I just bought as set of "Gaurdian" exhaust headers and pipes because I thought they would look cool on my 455 Olds. pictured here: http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=2488943546&ssPageName=STRK:MEWN:IT Since boat exhausts have water injection to muffle and keep them cool..., I don't think they will last long..., or at all on the street...! Has anybody ever run anything like these on the street? And would a High temp coatings keep the heat from building up in the aluminum casting...??? Mark
Edelbrock made some cool ones, I always wondered if you could plumb them into the cooling system? I vaguely remember this topic coming up 3+ years ago?
I think this could end in disaster... Aluminium has a low melting point, which is why you don't see it used in exhaust systems on cars at least. If it did work I think will would at least see it used in race cars where 'light weight' aluminium headers and even a complete system would be a great advantage over a steel/stainless steel system. I remember as a kid (mis-spent youth) throwing aluminium coke cans into my dad's wood burner because they were the only metal objects that would melt !! They may be used on boats because as you say (I can't confirm) they are cooled by water injection.
[ QUOTE ] you would have to fill them with block filler or something [/ QUOTE ] How about having them ceramic coated on the inside. The same as whats done to pistons, which increase's resistance to detonation but more important to your application reduced heat transfer.
I know a little about ceramic coating. I think its 'sprayed' on or to use the proper term a 'high temperature plasma process'! Its not as expensive as it sounds, try these guys as a starting point www.swaintech.com. I've seen pictures of it on pistons where the flame from a cutting torch was placed on it and it had no affect. Overall I think its pretty good stuff.
These aluminum logs are notorious for breaking at the bolt holes where the tabs are. I have had many, and I think only one pair was un****hed. These were in boats that might not have been hitting the same kind of bumps that a car on the road would.
The pyrometer on my Mack never goes above 1200 deg. on hard pulls at full throttol. Thats with 19 to 1 compression. I don't think A gas motor would get over 5 or 6 hundred deg. at the manafolds.Plus does't the water cooled exhaust on a boat have something to do with cooling the motor also?
As I recall from a Rayson Craft V-drive boat I had, the water cooled the engine, then went through the water jacketed exhaust manifolds and then was put into the actual exhaust outlet. The flow MAY have been through the exhaust jacket first and then the engine since the lake water is relatively cool and may have been "tempered" by the manifold before it hit the engine. Hooking them into the cooling system on a car is asking for overheating problems in my opinion. I'd hang them on the wall as garage art or sell them back to a boater.
In the early 60s Pontiac put aluminum exhaust manifolds on there light weight SD cars. They found the manifolds could not be used on stock cars just on the drag cars. Even then the occasional drop of aluminum was found on the ground under the car. Sorry it dont look good for your boat parts ):
my friends brothers old OLD beater *** mercedes that he got for 150 bucks had an system (not manifold) made of cooke cans sodered together. it stuck for a while too and didnt even melt.
Suffice to say the answer to your question is no. Sorry they sure do look neat, but I think there are to many difficulties to overcome. You'd have to seal them up so that the exhaust doesn't leak back out the water inlet. Ceramic coat them inside and out and it would still be iffy...
I say go for it. Seems that everyone here is telling you it shouldn't work, but no one has actually tried it. I say got for it. If it doesn't workand you slag your manifolds, your only out a few hundred bucks. You could also plumb in a seperate axiliary cooling system just for the exhaust manifolds with an electric fan and a Honda radiator or something. -Jeff
[ QUOTE ] I say go for it. Seems that everyone here is telling you it shouldn't work, but no one has actually tried it. I say got for it. If it doesn't workand you slag your manifolds, your only out a few hundred bucks. You could also plumb in a seperate axiliary cooling system just for the exhaust manifolds with an electric fan and a Honda radiator or something. -Jeff [/ QUOTE ] I agree. Damn I'm begining to think these boys do the traditional way to far, could it be they use only tried and true because of lack of imagination? I find that hard to believe but it's the way they come accross. But their real good at verbal ***ault. Fire away Boys!
[ QUOTE ] I agree. Damn I'm begining to think these boys do the traditional way to far, could it be they use only tried and true because of lack of imagination? I find that hard to believe but it's the way they come accross. But their real good at verbal ***ault. Fire away Boys! [/ QUOTE ] I don't think it's a lack of imagination. One the reasons I chose to give a "no" on the idea has to do with metallurgy. The aluminum alloys from the 50's and 60's were pretty piss poor. I think they'll end up ruined. But then again it's his money. The other thing is sealing the damn things, you have the water inlets and the ends aren't really conducive to addint he rest of the exhaust,or at least the Nailhead ones I had weren't. But then maybe you just trying to be a ****. Because that's what you're coming off as....
"You could also plumb in a seperate axiliary cooling system just for the exhaust manifolds with an electric fan and a Honda radiator or something." -Jeff" You have got to be out of your mind. That's about the most ignorant automotive modification ever conceived. You've got to be joking . . . right?
This has nothing to do with traditional or not, or lack of imagination. What a dumb-*** comment about a straightforward technical question. The question is whether an aluminum exhaust manifold can work. As a real ****in metallurgical engineer, not someone that has heard this or that BS, I deal with facts and knowledge. The answer is a definite maybe. It will not work if you pull a long full throttle run. Ever see a header glowing red? Red iron means like 1300-1500 degrees F. Aluminum melts at roughly 900-1000 F, depending on alloy composition. Do you see a problem here? However, the manifolds are thick and there is some heat conduction away from the immediate hot spots, so as long as you keep it moving with air flow over them (providing cooling) and not a real heavy throttle to keep the heat level lower, they will probably hold up. To my knowledge, the boat exhaust has water run through and then out the exhaust exit, they do not recirculate the water. Not only does this provide cooling, it also muffles the sound some. If the car is open hood and exposed engine it will have a much higher chance of success, as the aluminum can have cooling from the exposed air. I would agree that the internal ceramic type coatings are a good idea, but would leave the outside surface uncoated to help the cooling heat transfer. It will be hard to coat the inside with them being used and having the surface all contminated. Kind of hard to sandblast the inside surfaces completely. Depending on how much money you have in them, give it a try, worse that happens is they will either crack, or start to sag and distort. They won't turn to liquid, it will just get so weak as it nears the melting point, that they will have no strength and will more than likely get a huge exhaust leak or fall off the flanges due to the weight. I personally would not try it, but you can take the above info and decide for yourself.
