There is a provocative little bumper
sticker that can be seen in beach towns around the country that
states "Damn sand gets into everything !". Since
our whole sport revolves around playing in the stuff , we must
take great care to keep it out of our engines . Here , dirt is
the mortal enemy , and can reduce a well tuned , strong running
motor into an oil burning , low powered source of negative cash flow
in a surprisingly short period of time .
Stock automobile filtration
systems are wonderful for highway useage , but are quickly
overwhelmed by the sheer volume of dirt and dust encountered off
road . Your Volkswagen is no exception . Air and fuel delivery
sysetms can be greatly improved upon , for a surprisingly little
amount of money and elbow grease . Lets take a look at how you can
ensure the dirt stays outside the motor where it belongs .If you
have a Baja or a Rail , odds are the stock VW air filter is long
gone . What you replaced it with can make a big difference in
your engines longevity and performance .
Paper Filters
The filter of choice of every auto
manufacturer is the replaceable paper element . They are inexpensive
and commonly available in a wide variety of sizes , for custom
installations . However , they are not the best choice for
off-road filtration (Centrifugal housings are the exception).
Paper elements allow minute particles of dust to pass through (a Bad
Thing) and tend to plug up easily . Additionally , When a paper
element gets wet , it becomes very restrictive , causing your
carburetor to "run rich" , and thus decreases performance
and fuel economy . This too is a "Bad Thing". An
improvement to the paper element is the "Dual
Stage" filter , which add's a foam element around the
outside , but there are better choices .
Wet Sock Filters
Having nothing to do with laundry ,
the wet sock filter is an oiled foam element , draped over a
metal or plastic frame , and attached to the carb via a short
length of rubber hose . They are reusable and inexpensive , but clog
fairly easily .
Oiled Gauze Filter
These filters , manufactured
by K&N and others are the best all around choice for off
roading . They are reusable and are highly effective at
filtering out even small particles of dirt . AS LONG AS YOU
KEEP THEM OILED ! If they become dry , they are said to filter
worse than a paper element . Some people also add a foam ring to the outside for increased filtration , while others swear the
filter works better when its dirty ! While the initial cost is
higher for these filters (including oil and solvent) , they pay for
themselves with increased filtration , higher air flow and
reusability .
Centrifugal Filters
These are most likely the most
effective filters of all , but also the most expensive .
Currently in fashion in off road racing circles and used for years
by desert runners , they were originally developed as filtration
units for heavy equipment that spent its life working in high
dust environments . As it's name implies , the system works like
a centrifuge , throwing heavier dirt particles to the outside
and away from the element , so that it only has to deal with the
smaller particles . This keeps the element from clogging as
quickly and allows for free flow of air over a longer period before
the need for cleaning . The paper element is rumored to last for
years on a recreational vehicle and several races on a racing
vehicle . Another advantage is remote mounting . The canister
can be mounted inside a car , and then connected to the air box by
means of a section of rubber hose .
* SPECIAL NOTES *
When installing an air filter in its
housing , use a thin layer of grease around its mating
surfaces to ensure the only air the engine receives , comes through
the filter . When using rubber hose to connect the carb to the air
cleaner , use as short a piece as possible and NEVER use
"Flex" hose . It is highly restrictive .
Fuel Filter
A fuel filter is a must for any
vehicle . More so with ORV's . With gasoline of questionable quality
coming from cans , jugs and even gas stations themselves , a couple
dollars spent here is real cheap endurance for the Desert
Beast's continued good health . One word of caution . Two actually .
Glass filters . Don't use them . Popular with the street
crowd for thier trick appearance , they are out of place on an ORV .
One rock hit can shut you down in short order and possibly
cause a fire . Your best bet is a metal canister filter of sufficient size . Even a clear plastic filter is a
usable alternative . They are available everywhere for a low cost . A good idea is to keep a spare in the car , just in case .
Oil Filter
The stock VW filter is a mesh screen
that is good only for catching larger chunks of metal , which
probably came into being by not having a proper oil filter in the
first place . This is one of the most important mods you can make
to the engine , if not the whole car . There are several ways to add an oil filter to a VW motor . The best , but most expensive
and labor intensive is to "Full flow" the case .
