A few days I asked for help from the list concerning items on my 1980
Federal MGB LE - aka Black Beauty or Beauty.
First, with respect to the hazard lights switch. I never did have to find
the flasher for the hazard lights (but I am told it is behind the radio
console). The ears on the rocker part of the switch were broken. In my
parts box and on my two non-runners I managed to find enough parts to
completely rebuild one operative switch including replacing the light bulb
within the rocker. When i got it back together, the hazard lights worked
great but the turn signals were inoperative. After much contemplation I
concluded that I had to reconnect the pressure pad within the drivers
seat. I did and all is well. Thanks to all who gave me tidbits of info.
Second I asked for advice on desmogging Black Beauty. Again thanks to
all of the folks who replied - both in negative and positive vains. I
have concluded that I will leave things as is for now. In due course i
know i will have to remove/disable the air pump because it is getting
noisy.
Third, I asked about the switch located on the brake pedal box adjacent to
the brake servos. Turns out it is spark advance switch which is
connected to the vaccuum advance and which is triggered when the
transmission is in fourth gear. The connection to the vaccuum advance was
severed and I was able to repair it. When idling with the clutch in,
there is a marked inrease in rpm when shifting from 3rd to 4th. Jon
Larson sent me a marvelous explanation of this device and I quote it here.
Thanks Jon
QUOTE
Anyway, I never knew what the blasted thing was until someone on this list
mentioned that in later years MG put an electrically operated valve in the
vacuum line for the distributor advance. There is a switch on the
transmission case which is activated only by the gears being in fourth
gear. When the switch is engaged, the valve opens up to allow vacuum
advance. Quite a mysterious little setup, and one not readily apparent
until someone else tells you about it.
To test if yours is working:
Warm up the engine to achieve steady idle off choke
Depress clutch and move shift lever into fourth position (do not re-engage
clutch to engine - engine continues to run as in neutral)
If idle changes noticeably when fourth is engaged, it is working.
If it doesn't, you will have to troubleshoot whether it is the fault of
the transmission switch, the little vacuum valve itself, or your
distributor advance mechanism.
If you want to test the little valve alone, just disconnect the hoses and
try to blow or suck through it as you apply voltage to the terminals from
a battery source.
If you have a distributor setup different from the stock one, none of this
may actually be functional and may safely be disconnected or ignored.
END QUOTE
Fourth, I also asked if anyone knew of a good source of MGB tech articles
on the WEB. John Twist's site won hands down.
Fifth, I asked about a source for a gif/jpg version of the elecitrical
diagram for Beauty. I received no answers to this question. I wish i had
a scanner so I could capture it electronically and colour code it before
printing it in the size i want. Is anyone willing to scan it end and send
it to me electronically?
NEW QUESTIONS
The following items may or may not be related.
My fuel pump clicks very loudly when I turn the key then when pressure is
achieved, although the clicking softens, it is still very loud. What
stumps me is that once the engine is shut down (and the ignition is turned
off with key removed) the clicking continues for a while. Any ideas what
is wrong here? What can i do to diagnos the problem?
Last month I got fed up with antics of the automatic hot water controled
choke and replaced it with a manual choke from Moss. While I am having a
bit of problem learning the exact choke withdrawl distance in conjunction
with the accelerator kick down to set the choke (yes a kickdown is still
needed), I am not getting a throttle effect from the choke. (I think the
choke should not only change the gas/air ratio but should also increase
rpms). I pulled it all apart yesterday to make sure that the lug of the
choke drive spring is engaged with the operating lever. Thoughts?
In recent days (I do not know if it is tied to the choke installation but
it may be), the smell of gas is present. When I run my fingers along the
bottom of the float chamber (i assume this is what the large 'box' like
device is on the bottom of the carb) they come up wet. I dried it off and
a few hours later the bottom is wet again. The choke is off and the car
has not been run in between wipes (although while trouble shooting my
speaker wires I did turn on the ignition (and thus the fuel pump) a few
times). The connection to the gas line seems to be dry. Any ideas?
I have Haynes Zenith Stromberg book for CD carbs (thru 76) but it does not
cover the 175CD-5T found on Beauty. Is there a later Haynes manual that
does or is there another source that I should be looking for?
As I think about these fuel related problems, I see myself making my
first ever adventure into the world of carb rebuilding. My Brit VIC
catalogue does not say much about the contents of their carb rebuild kit.
Are instructions included? What parts are provided in the kit? Will I
need any parts beyond those in the kit? Should i change the metering
needle? What are the pros and cons of the Grose jet? Having never opened
up a carb, I will accept all and any advice on how to proceed, how to
check for other worn parts, what cleaning materials are needed, etc.
Thanks for any and all advice you may provided
|-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-==-=--
| It will soon be MGB top down time.
| Betti Ann and Preston Smith in the Head of St Margaret's Bay, Nova Scotia,
|Canada.
| email: prsmith@navnet.net
|