New exhaust is very noisy

[James k]

Hi,
I had to fit a new exhaust to my Traveller yesterday (two piece mild steel from ESM). After a lot of struggling with a stuck bolt and fiddling with the too-short bolts supplied, I managed to get it on. It's much louder than my old exhaust and makes that morris minor 'parp' on gear changes and overrun. It also becomes extremely loud when driving at high revs. I've checked it for leaks and haven't found any so the question is, is this normal? I've heard about Morris Minor exhausts being very noisy but mine never was. I'm wondering if it just varies from exhaust to exhaust or if there's anything that I can do about it.

Thanks,
James

[midget]

Experienced the same with my van. Only difference is that mine came from BM--probably the same supplier to all minor outlets?
Not at all worried about it though--I quite like it, particularly the overrun "Phart". Thats what Minors are supposed to sound like in my book.
I do not drive mine long distances(due to the cramped driving position) so may be annoying for every day use.
Helps if you're , like me, a bit deaf as I take my hearing aids out

[James k]

It's okay at when driving slowly but I just drove it at 60mph and it was virtually undrivable. I could drive at 70 before and not have too much noise but 60 with this new exhaust is unbearable I'm starting to wonder if it is blowing and I didn't notice.

[SteveClem]

If the noise is coming from under the bonnet it's maybe the exhaust manifold junction. Lots of tips on here about possible fixes. Lots of these modern exhausts are a less than perfect fit and need a bit of fettling.

[IaininTenbury]

A lot of new exhausts I've encountered seem way too noisy. I suspect its a generic silencer used in production which isn't to original spec and not really suitable. People put up with it because its an old car so noisy, and don't all Minors make that overrun noise etc etc..
Well, yes most of them do, but theres a wide range of overrun 'parrp' from 'background' to 'scaring pedestrians and being unsociable'. Obviously the cars were never as bad as that when new - a major motor manufacturer would not have produced a car as noisy as that without, at least it being remarked on in period road tests.
So it looks like another case of sub standard replacement parts...
In your case, on a traveller, you hear more exhaust noise from the back doors anyway, so a real 'rasper' would be quite noticable. A chrome tailpipe trim, especially a downwards pointing one may help in moving the source of the noise further from the back doors. A mod I've encountered a few times now, is another silencer box just in front of back axle where there is space. (My convertible came with an extra silencer and its very quiet on the exhaust - you notice much more with no roof!), so may be worth a try. I doubt if you'll get anywhere complaining to the suppliers. Likely response on the lines of "we sell hundreds of these and no ones complained before" etc...

I replaced the ancient Unipart system on my Minor van (the type with the crimped ends of the silencer) because it was falling apart last year and now have one that can set car alarms off with if you back off suddenly on a busy street. Very unsociable and I don't feel the need to attract that much attention! I've now found another old stock 'Unipart type' van system and will be fitting that in the next week or so. If I hadn't, another silencer in the tailpipe would have been the way to go.

I may have a look at dissecting the old Unipart silencer and the replacement one to see what differences there are in the baffling arrangements, unless someone already has and can save me the bother. What it would achieve I'm not sure as we're back to the "we've sold hundreds of these with no complaints" situation with the suppliers. And for the record, we can't really blame the Minor suppliers, they probably all get the exhausts from the same manufacturers... Wether theres another manufacturer, without having a bespoke system made every time I don't know.

Some stainless systems were hideously noisy. A friend called round in his traveller a couple of years back and knowing that his exhaust was on its last legs, I jokingly commented that he still hadn't got round to fitting his new system, only for him to point out the shiny new stainless exhaust under his car. Oops... Mr Tact again... Still sounded horrible though!
Having said that I encountered a new stainless system recently that didn't sound bad so maybe theres an improvement there possibly...

[midget]

If it does bother you that much then yes, obviously fit either an extra silencer to the rear,or chop the existing out and replace with a similar (pipe size) alternative. I have found that some exhaust suppliers are helpful with this. If you then need to check that you wont be branded an anti social hooligan Minor nut case test it by taking it through the Rotherhithe tunnel in London !!!
I can confirm from experience that S/S systems are prone to be louder than M/S.

