, and those seem to be OK on your system.

You might be able to make a test tool by reversing the washer in a bicycle pump so that it sucks instead of blows or try making an adaptor for a vacuum cleaner. Some camping Airbed compressors have a suck inlet for quickly deflating an airbed. and they come with several adaptors.

Useful tips for finding vacuum leaks here:
elan-archive-f16/vacuum-leak-t9282.html


Here is the topic with the photos on how to repair the vacuum 'switch'
viewtopic.php?t=13457