David wrote,
>Am I missing something?
Yes, see below -
>(Valves? - I haven't touched them yet.)
Valves should be your starting point, followed by the ignition, followed by the
carbs.
Offhand, it sounds like your timing is too late. B engines _really_ respond to
changes in timing, this can dive you crazy in short order. Set your timing to
where the engine doesn't ping, THEN set the idle speed.
In my experience (ok, one MGB does not an expert make, but as Keeper of the
Records of the Concours D'Exhaust, and an interested spectator of the Silly Car
Wars, AND a darned wordy kind of guy,...)
The ONLY way to tune an MGB is to start with the valves, even if you "just
did them last week". I've gone around and around on this one, and it seems
strange, but my drill has become:
1. Set Valve clearances (a LOT depends on this being right. I think stock is
.015 cold, but my Delta D-9 cam says .018 cold. Make sure you set them when
cold.)
2a. Take distributor out. Check operation of vacuum advance. Make sure
Mechanical advance is free. Check points gap. Check points gap while sucking on
vacuum advance so that points plate is pulled around to other end of travel.
Note difference in points gaps. Gripe about unavailability of base plates.
Release vacuum advance, and recheck points gap at rest. I shoot for a middle
ground, mine is a loose .014 at rest, and a tight .016 at full vacuum advance.
Darn, I just remembered you have electronic ignition. Well, any comments from
the SOL on my procedure?
2b. Replace distributor and check static timing. After a year of attempting to
do this by "ear", I broke down and got a light. B engines have too broad a
range of timing that they will run fairly well at, but the optimum setting is
near impossible to set/reset/find, particularly by listening to the idle speed.
Do the trial/error routine: set timing, drive car. listen for pinging on
acceleration. Keep advancing timing until you hear faint pinging, then back it
off a degree or two (or three to be safe). Then, make a mark somewhere ofn the
distributor mount so that you can easily reset the timing later on.
4. Then look at the carb. I've got a Weber, and don't remember the drill for
setting them. (Webers are _way_ easier, and you get an accelerator pump -
instant response! 8^))
Hope this helps,
James "I like points ignitions" B.
'71 MGB
'71 LeSabre
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