Philip E. Barnes writes:
>Since the car is now on the road, one of the things that needs attention is
>the speedo. It "hunts" back and forth, sometimes with wild oscillations,
>and does not register a steady speed. I imagine that the grease or whatever
Almost certainly the cable. I'd just bite the bullet and replace it.
I replaced the cable on my TR6 tach, and boy did it improve, even though the
old one felt ok rotating it by hand. Rock solid now.
Philip E. Barnes also writes:
>In the course of re-assembling the TR6 I had the pleasure of installing a
>new main harness. I found that the harness I got from TRF, while identical
>to the one I removed, did not match the schematic in the Bentley manual for
>a 1971 model. The car was built in late 1970 and tagged for January 1971.
>It was more accurate to follow the diagram for the later (1972-1974)
>models. My car has the key buzzer as well as a horn relay, which are not
>shown for a 1971 model. I am quite sure that the DPO's never went to the
>bother of updating the electrics in this car. Any comments?
My March '70 also has the buzzer and horn relay (which had died due to
apparent water damage; replaced with a cheap one from Pep Boys - far cheaper
than the correct part). My buzzer is long-disconnected. There are other
things that don't quite match the diagrams.
Use the diagrams as a guide, and chose whichever one seems to fit the
car (at least for the part of the harness you're playing with).
TJ Noto writes:
>But Kelley's TR6 has be thoroughly dumbfounded....the car does not really seem
>to care WHERE you put the spark...it's not going to ping. I recently disabled
Later TR6's were pretty low compression - less than 8:1 (7.75?). On
premium, they aren't likely to ping at any advance. The earlier 6's had 8.5
or 8.75:1 (I forget), which still isn't that high - 89 (modern) octane would
probably be ok, certainly 92-94 (current UL premium). 87 (UL regular) might
be iffy, though.
Time for best acceleration, rolling start, say 1500 to 4000 RPM in 3rd,
with no pinging.
>the vacuum retard because it was irritating when coming to
>stoplights....previous
>to that I'd set it according to the Bentley manual, 4 degrees ATDC with the
>engine
>running (dynamically) timing light on, and the vacuum retard disconnected.
I think 4ADTC is with vacuum _enabled_. In fact, it has to be if the
static timing is 10-12 BDTC. My retard was annoying at stoplights because the
ignition was too retarded. I advanced until it didn't mind stoplights.
>Acting on the wisdom of the list I disabled the vacuum retard and then set the
>spark
>static (turn engine to #1 cyl, timing mark 12 BTDC and rotate distributor till
>it just
>fires) at 12 BTDC. This is supposedly the correct timing for the 70 model
>year.
>
>The car runs just fine....but when I put the timing light on it, it's firing
>even
>earlier (in fact it's off the scale)...I'd suspect somewhere around 18 to 20
>degrees
>BTDC.
This means you're idling high enough that you're on the centrifugal
advance, and dynamic timing can't be done. Probably various vacuum leaks and/
or carb adjustments and/or leaky throttle shafts.
>Am I needlessly worrying about this? Probably....
Yes. Set to 10-12 BTDC and ignore, or use acceleration tests.
Calvin E. Hilton, Jr. writes:
>My friend has a '76 TR-6 and he changed the Zenith's to 1 3/4 SU carbs.
>My question is what the timing should be set at.
The same as normal. If you care, do the acceleration tests, and
back off a couple degrees if it pings (unlikely).
--
Randell Jesup, Scala US R&D, Ex-Commodore-Amiga Engineer class of '94
Randell.Jesup@scala.com
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