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Exhaust Header
Posted: Mon May 02, 2011 1:05 am
by TBjerknes
I want to install a 1/2 SU on my 1959 Traveller, I think the best installation would also include replacing the stock exhaust manifold with a header. Is anyone aware of a manufacture of such an item or is there a plate available to cover the hot spot on the factory manifold, if I need to continue with that?
Thanks for the help
Re: Exhaust Header
Posted: Mon May 02, 2011 9:05 am
by chrisryder
you can get LCB manifolds (if that's what you mean by a header) and large bore exhaust systems from most minor parts suppliers, and Maniflow do a full stainless one too.
here's mine:[frame]
[/frame]
although my heatshield kind of blocks the view somewhat! it's a Long Centre Branch (LCB) in that the two outer (front and rear ports) go down and joint together into one, and then that pipe joins the centre pipe just as it exits the enginebay. that then goes to a scaled up version of the minor system (same route) with the exception of an extra silencer at the back (see below)[frame]
[/frame]
all of this is a larger bore than the standard minor. this is 1.5 inches as opposed to the 1.25 originally.
alternatively you can fit a marina cast one-piece manifold, i believe mmjosh is selling one. this is just like the minor one, but scaled up, and will take the 1.5 inch carb. this can still be fitted with a large bore system, you just have to use a downpipe instead of an LCB. you can ofcourse, separate the manifold and fit a separate inlet manifold to remove the hotspot.
Re: Exhaust Header
Posted: Mon May 02, 2011 2:39 pm
by TBjerknes
Thanks for the information. In regards to the heat shield is that a manufactured item or did you make it?
chrisryder wrote:you can get LCB manifolds (if that's what you mean by a header) and large bore exhaust systems from
most minor parts suppliers, and Maniflow do a full stainless one too.
here's mine:[frame]
[/frame]
although my heatshield kind of blocks the view somewhat! it's a Long Centre Branch (LCB) in that the two outer (front and rear ports) go down and joint together into one, and then that pipe joins the centre pipe just as it exits the enginebay. that then goes to a scaled up version of the minor system (same route) with the exception of an extra silencer at the back (see below)[frame]
[/frame]
all of this is a larger bore than the standard minor. this is 1.5 inches as opposed to the 1.25 originally.
alternatively you can fit a marina cast one-piece manifold, i believe mmjosh is selling one. this is just like the minor one, but scaled up, and will take the 1.5 inch carb. this can still be fitted with a large bore system, you just have to use a downpipe instead of an LCB. you can ofcourse, separate the manifold and fit a separate inlet manifold to remove the hotspot.
Re: Exhaust Header
Posted: Mon May 02, 2011 3:01 pm
by chrisryder
i made that. once i fitted the carb over the manifold i saw how close the float chamber was to that front pipe!
whipped out the cornflake packet and bolted it in place and drew around where i wanted the shield to go. bit of hacksawing and milling, and bending, and bob's your mother's brother.
[frame]
[/frame]
included a bit at the back to reduce heat rising up to the fuel pump feed pipe.
Re: Exhaust Header
Posted: Tue May 03, 2011 4:01 pm
by bmcecosse
No need for a heat shield........ the standard exhaust is perfectly adequate for a 948/1098 engine - and judging by your comment re a 'plate for the exhaust' I'm guessing you have an early 948 engine with H2 carb. The simplest mod is to use a Mini manifold which will take the HS4 carb and the Minor exhaust without ANY modifications - but it doesn't loose the hated hot-spot. So - an alloy Metro inlet manifold (which also takes the HS4 carb or the later HIF38) and the exhaust part only (cut the inlet off) of the later Minor (or Mini) combined manifold is the best way forward. The LCB and large bore exhaust is only a benefit with a much modified engine - can be a disadvantage with a standard engine.