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Here's a description of how you can change over to the K&N setup, retaining your stock Cooper setup for future use or shows. These instructions are for MGBs that have the black "Cooper Can" setup used for most early years. Thanks to Bob Muenchausen in Boise for the ideas herein! That's why I call my new air cleaners my "BOB CLEANERS"

These instructions assume you're familiar with the stock Cooper setup on your car now.

Parts Needed:

• The first thing to do is order a pair of K&N E-2400 Filterchargers®. These elements are the same size as the stock elements. If you ever want to go back to the stock "Cooper Cans" that came with your MGB, these elements will fit right in and you will never have to buy any other elements, saving you some money. You should be able to order these from any parts house that stocks K&N products, or most MG parts suppliers. I already had some K&N filter cleaner and filter oil to service the filter. If you don't have this, you might consider buying it now. The filters will arrive already oiled and ready for use, but sometime you'll want to clean and re-oil them.

• From a well equipped hardware store, pick up the following:

  • The end covers I used are made of tough plastic. I bought them at a Home Depot store and in "real life" they're actually plastic wall protectors to put where a doorknob could damage a wall! They're the perfect size (same diameter as the filter elements) and have a beveled edge that looks good. You could make these covers out of anything - sheet aluminum, steel, paint can lid, etc. Bob tested their resistance to heat and didn't find a problem, so I opted to go with the same parts. I scraped off the little adhesive strips on the back of them and then painted them "MG Maroon" to match the rest of the engine. I may upgrade to sheet aluminum someday, but these work just great.

  • A piece of steel tubing that will fit over the shank of the same 5/16" bolts that attach your stock air cleaners to your carburetors. You'll need approximately 16" of tubing. I found this at a local hardware store. You may be able to use the ones that are already used in your stock setup, but I did not want to modify mine in case I want to re-install the stock housings sometime.

  • Some rubber gasket material or thin foam to sandwich between the end covers and the filter element. I used red colored rubber gasket material that's probably 1/32" thick or so. The benefit to using thin material here is, you'll be able to use the stock 5" X 5/32" bolts that attach your stock housings now. If you get something thicker, just get 4 longer bolts to account for the added thickness.

  • 4 rubber washers to fit on the stock 5/16" bolts already used to secure your stock housings. I also picked up 8 stainless steel washers to fit the 5/16" bolts as well.

How to Build the Setup:

• Use the stock Cooper cans as a pattern for locating the holes to drill in the plastic disks you bought. Drop the plastic disks into the inside of the Cooper cans and mark the position of the 2 holes you'll have to drill in each. Drill holes that will allow your original 5/16" bolts to fit. I used a sharp brad point wood bit in the soft plastic so I'd get a clean hole.
• Paint your plastic disks whatever color you want. I painted mine "MG Maroon" to match the engine.
• Next, use the plastic disks as a pattern to cut matching gaskets out of the gasket material or foam you bought. I simply took an X-acto knife, placed the plastic disk on a sheet of rubber and cut around it. I used the same brad point bit to put holes in the rubber gasket to match the holes in the plastic covers. (If you do it this way, the brad point drill bit has to be extremely sharp to cut through the rubber cleanly.)
• It is probably a good idea to glue the gasket to the plastic disk, just to keep it together.
• Use the stock bases, with the stock black rubber gasket. Set the K&N element on there and cut the 4 lengths of steel tubing to allow you to tighten the air cleaners without distorting the plastic end covers or crushing the air cleaner element. Mine ended up being about 3 3/8" long, which I then "fine tuned" with a grinder to their final length. Trial and error will get you there. With the bolts tightened adequately, my new filter elements are held snugly in place - tight enough to be air tight.
• After trimming the tubing to the right length, assemble the setup, using the rubber washers under your nice new shiny washers, to seal the bolts where they go through the plastic covers. It is just as simple as the picture appears. You may want to use a washer between the steel tubing and your gasket material, depending on what it is. (You can also use washers to "fine tune" the tightness of the fit.)
• That's it. You're done.

Tuning, at least in my case...

• With the K&N filters, your engine will get more air than it used to, meaning it will be running with a leaner mixture than it was with the Cooper setup. In my case, there was enough adjustment left with the stock carburetor needles to allow me to simply richen the mixture to account for the increased airflow. I had to richen the mixture approximately .5 turns (one half turn) of the adjustment nut (for standard S.U. HS4 carbs like on my '69, down=richer, up=leaner). As a final test, after adjusting the mixture according to my S.U. service manual, I test drove the car and then checked the color of the spark plugs.

My Results

• Immediately, I noticed that the engine appears to rev more freely and it seems as if the throttle response has improved. I think this is a great improvement, it's relatively inexpensive (very inexpensive if you use the standard paper filters and don't buy K&N elements) and it allows you to return to the stock setup in just a few minutes if you're going to enter your car in a show, etc. You won't be disappointed if you do it.

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