6 replies to this topic

[minitman]

Hi I'm new to this forum and computers so bear with me

998 Mini city 1985. It was running nicely for 3 months, after a lot of hard graft to get it back on the road, but started to misfire wildly on the motorway at 60 MPH. It will run after minor maintenance cleaning the points etc but soon begins to misfire again. Distributor is filling with oil and the engine will stall when the filler cap i sremoved. I have changed the breather pipe(breather to carburettor manifold) and it breathes when running. Have fuel, have spark, but I'm very worried it may be a blockage somewhere. Help is appreciated
Standard engine setup so no dodgy mechanics to worry about

[Ethel]

The distributor spindle isn't sealed so some oil can get by to lubricate it, but it should only be slight an there is a drain hole in the bottom of the dizzie's body.

It sounds like excess crankcase pressure, but if it leans out enough to stall by sucking air through an open oil filler it sounds like the crankcase ventilation is working. Though maybe it's actually running on engine fumes when the breather is attached?

I could be a game tracking down the cause; you could block off the breather pipe at the carb and see if it makes any difference to the idle. Stripping down the distributor to look for spindle wear is worth considering too.

[minitman]

The distributor spindle isn't sealed so some oil can get by to lubricate it, but it should only be slight an there is a drain hole in the bottom of the dizzie's body.

It sounds like excess crankcase pressure, but if it leans out enough to stall by sucking air through an open oil filler it sounds like the crankcase ventilation is working. Though maybe it's actually running on engine fumes when the breather is attached?

I could be a game tracking down the cause; you could block off the breather pipe at the carb and see if it makes any difference to the idle. Stripping down the distributor to look for spindle wear is worth considering too.

Thanks Ethel, I am at a loss, i appear to have excess oil pressure at the dizzy but not at the breather. it is my first dabble back with mini's and I do not know much about the engine construction. I am fair mechanic (I'm a tradesman) so I'm happy that the basics are right but i don't know what's on the other end of the dizzy drive shaft or where the oil ways go. I am concerned that the oil way up to the top of the engine may be blocked and that the oil is being pressured out at the dizzy. As I ssaid minor cleaning and setting up gets it all going again but only for 5 mins or so an dthen it is all saturated again. Suggestions anyone?

[Ethel]

There's no pressurised feed to the distributor, there will be plenty of oil thrown its way off the crank. If you remove the clamp it will just lift out - scratch a line across it's base and the block so you can match it up to refit it the same & restore the ignition timing, note the position of the rotor arm too.

[minitman]

There's no pressurised feed to the distributor, there will be plenty of oil thrown its way off the crank. If you remove the clamp it will just lift out - scratch a line across it's base and the block so you can match it up to refit it the same & restore the ignition timing, note the position of the rotor arm too.

Thanks Ethel. I am aware that there is no feed here, and now I have re-read, I see what I have written is a little misleading. sorry. The oil is coming into the dizzy because the crank case appears to be pressurising due to 'blow past' of the rings or whatever. my problem is the breather system does not seem to be working and subsequently the engine is pushing oil out everywhere, the dizzy being the most crucial because it is stopping the engine by removing the spark. what I need to know is why is the crankcase pressurising without relief? what normally relieves the pressure? where should I be looking for an oil way or relief system? cheers

[paulhibb]

There's no pressurised feed to the distributor, there will be plenty of oil thrown its way off the crank. If you remove the clamp it will just lift out - scratch a line across it's base and the block so you can match it up to refit it the same & restore the ignition timing, note the position of the rotor arm too.

Thanks Ethel. I am aware that there is no feed here, and now I have re-read, I see what I have written is a little misleading. sorry. The oil is coming into the dizzy because the crank case appears to be pressurising due to 'blow past' of the rings or whatever. my problem is the breather system does not seem to be working and subsequently the engine is pushing oil out everywhere, the dizzy being the most crucial because it is stopping the engine by removing the spark. what I need to know is why is the crankcase pressurising without relief? what normally relieves the pressure? where should I be looking for an oil way or relief system? cheers

had a simular problem on my dauters oil leak on clutch oil seal then on rocker bolts rubber seals due to pressure changed the clutch and seal but still had oil leaks started to run sluggish so did a compression test two were fine and the other two gave low readings removed the head and it was only the gasket so cheap fix oil and water was always ok even had oil pushing up past the dipstick as well this was over about three months but she does not use the car that often head gasket had gone in between the two pistons giving the low compression readings its now ok may be worth doin a compression test i changed the clutch seal thinking that was the problem but looks like that was the weakest piont due to the pressure hope this helps

[minitman]

There's no pressurised feed to the distributor, there will be plenty of oil thrown its way off the crank. If you remove the clamp it will just lift out - scratch a line across it's base and the block so you can match it up to refit it the same & restore the ignition timing, note the position of the rotor arm too.

Thanks Ethel. I am aware that there is no feed here, and now I have re-read, I see what I have written is a little misleading. sorry. The oil is coming into the dizzy because the crank case appears to be pressurising due to 'blow past' of the rings or whatever. my problem is the breather system does not seem to be working and subsequently the engine is pushing oil out everywhere, the dizzy being the most crucial because it is stopping the engine by removing the spark. what I need to know is why is the crankcase pressurising without relief? what normally relieves the pressure? where should I be looking for an oil way or relief system? cheers

had a simular problem on my dauters oil leak on clutch oil seal then on rocker bolts rubber seals due to pressure changed the clutch and seal but still had oil leaks started to run sluggish so did a compression test two were fine and the other two gave low readings removed the head and it was only the gasket so cheap fix oil and water was always ok even had oil pushing up past the dipstick as well this was over about three months but she does not use the car that often head gasket had gone in between the two pistons giving the low compression readings its now ok may be worth doin a compression test i changed the clutch seal thinking that was the problem but looks like that was the weakest piont due to the pressure hope this helps

Thanks for the feedback. I think I have cured it and I'm feeling a bit sheepish. Fat bloke down the pub told me that it was the wrong distributor as this one has an oil way but doesn't know what car it is from so a quick change over to an old one I have has fixed that and in changing over i pulled the lead from the condensor to find it had never been properley crimped. Oops basic stuff. I should have checked this better or changed it sooner so misfire was innevitable, just a shock it took so long to develop into complete failure. the oil pressure relief valve on a 998 is just below the oil feed pipe on the front near the dizzy and that was clogged up a treat so cleaning with a wire and cloth has sorted the pressure I hope. I shall invest in a pressure gauge for the major rebuild I have planned.(fast road) Thanks again for the help, and remember the faster you go the more exciting life gets.