>'66 MGB questions:
>
>1) Haynes lists 14 and 12 degrees depending on if I have high compression or
>low compression... how do I know that?
>
>2) Is there some secret to getting the distibutor to turn? I loosened the
>bolt that hold it tight but it wouldn't budge and finally got hot that I
>couldn't tough it.
>
>3) Haynes says to time at 600 rpm but I couldn't get it lower than 750, is
>that a problem
>
>Also, in general what does a high setting do? Better performance? Better
>Gas Mileage? Better anything?
>
>Also (again) the reason I am adjusting the timing is that the car is slugish
>under hard acceleration... in the higher rpms it tends to give little
>backfires. Normal driving seems fine, but when I hit the pedal to speed up
>the car some times slows down... not a good thing <g>
>
>I check the spark plugs and they had a slight carbon build up and I am going
>to tune the carbs after the timing, but I thought I should set the timing
>first. Right now the timing is at about 11 degrees. I was going to set the
>timing statically but I couldn't find a socket big enough to turn the engine
>over <g>
>
>Thanks for any help,
>Ross
>+-----------------------------+
>+ Ross A. Goldberg (aka Loki) +
>+-----------------------------+
>
>
Ross,
1:
It is very likely you have a high compression engine on a 66 B. The way to
tell is by the engine number. It should be something like 18GB-U-H/some
number. The 18GB is the series of engine (all 65-67 should be GB unless the
engine has been replaced; there were also 18G, 18GA, 18GF, 18GH, 18GL,
18GK, and 18V for different series and years (I hope that's all of them)).
The next letter can be U, R, RC, or RWC. I am not sure exactly what this
all means, but the U is Center gear change, the R is overdrive, the RC is
automatic, and the RWC is center gear change with overdrive.
The next letter is H or L. H is for high compression, and L is for low
compression. Hope this clears up the specification of your engine.
2:
This may not be easy. If your distributor hasn't moved for a while, you may
want try to make your adjustments with the verneer adjuster on the vacuum
advance. You can't adjust very far that way though. If you have a big pair
of channel locks, you can try that, but it is hard to get to the distributor
with them. You can also spray it up good with WD-40, and hit it a couple
times with a hammer.
3:
In general, every book will say don't set the carbs until the timing is
correct, and in the timing section it says don't set the timing until you
get the idle down to the right speed. This is important, as the idle speed
can make some centrifugal weights in the distributor change your timing.
I'd say spend a nice afternoon playing with both, and if you can, get a
stroboscopic tachometer, or an engine analyzer that can give you a better
rpm reading than your gauge.
I'm not sure what you mean by a high setting (over advanced, or over
retarded timing), but they have effects on acceleration, top speed, and fuel
mileage. You should get about 26 mpg if you are set correctly, and do a lot
of highway driving. Any deviation from the proper setting may have pleasant
short term effects, but is not good for your engine.
You should be able to turn the engine by appropriately pulling on the fan
belt, and making sure you are adding a little tension when you do it.
Phil Bates
67 MGB
75 Jaguar XJ12C
52 MG TD replicar (VW)
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