Projects How to convert a 235 Chevy oil bath air filter to a modern air filter while maintaini

This post explains how to convert a 235 Chevy oil bath air filter to a modern air filter while maintaining the stock look. In this case the 235 Chevy engine is out of a 1954 Chevy Bel Air.

I was on HAMB and someone mentioned that they had done this. Sounded like a good idea. I went ahead and did it on my engine and here are my steps.

Tools:

• Drill with step drill bit
• Grinder
• Small cut off wheel
• Grinding disk
• Wire wheel

Supplies:

• JB weld (Note, the picture shows ultra blue gasket maker but in the end I went with JB weld instead)
• Mr Gasket paper air filter (includes base and top) Should cost about $20 at your local auto parts store.
• Por 15 rust inhibiting paint
• Por 15 top coat
• Stock decals
• Por 15 Metal Ready
• Degreaser
• Some metal washers or some type of spacer

Here are the steps:

1. Remove the top of the stock air filter. Clean the bottom and the top of the air filter to remove all oil. Use a wire wheel attached to a grinder to remove all paint from the air filter (top and bottom).
2. Flip the top of the air filter over. You’ll see what looks like steel wool being held into the top portion of the filter by a piece of metal that resembles a 6 pointed star. You’ll need to make 6 cuts with the small cutoff wheel to remove the portion of metal that is holding the steel wool looking stuff. Once you do this you can remove the piece of metal that holds in the stuff that resembles steel wool and pull out the steel wool looking stuff with a pair of pliers.
3. Now take a grinding disk and grind down the 6 cuts you just made to remove any sharp edges. By now you’ve opened up a large cavity inside the top portion of the stock air filter. Use the grinding disk to make the cavity larger (large enough that the modern paper air filter can fit inside the cavity).
4. Next take the step drill and make a series of dime sized holes on the sides of top portion of the stock air filter. This is so that air can move freely and get to the modern air filter which will be sitting inside of the top portion of the stock air filer.
5. Now take the bottom of the stock air filer and place the bottom of the modern air filer inside it. The bottom of the modern air filter should look like a metal ring which the modern paper air filter sits in. The metal ring should be small enough that it sits flush against the bottom of the stock air filter. The metal ring won’t exactly sit flush against the bottom of the stock air filter because there are some small ridges along the bottom of the stock air filter. Now use JB Weld to attach the metal ring to the bottom of the stock air filter. The JB Weld should fill any gaps and make a good seal between the metal ring and the bottom of the stock air filter. Let the JB Weld dry overnight.
6. Time to paint. Clean the top and bottom of the stock air filter with degreaser. Now clean the parts with Metal Ready to prep for paint. Next paint the parts with Por 15 black rust inhibitor paint. Note that the modern air filter comes with a chrome top and this is the one part that I didn’t paint. It will be hidden inside the stock air filter so no one will ever see it anyways. Once the rust inhibitor paint dries paint the parts again with Por 15 black top coat. Let everything dry.
7. Now it’s time to assemble. Place the bottom of the stock air filter on your carb so that the threaded metal rod that the wing nut attaches pokes out the center. Place the modern paper air filter into the bottom portion of the stock air filter. The paper air filter will sit on the ring that you used JB Weld to attach. Next place the chrome top on top of the modern air filter. The threaded rod that holds the top of the air filter on goes right through the center of the chrome top. You’ll place the stock top portion of the air filter over the top of the modern paper air filter and it will completely hide it so no one ever knows it has a paper air filter. I used a few metal washers between the chrome top and the stock air filter top to get the spacing right. When I was done getting my spacing right the top portion of the stock air filter sat just slightly higher than it would if it was all stock. Obviously install the wing nut on the top of the stock air filter to hold everything together.
8. Last step was to put the stock decals onto the air filter. You can buy the stock decals from Chev’s of the 40’s.

If you looked close at the air filter when it’s installed on the engine you could just barely see the dime sized holes that I drilled and you might notice that the top portion of the air filter sits slightly higher. At a glance you would never know everything wasn’t stock. The air can now move much more freely. The air can come through the dime sized holes I drilled and from there it will circulate through the modern paper air filter. Also, because of the washers I used to create some extra space, the air can flow down and around the edge of the top of the stock air filter and get to the modern paper air filter. If you did the project right there shouldn’t be any way that the incoming air can bypass the modern air filter and get right into the carb.

When it comes time to replace the paper air filter I will replace it with a K&N filter. The only reason I bought a MR. Gasket air filter was that it came with the base and the chrome top which I needed for the project and the Mr. Gasket air filter was cheap.

I attached some pics to help anyone that wants to try this.

As always, I’m grateful to the HAMB community for all of their help on my 1954 Chevy Bel Air project. This “how to” article is my attempt to pay the community back for all the help they give me.

 

Thankyou


Sent from my iPhone using H.A.M.B.

 

A swap meet oil bath filter, AD truck I think, I adapted to a '70's Rochester 2 barrel. I think it was terne coated and it was a filthy job.

Gary

 

Why would you want to? The oil bath works fine, all you need to do is rinse it in solvent every 10,000 miles and give it a little 50 motor oil. A quart of oil will last for years. A little extra work but a lot cheaper than buying paper filters.

 

I somewhat see your line of reasoning, but how many open element filters have you converted to oil bath to save 15 bucks a year?

 

On the subject of oil bath filter I have seen people over fill them on diesel engines. They start the engine up, the engine start sucking oil out of the filter and rev its nuts off.

 

Are you retarded?

 

No, but ease of maintenance with a paper air cleaner is sure easier than an oil bath one.
I cleaned mine at each oil change, sill scraped spooge out of the bottom, then rinse and clean and wipe it out.

I’m not “retarded”, then again I didn’t stay at a HI Express last night either.