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MG Midget and Sprite Technical - harmonic balancer???????

Today I tried to find my timing mark and found that it was difficult to see (I did succeed). However, I was confused by the fact that I have a harmonic balancer installed in front of my pulley and I can't find any mention of it (nor see it pictured in any diagrams) in my workshop manual, my Haynes manual and the moss motors catalog exploded diagrams.

I now have a timing mark painted onto the outside of the harmonic balancer opposite the place that was apparently marked on the pulley.

Did my car have a harmonic balancer orignally? Why is it not mentioned in any documentation?

I think that my timing is set correctly (but on the slightly regarded end of the range - I advanced it a little but want to verify that it does not ping before advancing it a tiny bit more).

R Harvey

Forgot to mention that my car is a 1973.
R Harvey


The crankshaft in the A Series motor is particularly badly designed. That is to say that the crank balance webs don't really do they're job well.

The crank pulley, therefore, has a harmonic balancer built into it. If you look at the front pulley you will see that there is an inner ring bonded into the pulley via a rubber membrane - this is the harmonic balancer.

If you have a stock A series crank (whether wedged and/or bladed or not) it is ESSENTIAL you have a crank balancer!

If you don't have the balancer then, with high rpm, your crank WILL snap!
Deborah Evans


I have a harmonic balancer (I don't know if I have an A series). My engine does not have a data tag on it. How can I tell?

Can I assume that if I have a harmonic balancer I have an A series engine?

Howcome none of the manuals and catalogs mention this harmonic balancer (and they don't show it in any of the pictures)? I am assuming that my engine came with it. Howcome none of the pictures mention it?

Also, of the 1275 engines, which one is the best? I assumed that I had a later engine because I have a late model 1275 powered car.

Most engines that I have ever seen have a harmonic balancer (I am not taking about MG engines, they are new to me).

Which model 1275 engine is the best (if I was going to search for a core to modify)?

Thanks for the info.
R Harvey

The 1275 is an A series engine. The CV designation in the 1973 had a lower compression ratio than the previous CE and CJ versions that were used previously.

These indeed came with a harmonica balancer while the earlier A engines had a simple pulley.

I have had problems with the outer portion of the pulley creeping away from the inner piece on my Volvo. As the rubber dries out, it finally breaks loose altogether on the Volvo 240 engines and timing to the mark becomes impossible. I suspect that the timing mark on the midget's harmonic balancer has also crept. The timing "hand" is long gone from the timing cover so it is impossible to time accurately with a light anyway.
Glenn Mallory

hey Reb,

there where several designs of the A-series 1275

there was the standard version we have that goes in the midget and sprite, then there is the A+ series 1275, these are used on front wheel drive cars and sit side ways and have a differant crankshaft and rear engine plate, and crankshaft mains but share the same cly heads, connectiong rods, pistions ect ect. these are found in mini-copperes

then there is the 3rd type used in the mondo, I have no clue on those as they are not here in the USA, so no need to know anything about them.

obivisiously you have found the timing marks on the bottom of the timing cover...yeah its a 2 man job to adjust the timing, one poor idiot to lay on there back head 1st under the car jacked up and running with the timing light and the other person to twist the dissy and call the prist when the car falles off the jack and runs over the poor idiot. LOL

what you might do is devise a timeing pointer on top of the engine to adjust the timing. here is a easy little kit that can do the job, just make extra photo copies of the timing tape in the exact same size so you have them if needed



hey Prop, thanks for the tip. I ordered that timing mark kit.

R Harvey


when you get the kit, take the tape to a photocopy center and have an exact size copy made, then get about 3 additional copys made on lable sticky paper, and keep them back...YOU will need them.

Then get some clear packing tape from UPS or the post office,,,the good thick commercial stuff, its like scotch tape but thicker and stronger, and place a piece over the timing tape on the pulley...that will protect it from fluids and dirt


good tip thanks.
R Harvey

I ordered one too. Thanks Prop!
Glenn Mallory

Once you get the new pointer set up, set the motor to TDC and put a nick in the pulley opposite the new pointer. That way, if the timing sticker falls off the pulley you still have a timing mark!
Deborah Evans

Do the 948 engine need a harmonic balancer as much as the 1275?


considering how far out these crankshafts are..Id certianly Put one on if it didnt have one.


As far as I can remember, all the 1275 engines had a harmonic damper. The Cooper S had a larger two piece damper and this in my mind is far superior to the std unit found on all other 1275s.
I also know that there are some good aftermarket dampers available.

M T Boldry

Here's another possibility: Take a look at the ones offered by MiniMania. I bought one from them years ago and the timing notch on the pulley is placed so that the reading can be taken from topside. Requires that a timing pointer be placed topside also. It's been years since I've done it so can't remember all of the details.

JM Morris

This thread was discussed between 05/07/2010 and 22/07/2010

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