Does the stock air cleaner housing fit PMO carbs?

[Noah]

Searched and searched, but cannot find this info anywhere, including on the PMO FAQ page. Might be getting PMO's and want to know if the stock Weber air cleaner housing fits, or can be made to fit, the PMO's. Thanks in advance.

[VintageExcellen]

Yes the mounting points on the PMOs are the same as weber. You can use any air cleaner that fits your webers on the PMO.

[Noah]

Thank you Mark, much appreciated.

[nathan]

I have done this, and in my experience it was not a direct fit between the two.

That is if I am understanding your question correctly? Apologies if not.

From memory there are the additional idle air jet holes and the three main venturi holes are bigger as well. The main jet/air corrector/emulsion tube stack of the PMO doesn't fit out the hole in the weber base plate without enlarging it.

Initially I reamed the weber air cleaner base plates to make them fit, but the metal got a little thin between some of the holes.

I ended up using the PMO base plates as a pattern and got a sheet metal guy to weld them into the bottom of the stock air cleaner bases. This was on a 1969 911T

Brooke (RSwannabe I think?) has done this, posted on pelican or here as part of his build I think?

Also, the PMO air horns are a tight fit in the weber air cleaner bases, I notched mine so I could bolt them down more easily.

My air cleaner housing fits fine with PMO manifolds, but I am not sure if I have the tallest ones they sell. Just one more thing to be aware of...

Cheers

Nathan

[Noah]

Thanks Nathan. Interesting. Any idea whether the PMO trumpets are taller than on Webers, or just a little wider? I'm rebuilding the engine in my Targa this summer and am pretty intent on using the stock air cleaner/snorkel on it. I found that with the Targa top off and the flat-top air cleaners the car came with, it was just too loud for my tastes. I imagine the rain shield air cleaners may be a tiny bit quieter than flat-tops, as perhaps they deflect some noise downward. But it can't be anywhere near the noise reduction of the stock air cleaner.

[Noah]

Found the answer. Here's the RSwannabe thread:

http://forums.pelicanparts.com/porsc...rbox-pmos.html

Looks like the only mod that needs to be made is to the base plates that bolt under the trumpets. Doesn't seem too complicated.

[nathan]

the PMO trumpets are a certainly a bit wider, it makes trying to bolt them down a bit tight against the weber air cleaner bases.

If you can get hold of both the weber and PMO carb top gaskets it is an easy way to compare the differences and see what has to be done.

The stock air cleaner set-up is much, much quieter compared to flat tops or rain shields. The majority of in-cabin noise (i.e. heard by the driver) is from the intake from my experience.

I am still running a twin outlet pea shooter and will not be changing it out...

[VintageExcellen]

Never a perfect fit with aftermarket. Some slight mods required but it will work. Once you adapt the stock air cleaner bases then the rest should fit fine. Getting on those 8mm nuts that hold the air horns and air cleaner bases is always a bit of a challenge, use a small socket wrench.

[Noah]

The RSwannabe thread suggested that modifying the stock air cleaner bases was more difficult than cutting them out and welding in the PMO bases. Obviously, I'd rather not have to do that. Mark is your sense that modifying the stock bases to fit the PMO's is feasible?

[Stretch32]

Having looked at this as well, I was able to get pictures and info from a guy local to me who had done it. He also had PMO base plates made and then, after cutting his original Zenith base plates, welded in the new ones. If you're starting with Zenith carbs the air cleaner bases are not a direct bolt on to the PMOs.

Stretch