Hello Alpiners:
Here's an update on my "backfire" through the Strombergs when
accelerating. Thanks to all of you who offered suggestions. In following
them, I checked the timing, thought it may be a bit too advanced, so I
backed it off a bit. No good. The car still "burped" under a load. I
checked the ignition wires, the wiring to my electronic ignition, coil
ground, etc., and all seems attached properly. I checked manifold vacuum
and it seems normal, 14-15 lbs. at idle (just a slight variation), and
20+ lbs when the engine is reved up (after the prescribed quick drop as
you hit the pedal), and absolutely steady with no variation.
Next step, this morning I re-checked and re-set valve adjustment.
Whatever the heck I did, it seems to have worked as the car no longer
backfires through the carbs. One of the intake valves was considerably
tighter than the others (although not totally tight) and a couple of the
exhaust valves were considerably looser than recommended. I did a quick
readjustment of the offending valves and the problem seems to be cured.
No more hiccups or hesitation. I did notice that the car didn't seem to
rev up as readily as I'd like. Tonight, on the way home from work, I
remembered setting back the timing yesterday. Re-advancing it a bit
brought my mighty and brutal 100+ horsepower Alpine beast back to life,
and it again reved all the way up to 75MPH on the freeway very willingly
(not that I would ever break the speed limit).
All the valves are set a bit looser than the book calls for, which seems
to be the ticket. My engine has been rebuilt with .60 over pistons and a
little more agressive cam, so I wonder if this requires a bit wider
valve gap to function well. In any event, I don't know that it's even
logical that this latest adjustment would cure the problem, but it did.
Here's a question relating to this. I'm not sure I'm even adjusting the
valves correctly. The shop manual says, for example, to adjust one valve
while the required other valve is "fully open". If you follow this
exactly, the valve you are adjusting is NOT fully open. To get it fully
open, I must "tweak" the starter a little, at which point the
corresponding valve, which is supposed to be fully open, has closed a
bit. In other words, if you follow the book, the valve you are adjusting
is NOT in its fully open position. Does this make sense? I hope so.
What's the opinion out there on this?
By the way, I got a rare chance to test out all the Alpine's weather
equipment today as we had some rain here in Southern California.
Everything works, the heater puts out plenty of heat, the defroster
actually works (as best it will), the wipers did their thing, and not a
drop of water leaks into the car (until you open the door) under a heavy
downpour. Just the way the factory designed it to work!
Regards,
Steve Sage
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