Hello Everyone:
I need some Alpine advice for my '67 Series V. I had my 1725 engine
rebuilt a few months ago and it has been quite "zippy" until recently,
the only problem was that I couldn't get it to idle smoothly below 1200
RPM.. I started having problems starting it when cold, and got a couple
of backfires through the Strombergs. I went step by step through things.
I synched the carbs. Set the mixture. Tightened the carbs to the
manifold and the manifold to the engine. All were a bit loose. Checked
for intake/carb leaks by spraying carb cleaner in various places.
Everything seems OK. I checked the plug wires...all seem to be OK.
Installed new plugs. I've noticed that the back Stromberg, when you lift
the air piston, does not seem to affect (stall out) things nearly as
much as lifting the front piston. Finally, I adjusted the valves. In
checking them with the motor dead cold, I could not get a .006 feeler
between any of them. All the valves were very tight. They had "tightened
up" like this in just about 2000 miles since an adjustment after the
rebuild. This doesn't seem normal. I set the valves, again while cold,
to .008 for the intakes and .10 for the exhaust. (and actually, a bit
looser than that), as I've been advised to do by the mechanic who
rebuilt my engine. The difference in the idle is dramatic. It can idle
smmothly now at 8-900 RPM. It starts right away now. However, the valves
are definitely pretty noisy now, and acceleration is definitely off of
what it was before I started having the starting problem. Also, it's
still doing the following, which it also did before the valve
adjustment: On starting up cold, and a lesser extent warm, it seems like
it's only firing on 2 or 3 cylinders, not all 4. Then, all of a sudden,
it smooths out and it's fine after that. This only happens on starting
the engine.
I wonder if I've got the valves set too loose now (would this cause
sluggish acceleration?) and should instead only adjust them when "very
hot" as the shop manual advises. What are the performance results, if
any, of valves being on the looser or the tighter side? Could that start
up "stumble" be a bad PCV valve? What's going on with that Stromberg air
piston? Finally, no matter what I do, the same "back" Stromberg throttle
bar, on letting off the gas pedal, will not "seat" completely to the
idle position unless I manually push the screw to the base with a
screwdriver or whatever.. I notice there's a return spring on each carb,
but is there any way to replace or bend these out without dismantling
the carbs?
Thanks in advance for any help in solving all my current problems. I'm
sure I'll have more in the future!!
Steve Sage
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