>
> Here's the puzzle... My car has always had a rough idle. The reason
> for this is that it's not firing on all 6 at idle. It's erratic, and
> the problem goes away on the road. It runs great on the road... My
> distributor shaft has a bit of a wobble in it, so I figured that the
> points didn't have the opportunity to open all the time. This must be
> the source of my bad idle right!?!? Humm... I decided to replace the
> points with the electronic ignition system... A few weeks ago,
> Lawrence Buja and I installed the sucker on the TR. I removed all the
> plugs and set the engine at 4degrees past TDC to set the timing with
> the new module. That went easy, and upon starting the car, it settled
Ummm, that's a problem, unless you went back and reset the timing dynamicly.
That era TR6 static times (what you did) at something like 8 or 10 degrees
BEFORE tdc. The 4 after number is for dynamic checking, which is done at
standard idle, with the vacuum retard can kicked full in. Note that the same
problem can happen when setting timing dynamicly if the vacuum retard is
inoperative. If in doubt, pull all the vacuum hoses off the distributor, and
then dynamic time to 10 before (or so).
> reassembled the engine, (several years ago now) I'm not sure I had the
> cam exactly in time with the low end. BUT, I used exact marks and
> think I got it right. However, this is a new grind on the cam, A
> chambers BL2 grind (similar to the PI cam) so things are a bit
> different now.
Each and every Truimph pushrod engine was hand timed at the factory. Those
"timing dimples" on the sprockets were hand punched after everything was
assembled, and they only apply to that particular group of parts. Change
anything, especially the cam, and you really need to retime. Rather than
design for tight production tolorances, Truimph made the cam gear degree-able
by putting two sets of bolt holes, and making it flat so it's reversable.
In reality, the tolorances are good enough that dropping a new cam in using
the old marks will run. But it's pot luck on how well it runs.
>
> I'm guessing I have a timing problem. My next step is to remove the
> plugs, find TDC by watching the number one piston come up (using a
> screw driver through the sparkplug hole) and see if the timing marks
> are correct. The valves should be in their right positions, me hopes.
> Anyone got tips on how to do this? Any good fixes other than pulling
> the timing cover if this is my problem? Any other ideas on why the
> car ran so GREAT for 5 minutes once?
>
One idea. Have you checked the distributor phasing? This has been a real nasty
problem since Lucas quit making the *wide* armed 6cyl rotor. What happens is
in certain positions of the vacuum retard (full on or full off), the rotor
is pointing near, but not at, the dist. cap lug. Having to jump a 50 thou
air gap, before even getting into the plug wire, does not help the spark
quality on bit.
Checking it is a lot like static timing. Put a mark on the distributor body
exactly below the number one wire, and remove the cap. Turn the engine around
by hand to the point #1 is firing (watching points or breaker ring). At this
point, the rotor should be pointing (covering) your mark on the body. Now,
use a vacuum pump to pull the retard can in fully. Turn the engine until
#1 is firing, and make sure the rotor is still lining up. If yours also
has an advance can, pull that one down and check the alignment.
If you find the phasing off, you correct it by moving the points/pickup
in relation to the dist. body. Normally on a TR6, the easiest way is to
remove the rollpin holding the retard can, move the can in or out until
joy is achieved, then drill a new hole and knock the rollpin back in.
> Cheers!
>
> -Scotty
>
Randy
randy@taylor.wyvern.com
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