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MG Midget and Sprite Technical - dynamic timing a 1972 midget

Hi All,

This may be stupid but I am stuck.

I changed my points for electronic ignition and following reassembly of the distributor the car started fine, though a slight cross-fire.

I figured I need to set the dynamic timing however, when I looked I couldn't see where the TDC and cam pully marks are supposed to be (there is so little room!). Do you need the car on a ramp to find the marks from underneath?

Second question is that in the Haynes manual there are a whole bunch of different potential settings and from what I can work out my 1972 125cc car should be either 10 degrees Btdc or 13 degrees Btdc. Does anybody know which or how I could tell?

The distributor is a side entry model if that helps.

Sorry if this is a basic question or it has been asked before.

Cheers
Ian
I Milton

You just have to climb under it - or re-situate it :)

Yet another good reason for NOT having a RWA 1275 :P!!!
rachmacb

I did have aquick look underneath but the cam pully seemed to be sitting in a protective metal channel across the whole of the bottom of the car. Should I have just tried different positions?

Cheers
Ian
I Milton

You have to kind of get right under it to see it from below, I wish I could give you an example photograph - but people have been banned from taking photos of me underneath cars now!

Seriously, if you sort of go under and look up you should be able to see it, and, if you're planning on keeping the car, then it's probably worth relocating it as it is a pain in the back - lol - literally
rachmacb

Hi Ian

The A series timing marks can only be viewed from in front and above of the front chassis crossmember. From underneath looking above the crossmember towards the front pulley you should be able to make out the timing marks and hopefully see the notch on the front pulley.

If you can find these 2 marks line them up and then from above mark a point on the pulley and also a point adjacient to it on the timing cover so that you no longer have to struggle under the car.

Now if you have a dial in type timing lamp set it at 32 degrees, disconnect the vac advance and start the engine. With the engine revving at above 4500 RPM set the timing marks together. This gives you the optimum timing of 32 degrees before TDC at 4500 rpm or in other words mech advance fully in.

If you do not have such a lamp you can get a portractor and put a point on the front pulley 32 degrees before the TDC mark and this time line that up with the original mark at the sam RPM.

Robert (Bob) Midget Turbo

Hi,

The strobe I am using does allow me to dial-in the angles so I just need TDC.

I will have another look from underneath tomorrow.

Thanks
Ian
I Milton

Excellent should be a breeze. :)
Robert (Bob) Midget Turbo

Static timing with the marks provided seems much less hassle... and whether you time static or dynamic, the next excercise is normally to +/- the timing around 2.5K to optimise this important part of the rev range for best torque without pinking.

A
Anthony Cutler

The marks are not so hard to see, if you get on your knees sideways on to the front of the car. Lean forward so your eyeline is just below the front valance.

This picture was taken along my line of site doing just that.

Mine is a '66 1275, and I think the later timing marks might be slightly different. Somebody else can confirm or correct that.


Lawrence Slater

On mine "gold seal" 1275, I also was not able to find a mark on the pulley. Apparently it is not always so easy.
J.W. Vlaanderen

I confess the white scribe mark on the pulley is one I seem to remember putting there myself many years ago.

Just behind it, on the the other side of the fan belt, is the original notch in the pulley. The white paint I put there isn't so visible in this picture. However when the strobe flashes on it, is far clearer.

And as the notch is nearer to the timing markers on the Cam chain cover, this is more accurate. (If it needs to be that accurate).
Lawrence Slater

If you really cant find the marks, you can always try marking it yourself.
There is a John Twist video that shows how to do it www.youtube.com/watch?v=Aw7IdW4Qxcc but there are other ways that dont involve pouring oil in the cylinder.
Graham M V

Today I lifted the front of the midget by about 4 inches and could then get sight of the marks. I was then just about able to squeeze the timing gun in and to make the adjustments. I am not sure how many times I had to climb off the floor to adjust the distributor! However got ther in the end and the car feels better than it has done in a while.

Thanks for all your help.

Ian
I Milton

Once you have found TDC, it is a simple job to paint some marks on the timing cover and pulley...


Dave O'Neill 2

Yup, it only takes a but few sec's to whip the engine out to facilitate this. :)
Lawrence Slater

This thread was discussed between 13/10/2011 and 15/10/2011

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.