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MG Midget and Sprite Technical - 1098 running problem

Hi all,

Can anyone help ?

Just bought a 1965 1098 Mk 2 and returned home with it, running on three.

-Engine does not lose water and no obvious oil leaks.
-Spark is good on all cylinders.
-Fuel delivery is fine.
-I've pulled the head and N° 1 piston is black, with burnt deposits and oily.
-The valves look fine, with no pitting or burnt edges.
-N° 2, 3 and 4 cylinders all look OK, with no burnt deposits and no oily residue.

I've just dropped the sump, expecting to find bits of broken ring in it, but there's just a couple of bits of swarf.

Am I right in continuing with the broken ring theory, or should I be looking for something else ?

Any help would be appreciated.
Graham

I experienced similar. Spark looked OK, but turned out to be a dodgy plug. Change it - in fact change them all out. May as well, as cost is peanuts anyways.
Mark O

Since you've already elected to take off the sump you may as well pull No1 and look for broken or possibly stuck rings. You can also change all the big end shells and look at the center main and thrusts while you're at it.
With the head off lap the valves,and renew all the top hat seals too. It's just sensible to do it now it's apart.
You've checked the spark - presumably with the ignition on and no load. Plugs, wires, coil and rotor arm can all break down under loaded conditions, so if nothing mechanical turns up it's likely you have an electrical issue.
F Pollock

Thanks Mark & Fergus for your help.
Graham

any chance you did a compression test before you pulled it apart?
David Smith

Rule of thumb no 1 - Eliminate the easy stuff first!
Mark O

This thread was discussed between 14/08/2013 and 16/08/2013

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