The Fordson Tractor Pages Forum

Just realised that my repro mushroom is an awful copy of my original.

Correct me if I'm wrong, but pretty sure the mushroom is designed as a swirl-tube air cleaner (ie dust ejector). IE incoming air is swirled to throw dust outwards and out through the ejector vents at the top. Clever stuff if it works!

But see comparison of the gills on the underside. Apart from being poorly formed, the gills on the repro unit(right) swirl the incoming air in the clockwise direction when seen from below, the opposite way to the original.


But the dust ejection vents at the top, face the same way on both, ie the wrong direction to eject dust for the repro. Notice also the vents on the original are at the top of the cone and the cone is higher, presumably Ford did this for a reason.


And the original mushroom(below) has swirl vanes in the downpipe, the repro has none!


All in all a very poor repro unit.

So out with the repro and in with my original. I have straightened it and cleaned it up, should look good when painted !

So once again beware of repros - unless anyone has come across a better unit?

Ben
The repo is probably a southern hemisphere style where air or water swirl the opposite direction
Another reason to always reuse/repair your original parts if possible.
Kiwi Kev

Seems this topic has come up before.
http://www.fordsontractorpages.nl/phpbb ... hp?p=15195

Note interesting pics from Terry below, showing swirl vanes in the air cleaner body down pipe, which according to Brian, UK tractors never had. Did US tractors like Terry's have vanes in the cap as well?


Picture of Terry's original mushroom (looks just like my original), again a clockwise swirl (when viewed from above).


According to Terry, the original design of Dexta cap does indeed eject heavier chaff etc from the vents at the top of the cap before it can go down the tube.


How does a Major's cap swirl...??

The significant difference between the two pre cleaners is that the openings on the original are larger than on the repro one. When I fitted a new reproduction precleaner to my tractor she immediately slowed down and speeded up again when I removed it. Suggesting that the new precleaner was restricting the air flow to the engine, once I enlarged the openings with a screwdriver the engine speed was maintained.

It is essential with the early Dextas' with a pneumatic governed injection pumps to ensure that the air filter etc. do not restrict the flow of air to the engine. As any restriction will effect the maximum speed of the engine due to a drop in pressure/flow at the throttle. This of course can occur due to a dirty air cleaner.

Gerald

+1
It would be nice to think the dust ejector was working as designed, which seems unlikely with some of the repro units.