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Semi Proffessional Prat
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3,489 Posts
Discussion Starter · #1 ·
Sounds simple, how can I draw two parallel lines along the length of a piece of tube. 2 lines 27mm apart, on some 44mm diameter tube.
 

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Rust buster...
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602 Posts
Clamp tube to flat workbench.

Tape pen/scribe/whatever to a block of wood, run along side of tube.

Spin the tube around the required amount, and repeat...
 

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richard rawlplug
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8,132 Posts
ask rolf harris.
 

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Semi Proffessional Prat
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Discussion Starter · #8 ·
Mr Monkey, yes, that'll do. I knew there was a simple solution, I just couldn't see it.

Alan, I am trying to make a better flowing exhaust system for my truck, as you are probably (possibly?) aware they have what's known as a hockey stick exhaust. It runs from number 4 to number 1, then back on itself. In effect the exhaust hits a brick wall, and not at all efficient. The exhaust manifold is a tube, set into a D groove in the head. With the help of Roy the racer, a better flowing system is in the pipeline, and the two 27mm lines are for the top and bottom of the exhaust ports, which are square. I am using a piece of 44 mm tube, to make flanges for each port, then slit lengthways, and a flange and end plates fitted.

Hope that makes sense.
 

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Premium Member
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5,809 Posts
Mr Monkey, yes, that'll do. I knew there was a simple solution, I just couldn't see it.

Alan, I am trying to make a better flowing exhaust system for my truck, as you are probably (possibly?) aware they have what's known as a hockey stick exhaust. It runs from number 4 to number 1, then back on itself. In effect the exhaust hits a brick wall, and not at all efficient. The exhaust manifold is a tube, set into a D groove in the head. With the help of Roy the racer, a better flowing system is in the pipeline, and the two 27mm lines are for the top and bottom of the exhaust ports, which are square. I am using a piece of 44 mm tube, to make flanges for each port, then slit lengthways, and a flange and end plates fitted.

Hope that makes sense.
Just tell Roy to make a set of zoomies with some bike baffles. Sorted. :tup:
 

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Semi Proffessional Prat
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3,489 Posts
Discussion Starter · #10 ·
Well that's the kind of thing, but because the head had a d groove down it, still got to make it fit. Most heads are flat on the exhaust ports, but mine isn't. New engine is ready to go in, and I see no point in generating power if I am going to loose 20% plus in the manifold. It's not a question of power, more efficiency in the system. Oh and the learning factor as well.
 

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Nowheresville
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3,056 Posts
Get a length of 1" x 1" angle (aluminium or iron should do), lay it on the tube and draw a line along one edge of the angle. Move it round the tube 27mm to where your next line will be, then draw the other line. Obviously I'm assuming your tube is straight!
 

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Registered
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12,503 Posts
I had a MK2 Zephyr with a six branch tubular header - that used 'D' shaped steel spacers that corresponded with the radiused bit that the 'hockey stick' tube locates in and acted as a flat surface for the header flanges to sit on.
 
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