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MG MGB Technical - stuck distributor

Hi,
71 roadster, 25D dizzy. 18V engine.
The dizzy wont come out. Have removed the two bolts, loosened the pinch bolt but it will not turn or come out, yet I took it out a couple of years ago when rebuilding the engine. there is the slightest of movement turning but only couple of mill. Am reluctant to get heavy handed with it as they can be a bit fragile , any suggestions please.
Trev
Trevor Harvey

Dribble a little oil round the clamp behind the pinch bolt and keep working at it, if you have even the slightest movement it will come eventually.
Chris at Octarine Services

Make a 50-50 mixture of ATF and acetone. It is the worlds best penetrating fluid bar non.
Sandy
DARNOC31

In my earlier thread I thought there was some movement from the dizzy. I have had another go at it today, with no success. The little movement detected is coming from the tube that the dizzy sits in. Will have a go at Sandys suggestion.
Trev
Trevor Harvey

Don't you have to undo a bolt in the dizzy drive shaft?
Art Pearse

Art. No. You simply have to loosen the clamp bolt to remove the distributor.

Trevor. If the distributor is not moving, but the piece (distributor housing) between the engine block and the distributor is moving there is some form of problem. The distributor housing is held in place by a single flat headed, counter sunk screw and should not be moving. The ATF/acetone mixture, squirted around the base of the distributor, should help to free it up, but may take a while. First thing to do is to get some rotational movement, then add more penetrating oil and keep trying for more movement. Eventually, you should be able to remove the distributor. But, under certain conditions, the body of the distributor oxidizes--seen as a gray/white deposit on the surface of the distributor, and makes removal quite difficult. Best method is to keep soaking the area with penetrating oil, over a period of weeks if necessary, until you can get rotational movement, then outwards movement.

Les
Les Bengtson

Les, The distributor housing is moving very little, I think this has loosened by my attempt to remove the distributor.
I think the seized dizzy has occurred because of a slight water leakage over a period of time from the heater water valve situated directly above the dizzy, and running down the block. One of the bolts holding the valve in place was so tight I was sure was going to shear off so was left alone and I was unable to renew the gasket when working on the engine a couple of years ago. So I am paying the price for neglecting it.
Trev
Trevor Harvey

Trevor. Is the large, flat head screw still in place, holding the distributor housing into the engine block? If you can remove the screw (assuming it is in place currently) you can remove the housing and distributor as an assembly, then attempt to separate them. Aluminum oxide, like iron oxide, is larger than the base size of the piece that has oxidized. Both are, also, abrasive in nature.

If removing the distributor housing, be careful not to move the distributor drive shaft from its seat below the housing as that will cause a change in ignition timing. If not moved, however, there should be no significant change to ignition timing.

Les
Les Bengtson

Hello Trevor,
Ive been here before, I usually crack out a benzine torch like this!

http://www.sears.com/c-r-laurence-crl-complete-propane-torch-kit/p-SPM518414501?prdNo=16&blockNo=16&blockType=G16

I slowly sparingly use heat at the base of the engine block and distributor circling the torch tip around these areas. Give generous heat to these areas but do not ruin what your working with. Then dump a pan of cold water on that area. I usually repeat the process over and over until I get the thermo reation to release the disimilar metals bond. You can tap gently with a hammer in between intervals on the distributor until you get some movement.
If you can get it to start keep repeating you will get it out!

If you dont want to use the torch I would use boiling water and poor that over the area then let it cool doing this over and over cycling from hot to cold tapping the distributor with a hammer.

Have patients, tap gently or use a small wood dowel to transfer the energy to tap the distributor.

You will eventually get it out! Ive used this method many times and it always works. Take your time!

Good luck!
Steven Devine

Thanks for the info. I have got the dizzy out by removing the set screw as Les suggested, taking out the housing. I was surprised to be able to get access to it, I thought the dizzy had to be removed first to be able to get at it but it is possible. Its in soak now and I will have a go at getting them apart later using the hot water treatment
Good advice Les. and Steven.
Trev
Trevor Harvey

This thread was discussed between 18/06/2013 and 20/06/2013

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