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MG MGB Technical - Gas smell and shifter vibrations

I have a 1980 MGB, with 57,750 miles on it. The car as a whole is in pretty god shape, but I have a couple of problems I hope someone can help with.
#1. I have a gas smell in the trunk that is overpowering! I have checked the filler tube and tank for leaks...nothing found. The charcoal canister on the right side of the trunk looks like it is vented properly. There is never any liquid gas or puddles in the trunk, just an ever present smell that renders the trunk un-usable.

#2. The shifter makes a metalic noise while driving. The car shfts fine and stays in gear, but the noise seems to be coming from the shift knob. I have tightened the nut inside the knob, but it works it's way loose after a couple of weeks. I would like to replace the plastic knob with a Walnut version, but the only ones I found need to be screwed on, and my current connection is a nut inside the knob.

Any suggestions would be appreciated!

Thanks,
Jeff
Jeffrey Davis

Jeff. The vapor seperation can in the trunk should not be vented. It is attached to a steel line which runs throught the floor, along the underside of the car and up near the charcoal cannister where it is attached to the charcoal cannister with a rubber hose. Sometimes the steel hose becomes plugged and people disconnect the line at the vapor can which results in a build up of fuel vapors in the trunk area--right where the fuel pump is merrily clicking its points away.

A drop of blue, medium strength thread locker, Loctite on the shifter will correct the loosening of the special nut. If your car has an overdrive, the switch is located on top of the gear shift knob, a la Truimph. If you have a non-OD car, you can remove the nut, lift off the gear shift knob and replace it with another knob. (On my cars, including the overdrive equipped ones, I moved the OD switch to the dash and turned gear shift knobs from aluminum--aluminium--round stock using the lathe. This also allows one to shorten the threaded portion of the shifter, relieve the lower portion of the hole in the knob to fit over the shaft and results in a shift knob sitting just above the rubber boot. Makes for a quicker gear change and looks more attractive to me.)

Les
Les Bengtson

> aluminum--aluminium

I like the translation into English! That's a good idea about the custom shift knob. I might try that as I was thinking of slightly shortening the gear throw but didn't want to mess with the gear stick shaft to do it. I really like the black, round knob with the white shift pattern etched on it though.

Simon Jansen

I had the same thing with fuel vapors in the trunk
and it drove me bonkers for weeks looking for the
source.

I checked the filler neck for cracks and leaks
and I also checked the vapor tank and hoses.
Everything was dry and looked OK...but the fumes
were definitely present in the trunk area.

Then, one day, I went to my local gas station, and
just before adding fuel, I opened the hatch and
raised the trunk floor on my B/GT.

As I pumped in fuel, I kept a sharp eye on the filler
tube area and...whoila! A very small amount of fuel
was seeping past the rubber connector collar and
was evaporating (dry) quickly within a few seconds
or so.

I doubled the number of hose clamps on each
end of the filler tube rubber collar and positioned
the screw tightening mechanisms on the clamps
so that they were on opposite sides of the tube.
ie: 03:00 and 09:00 o'clock.

No more leaks. No more fumes.

Sometimes you just have to catch the culprit
redhanded, in the act.
Daniel Wong

Hi Jeff.

I would take the knob apart and investigate, a little packing might be all that is needed.

It is also possible that the vibration might work-harden the wires which could eventually result in wire fracture, and mysterious overdrive drop-outs.

Please be very careful with the wire insulation, though.. you have got the standard overdrive feed fuse mod in place, I hope ?.

Don
Don

This thread was discussed between 23/09/2005 and 24/09/2005

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