1275 exhaust options

Post by **redcar** » Sat Jun 09, 2007 1:38 pm

Hi all, I'm fitting the Midget 1275 engine and not sure what exhaust to go for. I know the specialists do stainless systems, but I have heard of this type of LCB cracking on more than one ocasion. Interestingly I have looked into the Maniflow option ( good reputation in the mini racing scene) and they dont make the LCB in stainless as they say it would crack, Im sure this would be a very good system but at £300 not the cheapest. So any other ideas would be welcome.

Thanks, Dale.

Post by **picky** » Sat Jun 09, 2007 3:48 pm

depends on how much power you want. I believe that the standard minor system will bolt onto the 1275 without any issues, but this is not very efficient. I have the maniflow LCB, and it does rust! You can buy VHT paint (very high temperature) and if you spray that on the maniflow LCB then it would last alot longer I imagine. I sprayed it onto the manifold a bit too late so the surface rust came through anyway.

if you painted it as soon as you buy it then should not be a problem.

Post by **redcar** » Sat Jun 09, 2007 4:47 pm

Im not sure, but I think exhaust gases rot the inside a lot faster than any surface rust problems on the outside. What do you have after the maniflow LCB for exhaust?

Post by **picky** » Sat Jun 09, 2007 7:17 pm

I dont know, but I would have thought that the intense heat would mean that no moisture could ever get to the inside unless it is left standing for a long time!

I bought the maniflow exhaust system to go with the LCB, it has two performance silencers, one in the place of the normal minor silencer and one just before the end of the exhaust. they even give you a chrome exhaust finisher! I will admit its alot of money for what you get, although the exhaust system is painted so will not rust as quickly. It doesnt sound anything like a morris minor, and is a fair bit louder, although not as loud as your average souped up nova.

Picky

Post by **alex_holden** » Sat Jun 09, 2007 8:04 pm

Never seen steam coming from an exhaust on a cold morning? Exhaust gasses are full of water vapour.

Post by **Packedup** » Sat Jun 09, 2007 8:17 pm

As well as being quite acidic.

Post by **picky** » Sun Jun 10, 2007 8:06 pm

Re: exhaust rusting

I have had a look inside my manifold, and there is a coating of carbon all round the inside of the exhaust, when this is rubbed off the metal appears to have only a light coating of surface rust. I imagine the carbon/muck is protecting the metal. The outside has serious surface rust even though I have tried sanding it off and painting it in VHT

IMO the outside will rust faster than the inside, but its really a chemistry question and I am a little out of my depth.

Food for thought anyway.

Just wondering, what is it about stainless that makes it crack? Do the stainless ones always crack in the same place?? Modern exhaust systems tend to have those flexible joints to relieve stress in the exhaust manifold, I am assuming the stainless minor ones dont have this?

Picky

Post by **Welung666** » Sun Jun 10, 2007 8:12 pm

If ever you see a burnt out car even the day after it burnt it is rusty! It's the effects of very high temperature and water. This is the same as your exhaust just a sped up version. Exhaust gets very hot, cools down, gets damp overnight in the cool air and then heats up rapidly next day. The carbon deposits inside the exhaust will protect it to a point but the outside will suffer faster once the original paint has burnt off.

Post by **Pyoor_Kate** » Mon Jun 11, 2007 10:47 am

Just wondering, what is it about stainless that makes it crack? Do the stainless ones always crack in the same place?? Modern exhaust systems tend to have those flexible joints to relieve stress in the exhaust manifold, I am assuming the stainless minor ones dont have this?

IME it was atrocious quality that made it disintegrate. That and a not terribly good design in the first place...

Post by **picky** » Mon Jun 11, 2007 10:53 am

Kate,
I would be interested in any photos you have, or that anyone else has of the broken manifold, before and after would be very useful.

Picky

Post by **Matt** » Mon Jun 11, 2007 11:41 am

Ive got a mild steel LCB, made by ripspeed apparently. Its quite rusty, so I was intending to clean all the rust off electrolytically and spray VHT paint inside and out

Post by **dunketh** » Mon Jun 11, 2007 2:36 pm

Why should a stainless one crack?
(Excuse my complete novice approach to metallurgy here).

Magnex and the like have been knocking out SS manifolds for fords, vauxhalls etc for years. Then you've got companies like powerflow who custom build them to your spec provided you have a deep enough wallet.

Surely if a stainless manifold cracks its more to do with crap quality than metal properties?

Besides, manifolds never rot anyway. Just get a mild steel one. Fair enough exhausts fall apart every couple of years but manifolds get so hot they seemingly last forever, they also dont 'collect' water like a horizontal pipe would.

Post by **Matt** » Mon Jun 11, 2007 5:44 pm

as I understand it stainless is far more prone to fatigue. I think the problem is due to the length/shape and lack of support. But yes, with most things aftermarket (some noteable exceptions apply) the general quality seems somewhat poo!

Post by **Pyoor_Kate** » Mon Jun 11, 2007 9:50 pm

It wasn't actually the manifold that failed on mine; it was the first segment of the LCB exhaust...

Post by **Packedup** » Tue Jun 12, 2007 4:16 am

There's different grades of stainless, and they have different qualities. Not that I know what they are!

But stainless as a rule is more brittle, so more prone to fatigue failures if the system is flexed much. Presumably better quality systems use better quality metal, better shaped, and where needed more of it maybe? So it's sort of build/ design quality, but the same thing in mild might be passable due to the material being more forgiving. Or something like that

Post by **bmcecosse** » Tue Jun 12, 2007 7:41 am

Does anyone have an old cracked one they would like to sell me - i'll deal with it?!

Post by **LukeBoorman** » Tue Jun 12, 2007 12:02 pm

I have a stainless LCB system (Mr Grumpy's i think). Got it off eBay £150 about 2 1/2 years ago had only been bolted to sellers car. I fitted it with new straps under the car. I haven't had any problems. The manifold is a little tarnished looking due to the heat. Its a single box system, so noisy but i quite like that. The only issue was getting the thicknesses of the exhaust and inlet manifolds the same to prevent the exhaust blowing.

I have beefed up my head steady with a M12 bar and poly bushes to stop it all moving so much.

My mate has a 850 Norton Commando and he has constant stainless exhaust issues, but his engine vibrates a fair bit more than mine.

Post by **Peetee** » Tue Jun 12, 2007 5:05 pm

Its a single box system, so noisy

The two box system isn't exactly quiet either!

Post by **redcar** » Sun Jun 17, 2007 7:56 pm

Thanks for all your advice, think ill go the steel LCB route.