Welcome to our resource for MG Car Information.



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 MGA - Distributor won't lock down

Greetings all,

Well, I thgouth I was ready to lift the body over onto the frame assembly. I installed electronic ignition since trying to replace the points was going to be exteremly difficult with the crossflow head placing the carbs directly over the distributor. Anyway, got that done and have folks lined up for the lift on Sunday afternoon. Went out to the garage to get some details completed and while reaching into that area, the back of my hand pushed on the vaccum advance and oh crap, the whole distriubtor twisted. So I quickly placed it back just as it was and retighten the distributor know the one I thought I had already tightened. Well, now it's drawn down as far as it can go guess it, the distributor still moves about easily. What gives???? Any thoughts. Thanks!
Robert Maupin

This is a common fault caused by overtightening many times in the past. The only solutions are to fit a new one or to reshape the current one.
When tightened correctly there must still be a gap in the clamp.
When in good condition they only need light tightening to hold the Distributor from turning.

M F Anderson

Hope it is just the clamp! If you have an original distributor body, the flange is prone to breaking at the clamp, also due to too much over-tightening through the years.
Neil McGurk

Read what the mga guru has to say on the subject ( Also, it probably a stupid question do have the clamp fitted the right way around with the feet toward the engine block, don't you?
Andy Bounsall

The area of the distributor where the clamp ring touches is weak because it has a groove machined behind it. Filling this in with JB weld or equivalent will make it stronger.
Art Pearse


Yep! Clamp turnind the correct way. I was talking to a fellow in our local car club last night and he said there is a "shoulder" which isn't very deep/thick so he thought the clamp might be situated under this. He suggested backing the clamp out all the way, pressing down on the distributor to ensure it is fully seated. However, Now I can't get the darn clamp to re-expand after having backed the tightening nut out completely. I eventually removed the carbs so I could find an easier job of it.
Robert Maupin

You will have to remove the clamp and bend it open again.
Art Pearse

Robert, I've found that the two bolts that hold the clamp to the block have to be slackened to allow the clamp to open up.
Lindsay Sampford

Robert. Remove the dizzy. Remove the dizzy clamp. Spread the clamp open and test fit to the dizzy. It should be just a little loose. If it is excessively loose, tighten the clamping bolt until there is almost no play between the two.

Install the dizzy and the clamp as an assembly. Install the two bolts holding the clamp to the block. Set the timing. Tighten the dizzy.

While the two parts are out you can examine the body of the dizzy for cracks/breaks in the area the clamp tightens on. Epoxy into the thing ring is an excellent idea as has been suggested. Check the clamp for deformation and straightness. New clamps are available, if necessary. Generally, only opening the gap and slight straightening are required.

Les Bengtson

If you distributor has a broken flange or any other issue. Send it to Jeff at Advanced Distributor. He can fix the flange, bushings, palte, springs, etc etc etc.

His web site is:

JP Jim

Got it taken care of. My car club friend hit the nail on the head. The clamp was poistioned under the "shoulder". So, I had to pull the distributor, respread the clamp, refit the assembly ensuring the distributor was fully home and the clamp not hold it off the block. Back in business. Big day for me as some neighbors are coming over after lunch to help lift the coupe body back onto the frame. Yea!
Robert Maupin

This thread was discussed between 29/04/2010 and 02/05/2010

MG MGA index

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