Micky,
On the '72 you should get vacuum at the Retard unit on the distributor at
idle IF the engine is cold to warm. When the engine goes hi-temp the
thermal switch in the cooling line vents the vacuum source. Surprisingly
with everything installed mine actually does move the timing around properly
as the engine temp goes up and down.
I have looked at the vacuum at that point and been concerned about it being
only about 12 inches. Reading the other replies to your question makes me
want to check mine at the brake booster to see what it really is. The
explanation of the butterfly affecting the vacuum at the "retard" port on
the carb makes a lot of sense
Regards,
Steve
1972 TR6
tr6@kc4sw.com
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net]On
Behalf Of Lumia, John
Sent: Monday, August 18, 2003 9:45 AM
To: Mickylong@aol.com; 6pack
Subject: Re: Rough idle REDUX; status report
Micky, ISTR that the 72 uses a lower vacuum fitting that goes to a
thermoswitch and then on to the distributor vacuum advance. I cant be sure,
but you should get some kind of vacuum from this fitting. If not try a
higher
engine speeds. If you get nothing at all at any speed, then in all
likelihood
it could be plugged up. Later cars have a fitting on top of the rear carb
that is used for the EGR valve, but ISTR that this fittling doesnt noormally
produce much vacuum at idle. But if you are trying to check vacuum for
diagnosis putposes, the intake manifold is the most accurate. You probably
have a port coming off the intake manifold itself. On later cars there is a
fitting that supplies vacuum to the brake servo as well as a fitting to the
charcoal canister.
John - 1976 TR6
Micky wrote:>
Been following your troubles with interest since it seems like I have much
the same issue with my 72. I just checked spring length and found one at 5
1/2
and the other 5 3/4. Ordering new ones today to see if that can fix the
trouble. I also found on mine that I could not get ANY vacuum reading at
the
rear
carb port. Not sure what I'm dealing with there. Will be interested to see
if
the new springs fix the idle problem.
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