14 replies to this topic

[rom44]

Hello,
I have a British Open 1992 (low compression 1275) and I noticed that the vacuum pipe is missing on the dizzy. The vacuum nipple seems tapped on the carburetor. Is it normal? The engine runs fine (but I'm not experienced in Mini)
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 IMG_20190630_214723.jpg   42.95K   4 downloads

Also, no pipe on the thermostatic vacuum switch:
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Edited by rom44, 30 June 2019 - 07:51 PM.

[unburntfuelinthemorning]

You'll get better part throttle fuel economy with the vacuum advance operational.

[rom44]

You'll get better part throttle fuel economy with the vacuum advance operational.

Thanks. So I'll fix it but no blocking issue. I can still use it before?
Do you have picture or drawing where the pipe should run?

What about the thermostatic switch?

[unburntfuelinthemorning]

Yes it's fine to drive without vacuum advance.  When connected it just advances the ignition more at part throttle to compensate for a slower burning mixture. 

 

I'm not familiar with the thermostatic switch on your model.  It probably cuts out the vacuum advance under certain conditions for emissions purposes. 

 

I'd say connect the vacuum advance but don't worry about the switch.

[Ethel]

The thermo valve was mostly to control the emissions come fuel venting system, though it also acted on the vac advance. Since it has broken hose connections, just connect the carb direct to the distributor. 

[rom44]

OK, thank you for your help! I guess I will have to adjust the timing. I will buy a stroboscopic lamp.

[unburntfuelinthemorning]

You just need to connect the vacuum pipe however it is wise to check the ignition timing is adjusted correctly anyway.

[blacktulip]

You just need to connect the vacuum pipe however it is wise to check the ignition timing is adjusted correctly anyway.

Agree

[viz139]

On my brothers Open Classic we found it ran better cold when connected through the thermo switch.

If memory serves me right the carb goes to one side of the switch and the dizzy was T to the charcoal canister. 

[cal844]

On my brothers Open Classic we found it ran better cold when connected through the thermo switch.
If memory serves me right the carb goes to one side of the switch and the dizzy was T to the charcoal canister.

That's correct

[rom44]

Found that in the Rover manual:
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Edited by rom44, 02 July 2019 - 10:43 AM.

[unburntfuelinthemorning]

That's interesting how the ignition's retarded during warm up to increase the exhaust gas temperature and get the converter working sooner.  It's worth having it working properly for ignition retard and purge control as there's no real disadvantage to it and it helps keep the emissions down.

[cal844]

I removed the cat and the charcoal canister on my 94 sprite, it gained 2bhp and 5nm torque and also made the engine more responsive.

[unburntfuelinthemorning]

Ok.  There's no major disadvantage in keeping the ignition retard operational if you're keeping the cat and it's probably a good thing as the cat works sooner from cold however ditching the cat will of course reduce the exhaust back pressure and potentially give you more power as Cal says and in that scenario the ignition retard device is pointless.  The purge system is probably worth keeping if fitted though as it doesn't affect performance if it's operating correctly.

[cal844]

I agree with that statement ? my car needed a good Italian tune this year to get the emissions within Cat limits but it usually passes and runs very well indeed