4 replies to this topic

[Snotpot]

Hi all,

My wife came back from shopping yesterday and the exhaust back box was blowing. I went out to look but it sounded more than just the rear box. I temp fixed the rear the box today (although it sounds like the baffles have gone inside) but the air filter sucking is different, it's really loud and doesn't really want to pull away without really revving it.
It has a K&N bolt on cone which was loud in the first place but now the sucking is more high pitched and more "pop pop pop". I have checked all the gaskets and nothing is loose or blowing (inlet/exhaust/manifold etc)

Any ideas?? I have no idea what to do/go next.

Does anyone have a standard air filter box/elbow they want to sell??

It's a 1.3 cooper 1991 (last of the carb models)

Thanks in advance

[minimender]

I had a similar problem once and the carb had been bashing on the bulkhead and cracked the inlet manifold. There was a small piece missing from the underside of the manifold and it was sucking air.

[mini_mad69]

I had a similar problem once and the carb had been bashing on the bulkhead and cracked the inlet manifold. There was a small piece missing from the underside of the manifold and it was sucking air.

I agree, how are your engine mounts? Sounds as if your engine is moving around too much causing the exhaust to move to much, check your manifold nuts too make sure they're tight, they can appear tight but still suck in air, manifold gasket may have gone too.

[Sherlock]

I had this happen on a Rover 216, the silencer collapsed internally causing a lot of back pressure which gave a completely different intake noise. Worth checking, if that is the cause, it won't do your engine any good.

[Snotpot]

I have checked the maniforld studs and they are all really tight and have sprayed lube around to see if there was a difference to sound etc, but no.

I like the exhaust idea. Perhaps the baffles have gond and it is causing too much back pressure. Even though it's no longer blowing the back box does sound really different - as if all the insides have broken up. Never heard of this before though.

It has a maniflow system on there at the moment. Do you know what sizes they come in as I want top order one today. It's looks like a large bore but not sure on size.

Thanks for replies!