electric window mod

[Barrykearley 7,190]

It’s the resistance of the switch and it’s contacts - they get warm - that’s a voltage drop - window is slower 

[giorgio67 185]

if you read 12V on the wiring cable they are not...😜

[Barrykearley 7,190]

A charged battery should give you over 13.2v

[drdoom 447]

Jon and Barry are correct, Giorgio is in error just a bit perhaps. The draw in total is measured in volt-amps, or Watts more commonly. That 12v at the motor while inactive should be nearer 13 with a healthy state of things, and any reading will drop when the motor is activated due to the current draw. It is a sign of trouble when a switch or wire show heat as this is indicative of energy loss due to resistance. So the proper approach to solving Lotus' inadequate build is to serve the motors with adequate power ( again, V-A ) via relays served via adequate gauge wiring.

As to difficult or stuck window glass it bears reflection on how friction may be unreasonably high due to misalignment and/or neglect. Frame adjustments, while somewhat difficult, should also be made when called for. Silicone spray in the felt guide channels can also help a bit.

Cheers

[giorgio67 185]

I’ll stand correct but mine have original wiring and works perfectly, well... I spent a week setting window frame guide etc.. 

G.

[Tony D 59]

Thanks for reactivating this thread. A great mod that I hadn't thought about for my 74 Elite. 

Years since the Windows moved under electrical power (long term, very slow resto), but this definitely needs to be on the todo list (along with several other relay additions where evidence shows things have got hot). 

Tony 

[Lotusfab 3,318]

I have spent months messing around with the window operation on the S1 and Turbo. They now all work perfectly without any relays. They didn’t work properly when I got the cars because of many things. The torque of the motors was reduced in the S1 as the magnets were weak. The rest was down the the window frame adjustment. Too much resistant. There are lots of possible adjustments.  It is possible for them to work really well If you spend enough time on them. I recently dismantled and adjusted the frame on the Turbo drivers door to stop a leak. Whilst I was at it I completely shimmed  the frame again. Its now working the best ever, very little resistance. The original wiring is adequate, assuming the switches are in good condition. John Mountain I think designed some of the electrics, we could ask him if he's on here? One thing though the guide rail didn’t work without shim washers behind. Also the four wheel plate needed lubrication.

[drdoom 447]

Fabian, it's good to hear of your success through diligence and care👏. I'd suggest though that it is preferable to spare the switches the current drawn by the motors. If not today, someday the switches may well be unavailable for replacement. Automobiles are built with such relays for good reason, right?  

[Lotusfab 3,318]

Yep no harm in relays it will preserve the contacts over time. Be aware though it won’t fix a poor window set up. Far better to adjust all of the bits get it working with little resistance and if you wish add a relay. The windows get such little use I haven’t bothered to add relays. 
I have new motors on both drivers doors. They are off a corvette and many other US cars. They have been remanufactured and I bought both of mine from the USA, quite cheaply. Details on my blog somewher of the exact type for ordering. Heres a quick guide how to set up the window.

Remove everything except the glass counting how many shims on each part of frame. Measure their total thickness and write it down. Remove motor and all the other bits, leave glass at bottom of the door. Ensure the door is seated correctly on the car before you start. 
Put the frame in. Check its set at the correct height and not bent! If its way off there is a chance it has bent over the years. You can bend it back but its very risky! Something might break! Shim it so when closed and you run a piece of paper between the frame and the door seal until there are no gaps. Once you have done this ensure the outer seal is flush against the glass. If it isn’t remove the metal strip and seal. Drill out the rivets and reposition.  Rivet and put back in. There is quite a bit on adjustment on the rubber seal that is riveted. You need to leave the glass in the door with the guide rail and plate removed whilst shimming the frame. Install the guide rail and plate. They must be orientated correctly else they will jam. Once they are fitted without tightening the set screws run the window up and down by hand. Move the frame door catch end and middle until the best position with least resistance is found.  Ensure the four wheels move freely on the plate and grease just the spindles, no grease on the guide rail. The wheels need to turn as the window moves, not slide on seized wheels! If there is resistance when the guide rail is fitted, as the window reaches towards down, try putting shim washers behind the guide rail. They need to be narrow so the four wheels don’t jam. The window should fall freely if you let it go all the way from up to down with little resistance. You should be able to raise it with finger and not much force, just really lifting the weight of the glass. Make sure the spring on the arm thats connected to the motor is set correctly. The spring should be in tension when the motor is inserted in the arm so that it is effectively pushing the glass up and reducing the motor load. Install it back in. It is essential to get the horizontal position of the motor correct because it is connected to the door restraint. Too far towards the front and the door restraint will allow the door to open too far and your paint may get damaged as the door wedges against the shut area. Once you have got the restraint where you want it tighten the motor bolts and test. 
I did all this in a day on my Turbo, but I have had lot of practice. When you are new it seems it will never work no matter what you do. I never had any guidance on how to do it so the above is a massive help. It took many many man hours to figure out how to do it. I spent many many weeks adjusting and getting nowhere. This is because I assumed itbwould work just being bolted together as per the diagram. Well this isn’t like most other production cars. I still need to adjust the passenger door frame on my S1. The frame has a tiny gap at the front left, where water gets in. I did this door several years ago before I had perfected the technique. The glass goes up an down perfectly,but water ingress is no good. The paper really helps with finding gaps between the frame and the seal. I can’t take credit for that idea Andy on here suggested it! 

