quote from laurens: "Not sure if it's a good idea. I can remember that i saw a post of Swissghost that he got an broken pipes near the cylinder head. Could be caused by the wrapping ??"
laurens: take a closer look at the crack in my exhaust! this crack has nothing to do with wrapping. as a trained welder and metalworker, i tell you this is a material error! the pipes are way to thin for all the vibrations and the stress due to differences in heat and cold. if metal is stressed with different temperatures on the same piece, it begins to work against itself. that's physics. so, making sure (with wrapping) the temperature stays the same for the hole header (from cylinder exit to the cats), you release the stress on the steel. the wrap is made of ceramic and its very light. so no arguing cause of weight. this is not a normal stress caused crack. not at all. that crack would look very different. one other reason: material of the pipes and material of the header-piece (last 4cm) is not the same! also different ways of production of those two pieces. so, making sure the engine breathes out very fast, means the exhaust-temperature has to stay very hot, and the hot exhaust fumes run the cats well, you have to wrap the headers!!! period! my brother in law worked for a company producing exhaust systems and diesel particulate filter, they all agree with those facts! wraping the headers for the looks is one thing. but to do it for the reasons i do it, is a completly different story. by the way: mmc and all the engine and exhaust manufatures all agreed with me when they saw the pic of the crack and heard on the specifics of our engine and exhaust configuration.
quote from laurens: "Not sure if it's a good idea. I can remember that i saw a post of Swissghost that he got an broken pipes near the cylinder head. Could be caused by the wrapping ??"
laurens: take a closer look at the crack in my exhaust! this crack has nothing to do with wrapping. as a trained welder and metalworker, i tell you this is a material error! the pipes are way to thin for all the vibrations and the stress due to differences in heat and cold. if metal is stressed with different temperatures on the same piece, it begins to work against itself. that's physics. so, making sure (with wrapping) the temperature stays the same for the hole header (from cylinder exit to the cats), you release the stress on the steel. the wrap is made of ceramic and its very light. so no arguing cause of weight. this is not a normal stress caused crack. not at all. that crack would look very different. one other reason: material of the pipes and material of the header-piece (last 4cm) is not the same! also different ways of production of those two pieces. so, making sure the engine breathes out very fast, means the exhaust-temperature has to stay very hot, and the hot exhaust fumes run the cats well, you have to wrap the headers!!! period! my brother in law worked for a company producing exhaust systems and diesel particulate filter, they all agree with those facts! wraping the headers for the looks is one thing. but to do it for the reasons i do it, is a completly different story. by the way: mmc and all the engine and exhaust manufatures all agreed with me when they saw the pic of the crack and heard on the specifics of our engine and exhaust configuration.
here a better picture of my cracked exhaust on the right side!
I wonder how much greater the forces are on this joint than say the Moto Guzzi engines I am more familiar with. Although both are fitted as in-line engines, the Guzzi exhaust port is in line with the crankshaft rather than at right angles as on the S&S. The inevitable V twin rocking forces are radial so better absorbed on the former at the pipe to port joint. On the S&S they are axial of course with only the joint much further down the line to offer some flex.
A first impression left with me during my M3W test drive was the very noticeable movement of the engine particularly at start up and idle. That flex joint is certainly needed, but I wonder if it could be improved.
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
It also looks like the pipe is welded right at the break. In most Harley applications there are no welds at the flanges. Believe me when I say my Harley shakes at idle and the exhaust is mounted on sliding rubber mounts at the rear of the bike. My mufflers can move as much as 5mm to 6mm lengthwise to the bike. This puts lots of stress on the flanges.
I've seen videos of the M3W motor vibrating on idle and it's no where as much as the rubber mounted Harley touring bikes have.
But with the necked down tip of the header pipe welded to the larger pipe, that has to be a weak point. Just as the pipes are breaking at the welds on some of the Brookland pipes leading into the mufflers.
I've made up a few V-twin header pipes from scratch using "J" and "U" bends with straight pipe. I've also modified several car header systems. I've used both MIG and TIG welding techniques and other than looks, both seem to have held up well.
I would never use anything less than 16 gauge tubing. All of my pipes have been mild carbon steel, not stainless. 16 gauge is 1.6mm wall thickness. At this thickness I've never had a pipe break at a weld or break period.
The M3W is unique in that the length of the header pipes is quite long and the flex couplings are not all that flexible. This length does put an unusual amount of stress at the head flanges.
Good point about using mild steel in preference to more brittle stainless for exhaust front pipes. Whilst as Guzzi parts distributor in the UK we sold plenty of the standard mild steel double skinned chrome plated pipes during the 20 years I was in the business, they were bought to the best of my knowledge, exclusively for cosmetic reasons.
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
today, took out all the leather parts. will clean them wet and then treat them with beeswax-cream. that stuff is great....for the leather: no damage from the sunlight and completely waterproof! will change also the aluminium plates form the exhaust mounts at the cockpit inside. will use stainless steel ones instead. also, have to clean out the cockpit....bloody dust!!!
