[TR] K&N Filters

[Alan Myers]

 I can't believe this thread's still running!

Hmmmm. I wonder what would have happened if a paper filter cartridge were
soaked under the same circumstances!

On the other hand, the paper filters I use my Starbucks Barrista coffee maker
uses seem to hold up pretty well getting wet... And I use the cheap generic
ones! Of course, I only use them once.... Unless I run out and am really,
really desperate for some caffeine.

I've had K&N on a number of cars and I agree completely with Justin's
comments. You have to keep them clean... They may be "permanent" filters, but
that doesn't mean "maintenance free" by any means. They probably need
attention on about the same intervals as a stock paper filter, ideally.

It's pretty amazing what comes out of one of those filters when you wash it.
But in all the years I've been using and maintaining them, I've never seen any
indication that washing them with water and pretty strong detergents were
degrading the fabric of the filter in any way. You'd think if road splash
could cause a filter to disintegrate, then a half hour in the kitchen sink
with really hot water and strong soap would really destroy it. Not that I'm
doubting the story at all... Hey it's possible. I am trying to form a mental
picture of someone putting a Weber triple downdraft carb under a microscope,
though. ;-)

As to air flow, well any filter is going to restrict it to some extent. On the
other hand, I've read and been told that sidedraft Webers, which I've got on
my TR4, as well as the similar downdraft models will work best in "quiet air",
i.e. no ram effects and with minimized turbulence around the entry to the
throats of the carbs. A set of nice, oversize K&N can help provide that. A
sock over an air horn probably doesn't. I really don't know if the same is
true with either the SU or ZS that many of our cars use, but would think it's
safer to assume so.

I also use two sets of K&N per car. One kept clean and ready to go, the other
installed in the car at any given time. That's because whenever you clean a
K&N filter it takes quite a while to dry completely. You really shouldn't try
to force dry it by putting it in a low temp oven or using a heat gun on it.
Too much heat can cause the cloth to shrink, warping the filter or even
causing the cloth to tear. I've used a hair dryer on low heat without any
problem, but it still takes quite a while. And, once it's dry you should oil
it very sparingly and give the oil some time to wick into all the nooks and
crannies evenly. It's easiest just to have one ready to pop in the car, then
clean the dirty one that was removed the next time the kitchen sink is free of
dirty dishes.

The only thing I'd add to Justin's comments is that the main issue I've seen
with K&N is over-oiling them. Some people think if a little bit is good, then
a lot more is bound to be way better. Too much oil on the filter will
definitely restrict air flow. It's equally important to use a very light oil,
such as K&N sells for the purpose (dyed red so you can see that the filter is
evenly oiled). Too heavy an oil would undoubtedly cause problems, too.

At the very least, K&N have got to be one heck of a lot better than the
reusable, "oily coarse steel wool" filters that came stock on a '60s era VW
bug I had, and for that matter I think might have been original on my TR4 (by
the time I bought it, it had disintegrating foam filters on Hitachi SU/240Z
carbs).

No filter that allows air to flow reasonably freely is ever going to stop the
smallest micro-particles completely.

I'll keep using K&N... My TR4 - when it's running - is a fair weather car,
anyway. The K&N in my Land Rover for the past 60,000 miles has managed to not
disintegrated through all kinds of rain, snow and slop. But I frankly don't
know that it's ever gotten particularly wet, since it's housed inside a pretty
well weather sealed box.

But, paper filters are darned easy, too. Just pop in a new one every so
often... and send the old one off to the land fill (today is Earth Day, after
all).



Alan Myers
San Jose, California
amfoto1 at aol.com
'62 TR4 CT17602L
http://www.triumphowners.com/640