Plus2 Heater Cable Adjustment

[gwiz22]

Has anybody got any tips on how to adjust the heater cables on a Plus2S 130? I cannot seem to get the Hot/Cold lever to traverse from one end stop to the other. I can set it to be hard up against the HOT end (LHS) of the slider but as I slide it over to the COLD (RHS) it stops around 75-80% of the way across. I've fiddled about with the screw type adjuster at the heater end on the cable and also at the lever end but to no avail. The manual say, and I Quote "Should be adjusted to ensure the that the flap covering the heater matrix is fully open when the control lever is at 'HOT' and fully closed with the lever at 'COLD'."

The attached pictures show the Air Temp lever and the travel distance is approx 25mm. The pictures of the lever show it at the fully over to the LHS (when viewed from the dashboard) I.e. pulling the flap to the OPEN position, therefore hot. The red tape is simply a market. The other picture of the lever shows it in the fully to the RHS which would place the flap in the closed COLD position, The travel movement of the cable is approx 31mm. Hence the lever not being able to make the full travel from side to side. Any would be grateful if anybody has come across this issue and managed to fix it. Lastly, just to check could someone with a Plus2 confirm that the air temperature lever should have full movement from the HOT to COLD sides.
Thanks
Graham

[wotsisname]

Early +2, but looks the same.
both levers will move the full distance , right to left and I was able to set the travel at the heater end as per the manual.
couple of thoughts spring to mind
- does the inner cable move reasonably well when the cable is not fitted ? The inner is a single wire and a kink will probably cause it to snag. .. maybe turning the fitting at the heater end 180 degrees would change this behaviour ?
- my direction lever would not adjust correctly , then I noted that the "feet" of the heater had been bent inward on one side.. once fixed, all was good... so check the flap movement without cable first.

Adrian

[The Veg]

Agreed about the flap. The cable may be right as rain but if the flap doesn't move freely throughout it's range you won't get full function.

[gwiz22]

Hi Adrian,
Thanks for your suggestions. The inner cable moves quite freely. Even though I still held it vertically and dripped oil down the cable til it ran out the other end. I haven't thought of kinking the cable to see if the level of movement at the heater end varies but will give it a try. I'm not sure what you mean by "fitting the heater end 180 degrees" as the fitting that holds the outer cable and is affixed to the side of the heater, is above the lever so there would be nothing to retain it if I positioned the cable to come from beneath the lever. Also I don't understand what you mean by the "feet" of the heater. Do you mean the bit that bolts to the body? The flap lever movement without the cable connected is approx 2.5cm as shown in my photos. I know that this is the maximum travel for the flap as I can hear it bang against the upper and lower parts of the heater chamber as I move the flap lever up and down without the cable connected. If you or anyone else has a Plus2 heater out of their car, I'd be grateful if they could measure the distance that the end of the flap lever moves from the up to the down position.
Thanks again
Graham

[TeeJay]

Hi Graham.

I’ve looked at my photos of when I refurbished my Heater Box, as I had some difficulty; very stiff at Cold position; when the dash was reinstalled.
I repositioned the Hot & Cold cable to be behind the Defrost – Interior cable, see photo.
You can also get some additional movement of the cable by repositioning the outer cable at the clamp by the lever.

I’ll remove my side panel later and check my total movement and let you know.

Hope you solve it.

Heater Cables

Heater Box

[TeeJay]

My movement at the heater box, cold - hot flap is 27mm.

[gwiz22]

Hi Teejay,

Thanks for taking the trouble to send me the info. 27mm movement on the H/C flap is more or less the same as mine at 25mm. Of course it's a difficult measurement to take but I think 2mm is withing the realms error.

The problem therefore seems to be the inner cable and the dash lever quadrant. Moving from extreme left to extreme right is 3mm. So the flap becomes fully closed or open (depending upon how you adjust the heater end) before the dash lever gets across to the other end of its travel.

Does your H/C lever move from extreme left to extreme right on the dash?

Thanks again.
Graham

[TeeJay]

Graham, yes it does and without any stiffness.

[wotsisname]

Hi Graham, sorry.. I think my thoughts weren't clear.
I was wondering if the inner cable had a small bend / kink in it. when the outer cable is in position it has quite a curvature. I was thinking that any issue with the inner cable would snag due to this. At the heater flap end it has a loop of wire, if this were rotated 180 (fit with loop "upside down") after releasing the dash end, this may change any behaviour due to snagging.

The feet... not a good description from me. The bottom of the heater unit has a cutout on both sides at the side nearest the driver. This part sits on or just above the tunnel. Mine had bent inward a little and caused the lower (air direction) flap to not move through the full range. Not the issue you have , and sounds like you have enough travel on the upper flap.
HTH
Adrian

[TeeJay]

Graham.
Your situation, most probably, is one of minor adjustment or lever position on the flap.

I’ve taken more photos of mine which shows the position of the lever on the heater box, in both the Hot and Cold positions. You should be able to compare by sighting it against the Resistor Plate.

When I removed my Box, before disassembly, I marked my Lever position re the shaft on the flap, this was to ensure correct reassembly.

