8 replies to this topic

[bg158a]

I have been working on a mini that I bought a few months ago.

It has a metro 1275 engine. When I bought it it ran but had a very bad blow on the exhaust was able to do a reasnoble speed on motorway not really pushing it.

Have done alot of work on suspension components new lcb and RC40 exhaust. Ran it back up on Saturday to find that it has a missfire shown by the engine vibrating at idle. I am know not sure if this was always present. The missfire apears to be in cylinder 3 if I take the HT lead off their is no change to the engine at all. Cylinder 2 also seems to make very little difference if disconnected. If cylinder 2 and 3 have the HT lead removed the engine dies. The spark plug from cylinder 3 is in a real state see photo, what would cause damage / corrosion like this. I have had it suggested that it may be a head gasket failure between cylinder 2 and 3 does this fit.

Dizzy cap, rotor arm and plugs all new, electronic ignition so no points to change. Their is spark at all plugs.

Any suggestion greatly appreciated.

Ben.

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[cowboy]

dont be quick to say its the head gasket thats gone

that spark plug is certainlly knackered

have you done a compression test or checked anything else, do you have any knocking noises, have you checked the tappets, do you have the leads on the right plug, a mini will run if you have the leads for 2 & 3 on the wrong way round ( i did it myself) :fear:

[clubman katie B.F]

like cowboy said....don't whip off the head too hastily.
mini owners always assume the worst, try other (cheap things first, spark plugs, check your mixture, if that is oil on the plugs maybe it is running too rich. am not taking the p%%% but are the leads the right way round, i had this probmlem as i assumend the dizzy rotated clockwise not anti clock wise. whats your timing like?

how powerful is the sparK? are the ht leads past there best? a compression test would be a great idea, and put your mind at rest, and will save you a lot of hassle in unneccesarilly replacing the head gasket. i think you are looking at about 150 psi, not to worry if they are not that high, but they need to be over 100 and very similar reads for the four cylinders.

the big one to go on the gasket is between pistons 2 and three, so if these are both down then it may indicate a gasket/ head problem.
you can also try the compression test and if the pressure is low add a dash of oil into each cylinder, if the pressure momentarily comes back up, this could indicate your piston rings are on the way out.

is the car burning oil and going though water another head/gasket pointer, check your exhaust for lots of moisture in the gasses, and check under your rocker cover for a mayonaisse type substance, which is a classic giveaway for a blown gasket.

check the little things before giving yourself the hassles of a cylinder head change. if you do these checks and then still have to change the gasket, you will be safe in the knowledge that when you fix it, the other related bits will all be working and in top notch nick.

compression testers are available from halfords for 17 quid, a great bit of kit, invaluable for checking the health of your engine, if checked on a periodical basis.

NB mini docs and others, please feel free to poo poo my reply, i am only going on my own experiences.

[cowboy]

ok you asked for it

poooo poooo

[miniboo]

do you remember the sketch in Blackadder about not poopoo-ing a poo poo. etc etc think it was blackadder goes fourth, Colonel melchard?(spelling)

[Jammy]

Yea, Blackadder goes Forth, the epsiode with the spy in the field hostipal (as Baldrick pronounces it!). I remember it well, I LOVE blackadder!!


As for the misfire, try swapping one of the spark plugs with another without changing the order of the HT leads, you may have a dodgy spark plug..

[clubman katie B.F]

" i have a cunning plan" said baldrick

[Jammy]

LOL!

Bladrick: What we do is we wait til our heads have actually been cut off.
Blackadder: And then we spring into action??
Baldrick: Yea.

[clubman katie B.F]

i have turnip for dinner tonight....don't laugh i really do