After putting putting six hundred miles on my revived TR-3A and doing a
lot of weekend restoration, I had regained enough presence of mind (after
two decades not working on cars) to realize it needed a tune up. Both
mechanics who worked on the car overlooked this issue.
When I checked into the situation, I found:
1. Potentially dangerously and mismatched spark plugs installed by first
mechanic (three BP6ES and one B6ES) (see Nick's post, appended below).
2. Plugs little more than finger tight.
3. Valve clearances between .004 and .0095 inches (left over from the car's
first incarnation 30 years ago).
4. Points set at .009 rather than .015 inches (second mechanic didn't check
this after replacing vacuum advance on distributor).
I've had a serious overheating problem when the car is idling. Perhaps
some of these screw ups are partially responsible.
I'm in the process of sorting all this out and will eventually report
results.
John
Portion of Nick's post:
The correct NGK for your car should be BP6HS. The BP6ES plugs have a longer
threaded area and are basically, just not remotely right for your car.
Luckily the TR head is far enough away from the piston that physical
interference is not a problem. However, the end of
the plug is now closer to the piston and the fact that the "hot" end of the
plug can not cool itself (not touching the head), could lead to some
serious heat related melting of the piston. Additionally, the threads that
are exposed will become caked with carbon deposits which while making it
very difficult to remove them, can also tear the threads in the head up
badly when they do come out. Hopefully you have not damaged anything, but I
would look into the plug hole with a good bore light, or the like, and
check the top of the pistons, especially number 3 (it runs the hottest).
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