Idle adjustment knob

[mleadbeater]

Hi, 

as my ‘6 doesn’t have the original throttle linkage, I am unable to set a fast idle during warm up.

To solve this I have fitted a valve connected to the air slow running valve, with a cable on the dash to allow me to set the idle speed from the drivers seat as the engine warms up.

The valve is a heater control valve, which works well to control the air intake.

Maybe of interest,

Mike

[Waldi]

Now that is a smart idea Mike.

Waldi

[PodOne]

Hi Mike

A sneaky solution like it - an adjustable air choke. Likely easier to set the fast idle than the current mechanical set up with all its potential for wear/play in the linkages. So does this replace the air bleed screw ie is it full open to allow base idle to be set as well with the heater valve. 

Any more pics and what heater valve have you used?

Andy

 

[Andy Moltu]

Looks like a Reg Bowler linkage.

He borrowed my Revington linkage and re-engineered it to make it less floppy. I never fitted the fast idle mechanism when I put the linkage on originally so wasn't there to copy

Personally I use my right foot to control the idle speed when on choke.

[mleadbeater]

Thanks, I was hoping to make it operate electrically, but couldn’t find a large enough solenoid valve suitable for low vacuum, but the cable operation gives good control and works fine.

The valve is just a standard water heater valve, from ebay, see photo, you also need a solid inner cable for full push/pull control .

heres the ebay link: 19mm (3/4") Heater Control Valve Push to Close Taxi TX1,Kit Car, Classic Car

I've set the existing air valve to well open, having set the butterflies  for even airflow using the throttle linkage arms, giving from around 1200 rpm open to 800 fully closed.

Next challenge is  to sort a “bog-off” system to improve idle pickup, needs some sort of valve to control the metering unit vacuum supply, tried the idea manually by releasing the vacuum as the throttle is opened which seemed to improve pickup. I may need to master the Arduino , that’s another challenge.

All part of the  fun of old “ pre-electronic “ cars, happy days…. yes?

Mike

[Mk2 Chopper]

I like the idea, very clever. 

Is it possible to link this to a single cable/control for ease of use, enriching the MU while increasing revs at the same time?

Gareth

[mleadbeater]

Gareth,

the original system on PI cars has a cable which splits into  two, one to the metering unit, the other to the idle cam, which both enriched the fuel and opens the throttle, so if you have an original system this does as you ask.

My car with modified throttle linkage only had the enrichment cable, which is why I did this mod.

You may need to adjust your throttle cam setting screw to get a faster idle, this should be in your manual.

I still have the original split cable, but the throttle part is defunct, and not a solid wire so it won’t push the valve closed, I would need a return spring, which I didn’t want.

Hope this answers your question.

Mike

[Mk2 Chopper]

Hi Mike, 

Yes my set up is still the original split cable, I was just wondering if you could incorporate a single knob to your modified one for ease of use.

Gareth

[jerrytr5]

"I was hoping to make it operate electrically, but couldn’t find a large enough solenoid valve suitable for low vacuum"

I did something similar using a washing machine water valve(12v) to control fast idle.

Jerry

[mleadbeater]

Sorry Gareth, I still can’t fully understand your question, the original split cable wont push the new valve closed, a spring to do so would be required, but the double cable would work, but with out independent control of either mixture or idle.

Jerry, I bought a water valve for washers etc, its a diaphragm operation so it won’t work under negative pressure, unless I'm missing something?

 

cheers

Mike

[jerrytr5]

Mine is just a solenoid on/off valve with 12mm pipe connections probably off ebay. I hid it inside an old coil with the internals removed.

Jerry

[StuartG]

I fitted the Fred Miltern Twin to Single Choke Cable Conversion Kit - 

https://www.fredmillturnparts.com/products/choke-and-throttle-cables

This is very well made (especially when compared to the rather nasty twin cable things sold by the usual suspects) and works very well.

 

 

 

[Jonny TR6]

On 4/17/2024 at 11:08 AM, StuartG said:

I fitted the Fred Miltern Twin to Single Choke Cable Conversion Kit - 

https://www.fredmillturnparts.com/products/choke-and-throttle-cables

This is very well made (especially when compared to the rather nasty twin cable things sold by the usual suspects) and works very well.

 

 

 

Likewise - I spent ages faffing around with my underslung “shall rename nameless” rose jointed adjustable linkage and couldn’t get an idle below 1200 rpm. The Fred Millturn ball bearing linkage with original style adjusting rods and the choke mod worked a treat, so it’ll sit there at pretty much anything over 650 rpm, albeit a bit lumpy at the lower revs.