[ QUOTE ] The pyrometer on my Mack never goes above 1200 deg. on hard pulls at full throttol. Thats with 19 to 1 compression. I don't think A gas motor would get over 5 or 6 hundred deg. at the manafolds.Plus does't the water cooled exhaust on a boat have something to do with cooling the motor also? [/ QUOTE ] I think that it depends on the motor what the actual exhaust tem will be. I know that I have a real hard time keeping 1200 degree header paint on the headers on my small block. The real heat problem will be where the headers meet the exhaust port. I don't know if I can go the whole '60s metalurgy thing. Not to be testy but just food for thought. I had a '39 Flathehad Harly that had aluminum heads. It was air cooled and the heads are where the combustion happens. I don't recall what combustion chamber temps are but I'm sure one of the numbers guys does. Lots of flatheads run aluminum heads also. Now getting back to it, I think that the ceramic coating on the inside is a cool idea. If the headers are already paid for why not give it a whirl. if it works you could be starting a new trend. Oh one other thing that just occured to me. As I was going into the garage to try and do something productive. Ford ran aluminum exhaust mainfolds on the FE for a awhile. I'm sure there was a reason that they abandoned the idea. But I have seen the old manifolds at swap meets, they are usually pretty pricey. I think they are a 427 item. Won't work on your standard run of the mill 390.
[ QUOTE ] However, the manifolds are thick and there is some heat conduction away from the immediate hot spots, so as long as you keep it moving with air flow over them (providing cooling) and not a real heavy throttle to keep the heat level lower, they will probably hold up. To my knowledge, the boat exhaust has water run through and then out the exhaust exit, they do not recirculate the water. Not only does this provide cooling, it also muffles the sound some. [/ QUOTE ] When I had a pair I thought about it, but after looking at them they ended up not seeming to be as thick as I thought they would be, there was a water jacket on the main section. I think you can see it on the pics at the link he posted. As for my comment about aluminum from the 50s and 60s, this basically came from dealing with motorcycle engines from that era. Especially two stroke, they seem to be much more prone to meltdown than the later engines were. I was told by an engineer at Yamaha that the metallurgy made great leaps in aluminum alloys at the end of the 60s and into the 70s. I was also told that castings improved at that time as well. Maybe it was BS. But I did notice that have the jetting a little lean on a mid 60's race bike had it melt down very quickly were the mid 70's bikes seemed to withstand a little more. Could it have been the age of the metal? There didn't seem to be near the problems with 4 strokes as the 2's. I think it's much easier to make a head and piston work under these conditions than an exhaust. The combustion chamber of a four stroke only sees the heat every other stroke it is then scavenged out of the combustion chamber and replaced with a new cool fuel charge. The exhaust is under constant onslaught from the exhaust. Therefore the heat will be higher there. I am a firm believer in ceramic coatings and there are a number of them you could try. And yes the manifolds look very cool. Would be great on a hoodless car. Sure give it a shot...
I don't think it's a lack of imagination. One the reasons I chose to give a "no" on the idea has to do with metallurgy. The aluminum alloys from the 50's and 60's were pretty piss poor. I think they'll end up ruined. But then again it's his money. The other thing is sealing the damn things, you have the water inlets and the ends aren't really conducive to addint he rest of the exhaust,or at least the Nailhead ones I had weren't. But then maybe you just trying to be a ****. Because that's what you're coming off as.... [/ QUOTE ] Sealing the water ports will not be hard or nessecery a: use em as suggested with a seperate system b: tap and plug em C: the air space betweem will have a cooling effect of it's own sorta like a heat shield. I may or may not sound like a ****, it's of no matter to me. I call em like I see em Good or Bad. Sometimes folks don't like that.
[ QUOTE ] Sealing the water ports will not be hard or nessecery a: use em as suggested with a seperate system b: tap and plug em C: the air space betweem will have a cooling effect of it's own sorta like a heat shield. I may or may not sound like a ****, it's of no matter to me. I call em like I see em Good or Bad. Sometimes folks don't like that. [/ QUOTE ] If you use the water ports as suggested it'll be a total loss system as it dumps the water into the exhaust and does not recirculate it.
[ QUOTE ] If you use the water ports as suggested it'll be a total loss system as it dumps the water into the exhaust and does not recirculate it. [/ QUOTE ] That makes A: out of the question.
I seem to recall hearing someplace that they use aluminum for cylinder heads? Aluminum heads don't melt down that often, even the early flathead heads cast using substandard aluminum in the 40's and 50's. Or the early aluminum Buicks. If an exhaust port won't melt with proper cooling, then the same should hold true for an aluminum manifold with proper cooling. 'Course the head has more material around it probably. FWIW, air cooled VW heater boxes have cast aluminum inner pipes run almost directly off the heads, and even without cool air moving over them(like when the heater is disconnected)they don't melt. -Jeff
I should have taken a picture of my headers the other day, with the big tunnel ram on it the front tubes were bright orange. if those things were on it there would have been molten aluminum blasted all over the garage. aside from the novelty I see absolutely no reason behind using them, maybe you could take the steering pulleys and cables out of the boat and hook them up too? Paul
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