Aluminium Manifold?

[ddu]

What temps do the std cast iron exhaughst manifolds run to?<br>
I work in a large tooling manufactures and have the ability to cast an exact copy of the original manifold in Lm6 or Lm25 ally.. <br>
I know some modern cars now have ally outlet manifolds<br>
and wondered if my sprint would still perform the same.<br>
The lightened flywheel/bigger carb and K n N brigade would benifit from a huge weight saving(about 7kg at a guess) ,but would it collapse with the heat?<br>
does anyone have any tech specs or info?<br>
Would there be a market for them?<br>
Any thoughts anyone?

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[Carl]

Isn't LM25 what the head itself is made from ?

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[davepoth]

LM25 should be fine, I'm pretty sure it's the same stuff used for the Dolomite cylinder head, and I can't see the manifold getting hotter than the combustion chamber.

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[ddu]

Ta.<br>
Wanna buy one?<br>
new engine going in, so I'll do myself one and let you know.<br>
Is there anything you guys dont know bout dollies?

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[Sprint36]

Great idea! Anyone for aluminium exhaust valves? THey should be nice and light!<br>
<br>
Melting point of aluminium 660C<br>
Melting point of cast iron 1200C<br>
<br>
David

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[alun n]

<!--EZCODE QUOTE START--><blockquote><strong><em>Quote:</em></strong><hr>and I can't see the manifold getting hotter than the combustion chamber<hr></blockquote><!--EZCODE QUOTE END--><br>
<br>
You can bear your hand on the head when the car is hot...I wouldn't recommend trying the exhaust manifold!<br>
<br>
1: The head and combustion chambers have a water jacket cooling them (usually)<br>
2: Added friction heat in the manifold due to 90 degree change in direction and slowing of the gasses.<br>
<br>
I suggest that what they could make out of ally is already made of ally, ie inlet and head only. They already had a problem with the engine being top heavy toward the exhaust side hence contrived alterations to the Sprint mounts/subframe, so if weight could have been saved here I'm sure it would have been?<br>
<br>
Worth a sacrificial guinea pig though to prove me wrong...

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[Jon Tilson]

The blow torch or what it gets pointed at?<br>
<br>
No way could Ally stand to be a dolly zorst manifold...<br>
<br>
Alun is spot on...although I wouldnt call the interaction between exhaust gases and manifold friction but thats being pedantic.<br>
<br>
Once a physicist....always a physicist...<br>
<br>
Jonners

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[tinweevil]

Could an alloy be ceramic lined? That stuff can achieve pretty astonishing thermal differentials. You'd be totally reliant on 100% integrity of the ceramic, a crack or gap would get exploited by the gasses pretty fast. May be a runner for the racers. Like Alun, I'd love to see a trial. I doubt an exact copy would take the strain at the downpipe joint.<br>
<br>
How about:<br>
An inlet manifold with fittings for modern injectors.<br>
Alloy air box back plate (gotta be a few kilos there).<br>
a plenum chamber to fit above and accept a cheap/common/good throttle body?<br>
<br>
Tinweevil

<p>1978 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/704">Dolomite Sprint</a><!--EZCODE LINK END--><br>
1972 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/754">Spitfire IV</a><!--EZCODE LINK END--><br>
1968 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/705">GT6 II</a><!--EZCODE LINK END--><br>
1973 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/755">Dolomite Sprint</a><!--EZCODE LINK END--><br>
1980 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/864">Dolomite 1500HL</a><!--EZCODE LINK END--><br>
39 anorak points on the Nicholas scale<br>
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[Sprint36]

Sorry I may not have made my sarcasm clear there! No way will an aluminium exhaust manifold work. If you want proof fix a bit of alu to your manifold with a jubilee clip and watch it melt when you run the engine hard. If it doesn't melt it will at least go soft. Exhaust gas temp from a petrol engine at full load can be anywhere between 800C and 1000C depending on set up (mixture, timing, etc).<br>
<br>
Recreating the Weber inlet manifold (with injector bosses) would be a much better use of resources. If you can turn them out for under a ton you'll have a queue forming at your door. Let me know and I'll be at the front!<br>
<br>
David

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[SprintMWU773V]

Go the whole hog and have one made from some space age material. Did a week's work experience at mclaren F1 team in Woking some time back and they used Titanium I think, very light and doesn't melt on their race cars, presumabaly cos the engines don't last long enough.<br>
<br>
Mark

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[alun n]

...as a physicist you will know that you cannot destroy energy, only change it from one form to another. The gases slow down as they change direction and this energy loss is dissipated as heat; if its not friction what would you call it?

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[davepoth]

I guess some is lost as noise, but good point. <br>
<br>
I stand corrected about the manifold. But how hot does the combustion chamber get then?

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[barracuda816]

alun i dont understand, you arn't saying the heat is a by-product of friction are you? friction only applys a VERY small amount to gasses, the main reason the gasses slow is due to obstruction (the pipes) alowing the molocules from dissapating in random directions this causes the molocules that are being prevented from excapeing (in random directions) to colide with each other causing turbulence. can any one enlighten me about the sciences of stacking (i think thats the term) the exaust pulses to premote a sort of sucking the gasses out of the engine. trying to design exaust header (and system) not to build yet but just because im bord of researching cylinder heads (still dont quite understand combustion chamber shapes), cams inc vvt, the sleeve valve engine (very confusing if you look at the Knight version), doube helical gears, magnetic fields (to replace main brgs) and a multi valve system to increase the eficiency of carbed cars by reducing fuel loss by scavenging. im not a geek am i? <!--EZCODE EMOTICON START :( --><img src=http://www.ezboard.com/intl/aenglish/im ... /frown.gif ALT=":("><!--EZCODE EMOTICON END--> <!--EZCODE EMOTICON START 8o --><img src=http://www.ezboard.com/intl/aenglish/im ... s/nerd.gif ALT="8o"><!--EZCODE EMOTICON END--> (oh and sorry for hijacking the thread <!--EZCODE EMOTICON START :p --><img src=http://www.ezboard.com/intl/aenglish/im ... tongue.gif ALT=":p"><!--EZCODE EMOTICON END--> )

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[Sprint36]

Getting back on topic (sort of), making inlet manifolds for webers or throttle body injection would be time well spent. Get you hands on one and see what you can make them for. Who has one they want to loan to make a pattern?<br>
<br>
David

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[Carsreunited]

I think Stourbridge Triumph might have one. I'm sure he would insist on it being a club supplied product though if it was a success!<br>
<br>


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