Morris Minor Owners Club

A tale of caution.

I have those on my moggy and 1800 landcrab. This happened on the Landcrab but could equally well have been the Moggy.

A few weeks ago the engine went 'bang' and the car ground to a halt. The RAC kindly returned it to barracks for me.

Head off, and I found a bolt lodged under No 1 cylinder inlet valve No idea where it had come from and nothing was missing from the car.

The offending wee beastie





it was removed from under the valve, engine reassembled and it works well.

I posted the photos on another forum and eventually a member identified it as coming from an aftermarket pancake air filter.

All of the bolts on my filter remain intact, however more than 3 years ago traveling there was a a loud bang. Inspection revealed the air filter had deserted its post, presumably embedded in tarmac somewhere.

This bolt must have dropped unobserved into the inlet manifold and remained there whilst the car covered in excess of 10,000 miles before deciding to jam the valve

I have further examined both the filters on the cars and at the moment ll seems well, but such examinations will now become commonplace. If that bolt had dropped into the cylinder it could have wreaked so much more havoc and I would probably been searching for a new short engine

Most 'pancake' air filters actually LOSE power - the flat face is far too close to the carb inlet. Best type are the 'cone' filters as sold by K&N - although there are some perfectly good replicas about too. And no stray bolts to come loose either!

What did the head and the top of the piston look like?
That bolt has been rattling around for some time, wasn't there a tapping noise from the engine?

There were no extraneous noises from the engine at any time.

Pistons were fine and there wasn't any damage to the inlet valve either. The only casualty I could find was the oil seal (top hat type) on that single valve. Despite extensive searching I couldn't find anything wrong with the rest of the head (I had another head on stand by just in case, but not needed)

I was very lucky on this occasion

I find that the pancake filters have increased, not decreased, the power on both cars. When these come to the end of their lives, I will try the cone ones for comparison - especially as you say there are no bolts to mess things up!

The perils of fitting non-standard parts. If the design engineers thought it was better to fit this type of filter, they would have done so at the factory.

The 'pancake' air filters increase NOISE = perceived increase in 'power".... The noise would not be acceptable to most Minor owners when they bought these cars ~50 years ago.....