Vance,
Distributor cap and\or rotor damaged or dirty.
Gary
'73
----- Original Message -----
From: "Navarrette, Vance" <vance.navarrette@intel.com>
To: "6 Pack list" <6pack@autox.team.net>; "Triumph List"
<triumphs@autox.team.net>
Sent: Monday, July 09, 2007 10:12 AM
Subject: [6pack] Colicky TR6. Prize for correct diagnosis.
> Listers:
>
> Just thought I would share my recent frustrations fixing a low
> speed miss.
>
> Since I brought the 6 out of storage, it has been very colicky.
> At first I thought perhaps bad gas, then I thought it was just bitter
> about not being driven all winter. Hey, don't laugh, I am sure you would
> all swear your TR6 has its moods.
> The symptom was a low speed miss when pulling away from a stop.
> Sometimes it would miss once, sometimes it would miss twice, sometimes
> no miss. This is not a bog, but a soft pop and the car will jerk
> sharply. Adjusting the choke made no difference, and the problem would
> occur when both warm or cold, although the problem got somewhat worse as
> the car warmed up. The engine would rev just fine with no breakup or
> missing at the upper RPMS. Battery voltage was about 14 volts,
> temperature in the middle of the gauge, healthy oil pressure. Stock
> ignition (Lucas coil and points, no Pertronix). No blue smoke, no white
> smoke at idle or any other time.
> My TR6 has a 270 degree cam, 9.6:1 CR, stock exhaust, dual
> zeniths with B1AR needles. Carbs have been rebuilt, compression in all 6
> cylinders is 145PSI +/- 5 PSI. K&N air cleaners in a stock filter
> housing. Manifold heat is connected. 1974-1/2 car with EGR and all
> emissions systems connected. Stock rockers, valve lash set at 0.015",
> idle at 900 RPM - with what sounds like a very *slight* miss at idle. <-
> another clue!!
> OK, those are the symptoms. Here are some additional clues so
> that you hairy chested LBC drivers can test your diagnostic acumen. I
> say this because I always love a challenge, and I might as well torment
> you all in the name of camaraderie. =:-o
>
> Here are some additional clues:
>
> 1. Fresh plugs made no difference (Champion 12NY).
> 2. Adjusting the mixture rich or lean made no difference.
> 3. Fresh gas made no difference.
> 4. New plug wires made no difference.
> 5. Checked the timing, spot on at 4 ATDC dynamic. No observable
> spark scatter when revved.
> 6. Wider or narrower plug gaps made no difference (+/- 0.005").
> 7. Vacuum retard functioning correctly.
> 8. Topped off the dashpots with penrite oil, still no
> difference.
>
> OK, listers. Do you think you know what I missed? Can you offer
> a shrewd insight (or a least a derogatory comment) as to my utter
> failure as an LBC mechanic? I know the answer, as the miss was resolved
> just this weekend.
>
> I am offering a prize for the correct diagnosis. The winner will
> receive one "attaboy", redeemable with $2.00 for a cup of Starbucks
> coffee and the glory of having his or her kung fu publicly acknowledged
> as the best.
>
> Post your guess to the list, Kastner wannabes!
>
> Vance
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