Large bore exhaust

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Sidney'61
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Large bore exhaust

Postby Sidney'61 » Mon Oct 10, 2011 11:38 am

My 1275 has a large bore exhaust system fitted and has done since i've owned it, this is however rather brittle and has already snapped twice so needs replacing. How much does the large bore affect the performance? would the midget engine just be suffocated with a standard exhaust? the reason I ask is that I cant afford a whole new large bore system and the standard is so much cheaper! Also, are the usual minor parts suppliers the best place to buy exhausts from?

Thanks
Andy
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______


bmcecosse
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Re: Large bore exhaust

Postby bmcecosse » Mon Oct 10, 2011 11:44 am

If it's just a standard Midget engine, then it won't be too badly restricted, although obviously it won't help! Can you not just weld/strengthen the exhaust you have?
Last edited by bmcecosse on Mon Oct 10, 2011 1:30 pm, edited 1 time in total.
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mike.perry
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Re: Large bore exhaust

Postby mike.perry » Mon Oct 10, 2011 1:03 pm

My large bore LCB system has been on the car since Jan 06 with no problems. Can you just replace the offending section?
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PSL184
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Re: Large bore exhaust

Postby PSL184 » Mon Oct 10, 2011 3:09 pm

Birmingham MMC sell the large bore in mild steel and in sections. Very cheap :-)
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Sidney'61
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Re: Large bore exhaust

Postby Sidney'61 » Mon Oct 10, 2011 4:45 pm

By the way I can't weld so whatever I do its going to cost to get it sorted out, my main worry is that this is the second time it has snapped and in a different place so I just fear that the whole thing is just too brittle and wonder if I get it welded up how long will it be before another part fails. I'll try and get a quote to weld it back on and we'll see what happens :-?
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______


Sidney'61
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Re: Large bore exhaust

Postby Sidney'61 » Mon Oct 10, 2011 4:54 pm

actually I'm looking into the birmingham mmc option now thanks Rich, it may sound silly but is it ok to add a mild steel section into the stainless system?
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______


PSL184
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Re: Large bore exhaust

Postby PSL184 » Mon Oct 10, 2011 6:02 pm

Sidney'61 wrote:is it ok to add a mild steel section into the stainless system?
Perectly acceptable - I've got a stainless LCB and the BMMC system on my black traveller - been on for about 2 years now and its still looking the same as when it went on. If yours is fracturing it would imply that it is fitted too rigidly and not being allowed to flex with the engine / body movement. I'd suggest looking at a new set of the correct mounts.....
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bmcecosse
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Re: Large bore exhaust

Postby bmcecosse » Mon Oct 10, 2011 7:23 pm

If it's the 'Falcon' system - I think others have also reported cracking problems......
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mike.perry
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Re: Large bore exhaust

Postby mike.perry » Mon Oct 10, 2011 9:58 pm

What is the Falcon system and how would one know if one had it?
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chrisryder
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Re: Large bore exhaust

Postby chrisryder » Mon Oct 10, 2011 10:21 pm

the 'falcon' one is the MMCB one. It has a little rectangular plate welded on saying 'FALCON'. Maniflow ones (i presume) have a 'MANIFLOW' plate welded on.

I'm not sure it's a particular fault with the Falcon one, more in how well it's fitted. If you fit a large bore system in the same way as a standard system, the manifold will fracture at the front due to the weight of the front silencer bouncing and flexing. If an extra strap is put at the front, just infront of the front silencer, then no fracturing should occur.

If you fit a Maniflow one badly, it'll fracture too. It's the nature of stainless steel.

mike.perry
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Re: Large bore exhaust

Postby mike.perry » Mon Oct 10, 2011 11:11 pm

Mine is the Birmingham system.The only complaint I have is the way that the section over the axle is joined to the front silencer section where it slopes up to the axle, and in order to get the pipe to fit over the axle I have had to twist the silencer so that it is almost on its side and only just misses the chassis crossmember. It would seem far more logical to join the pipes on the straight section behind the silencer then they could be twisted to any required angle
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Sidney'61
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Re: Large bore exhaust

Postby Sidney'61 » Tue Oct 11, 2011 11:25 am

If I do just replace the front section how do I go about separating it from the back section? They've obviously been connected for a long time!

P.S. I'm at my student address so very limited on tools!
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______


chrisryder
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Re: Large bore exhaust

Postby chrisryder » Tue Oct 11, 2011 1:51 pm

heat, soak with oil, hit with hammer, swear, repeat.

mike.perry
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Re: Large bore exhaust

Postby mike.perry » Tue Oct 11, 2011 3:12 pm

Kick the hub caps and have a cup of tea
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daveyl
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Re: Large bore exhaust

Postby daveyl » Wed Oct 12, 2011 4:42 pm

Just to confirm but do you have a Triple branch (lcb) front exhaust OR a mini/marina manifold with big bore down pipe, attached to a big-bore system?

Sidney'61
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Re: Large bore exhaust

Postby Sidney'61 » Wed Oct 12, 2011 4:49 pm

I have an lcb manifold. I've now managed to get it all apart in the correct places and have ordered a new front section :)
Andy W____________1961 2-door 948cc (Sidney)_____________1963 2-door 1275cc (Emily)_______


rayofleamington
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Re: Large bore exhaust

Postby rayofleamington » Thu Oct 13, 2011 12:34 pm

If you are looking to replace the LCB version and have a fairly standard Midget engine - I'd certainly recommend a Marina style manifold and large bore (single) pipe.
The Midget runs much better than people expect with the Minor 1000 carb/manifold/zaust.

If I'm correct you can mix and match the Marina manifold + large front pipe in place of the LCB and keep the remainder of the large bore exhaust.
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Jan 06: The Minor SII Africa adventure: http://www.minor-detour.com
Oct 06: back from Dresden with my Trabant 601 Kombi
Jan 07: back from a month thru North Africa (via Timbuktu) in a S3 Landy
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where to break down next?
2013... managed to seize my 1275 just by driving it round the block :(


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