This is a complex procedure involving engine disassembly and
machining , and wont be covered here . I have heard of a full
flow system put out by Bernie Bergman , which requires no machining ,but
I have not yet learned how it works . I will update this page when I
do . The easiest is to add an oil pump with an adapter for an oil
filter , but this is the least desirable choice , other than no
filter at all . The filter sits horizontally , and if it develops
a leak around the seal , you could loose your Vital bodily
fluids upon the ground . The middle of the road option ,
and the one used most frequently by off roaders is to remove the
stock cooler , add an adapter and external cooler (a Good
Thing) and oil filter . Price wise , it can cost from $50 on up ,
depending on the size and type of cooler you buy . There is one down
side to this setup , but this is only if you have a doghouse oil
cooler . In this case , because the doghouse cooler is a Good Thing
in itself , you would have to give it up to use this method . If you
want to have your cake and eat it too , you must use one of the two
other methods .
From George Lyle.......
" Don't forget that there
is no seal behind the pulley and that the pulley has a
spiral machined into it to push stuff back into the engine. Unfortunately
it will also pull stuff into the engine from outside! This area
needs a sand seal kit. You can either machine the case and pulley to accept a seal or get an aftermarket seal holder and
pulley that is a bolt-on proposition.
BTW, the integral oil pump filters
are junk! They fit loosely in the engine and put the filter in
a very vulnerable spot. A couple of things to remember about
remote filters : You're stealing oil pressure to run the oil through
the hoses and filter, so keep the hoses short and large in
diameter. Mount the filter upright so that you can fill it
with oil before screwing it in place. Otherwise, the
engine will run without oil pressure for several seconds after you
change the oil. Don't mount the filter to the fan shroud. The
tin will fatigue and crack in short order. It's better to
weld a bracket to the baja rear bumper or to mount the filter on
the firewall. "
Other Filtering Considerations
Oil Filler Vent and Drain
These often overlooked areas are a
major source of contamination in the VW's engine . The upper
vent (by the oil cap) can be vented to an external breather box or a
small individual filter . Some air filter housings allow you to vent
this outlet into the intake airflow of the carb , but this is not
recommend , as it can lead to increased detonation in
your engine . Definitely not a Good Thing .The oil
drain is a bit different . Dirt can be sucked into your engine
through this outlet during starting (for you scientists out there ,
the crankcase develops a low pressure area in the drain -outlet ,
and the higher external pressure pushes the dirt in as the high
pressure area fills the low ). While plugging the outlet may seem
like a Good Thing , it is not . This can lead to increased crankcase
pressure , and cause blow by on the rings . The solution is to attach a piece of open cell foam around the outlet . It keeps
the dirt out while allowing the case to vent properly .
Distributor
Yes you read it right , the
distributor . Point ignitions are somewhat tolerant of dirt , but
the newer electronic replacements aren't so forgiving . How does
dirt get into a VW distributor you ask ? There are vent holes on the under side of the housing , to keep condensation from
forming within the cap . plugging these holes defeats thier
purpose , and can cause stalling and skipping in the engine . Once
again , our friend foam comes to the rescue . Glue a small amount
of foam over the holes and your half way there . The other half
involves the cap . A small layer of grease around the inner rim
of the distributor cap , where it fits onto the housing , will
keep out dirt on that front . If you encounter a lot of water ,
silicon may be a better choice here , but it's a real job to get the
cap off for routine maintenance . Grease is a better choice in all
but the most extreme circumstances . As you see , there are many
ways to go about filtering your VW . This is a very important area
to consider when you decide how to best spend your off roading
dollars . A well thought out filtration system will help
ensure your VW stays healthy and that you stay happy .
Well this concludes
part 1 of "Beefing the Desert Beast- Engine , the first
in an ongoing series of articles on upgrading the VW's engine for
off-road useage . It is our hope that you find this information
useful and informative . Remember to work safely , and always
secure your vehicle before begining any work .If you have an
interest in writing tech tips or how to articles for Off-road-com. ,
we would love to have them . Send comments / questions to
Hey ya from Oz. I have a 1969 Baja. Recently I swapped wet sock filter for a pod racing filter. After driving on the h/way for 30 mins I reached my destination and found the engine covered in oil. I hit it with a high pressure cleaner to discover the source. It appears that oil is coming out from behind the crank pulley. On other sites this issue was discussed and recommended that the oil filler has a open pipe that needs to be connected (via a hose) to the air cleaner to create a vaccuum and equalise pressure in Crank case. I previously have just cover this hole with some foam. Now after reading your 'beefing the desert...1' on filters you say DON'T do this. I am pretty confused and don't know what to believe now. Any further info would be awesome!
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