Idle Box, how to set

[datzenmike]

Yup. Air filters are air filters even though K&N will tell you different to sell their product. I've never seen an air filter so plugged it affected anything to do with running. Screws on the carb may be loose and twisting and moving the air filter housing may have altered something. There are also hoses to the air filter housing, maybe one was off and now on?

[racerx]

maybe he had a vacuum leak which can cause his car to idle funny

[610StaWag]

The only thing I had done was taking out the air filter. The engine ran and idled perfectly. I couldn't believe it, so over the course of a couple days I went out and started it again. Perfect every time. I held the filter, which was totally black, up to and aligned to the cloudless sky and bright southern California sun. No light came through at all. Out of curiosity, I put it in the sink, used hot water and liquid detergent. The water that came out was black. After 15 minutes of cleaning, I took it outside and now I could tiny lines of dim light at the fold edges of the filter fabric. I do not remember ever changing the air filter.

[racerx]

your air filter could have been so dirty and grimey that air could not efficiently get in the carb. in order for a car to run properly, you need air, fuel and ignition. if one of these is not present or is limited, yes, it may not start or idle. main thing its now running.

[flatcat19]

Suck. Squish. Bang. Blow.

[datzenmike]

It would act like the choke was on. Could this be blow by oil?

[610StaWag]

Interesting, datzenmike,"blowby" Hmm,  long time ago, when I had that compression oddity, I put a lot of Marvel Mystery oil in because a few people told me try that. No luck with that. And you told me the thing that did work, mallet on the (rocker removed) valve stems. I think there was a time when there where backfires. Anyway, the filter could have been over twenty years old. Well, I got the K&N filter $32.xx, I put it in and the Datsun starts, runs and idles perfectly. I now have K&N air filters in all three of our cars. I do think the K&N airfilters are good. It isn't really that expensive.Since the K&N filters can be cleaned, there is a million mile lifetime. In the long run I don't think cheap air filters are really cheaper.  Guess I am starting to sound like an ad!

[datzenmike]

At 12,000 miles a year it would take 83 years to drive 1,000,000 miles so....  K&N didn't do anything that a $5 filter would have done.

[flatcat19]

I make a lot of money diagnosing and replacing parts because of K&N air filters.

 

 

 

End result...selling my customers a factory air filter after a couple of hours condemning their Mass Air Flow Sensor and/or Idle Air Temp Sensor that have failed because they are now saturated in red oil or dirt that got past the K&N.

[datzenmike]

Isn't there a special (oil?) spray used on them to trap dirt? Dirt sticks rather than being caught? This way they can have thinner filter medium? In a way the dirtier the filter, the more it traps? Maybe thinking of something else.

 

 

Took auto shop in Gr 9. Had to clean an old ford oil bath air filter. Air is drawn down past a sharp bend then up and into the carb mouth. Dirt being heavier, can't turn fast enough and swings wider and is caught in a puddle of engine oil at the bottom. Simple and you just dump out the dirty oil and refill. Paper filters are just easier and cleaner. 

[racerx]

yep, oil that is sprayed is reddish in color, prior to applying this spray, you spray it with a soapy substance and wash it really good, then let it dry.

[flatcat19]

Your description is how they work.

 

 

A dirty air filter cleans better than a new filter.

 

K&N calli g them filters is a joke. And cleaning kits for them? Why? Clean the filter so it can let more dirt through?

Seems counter productive and an inefficient use of time.

 

 

I know customers that want their K&Ns cleaned every 15k miles. Um...you're kind of defeating the purpose.

 

Give me a regular cotton/paper filter any day.

[flatcat19]

I will say I have whatever filter that came with the Weber. Is that a K&N?

 

As soon as it wears out I will adapt a round paper filter to it and never look back.

[datzenmike]

yep, oil that is sprayed is reddish in color, prior to applying this spray, you spray it with a soapy substance and wash it really good, then let it dry.

 

The perfect prescription remedy is one that does not cure, (what good is that?) but needs to be refilled over and over. Air filters can go tens of thousands of miles. I've never yet replaced an air filter that made any car run better. 

[racerx]

Had the 32/36 weber with what looks like a K&N filter for 14 years on the Datsun and still going.  But I'm interested in how you can construct a new filter that will fit the filter housing.  I did see someone here used the stock air filter housing and modded it so that the 32/36 will fit.