Morris Minor Owners Club

Hi all,

Does anyone out there own a 1275cc Midget and can let me know the following:

Plug gap.
Points gap.
Ignition timing details.

I'm having a tuning problem with my 1275 in a Minor that is causig me problems and this info would greatly help.
Cheers.

Plugs and points will be the same as a 1098 Minor: 15thou for the points and 25thou?? for the plugs. Can't remember the timing offhand, but 5deg static sounds like a safe starting point - I seem to remember it wants more advance than the Minor engine. Also depends on whether you're using unleaded or an octane-boosting additive.

Advance the ignition timing till it 'kicks' against the starter - then retard it slightly. Then check it doesn't 'pink' too much when slogged up a hill in top gear. A slight tinkle will do no harm - but serious detonation or prolonged hard pinking can damage the pistons.
But if the engine is not performing as it should - first set all the valve rocker gaps - 12 thou for inlets and 15 thou for exhausts - then get a compression test done on the engine and report back the findings. Do the test hot with the throttles held wide open - all the plugs should be out, and of course it must be a good fully charged battery - if need be set jump leads across from another car with the engine at fast idle, and wait a few minutes between each test. Best to do the test twice for each cylinder, and average the result.

I thought it was 12 thou for both inlet and exhaust...?

Sorry Smithy, forgot to check the manul last night (goldfish memory).

Well the exhaust valve gets much hotter than the inlets, and expands more - so tends to close up the gap when running. There is also the slight risk of exhaust valve seat recession - even if you have a so-called 'unleaded' head - and if the gap ever reduces to zero that's when the damage gets done. So it's best to leave that wee bit more clearance on the exhausts just to be sure nothing evil happens !