From: Dr. Keith Kenitzer;
kenitzer@bellsouth.net; I had similar
questions about twenty years ago when I purchased my 912 and decided to do some engine
performance upgrades / modifications. I added a VW type cooler with the adapter that
fit to the cooler tower. It also made sense to me that eliminating the stock cooler so
that #3 could get more cooling air flow and adding an external cooler and full flow filter
system was the only modern solution. I mounted the cooler to the underside of the
engine cover, below the air intake grill.
It all seemed to work quite well for a few thousand miles, until I developed a large
gushing leak around the cooler area. I am still not sure what caused the leak, it
was either a seal that went bad or a cracked case in the cool tower area. I say I
still don't know, because at the time it happened I was a poor college student without the
time or means to delve into a problem of this supposed magnitude.
Unfortunately, my 912 still awaits repair (and now also restoration) today because other
projects always seem to have higher priority. With hindsight being 20/20, even
though I am not sure what caused the oil leak, I would run, not walk, away from VW
solutions to my Porsche problems. When the day does come to complete my project, I
plan to go the Shasta piston route, boosting output to 1720 cc and to likely add cooler
and filtration based on recommendations in the 356 Performance
Handbook.
Along this 912 performance subject line, I might refer 912 enthusiasts to some articles
that appeared in the Feb. 2000 issue of 911 & Porsche World magazine. Good Luck, KeithFrom: jack frost; Thurs May 11, 2000; jfrost@jackfrost.com; I installed a full flow oil
filter, cooler, plus an electric accusump in my 1966 912.
I installed a 22 row, high quality oil cooler under the front left (opposite 911) wheel
well. Originally I chose an EMPI cooler, but they are junk and it fell apart before
I completed the installation. Porterfield (Costa Mesa, CA) has high quality oil coolers
for about $160, in addition to very good break pads. A simple home made bracket is
all that is needed to mount the cooler. I used 1.5" aluminum angle stock.
I also covered the cooler with stainless steel mesh (about 10 to the inch) to
protect the cooler from tire and road Debra.
I plumbed everything with AN-10 hose. Not cheap. about $450 to $600.
Since my 912 is a race car I chose to run the hose via the heater ducts to the inside of
the front trunk. I have a fuel cell so I was able to remove the insides of the fuel
filler cap and route the hose from the
inside the trunk to the wheel well, without any new holes.
I used a oil temperature thermostat to prevent the oil flow to the cooler until after the
engine is warmed up. A reasonable price is about $80. I would not recommend
the factory one at $400+++ dollars, just
because it isn't necessary.
I used a 2 quart, electric Accusump. This item is really essential for any spirited
driving. Unlike the manual version you don't have to remember to turn it on and off
and you can mount it in the most convenient space. I chose the wall in back of the
motor. Its readily accessible, visible and does not interfere with anything.
Price about $240 (Racer Wholesale).
I use a Fram HP1 filter and adapter. About $40 total.
With this system at willow springs on a 110 degree day, tires melting, over 10 laps and
the oil never got above "normal" operating temperature.
From: Patrick Van Asbroeck; Tues, May 09,
2000; p.asbroeck@uk.betalasermike.com;
Hi, The reason I started thinking about installing an external cooler is twofold.
1. #3 is running the hottest. By removing the cooler in the fanhouse it gets more air.
When you use a 050 distributor then all cylinders run at the same ignition advance.
Normally #3 gets less advance to help keep it cool.
2. it makes installing a full flow filter easy. Just fit it in series. The fanhouse cooler
can be replaced by a thermostatically controlled valve which is availeble in any VW shop
and should fit straigth-away. From this valve you can run some flexible tubing to the
external cooler and filter.We then come pretty close to the system as used on the
nine-elevens. Another benefit of the thermostaticall valve is that the engine warms up
more quickly after startup. Biggest issue is where to fit the cooler. At the VW shop they
fit a long cooler under the front bumper. These coolers are not cheap, around 300USD
for a new one but I heard BMW has used the same style cooler on one of their older models.
One of the guys at the breakeryard mentioned this to me as in the past he sold many of
these coolers to the dirt crossing fans. If I find which model I'll let you know.
