Dear Bud and anyone else interested,
After 15 years of owning my 1973 TR6, I have never had a problem starting the
car, in fact I would go so far as to say that the car was very reliable and I
was never afraid to drive her on any trips.
This year, after a new paint job (Mallard Blue) and attending my first season
of car shows, I decided to spend time cleaning the engine compartment,
renewing the engine to it's original clean state. When removing the carbs top
covers for polishing, I discovered a large tear in one air valve diaphragm.
This made me commit to the dreaded CARB REBUILD. After rebuilding with TRF
gasket kit and installing Grose jets and following the limited info that came
with the kit, I couldn't get the car started. The plugs were getting wet (mix
to rich). Even with the needles adjusted all the way down into the orifices
(the leanest setting), I still have was getting wet plugs and the only way I
could start the car was to floor the gas pedal and leave the choke all the way
in.
A fellow lister, Adrian from Canada, helped me out by suggesting various
things to check on my carbs. He even mailed me some carb info which gives very
detailed info on my ZS carbs. (Thanks again Adrian)
It seems that after dismantling the choke and adjusting the small screw (7
turns out) in the small diaphragm on the cold start valve might have helped. I
still think my mix is rich, but it probably always was. I can start the car
every time now :)
My new problem is very low oil pressure after reaching operating temperature.
At cold start, I get 60 psi, when warmed up, I get near 0 psi. Even when I rev
the engine, the oil pressure does not rise like it use to? I think all the raw
gas that has been going into the cylinders after the carb rebuild has
contaminated my oil in the base and from what I here, this makes the oil to
thin to pump and thus, gives a low oil pressure reading.
Is this true?
I have drained the oil and dropped the oil pan. The oil pan hasn't been off
the car in the 15 years I've owned the car. In the bottom of the oil pan,
under all the very black oil, was a thick gray colored muck, I think this is
worn steel powder that has settled over the years.
I pulled the oil pump off and cleaned and measured, the allowable clearance
between mating parts is max. .010", I had between .006" and .008" but I
noticed small scratches on all the outer services of the middle gear on the
oil pump. How much affect do these scratches have on oil pressure using 20-50
castrol oil?
I think I will put everything back together and add fresh oil and filter and
see if I get my oil pressure back to the 70 cold and 20 hot readings that I
use to have before the gas contamination.
Wayne from Massachusetts
1973 TR6
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