[Tony D 59]

Alternative to paper shim is to remove the door seal and measure between frame and body lip to get a consistent dimension all around the door and frame (or as best you can). Measure the uncompressed door seal (I think mine was around 20mm), measure again with full compression (around 14mm IIRC), then aim for the mid point, 17mm, as the dimension between body lip and frame, using shims as described to set. 

My experience of doing this is on a 74 Elite, but I'm sure the principle translates to Esprit's. 

BTW, when I did this on the early Elite, I found the gap along the bottom of the door was around 24mm when the outside door alignment was correct. Door could never have been in contact with the door seal on these early cars. I built the bottom of the door up to close the gap. Later cars have different inner door profiles which may have resolved this problem. 

Tony 

[giorgio67 185]

Here how my glass work with the original wiring prior any fine adjustment, now is working even better.

Sounds good? 😜

[Lotusfab 3,318]

8 minutes ago, giorgio67 said:

Here how my glass work with the original wiring prior any fine adjustment, now is working even better.

Sounds good? 😜

 

You were lucky there, both of my S1 and Turbo drivers door window wouldn’t close!

[giorgio67 185]

That's no lucky is called hard work!

G.

[gvy 391]

Giorgio,

You have done a good job and you are right, that the system should be fine adjusted in the first place.

On the other hand. Lotus should have used relais to open and close the windows.

Let me explain:

Of course you will measure 12V at the windows. But the fact is that as soon you start drawing current, there will be a voltage drop that you can measure at the windowmotor and that voltage drop depends on the loss ( impedance ) in the circuit. The current has to travel through to long and small wiring and the biggest impedance comes from the contacts of the lucas switches that are not up to their task in the long run. So if the system is not fine tuned, the motors have to work harder, the current will rise, but the contacts can't handle it so the impedance in the system is bigger, so the voltage drops during the movement, and it all slows down, or even starts to fail.  A well sorted system as yours will do good, but just as long as the lucas contacts will cope and as long as your system stays well sorted.

Using relais, the current comes directly to the doors with shorter and bigger wires and the contacts of these relais are way better than the lucas switches (the relais are made for these currents infact). EVen if the system is not finetuned and starts drawing more current, that does not matter, because the total impedance of the feeding circuit is so low that even at work the full 12V stays at the windowmotors. ANd that impedance will stay low , just because the thicker wiring and the contacts of the relais will not deteriorate with use and time. The lucas switch contacts are just needed for a small current to trigger the relaiscoil. They can cope with that for ever, they will not burn in. They were never made to carry the full windowmotorcurrents.

The proof:

In your video : Going down : 1.75 sec , going up : 2.57 sec.

This is good, but notice the difference in up and down : the motor has to work harder to go up and will draw more current. The voltage drops , because of the impedance in the circuit, hence the longer run to go up.  In your case, this is no problem because it all works just fine and even better after adjusting , but it is a system that in the end will fail.

In my video : Going down : 1.9 sec , going up : 1.97 sec

I did nothing to my system and before the mod the windows became slow. I just fitted the relais modification.

You can see that going up and going down are about the same times. That proves that , even if there is more current needed to do the work going up, it just does not matter here. The electrical circuit is up to the task and there will be no voltage drop at the windowmotors whatsoever, making sure the motors get the power they need to go up as fast as to go down.

 

This is why I started this tread. This mod will solve a lot of issues with slow windows. Even in wintertime, when frost makes it even more difficult, The windowmotors will get the current and voltage they need to do the harder job.

On the other hand, you are right that it is good to finetune the system in the first place.

 

 

 

Edited January 10 by gvy