I noted on your photo 2nd from bottom, “Flap Open LHS End Stop” that the lever has not travelled fully, i.e. to the Lug. It may be that it does and it’s just that’s where you took the photo.
Also on the same photo, the outer cable is clapped slightly different to mine, see my first photo “Heater Cable” above.

My linear cable movement is almost 27mm, but the radial cable movement is greater.
It all adds up.

Hopefully you will solve your issue.

Cable at Cold

Cold Position

Cable at Hot

Hot Position

Cable Measurement

[gwiz22]

Hi Trevor

Many thanks for taking the time and effort to provide such detailed help for my issue. Your pictures are of great assistance particularly the ones showing the H/C lever. As you noticed my lever appeared to be in a lower position than yours. I took a number of photos at differing angles endeavouring to replicate yours. And sure enough it was at a different angle to yours. Interestingly, I refurbished the heater a few years ago and felt sure I taken care to make sure the lever fitted the same way as it was before taking it apart. But I guess not. So I removed the lever and move it round clockwise one spline. That gave me some more movement at the dash lever end but not fully hot to cold. I've trial fitted the dash and poked the cables as far up and under the dash that I can so the loop of the cables does not have and tight bends. However, the dash lever is still stiff. Now I understand your comment regarding turn the inner cable arouns 180 degrees I might give that a try and also maybe move the heater lever up another spline. Trial and error I guess. The only other thing I can think of is when I re-furbished the heater I replaced the foam on the flaps. Maybe I took the foam right to the edge of the flaps and maybe this is stopping the flap moving that last 2mm. I'll have to get out the pictures I took at the time, although I have no comparison as the original foam had completely disintegrated. I'll let you know how I get on. But thanks again.
Regards
Graham

[john.p.clegg]

Graham
Re. the heater flap arm ,the mid travel position should place the cable at 90 degrees to the arm?

John

[TeeJay]

Graham - John.

My mid position, is slightly higher than 90 degrees.

That's the position that resulted from setting it to achieve fully open and fully closed.
But others may get different settings, typically Lotus

Graham, to answer your other question. The foam I used was 3mm thick and fully covered the flaps.

Heater Box at Mid Position

[gwiz22]

Hi Trevor
I've tried various positions for the flap lever moving it one spine at a time but that doesn't seem to resolve the issue of the lever movement distance. It always seems to be 2.5cm. So it must be the flap. I looked up my old pictures and I also used 3mm foam and fitted it to the edges of both sides of the H/C flap (see Pics). Looking back at these old pictures it now looks to me that the foam should have stopped 2-3cm from the edge of the flap. I guess I wasn't paying attention at the time, maybe thinking that the foam would give a better seal that metal on metal. So I'm not taking the heater out again to trim the edges. I would do but I don't think I can get to the heater hoses without taking the cylinder head off. So it looks like I'll have to satisfy myself with a lever that doesn't go full travel on the dashboard. So a lot of time expended but understanding what is causing the problem the problem has some level of satisfaction.

Following your suggestion I removed the inner H/C cable and it curved in two directions (see pics). Also running it between my fingers I could feel slight kinks which weren't easily noticeable by the eye. so I eased the cable into one single curve that was the same contour as the outer cable and did my best to smooth out the kinks. I re-oiled it and installed it in the car and the movement of the dash lever is much easier now. So thanks for that.

Regarding plenum chamber drain holes, there are none. I felt all along the area you highlighted and also used a small mirror to look up at the area. So maybe that panel was replaced previously or by 1973 Lotus didn't bother to drill the holes.
Thanks again.
Graham

[TeeJay]

Graham
In spite of your frustrations, very understandable, I think you could resolve the problem.

First thing to check: - with the Hot-Cold cable removed from the box and flap, does the dash lever move all the way to the cold. It should.
If it does not then it’s a cable problem.

I don’t think it’s anything to do with your Box or foam on both sides of the flap.
I’ve gone back to my photos and I can the flap with foam on both sides, covering the full flap. The original on mine did have foam across the full flap. I note yours may be different.

BUT thinking about it, the foam will help, in that it will reduce the total amount of required cable travel, so that’s helpful.
You will not have to remove your box and you don’t even have to sort cable adjustment right now, as you can return to it. On my completed car, I only had to remove a panel to look at mine to try to help you, so easy access for the future.

So, if your dash lever did move fully to cold; with the cable removed from box and flap, then continue.

With your Hot – Cold cable removed at the box and flap.

Put some masking tape on the box in a position as I did. Move your flap to the fully cold and mark its position on the tape for reference.

Position the Dash lever to fully cold, adjust the top nut on the cable to the top of the thread and refit the cable onto the flap and box. The flap should move away from the fully closed position.

Wind the top nut down the thread until the lever has returned to the fully closed position and fit the bottom nut and tightens.

Return to dash levers and check fully open and closed positions, hopefully all OK.

Apologies if you covered all this previously and the detail involved, It’s just that others my find this useful if they have a similar problem.
I’ve resolved most of my issues by searching this forum, so I pleased to assist, where I can.

Box showing Hot Cold Flap