paulf
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| posted on 25/9/04 at 09:15 PM |
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Missing exhaust packing.
I have been noticing that the exhaust noise from my car has been increasing, to such anextent that it was to noisy to drive any distance even with
earplugs.The performance seems a bit flat also compared to before.
Tonight i took of the silencer that has only done about 800 miles and found it to be completely empty of packing.
It is an MGB rear box and a decent make {bosal}.
I dont think it is worth repacking it as i would have to buy packin and it would be difficult to make a neat job of cutting it open.
Why has all the packing gone so quickly, could it be a faulty box or just that it is to close to the engine ?
I now need to find something decent to replace it with any suggestions?
Paul.
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Mark Allanson
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| posted on 25/9/04 at 09:46 PM |
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Bosal is the cheapest of the cheap - and then some!
When I was MOT welding for a living (hard work) I had replaced a system with a bosal, and the next year it came back blowing, rusted out, sagging in
the middle. They are OK for the last year of a cars life, just to get it through the test.
Treat your car to something decent
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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paulf
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| posted on 25/9/04 at 10:11 PM |
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I was told they were a popular make and ok, must have been conned. Do you think it failed just because it is a crap make or incorrect use of it?.It is
totaly empty of packing and seems a lot lighter than when i fitted it.I dont want to spend out on another one and have the same problem.
I intend to buy a proper repackable box sometime in the future but at present i am undecided about fitting a blade engine during the winter, so dont
want to spend to much on an exhaust yet.
I tried a carbon can from a ZX9 but that is just as noisy and im not sure if it would last either.
Paul.
quote:
Originally posted by Mark Allanson
Bosal is the cheapest of the cheap - and then some!
Treat your car to something decent
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Mark Allanson
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| posted on 25/9/04 at 10:23 PM |
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It may be that the harmonics of the system are just right (or wrong) and are burning out the packing.
Bosal are really cheap so it may be worth cutting it open and repacking, your welding won't be worse that the Usbeckistahn 7 year old that
welded it up in the first place
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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Dave Ashurst
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| posted on 26/9/04 at 02:28 AM |
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Paul,
I know what you mean!
In my experience, running with the xflow a bit out of tune - e.g. too rich, too lean or timing out can eat the silencer packing big style.
It's kind of a vicious circle. Once it starts then the loss of wadding makes it worse.. and so on.
Also any gaps in the packing seem to start it off too; it needs to be packed as uniformly as possible.
IMHO it probably is worth buying a bag of basalt wool or similar, modifying the silencer you've got for now and getting the carb(s) and timing
set up properly.
On the other hand, what sort of earplugs are you using? Just retune the engine and get some better ones perhaps?  
not much help, I know
cheers
Dave
PS I say I know what you mean - but I still haven't even HEARD your car yet, mate... 
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paulf
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| posted on 27/9/04 at 08:50 PM |
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Thanks Dave i remember you mentioning the loss of your silencer packing before, The engine is running on a twinchoke downdraught and electronic
distributor from a fiesta. I have set the static ignition at 12 degrees and cant really do anything with the carb as regards setup.It does go
reasonably well but suspect that if i keep the crossflow i need to fit twin 40s and have them set up.
I have found a source of basalt wool and will get some next week.
In the mean time i have just fitted the ZX9 carbon can, it does seem to run a bit beter now but is still rather loud but now a bit more mellow
sounding.
I also found a company called GDS exhausts who will make me a can with a 50mm bore and 150 od x 450mm long box for £65 , and a local agricultural
supplier who says that he can supply something similiar from his stock of tractor spares.
Paul.
I am using decent earplugs obtained from a local bike shop with an SNR rating of 34 if i remember correctly.
I was hoping to make it to Anstey one month before the winter sets in but it wont be this month as i am working yet again.Maybe we could arrange to
meet up one Sunday morning or lunch time if we have some good weather forcast and im not working.
Paul.
quote:
Originally posted by Dave Ashurst
Paul,
I know what you mean!
In my experience, running with the xflow a bit out of tune - e.g. too rich, too lean or timing out can eat the silencer packing big style. IMHO it
probably is worth buying a bag of basalt wool or similar, modifying the silencer you've got for now and getting the carb(s) and timing set up
properly.
On the other hand, what sort of earplugs are you using? Just retune the engine and get some better ones perhaps?
not much help, I know
cheers
Dave
PS I say I know what you mean - but I still haven't even HEARD your car yet, mate...
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