Mike:-
I'm having my morning cup of coffee here in Grapevine, TX at NAMGAR's
GT-22 and thought I would check my mail. By coincidence, yesterday we
had a tech session on machine work on the engine, and the speaker, Bob
Webber of SFD Engines in Dallas, told us that he no longer uses bronze
valve guides for _exhaust_ valves. Largely because the exhaust valve
just gets too hot and causes various problems, such as you describe.
Although he still installs bronze valves on the intake side, he says he
is also uses iron guides in many engines and is not sure whether the
advantage of the bronze guides are worth the potential troubles.
BTW, Bob did the machine work on my MGA engine 7 or 8 years ago and did a
fantastic job.
David Littlefield
Houston, TX
On Thu, 17 Jul 1997 17:22:38 -0400 Leckstein <bleckstein@monmouth.net>
writes:
>Over a year ago I reported the odd occurrence of my 54 TF "breaking
>up"
>while cruising along at 3800 rpm and taking on a very slight grade on
>the
>interstate. If I pushed in the clutch and let the rpms drop for a
>second
>the car recovered. The engine never died or coughed, and the engine
>would
>rev with the clutch in but would not recover unless it rested for a
>second
>or two . I could get through this without much loss of speed, but it
>was
>annoying.
>
>In other situations, or around town, the car ran great. In fact I
>usually
>forgot about the problem until I would go on a GOF, and drive for
>some
>time on the interstates to get there. Last month I drove from N.J. to
>Boston for the NEMGTR GOF and it drove me crazy.
>
>I have done the following.
>rebuilt the carbs, changed the needle and seats, floats, jets and
>needles.
>
>changed the fuel pump, blew the lines, changed the tank screen
>
>changed the coil, points condenser and plugs.
>
>It was even suggested that the air cleaners were clogged, so I tried
>driving without them. I also checked that the carb overflows were
>clear.
>Nothing helped.
>
>I bit the bullet and removed the head which was done three years ago
>to
>replace a burned valve and I when I had installed bronze valve guides
>with
>stellate valves so as to run un leaded. The problem was with the
>guides
>which apparently oxidized, would heat up and then move within the
>valve
>guide bore.
>
>Redid the head with old fashioned guides, stellate valves, and the
>problem
>is gone.
>
>Anyone else with bronze valve guide problems?
>
>Mike Leckstein
>
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