Shop B is populated by idiots, and should be avoided. I completely agree
with Jeff. Shop B wouldn't be Motorhead would it? Sounds like them.
Vacuum advance and retard units are designed with various configurations for
either manifold vacuum or port (venturi) vacuum. There is nothing on the
vacuum cans to indicate which they are to be connected to. When swapping
distributors around, you can make your life very interesting as connecting
to the wrong port leads to remarkably wrong ignition timing under various
running conditions.
While vacuum advance can have some running benefits, vacuum retard does not.
So blocking off vacuum retard and not using it is a very good practice,
especially for performance. I also very much agree with Jeff on using the
10 DBTDC as a starting point.
----- Original Message -----
From: <thenicholls@verizon.net>
To: <triumphs@autox.team.net>
Sent: Thursday, December 20, 2007 10:03 AM
Subject: [TR] Tuning after rebuilt dizzy from Advanced Dist.
> Listers, sorry this is a long post (and I have read previous posts before
> asking) regarding my 1972 Triumph TR6.
>
> My car had Petronix ignition installed by British car shop "A". When they
> did it, they plugged off the retard unit at the dizzy and carb and
> statically timed the car.
>
> Last winter, I had my carbs rebuilt by Jeff at Paltech (thanks #1 to the
> list for this project). He returned them to me, I installed them and then
> took car to get dialed in to British car shop "B". They said that the
> retard should be connected and then ran the vacuum from the dizzy to
> straight under the carbs. At this point, I had no thermostatic switch in
> the radiator hose because it did not work, I never have an overheating
> problem, so I removed it. They tuned the car to 6 deg BTDC with vacuum
> plugged and 4 deg ATDC with vacuum connected and it ran great. At that
> time, they told me that the carbs were totally leaned out and that they
> wanted to tear them apart. I contacted Jeff and he advised me he had some
> dealings with British car shop "B" and I should not let them tear the
> carbs apart.
>
> This winter I sent my dizzy for rebuild to Jeff at Advanced Distributors
> (thanks #2 to the list for this project). He rebuilt the dizzy and I
> installed this week. I currently have the dizzy vacuum retard connected
> to the carb.
>
> Just got off the phone with Dave at TRF regarding a part I was ordering,
> and I asked him about this situation. He stated to me that the unit on my
> dizzy is a RETARD not an ADVANCE. He is saying I should rubber plug the
> retard unit at the dizzy and at the carbs and retune.
>
> So, my question to the list is are people connecting the retard straight
> to the carbs and using it? Or, should I plug both the dizzy and carbs and
> set my timing to a static 10 deg BTDC (which Jeff at AD just recommended
> as a starting point).
>
> Any advice is appreciated! Happly holidays to all!
_______________________________________________
Support Team.Net http://www.team.net/donate.html
This list supported in part by the Vintage Triumph Register
http://www.vtr.org
Triumphs@autox.team.net
http://autox.team.net/mailman/listinfo/triumphs
http://www.team.net/archive
|