More 1275 exhaust manifold questions....

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More 1275 exhaust manifold questions....

Postby austinh7 » Mon Sep 12, 2016 11:01 am

Hi, I have a similar issue to the recent 1275 exhaust manifold questions thread but with a difference or two.

Currently I have 1275 (Sprite I believe) engine, with a 12G787 combined manifold. HS4 carb.

However I want to fit a better inlet manifold, I have a nice Oselli torquemaster with HiF44, K&N etc ready to go.

So the questions are:

1. What is the best bet for exhaust manifold? If buying new it seems the options are fairly limited to a Large Bore L.C.B. Exhaust Manifold (See #2). Looking at the previous thread it seems some modification / butchery can be done to existing manifold to split them.

2. Currently running a standard exhaust, which I think needs to be upgraded to large bore so that it can "breathe out" properly. So is it worth biting the bullet and going for the full Large Bore manifold and exhaust in one hit (and hoping the wife is out when it gets delivered)?
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Re: More 1275 exhaust manifold questions....

Postby geezer » Wed Sep 14, 2016 5:50 pm

I have twin HS2 carbs on mine. I did use the 1275 Spridget exhaust manifold. It was a bit tricky making the pipe bent at the manifold outlet. From there I ran 1 3/4" pipe all of the way back. I'm pleased. The best part is getting rid of that crappy clamp system at the original manifold to pipe connection.

BTW I'm not a fan of headers. I suppose for the ultimate in performance a header is a must. For the street a cast iron manifold is much more reliable.

Here is a link to my journal on another site. You'll have to scroll down a few to find it. Hope that helps.

Here's a link on this site. I also tried a Rover Mini exhaust manifold but that presented a challenge. I may still use the Rover Mini manifold when the 1275 goes in the car.

Give an Englishman a car and he'll make it leak
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Re: More 1275 exhaust manifold questions....

Postby gjoakes » Fri Sep 16, 2016 5:45 pm

I did similar to what geezer did and for mostly the same reasons. I did only use 1-1/2" piping. I figured if it was good enough for original Spridget it was good enough for the Morris Minor. The first couple inches, that mates to the manifold, is just standard Spridget piece. The rest is fabricated from 1-1/2" u-bends and straight sections.

Altogether, system works real well and can be made from commercially available mandrel-bent tubing sections. I'll try posting a few pictures.
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Re: More 1275 exhaust manifold questions....

Postby Panky » Fri Sep 16, 2016 6:04 pm

Nice job, I'm about to fit the clamp type manifold so your pics will be a big help in getting the pipe run right :)
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