Regards,
From: Rose, Revis CPO; Tues, May 09, 2000; RRose@d11.uscg.mil; Good question, where to put the
cooler. Well although my 912 is long departed from my garage. I still have the
911, the forward mounted cooler is needed in cars running "S" spec engines in
the specific output range of 80+%. Now that style oil cooler is overkill for a 912,
unless you are producing over 125 horsepower. I discussed this with Duane Spencer a
few years ago. He outlines how to do it in his book the 356 Performance
Handbook. He related to me that he installed his cooler in the rear quarter panel
where the 911 carries it's oil bag. The reason was simple, he uses his 912 for
vintage racing, but they don't allow modifications to the body work. Therefore oil
cooler mounting choice is important, and the cost to benefits achieved must be weighed
carefully. I think a full flow oil filter up grade is worthwhile, as I have said in
the past. Lastly about Duanes choice of using the rear quarter, it has one
unintended advantage, if you spring a leak in your oil cooler, dumping oil on the ground,
that oil will not dump in the front of your tires.;-) Revis Rose
From: Trenholme, Phil; Mon May 08, 2000; Phil_Trenholme@affymetrix.com; I agree
that a "stock" 912 motor probably did not require an oil cooler. But how many of
you out there have 1720cc engines? The solution to avoiding the need for an oil cooler is
to keep the engine stock and lower the C.R. to something that will work with today's
gasoline. The problems come about when more performance is desired. High performance
engines when pushed hard will require additional cooling that cannot be handled by the
stock oil cooler. And what is the point of having a high performance engine if it is not
being pushed now and then? This is also very dependent on ambient conditions. On a hot day
(95 degrees +) even a stock engine, when pushed hard, will start getting too hot.
Assuming your engine is running hot (others do not need to read further) the best solution
is to add an external cooler. And if an external cooler is being added you can do your
engine a big favor by installing a full flow oil filter into the system. I will not go
into the details of how to install a
full flow oil cooler/filter system, but a thermostat should also be
incorporated into the system to make sure that the engine is not over cooled. Except for a
race car an oil cooler(s) mounted in the front is not
required and adds more work to installing the system. Either rear fender well is an
excellent location for a cooler and filter. A properly installed full flow oil
cooler/filter system will extend the life of your engine due to cleaner oil and controlled
oil temperatures.
From: Bill Todd; Sun May 07, 2000; billtodd@t-6.com; Hi! I decided some years ago that an
external oil cooler on my 912 wasn't necessary at the time. I still do not have an
external cooler added, but I did modify the oiling system to get better flow and
filtering.
I drilled and tapped the case, and made new high pressure hoses. I'm an ex-aircraft
mechanic and have made hoses for aircraft for years. This is where "AN Hoses"
came from, AN signifying "Army Navy." This is NOT A MODIFICATION that you can do
with the case assembled. The chips that are generated when drilling/tapping could ruin
your engine at start up. Do this mod at overhaul when the case halves are split on a
stripped case. Thoroughly flush the case with high pressure soapy water and flush
that
solution out until clear, clean water emerges.
I first used high pressure commercial and industrial grade hose, but because of the
proximity to the exhaust headers, decided to go to military specification teflon hose,
with anodized AN fittings. I noticed
that my oil got very black very quickly after I installed the original set-up and I got a
few thousand miles on it. I found out that the hose between the headers was deteriorating
due to the heat, and became hard & brittle. It appeared to be "coking" the
rubber inside the hose. I remedied that by using "AN" stainless braided &
teflon lined hosing. (Read on for a further modification.)
I had my engine torn down for overhaul, and pulled the correct oil plugs that are
installed into the case. You drill & tap them, (I tapped for a 10/32" thread
using a bottoming tap) but not through the case, but about 5/16" down.
Next, you make a small "puller" by selecting a 3/8" drive socket that fits
over the plug. Get a long #10 bolt and run a plain nut up the threads until it bottoms.
Place a sturdy washer or two under the nut
head. Insert the bolt into the drilled/tapped hole, through the socket, until it bottoms.
Drop the washers against the socket, and then run the nut back down until it seats against
the washer.
