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Re: trying a new method

To: "1971MGB" <1971mgb@cox.net>, <mgs@autox.team.net>
Subject: Re: trying a new method
From: "Paul Hunt" <paul.hunt1@blueyonder.co.uk>
Date: Fri, 30 Sep 2005 19:02:33 +0100
Whether the charcoal canister was plugged or not, if it really *did* run
better in terms of performance and economy across the range, and not simply
with a higher idle speed which *will* be smoother than a lower idle speed,
then all it means is that the carbs are tuned to run with a bigger air leak
than the canister normally allows, i.e. it was running rich with the
canister connected.  Removing the oil filler cap will also make for a higher
idle than normal, even though if the carbs are correctly adjusted it will
result in a weaker mixture.  The higher idle results from a lower depression
in the inlet manifold due to the vacuum leak, which reduces pumping losses,
hence the higher idle.

However the canister or some hose or other probably *is* blocked, as the
restrictor in the rocker cover port should mean that there is negligible
negative pressure beyond it compared to what is present inside the crankcase
and rocker cover, so disconnecting it/them should make no difference.

Correct the blockages, then setup the carbs from scratch for air flow
balance and mixture.  And before that check the valve clearances, plug gaps,
points gap/dwell, and timing including vacuum and centrifugal advance
operation.  Replace plugs, points, plug leads, cap and rotor if any of them
are worn or tatty.

You will probably be pleasantly surprised at the results.

PaulH.

----- Original Message ----- 
> Here is what I did, I removed the charcoal filter and hoses, I have a
vented
> valve cover and un-vented oil filler cap. After removal of the items the
car's
> idle was smoother, what did I do right and what sort of problems am I
looking
> at down the road.




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