Loss of power / surging?

[nwxh]

Possibly! To inspect, do I have to do the same thing as removing the chain? Many thanks!

[bmcecosse]

Just have a good look at the pulley - with a bright light - looking for any cracking. You can't do anything about the chain without opening it up - and if you do, you may as well renew it!!

[nwxh]

Sorry I think I'm being a bit slow. Do you mean check the pulleys around which the fan belt goes for cracks?

If it is the timing belt, is this perfectly normal for an A series?

Many thanks!

[bmcecosse]

The pulley on the crankshaft - round which the fan belt is looped.... It's just a chance ! They have been known to make 'tinkling' noises shortly before exploding.... Timing belt - is not standard on the A series......although some are persuaded to go that route.......

[kennatt]

If you have a look at the bottom pully at the rivets that hold the pully onto the centre,Thats where they crack ,round the rivets,unless you are lucky and have one of the newer replacements which are one piece.

[nwxh]

Thanks.

I couldn't see anything wrong looking from above. I can't see through the radiator though.

Local(ish) garage think it may be exhaust related, but would prefer me to pay a visit so they can hear the sound. I will do this if there's any chance that it could be something about to pop.

[bmcecosse]

I doubt it.... But worth checking if the exhaust is loose - or touching the body ?

[nwxh]

The reason given was that, since it seems to be based on throttle position not rpm or anything else, it would have to be to do with exhaust or air intake. Would the sound get louder rather than stop as the throttle opens for something on the engine?

[bmcecosse]

Who knows! Is the noise there with the air cleaner removed.... Also check - is it still there with fan belt removed ?

[kennatt]

not just a tappet ticking ,what are the gaps set at,you can hear tappets on light revs but the engine noise drowns them out at higher revs.all these engines are a bit tappety even when set as per manual(Even more so if set to roys gaps which is to be recommended to avoid valve seat burning)

[bmcecosse]

I've never noticed the slightest difference in noise...and I use 18 thou with the 940 head.

[nwxh]

Thanks!

Maybe it is being drowned out, though it's the throttle that makes the difference rather than RPM.

I can't hear it stationary and wouldn't want to drive without the fan belt. Maybe I'll take up the garage's offer to pay attention to them at some point. I'd be surprised if it was the air filter but I can try with it removed.

[bmcecosse]

You only need to drive 200 yds......

[kennatt]

without going back through the thread,have you tried tightening up the manifold to engine nuts,slight leaks can cause fuel problems and noise from the exhaught.

[MarkyB]

I've never noticed the slightest difference in noise

Yet you think nobody could hear a radio in a Minor?

[bmcecosse]

Pardon ?? You'll need to speak up a bit ...

[nwxh]

manifold to engine

Is that what holds the carb in place (if so, I will check it's tight as I may have installed it too loose thus keeping the issue), or is this something else for the exhaust?

Thanks!

[bmcecosse]

The six brass nuts (1/2" af) securing the exhaust/inlet manifold to the cylinder head.

[nwxh]

I managed to identify four nuts, two of which are also serving a dual role holding a heat shield in place. All four seem tight and may even be seized.

A member of university estates who used to own minis saw me with the bonnet open. He said the tappets were loose, so I think this will be my next step. So perhaps the "engine noise drowning out" is true.

Should they be set as per Haynes, or different due to fuel differences. I use standard unleaded plus redex.

[bmcecosse]

Don't waste money on additives....unleaded is fine. I recommend 12 thou inlets and 15 thou exhausts.