[RobThomas]

Old silencer design included a series of plates inside the silencer 'can' to disrupt the flow and thus silence the pulses. Modern silencers go for better smooth flow and pierced steel tubes inside with sound-absorbing material wrapped round. These "Straight through" designs absorb noise but alow better flow and thus performance. I bought some new Mini silncers and they were straight through so I have 2 of them on the car to get the noise down to a sensible level rather than using an uneconomical design. Ya takes yer pick, noisy or cheap.

[James k]

Thanks for all your replies!
I've inspected the exhaust again and it had a slight blow at the manifold and a the pipe join. It's only noticeable when it's revved hence why I didn't find it before. I've sorted the one at the manifold by reseating it with some tin foil under the clamp. I don't know what to do with the pipe join though. I've slotted the pipes together and done up the clamp tightly but it's still blowing. Any suggestions?

[dalebrignall]

have you got a decent manifold clamp the cast iron one not the cheap pressed steel one , the latter is hard not to get a good seal

[myoldjalopy]

I had a blow at the pipe join too when I fitted the two parts together. Cured by stuffing some exhaust putty in the joint, tightening up the clamp nuts and then wrapping some exhaust tape round the joint for good measure.

[James k]

I've got a pressed steel clamp so I can try fitting a cast one at some point.

I had a blow at the pipe join too when I fitted the two parts together. Cured by stuffing some exhaust putty in the joint, tightening up the clamp nuts and then wrapping some exhaust tape round the joint for good measure.

Did this make a big difference to the noise of the exhaust? I'm going to try some exhaust putty and then look at fitting a second silencer if that doesn't cure it.

[MikeNash]

Just an outside chance - does your tailpipe protrude clear of the body? On my Trav my exhaust was a bit short and I've fitted a 3 inch extension to get the end just clear both the body and towing bracket and it made a small but worthwhile improvement.
Regards, MikeN.

[liammonty]

You need to get rid of the gas leaks before you start adding additional silencers! Are you sure the downpipe from the manifold is now totally sealed? You will be able to feel any hotbgases that are escaping with your hand. As already suggested, use some exhaust paste on the other join - ideally it isn't necessary, but it won't hurt to use some. Are the two parts of the pipe pushed together far enough to prevent exhaust gas leaking from the slots cut down the pipe that allow it to open up slightly to mate with the other section? You can often find that gas escapes through them.

You need to be able to tell the difference between a blowing exhaust, and one that is just inherently noisy. Leaks can be sorted without adding an additional silencer! While some of the new systems can be a little noisier than the originals, it's generally stainless steel ones that are louder, and IIRC you said yours is mild steel.

[Trickydicky]

If you do go down the route of adding a 2nd silencer you may restrict engine power. As others have said check the exhaust is sealed correctly at the clamp. I replaced my exhaust last year and bought a nos clamp from club spares but still needed exhaust paste to help seal the joint. Also use a trolley jack to help support the silencer and hold it against the exhaust manifold,don't rely on the clamp when you tighten it to bring the two together.
You also may find that the flange on the exhaust may now be distorted and not sit correctly on the manifold, if it is you may just need to dress it back to shape.

[midget]

Actually, I have asked this question to many enthusiasts, and still have not got a definitive answer, not that I object to it----BUT why does the Minor emit this noisy overrun?
Possible causes are the position of the silencer--which could be negated by fitting a Marina/Mini silencer to the rear?
Cant be valve overlap as all A series are the same, I believe?
Cant be the size of the small pipe surely?

I have a 1'' 3/4 Maniflow LCB on the 2 door and there is no over run noise at all. It does have 2 silencers though. Maybe I should try disconnecting the rear box to test?
Would welcome your thoughts.

[myoldjalopy]

Did this make a big difference to the noise of the exhaust? I'm going to try some exhaust putty and then look at fitting a second silencer if that doesn't cure it.

It didn't really affect the sound of the exhaust, James. It just stopped the leak at the join. The exhaust wasn't very noisy to begin with, just the typical Minor overrun sound, which I love!

[James k]

It seems now that the exhaust is just inherently noisy so I need to fit an additional silencer. Does anyone know where I could get one that's the correct size?

Thanks

[RobThomas]

Mini is a good source of smaller bore pipework and bends...

http://www.ebay.co.uk/itm/Klarius-AN583 ... SwA3dYfsqY

http://www.ebay.co.uk/itm/Classic-Rover ... _eLS_HYBOw

http://www.ebay.co.uk/itm/Classic-Mini- ... Swux5YUS4L