Strange rattle/knocking from engine

[stephenpolhill]

CLASSIC CARS!!!! My car has started to make a strange rattling noise, like a few nails in a tin thats slightly muffled. It only occurs on mid throttle. I can make the car make the noise by accelerating and lifting off enough to keep a constant speed and also when still by revving slightly and holding the revs, again at mid throttle.
The noise isn't there on idling or heavier throttle.
Please can anyone give me any advice on where to start as this is starting to get tedious sorting the problems and the car isnt reliable

Thanks!

[bmcecosse]

How's the oil pressure?

[stephenpolhill]

And how would I check that myself..

[bmcecosse]

With the very essential oil pressure gauge......it's by far the MOST important accessory for a Minor....... the yellow light gives a rough guide...... does it come on when idling?

[stephenpolhill]

Nope not at all. Everything SEEMS normal apart from that noise..

[MarkyB]

Sounds like a good description of pinking to me, retard the ignition a bit.

[bmcecosse]

Well - I wondered that - but he describes it as coming when he lifts off.......

[stephenpolhill]

Just tried retarding the ignition a bit but the noise is still there. I can accelerate with no noise, I can lift off with no noise its just in slightly higher revs (eg. in 3rd gear doing about 35 or about 20mph in 2nd gear). It sounds slightly like a diesel, bit rattly but not a 'hollow' known or rattle.

[bmcecosse]

Sure it's not just gear lever 'buzz' ?

[stephenpolhill]

Good idea but nope. Coming from the engine area and is a bit like an engine low on oil (which it isnt*)

[bmcecosse]

Well - nothing for it really but a strip down and investigate. I seem to remember there were some dubious 'issues' when you were putting the engine together?

[chickenjohn]

here's hoping it is just timing chain rattle!

another idea- adjust the valve clearances.

Yet a third idea- a new rattle- especially if from the front of the engine could be your crank end fan belt pulley about to disintegrate. Check carefully for cracks- after 40 odd years these can fail suddenly. First sign is a new rattle from the engine!!

[stephenpolhill]

Yes you are right BMC, there were a couple of issues but I can't remember which of many would link to this rattle. I will check the timing chain area and pulley first before ripping the engine out AGAIN!
Using her everyday I am slowly coming round to storing her for a year or so to give some TLC and have her back on the road when I can afford the luxury and reliability of a classic. Shame but she deserves to be looked after!

[taupe]

Hi

Have you got oil in the carb dashpot? if completely dry the whole piston can rattle.

taupe

[chickenjohn]

Yes you are right BMC, there were a couple of issues but I can't remember which of many would link to this rattle. I will check the timing chain area and pulley first before ripping the engine out AGAIN!
Using her everyday I am slowly coming round to storing her for a year or so to give some TLC and have her back on the road when I can afford the luxury and reliability of a classic. Shame but she deserves to be looked after!

When a Minor has been off the road for a number of years, or not maintained there will be a number of niggles that need sorting. Once you've got over these, typically you can expect excellent reliability from a properly maintained Minor.

[chrisd87]

Agreed with John's comment above! The same applies (in my experience anyway) to pressing a car that's only been used occasionally into service as an everyday car. A number of faults/niggles/wear issues that might have progressed slowly or only shown themselves occasionally tend to come to the fore and will need sorting. After that you should be fine.

[stephenpolhill]

Great points. I guess i'm just on a downer about the car at the moment because its a phase (a long one!) of problems and niggles and money and I can't afford it to break down.
We've had another listen and it appears to be coming from the oil breather pipe/chain area but we're not sure how to properly locate the noise. Should we take the rad out and the timing chain cover or what? Im just purely lost.

[ASL642]

Are you a member of a local branch. If so contact them and ask for local help?

[stephenpolhill]

Yeah I've emailed them a short while ago. Fingers crossed someone can

[bmcecosse]

There are few (if ANY) cheaper cars to run than a Minor...... just 'be prepared'........ Get hold of a spare engine/gearbox/rear axle - pick them up when going cheap - and have them ready for use 'in stock' in case anything goes seriously wrong. Everything on a Minor is dead cheap - and generally no depreciation either, affordable Classic Insurance - and FREE road tax. Very hard to beat it for low cost motoring......