Lotus Elan

Strombergs .. Removing the emission control

PostPost by: billwill » Mon Oct 11, 2010 10:51 pm

Looking at the various engine bay pictures in these forums
such as this one:


I see that a number of people with emission controlled Strombergs have removed the over-head air heater pipes and blanked off the ports for those pipes.

How does that work then? I presume you have removed the throttle butterflies nearest the block, but doesn't that leave lots of holes in inconvenient places and doesn't it mean that there is no balance pipe between the two inlet manifolds (see workshop manual page L34)?

Would it not be simpler to just remove the whole adaptor block thingy. Will the engine run on Strombergs satisfactorily without the balance pipe?

That emission control system is really weird isn't it, effectively it makes it into a single carb engine at low revs.
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PostPost by: garyeanderson » Mon Oct 11, 2010 11:14 pm

The Emission manifold has an internal balance pipe. plating over the top seals it from the outside atmosphere, it still acts as a balance pipe. It is not as good performance wise as the high balance non emission pipe but it didn't ice up like the high balance pipe that I had. Granted the freeze up only happened once with the high balance pipe but it never did happen with the emissions unit with the plates on it. Yes the secondary throttle plate is removed and the shaft withdrawn and the hole for the shaft plugged when doing this mod, its ugly but effective. I looked for the high balance pipes back in 1994 or so and they were not available so I used what I had. I still have the head and the rest of the parts to build up a stromberg engine, maybe someday it will happen.

Last edited by garyeanderson on Tue Oct 12, 2010 11:29 am, edited 1 time in total.
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PostPost by: leifanten » Tue Oct 12, 2010 4:49 am

whatever you do: do not remove the balancing tube/plate. That will make the middle two cylinders run lean and you will burn a nice hole in your pistons. (it has to do with the firing order, there are several posts on it in the archives)

The car in the picture is mine, and it was this way when I got it. An added benefit of deleting the emission control is that you can add headers instead of the cast iron emission control manifold. All it is a straight forward blanking plate over the flange in the balancing tube/plate.
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