Would this work....?

[Jenno1981]

Hi guys,
A quick one... I have a 78' 450SEL on gas (LPG) and has the current (Pic 1) air filter configuration.  Note the LPG vapour line that connects to the top.

I have acquired an air filter housing from a 350SE (pic 2), had it blasted and about to paint it.  I was initially going to sell it.... but.... I would love to have it in my 450SEL.

I'm assuming the LPG vapour line is just sucking out clean air from the filter.  My plan was to cut a hole in the new air filter housing and attach/seal the vapour line onto it appropriately.

Before I go cutting anything... can I get a general consensus about if this would work and any potential issues I might face?

[oversize]

The vapor line doesn't suck, it supplies the LPG to the engine.  It connects to the LPG mixer which meters the fuel into the engine.  Disconnect the two and your engine will not run or even worse it'll blow up!

[Jenno1981]

Oh..... that changes things!

[Jakob]

My LPG system has a ring 'mixer' that sits underneath the standard air filter.  It has vents in it that supply LPG to the intake manifold.  It sort of operates like a carburettor in that the gas is fed through according to air velocity.  The standard air filter sits on the top as it would the normal intake manifold opening.  The only difference to the standard air filter is that the two rubber mounts that the filter housing bolts on to have been extended vertically by the thickness of the mixer.  If you wanted to mount a standard air filter you could do this, although mine had to be modified to make the opening smaller.  This was to increase the velocity of air being drawn into the engine on idle.  Before doing this, there wasn't enough air velocity for the car to run properly at idle.

The system looks sort of like this http://www.prinsautogas.com/en/products/mixer_system/mixer_system.html

[Jenno1981]

Thanks for the reply Jakob, I'm sitting on the fence as to whether I have a go or not.  Got a couple of other things to see to while I make up my mind.
If you have a 'how to' thread or something you went off could you send it for me?
Cheers!

[Jakob]

The conversion was done before I got the car so I don't have a how to unfortunately.  I can take some pictures if you want?

[Jenno1981]

Jakob yeah that would be great if you could post some pics, might give me an idea of what type of job it might be.
Thanks!

[oversize]

Take the air cleaner off the mixer and take a few pics.  I'm sure the MB air cleaner assembly could be adapted to allow it to fit inside so your engine bay looks more 'factory'

[Jakob]

Attached are pictures of the LPG mixer on top of the intake manifold and also the extension bar to raise the filter housing bush.