12 replies to this topic

[rich2]

1979 Clubman 1100. Some light engine mods: cam, rockers, exhaust. Standard ignition. Electric fuel pump + filter.

 

 

Hi Experts!

 

I was powering up a hill the other day when suddenly the engine went 'weird' under load. Revs became irregular; it felt like it wanted to stall. I had to give it a lot of gas to get home. Came back to the car after a week or so and struggled to start it from cold. Again very unsettled idle (perhaps misfire?) and stalled. Now cannot get it to start at all. Cranks over fine on the starter motor but will not fire.

 

Things I have already checked:

- points - clean and correct gap

- dizzy cap and rotor changed. No improvement.

- tappet clearances - all correct

- fuel getting to carb - yes. Fuel is pumping. Can smell petrol in cylinders.

- spark present at HT lead - yes - tested for spark from all leads against head.

- cleaned all connections around solenoid. All wiring looks good. No obvious damage.

- carb partially inspected - fuel in float chamber looks OK. Piston, needle etc all looks normal.

- timing seems correct ballpark - (marks on the flywheel are in the right place relative to the dizzy and cylinder 1 at TDC.)

 

 

Things I suspect:

- spark plug failed? (Have ordered new ones to rule this out, awaiting arrival)

- something has slipped in the timing somehow? Chain jumped a tooth?

- spark is too weak somehow?

 

Engine is normally in good working order having only been rebuilt a few years ago, although it was running quite hot over the summer. Something has failed due to hot running? 

 

Any suggestions much appreciated!

[Clip]

a bad coil even though you’re getting some spark?

Edited by Clip, 27 November 2022 - 10:02 PM.

[rich2]

Ahhhh forgot to mention the first thing I did was change the coil for a brand new one. No improvement

But thanks!

[sonscar]

Head gasket?inlet leak?Steve..

[timmy850]

I’d suspect a head gasket failure. Try doing a compression test

Mine had a similar failure with similar symptoms a few months back

[Retro_10s]

As above, compression test is cheap and quick to do. I had an 1100 that did this, turned out the piston rings were absolute toast, but what you're experiencing (and in light of what you've checked) seems to point in direction of H/G failure.

Did you change/check the condenser?

[Ethel]

Condenser, points earth, or "frozen" distributor*. The bypass wire, if it's ballasted ignition.

 

*check the baseplate moves (vac advance) and the rotor arm has a bit of spring when turned (centrifugal advance)

[rich2]

Thanks everyone!

 

I have a compression tester so I will do that test.

 

Have not changed the condensor. I will examine the distributor more closely as suggested.

[andyapanel]

Put your fingers up the carb and check the piston can move.

Good luck

[rich2]

Replaced the points and condenser assembly and she lives! Thanks to everyone who helped me out here by making suggestions!

[coopertaz]

suggest fitting electronic ignition inside distributor and keep known good codensor and points as backup. did this years ago, sick of failing condensors on cold wet nights, been trouble free since.

Edited by coopertaz, 29 December 2022 - 09:33 AM.

[cal844]

I'd suggest going electronic ignition, will save you a world of pain and suffering changing points

[rich2]

Yep definitely on my list now. 👍