You're now ready to start removing the oil galley plugs. With a box end wrench, start
cranking the old plug out. They will come fairly easy, but in really stubborn cases, you
may have to take a propane torch to the area. As I recall, the plugs are about
3/8" long. They are probably installed in a hot case and maintain a "shrink
fit" to eliminate any leakage. I've never seen one leak, and there are several
installed in your case. These plugs seal off the drilled passages for the oil galley's.
I drilled and tapped the case to accept 3/8" NPT fittings. I used 3/8ths fittings
(and 3/8" hose) for several reasons: 1) The wall thickness is maximized in any tapped
hole you make. A 1/2" tap would take out a lot of meat from the wall. You can have
your case heliarced in the one critical area to build up material, but 3/8" hose is
plenty sufficient.
2) The original Porsche hose appears to be somewhere between 1/4" &
5/16" in diameter. Moving to 3/8" diameter hose is a modest increase. I happen
to believe that the original oil passages and gallery aren't 1/2" diameter, why do I
need 1/2 hose when the flow is gated to just under 3/8ths internally? There's what's
called a "coke-bottle effect" in flows. You can have only as much flow as the
smallest orifice permits. You could theoretically go to 1" hose, but you'd flow no
more than 3/8" hose.
The smaller diameter hoses/fittings/ends were economical. I made up my hoses for under
$80, including high temperature silicone hose lagging. This is a high temp silicone shell
bonded over a fiberglass woven tube. It slips over the hose and can be retained by
several methods. I take aircraft safety wire and bind the lagging down over the stainless
braided hose on the left side, between the header tubes. This stuff is used in turbine
engine "hot sections" and really reduces any possibility of damage to the
internal fluids from heat sources. I use a piece about 2' long, and route it up through
the engine tin. This also helps reject the added temperature from the muffler area too.
I used one straight, and one 90 degree 3/8" pipe x #6 AN fitting. Straight went into
the case on the side, 90 degree just under/next to distributor. Make sure that you can
adjust your timing with a 90 degree fitting in this area. My 90 degree is brass, and I had
to relieve it a bit to get clearance for timing. The case side fitting is blue anodized
aluminum.
Some other features of smaller hose: The smaller diameter hose also is further away from
heat sources than a larger diameter, and it bends into a tighter radius. I routed my hose
through a factory hole in my engine tin, and it just fits through with hose lagging. It
wouldn't fit with the next size larger, 1/2" lagged hose. This may be important if
the next owner wants to revert to a stock set-up.
There is some disagreement over the use of teflon tape as a thread sealant in a case. If
correctly applied, teflon tape is not an issue. If you use too much, it will tear off and
possibly get into the system, clogging a passage or under a relief valve. Correctly
applied, TT starts about two threads up on a fitting, two wraps at max! You're sealing the
top taper of a pipe fitting, not the bottom! You also wrap it so that at installation, the
tag end is "pushed down" as you insert the fitting, not trying to "peel it
off" up and into the system. (You'd be surprised at how many people just grab a roll
of teflon tape and wrap it around a fitting, not paying any attention as to how it's
properly wrapped!)
I obtained an aftermarket VW filter adapter and mounted it high on the fan shroud, between
the distributor and generator. This allows me to easily spin off the filter after placing
paper towels on the engine to catch drips. I placed the adapter in the recessed area at
the top of the shroud, inserting washers under the aluminum casting to prevent cracking
the shroud when it's drawn down.
Mann W930 oil filters with a black coat of paint from the factory were used exclusively,
but I'm having trouble locating them. Black paint helps radiate heat away, and a black
filter will run cooler. The new
filter I'm using is a Mahle OC61. It is a direct replacement according to my sources at
EASY in Emeryville, CA. It will still pass oil if clogged, and is painted black with a
thin coat of paint.
In doing this modification, you can also remove the oil screen in the sump area, but it's
not necessary. There is now a form of better filtering, and that large mesh screen in the
strainer assembly would pass a lot of small particles. The oil is now cleaner because of
better filtering, and it's no trouble to "spin-off" a filter. I generally go
about 4000 miles/change with Kendall 20W-50. I know people that change filters between oil
changes. While this admittedly helps, my oiling system seems very sturdy and performs well
on my oil change schedule.
