Listers:
I need the advice of the collective wisdom. I looked at a gorgeous '74 TR6
today, and I'm considering making an offer after I take it for a test drive
later in the week. The owner seemed quite honest about the car- he's owned
it 20 + years. He stated that he hasn't used the car much in the past 3
years and really doesn't have the time for it due to kids, house, etc.
He had the car set up with the dual down draft webers and tubular exhaust
header with a dual exhaust system. The car also has a lummenition (sp?)
electronic ignition. The car started right up from cold, no smoke, sounded
nice and idled smoothly.
Cut to the chase- the owner stated he had a slight backfire upon
downshifting. He said that his mechanic had explained that the Weber setup
and the freeflowing exhaust had caused the mixture to go lean, burning the
exhaust valve on the #1. This, he was told was the source of his backfire.
So, my questions are-
1.) How does one diagnose a burnt exhaust valve without taking the head off.
This guys mechanic didn't, so I wondering if this is the source of the
problem.
2.) Having no experience with the Weber carbs, could this be the source of
the trouble? Any of you guys running these carbs have problems with the
weber downdraft setup? Do they tend to backfire out the exhaust or through
the carb?
3.) Could the electronic ignition be the source? How would a sticky or non
functioning vacuum advance impact this type of ignition?
Hopefully, by Friday I'll be armed with enough info to make an informed
decision after the test drive. Thanks in advance!
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