MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Sluggish MGB

Greetings:
My 74.5 MGB is acting up. A couple of months ago during a local run it started the engine started to miss. While idling it would run normally, as soon as I started to climb some hills, its performance would suffer. I pulled over and the engine would rev fine.
I barely made it home. This weekend I decided to start working in it. Where should I start? fuel pump? Ignition/timing carburation?

AC
A Ching

The first place to look is at the ignition system. Check the point gap, and if that appears o.k. you might want to try replacing the condenser. These are notorously high up on the poor quality parts list and are subject to early failure. Then check your secondary ignition wires to make sure each is delevering a healthy spark. If these steps pass, pull the plugs and look for signs of fouling or a cracked plug. I'm sure other members will chime in with their opinions. Ray
RAY

G'day. Had a similar problem on my ZA Magnette two weeks ago. A new fuel pump fixed it. The old one just couldn't push the fuel to the engine when climbing hills. A couple of days later it couldn't even push fuel that far going down hills either. New fuel pump or refurbish the old one would be my answer.

Tony
Tony OIiver

It sounds like the advance mechanism in your distributor may be sticking and not properly advanceing the timing. You can check it by watching the timing mark with a timing light. Rev the engine and you whould see the timing advance about 25 degrees. The timing should return promptly to the idle setting when the revs come down.

You can also check the vacuum advance module. The vacuum line should be attached to the manifold in your application, so removal of the line while running should retard the timing about 20 degrees, bringing it down to around 10 degrees BTDC, +/- a few. If removal of the line makes no difference AND the line is attached to the intake manifold, the module is probably bad.

You should also verify the points are good and properly adjusted (as well as a good condenser) unless you have fitted an elctronic conversion such as pertronix or Crane.
Jeff
Jeff Schlemmer

Thank you gentlemen.
Mr Sclemmer, the car is currently stock. I've considered installing an electronic conversion, however I rather keep it as original as possible.
This afternoon I will check the points and the fuel pump.

Regards
A Ching

This thread was discussed on 13/08/2006

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.