The cost of the filter is not in question, the added safety and security of fully filtered
oil is worth a lot of bucks to me! I was told that the original Porsche oil filter was not
a full-flow oiling syste type filter. At best about 33% of the oil is filtered at any one
time in this by-pass oiling system. The inclusion of a full-flow filter means that all the
oil in the system is filtered, all the time. That contributes more than anything to the
added reliability of the little four-banger!
When I installed the newly assembled engine, I ran the oil pressure with stock springs and
plungers. After break-in, I shifted to a spring kit that gave better oil pressure. I
shimmed the springs to get 60 pounds of OP at start, and it drops to about 45-50 PSI at
operating oil temperature. I have an oil pressure and temperature gauge from a 911 with a
matching sender. There's also a warning light that can be installed in the oil temperature
indicator that warns of temperature excesses, but I do not have it installed. It would
normally illuminate at the end of the scale at the hot end. It would be trick to install
it, but it's not necessary at this point.
My oil pressure and temperature are excellent, and I have no need for the added hassle of
an external cooler. I live in the San Jose California area where temperatures in the
summer are excessive. I've
driven this car in/on 105 degree days with but a slight rise in oil temperature, and drop
in oil pressure. I feel that cool, clean, filtered oil is essential in an air-cooled
engines, and I can tell when my oil needs changing---I get a slight consistent
pressure drop and a temperature increase.
In my garage is a 911 oil tank, sender and combination fuel/oil quantity gauge. It will
fit in the right rear fender well really slick, but do I need all that now? I had been
considering dry sumping the engine, but
since it runs cool and holds good pressure, do I need all that over-kill? Not yet! Bill
Todd, 5/7/00
From: Larry Lehman; Fri May 05, 2000; fmarshal@ix.netcom.com; It doesn't seem proper to
go against what the Porsche family designed. The 912 engine has less heat to dissipate
than the S90 engines in the 356s. They didn't need supplemental oil cooling. A Volkswagen
did not have a full flow filter (just a screen) or an external cooler. It did
have less oil. It benefitted by the additional hardware (maybe). I run a good
quality filter and Red Line Synthetic oil in my 912. I did the same in my 356. It runs
cool. If you have the need to own an external cooler, just upgrade to a 911 where there is
alot more oil to cool things down. My 66 912 is all original so I would not carve it up
for that. I suppose it would be okay to do to a car that is raced, but these things were
race proven before they hit the market. Clarence
From: Rich Lambert; Fri May 05, 2000; red912@acmenet.com; When I fitted the oil cooler in
my '68 912 vintage race car, I took the advice of Duane Spencer's book, "Porsche 356
Performance Handbook" and mounted it in the left rear fenderwell behind the tire.
There's good air flow back there and with a non-restrictive protective screen, I didn't
have to worry about rocks holing the cooler. Another advantage to this installation is all
the equipment, i.e. full flow filter, oil cooler, and oil lines, are located in close
proximity to each other. That saves time and money by not having to route send/return oil
lines to the front of the car. The stock cooler was left in place as you can't have too
much protection. In the book there's a lot of information on full flow filter/external oil
cooler installation, including diagrams, explanations, and descriptions of how to do the
necessary modifications. I highly recommend this book to anyone interested in
doing
performance modifications to their 356/912 engines. Rich Lambert
From: Johnflacey; Fri May 05, 2000; Johnflacey@aol.com; I have not done this or even
considered it. Since the rebuild, it runs cool (max 1/2 or 5/8 temperature scale) in
all conditions, even mid-summer on three hour trips. In my old ' 66 coupe many years
ago, I removed the drain pan from on top of the engine and that reduced my heat issues
significantly. These were originally designed and manufactured with
Bavarian/European climate in mind, remember. Best, John L.From: Ron Anthony; Fri May 05, 2000; atladv@home.com; Here's a vote for after owning 2 912E's
and driving them in warm weather (Maryland) we never saw a compelling reason to install
additional engine cooling. It might have helped that the thermal reactors were
removed on both cars and the a/c was not used very often but one of the cars was a top
finisher in autocrosses! Take care, Ron.
New!
912 Registry Members can
share
technical information, add technical
information, and access quality, up to
date technical information on our 912 Wiki. |
Technical
Blog: