Original Cooper S manifold problem

[Gary Schulz]

I am trying to use my original Cooper S manifold on my restoration so I painstakingly had to rebuild it by replacing the large diameter pipe at the bottom (the part that attaches to the rest of the exhaust system). When I replaced the old rotted pipe I built up a fixture to accurately locate the old position so when I welded the new pipe in place it would be accurate viewtopic.php?f=3&t=20950&p=180462&hilit=header#p180462

It seemed I got a really good result and it reproduces the original locations well.

Now that I am assembling my car using this original repaired header I find that the route the RC40 exhaust pipe takes results in the pipe touching the central tunnel at the end of the remote shifter housing-

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Since this is the only pipe position that comes close it unfortunately results in an obvious downward turn at the point where it joins the silencer-

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Not sure what to do here because all these things are very unforgiving. I am thinking that maybe I need to use the different header (which I don't have). What is the best way to address this fitting issue? Is there a new header available that is similar to the size and function of the old original Cooper S one?

I have been dreading this...

[Dearg1275]

This makes a good substitute for the original manifold/header.

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D

[Gary Schulz]

Excellent. Thank you. I may have fiddled with it just enough to find a better location and fit but if it doesn't work out I will most likely try this out.

Gary

[Oneball]

Get a custom front pipe made up at your local exhaust place.

[iain1967s]

I think maybe your RC40 pipe is pushed too far forwards?

I had to use the Maniflow L71 angled extension to fit it onto my original S manifold.

I also have one of those Maniflow Freeflow manifold, and it has exactly the same exit position as the original S manifold. The L71 is designed for exactly this purpose.

[Gary Schulz]

Iain, I am unsure how far forward it is supposed to go. I was assuming the pipe should be pushed as far onto the manifold as possible but I can try backing it out and see how that looks. I am not familiar with the L71 extension pipe. I thought the RC40 was a direct fit...

[iain1967s]

If I remember correctly [couple of years since I did mine] the RC40 comes forward to the point that the Y collector would be for an LCB.

When using the original S or the freeflow manifold, it’s about 6” shorter so needs the L71 extension piece to make up the gap.

[Gary Schulz]

Maybe you figured this out then. I will need to have a look for that extension and give it a try.

[iain1967s]

I got mine from 7ent https://www.7ent.com/products/pipe-adap ... m-l71.html

Also, difficult to tell from your photo, but maybe the pipe is on backwards? IIRC the angled end is the rear box connection and the straight part slips into the L71 for the manifold connection. But then again, it could just be a different design - mine is the Maniflow double crimped box system.

Maybe this photo of my car might help give some idea where the ‘kink’ around the gearchange is...

[Gary Schulz]

Mine is the RC40 system (not crimped boxes). With the current line-up the pipe and silencer length seems correct. The tail pipe seems to be at the correct point. If I insert this L71 adapter it would push the whole thing out the back of the car (at least I think).

[iain1967s]

It looks like there are two different versions of the RC40 front pipe; well, three if you count the LWB version also.

Maniflow’s version stops at the LCB collector Y box, and requires the L71 extension to fit the original/freeflow manifolds. That’s what I have on my car.

Minispares also sell a longer version which goes all the way in one continuous run. So I’m guessing that’s the one you have?

I had to twist the L71 around quite a bit to get things to line up when I was fitting mine. I don’t see how that can be done for the single piece pipe... worst case you could cut the front end off and use the L71 with a slip joint to get everything in the right place.

[Gary Schulz]

Good point. If I cut the pipe I have and use this adapter it gives me another axis of freedom. I think I will try that.