Modern air cleaner for reproduction TC canister

[m_e_jablonski]

In response to a couple of requests here's how I modified my reproduction air cleaner canister for improved filtration. I don't know the make of my canister as it came with the car, but I suspect most are of the same design. This method does not apply to original air filter canisters these cannot be easily modified as they have a more complicated construction. I used a foam filter element from Finer Filter Pty Ltd in Sydney, Australia (see www.finerfilter.com.au), Rally Pod part No. FF4269 (see www.finerfilter.com.au/AMRallyPod.html for an illustration). These elements are soaked with thick oil. Once dirty they can be washed out in mineral turpentine and re-oiled. Uni Filter Australia (www.uniflow.com.au) and Uni Filter in the US (www.unifilter.com) make similar products. In use the open end of the element seals against the bottom of the canister. Elements with bonded elastomeric collars are also available ( www.finerfilter.com.au/AMFlangedPod.html). However my supplier didn't have one that would fit over the outlet and bridge at the bottom of the canister. The collar is clamped on to the air intake with a hose clamp and would provide a better method of attachment if one with the correct diameter could be found. The outlet on the inside of the bottom plate would also need to be machined cylindrical. The model I used gives sufficient clearance to allow flow down the sides, thus using the full length of the element for filtration. The annular area between canister and filter exceeds the air intake manifold inlet area and exceeds the sum of the two carburettor intakes. The 150mm length locates the closed end just below the bottom of the rectangular holes in the canister. With mesh under the holes the bright blue element isn't visible. The air cleaner canister is dismantled by removing the nut(s) at the top of the canister and then gently tapping at the "rolled" edges of the top and bottom whilst holding on to the canister body. The top and bottom plates are aluminium castings made to look like the original pressed-steel ends with rolled/swaged corners. They are held into the canister body by a push fit. Inside you will find fine steel wool enclosed in a coarser aluminium mesh. Remove the wool and mesh and carefully separate. The wool is discarded but the mesh can be used, folded loosely over itself three or four times, to lie against the rectangular holes, so imitating the mesh inside the original canister. The element has to be held downwards to seal against the bottom of the canister. I opened up the spring inside the element to fit over the bridge on top of the outlet on the inside of the bottom plate (also filing a little off the bridge). I then inserted a spring between the canister top cover and the top of the element. I also inserted a round plate (1.5mm thick aluminium) into the element to sit on top of the inner spring. This transfers the force between the top and inner springs via the top of the element. It also locates the top of the element, preventing sideways movement. Drill the plate for the central clamping rod to pass through. Also drill it out to allow airflow through the top plate. A better alternative to the round plate would be a flanged disk to go over the top of the element, with a central boss that can be locked to the central rod by means of a grub-screw. The disk could have openings to allow airflow through to the top of the element. The central rod will have to pass through the top of the element use a scriber to push a hole through the closed end of the element; do not use a wad punch as the filter foam has to stretch over the rod to form a seal. Finally, when assembling, wrap the mesh that originally contained the steel wool around the inside of the rectangular holes. With a bit of luck the mesh will interfere with the foam element and not slide into the canister, otherwise you may have to unfold the mesh a little to provide some interference. Keep the mesh loosely folded so as not to restrict airflow. It will imitate the mesh inside the original canister. Spray paint the folded mesh black so as to hide the shiny aluminium that would otherwise be showing. After assembly check that nothing is loose inside the canister by giving it a shake the element should seat firmly against the bottom of the filter and its top should not move sideways. You may need to retune the carburettors as the airflow through the filter may be different to that before the modification. I'd been running my canister completely empty (i.e., no steel wool) and with the extra resistance of the filter had to screw up the jet adjusting nuts by one flat. I should add that I'm still experimenting with this arrangement. So far it's covered less than 100 miles. I'm hoping to find dust stuck to the surface a fair way down the length of the filter indicating that the full length is being used. I also think that the two improvements of a bonded collar and a better top restraint are worth doing. I didn't do these things, being in a hurry to provide some form of filtration for the engine but will do so in time. With apologies for the length of this. Mark Jablonski Melbourne, Australia