Hi,

Does anyone have a good pic of a police pack Cooper S engine bay with the CCV setup on twin HS4 SU's, as apposed to the PCV setup found on most Cooper S?

Thanks
Fred

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66 MK 1 Cooper S
64 Grp N Cooper S
64 Grp N Cooper S (ex Bob Asher)
64 GRP N Cooper S (ex Fred Burley)

Here is a photo from Doug's car. Notice the plastic Y piece sits over to one side.



And another one.

Excuse all the dirt, grease and grime in my engine bay (pic above). That's how it looked after 20 years sitting doing nothing.

A few more examples of CCV below.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

Thanks Doug. I was just getting my engine bay photos uploaded on photobucket and you have saved me the trouble.

Here is another 1971 car.

BIG Thanks to the "brains trust",

This is what the forum is really about

go the blues!!!!!

_________________
66 MK 1 Cooper S
64 Grp N Cooper S
64 Grp N Cooper S (ex Bob Asher)
64 GRP N Cooper S (ex Fred Burley)

looks like a couple of restorers weren't sure which way to put the Y...

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did I tell you that I won a trophy?

For what it's worth…
When I bought my ex-police S in 1975 with the CCV system fitted, I found it hard to tune the carbs with worn spindle shafts in the carbs (air leaking in) and excess blow-by through the CCV, especially at idle because vacuum was greatest and the blow-by fumes went directly to the engine and interfered with the carb mixture settings.
I replaced the CCV with a PCV so the engine only sucks blow-by gasses when running above idle and can be better tuned.
This might not be a problem with new motors but made a big difference on a worn motor.

Does this type of CCV have a non vented oil filler cap or a vented? I would have thought a non vented.
Cheers

what do credit card CCV's and carbs have to do with each other?

Mine is vented.


The cakes and soft drinks you buy with your credit card can affect your carb (carbohydrate) intake.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

I think if you have a vented oil filler cap you will have trouble tuning your carbs as you are dragging excess air through your carbs.

This page from the BMC Engine Emission Controls publication AKD4957 explains how the CCV works, including the reason for the vented oil filler cap.

I can post the equivalent page for PCV if anyone's interested. PCV also requires a vented cap.

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

Thanks winnaby,

Kath, ports for ccv are behind the throttle disc so not under vacuum, and should not affect your tune (that much )

_________________
66 MK 1 Cooper S
64 Grp N Cooper S
64 Grp N Cooper S (ex Bob Asher)
64 GRP N Cooper S (ex Fred Burley)

I still think the CCV system used on police spec Ss is a poor setup as it allows excessive blow-by gasses to be fed into the "controlled depression chamber" (as per winabbey's diagram) which IS under vacuum from the motor. The breather pipes add blow-by into the carbs just before the butterflies.
Fresh air has already passed over the venturi and mixed with fuel from the jet - then it gets an extra load of blow-by contaminants before going into the cylinders.
Even the Mini K CCV setup put the blow-by gasses into the air filter to be diluted by fresh air.
This contamination is worst at idle because the blow-by makes up a larger % of the air/fuel mix to the cylinders; above idle, the contamination is less.

Bill, I think you are right.
I was thinking more of manifold vacuum and failed to consider the small amount of vacuum needed in the SU itself to lift the piston and needle. Clearly, if you have a motor that is breathing heavily that would pose a problem in that area as it would be negating that vacuum effect and weakening your mixture. The problem would only compound itself if you had wear in your throttle shaft bushes
I wonder if there would be any merit/effect in joining those two ccv ports to equal the vacuum across the two carbies, like the balance pipe does in the manifold??

_________________
66 MK 1 Cooper S
64 Grp N Cooper S
64 Grp N Cooper S (ex Bob Asher)
64 GRP N Cooper S (ex Fred Burley)