Date: Mon, 8 Jan 2001 02:32:51 EST
Reply-To: FrankGRUN@AOL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Frank Grunthaner <FrankGRUN@AOL.COM>
Subject: Re: "windage tray" and other I4 conversion comments
Content-Type: text/plain; charset="US-ASCII"
This is the end of an extensive travel period and the onset of the submission
deadline for a new round of NASA space science and Astrobiology research
proposals, so I have been in a more-passive-than-usual lurking mode. A few
quick comments about some I4 conversion questions:
First, on the issue of the Windage tray, the unit you want is the VW stock
item for many (not all) of the 2.0 l ABA engines. The part number is
037-115-220 B and is available from VW dealers, and most VW performance
aftermarket suppliers (Tectonics, etc.). The unit is quality with a capital D
(Deutsch). The unit is a stamped tray and feels as if it is made of copper. A
previous poster said the tray came with a rubber gasket. Not quite true. The
integral rubber gasket is molded as part of the tray. In the bolt hole areas,
metal sleeves are molded into the gasket to control gasket compression when
torqueing the pan bolts. The tray/gasket is designed for repeated use,
requires no goop for sealing and fits perfectly on all ABA and earlier e
ngines ( all 1.8 l, 1.7 l and 1.6 l I-4 blocks ) both gas and diesel.
Installation on the Vanagon I-4 gas or diesel engines requires removal of the
oil pickup tube to put the gasket in place.
The retail is $89 and I paid about $67 from Camelback. As I recall (it has
been awhile), there was no advantage to buying from Tectonics and I like to
support Camelback (as well as Bus Depot, Vanagain, etc). Check European Car
as several vendors like German ... and Performance ... and Euro ... recently
advertised the tray for as little as $55. Always insist on the part number.
Many aftermarket and dealer parts operatives will insist the plastic oil
pump pickup baffle is a windage tray. If you are quoted a price around $20
to $30, this is what they are quoting you. Remember, this is the America
doomed to continually repeat the Scopes Monkey trial!
The windage tray strips the oil film from the crank and helps keep the oil
pickup under oil during the most extreme conditions. It also has a direct
effect on the extent to which the oil is aerated (foamed by the crank
thrashing in the oil). The advantage of the windage tray is directly related
to the oil viscosity and film strength. That is, if you are running molasses
(SAE 50 or eq.) big effect, thin penetrating oil (SAE 0 W) then little
effect.
But what effect, you might ask? Well, the traditional value in HP at high rpm
for racing engines is given as 3 to 5%. These numbers are for traditional
engines where the static oil level is below the lowest point of the
crankshaft. In the basic line of I-4 VW engines both transverse and
longitudinal (remember, same offset angle) this is also the case. For the
Vanagon mount angle with the diesel oil pan, the oil level (static and full)
is at least 1.2 centimeters higher than in the rest of the I-4 family. There
is a several mm overlap with the crank at the static position. (BTW, I have
the full cross-sections of the I-4 mount in the Vanagon from the original
German technical articles and will send them on to a web site when time permi
ts). This means that in the hard-over mount condition, the effect is greater
than the 3-5% standard effect. Now, my measurements:
1. No horsepower difference measurements yet, but coming. By the notoriously
unreliable seat-of-the-pants estimate, the engine spins up noticeably faster.
2. No oil pressure light flash on hard braking or cornering. (Yep, had it
before).
3. Oil temperature at 5600 rpm under load, has dropped 12 degrees F. Probably
due to lack of air in oil. This is for my standard 5W-40 synthetic oil.
4. Amazing change in oil thrashing around in crankcase. As repeated in the
next section, I put a borescope into the former dipstick hole and have a tape
of the crank flying around and the agitation of the oil. I'll try to pull a
few frames to show the key points, but its not the frothing shower it was.
5. Finally, the gasket completely eliminated oil pan leaks.
Second, on the issue of the oil dipstick port on all I-4 engines (other than
the Vanagon diesel) which are mounted at the proper (engine cover conserving
design). Caution!!! This is a most important issue although proper resolution
is trivial. Remember that for Digifant II and CIS-E engines (I assume CIS is
similar, but haven't really looked at this primitive system) the crankcase
can only be ventilated via the PCV system. An air leak in the crankcase
system will effect fuel economy significantly. If one uses the diesel oil pan
and dipstick, this in-the-block dipstick port must be sealed. I cut the tube
off about 10 cm. away from the block surface (Dremel tool). Then used HT PCV
hose and clamp over the tube wall, and a long bolt (long enough to have non
threaded portion - 8 or 10 mm bolt - same OD as dipstick tube) to close it
off. I, on occasion, use this port to test modifications I have made
(measuring crankcase pressure, adding video boroscope to examine engine while
running, etc, etc). This clamped PVC hose approach has functioned perfectly.
I have seen other conversions with pinched-off tubes, stuffed rags, bolt with
permatex ... argh.
One listee commented about complete removal and replacement with the oil
dipstick tube used on the later diesels and turbo-diesels delivered other
than in the USA. This will work if carefully done. In my correspondence with
a German colleague, I was told that the bore in the block was different. So I
did not investigate further. I saw one conversion where the owner cobbled up
the dipstick system from the later waterboxers and crafted a Swagelock
transfer between the WB parts and the I-4 dipstick tube. Bad. Had to
calibrate actual oil level to get proper stick length. Dipstick often caught
during insertion. ...
Third, on the issue of rear battery location and engine heat. The comment
that engine heat is not an issue is simply wrong. All diesels were delivered
with engine area battery mounts. Indeed, as I have said previously, I run the
primary and auxiliary battery in this area. For years since the original
purchase in 1982, I had gone through batteries as fast as I went through
starters. Maintenance free batteries. There is no problem if you religiously
check battery water level with every other fill-up, but my Westfalia is
always loaded or I'm in a hurry, etc. The engine compartment temperatures are
so hot that the water level falls quickly. Sulfonation of the exposed plates
occurs, and capacity falls. Generally no problem in the summer. Onset of late
fall and early winter, temperatures drop and no battery capacity. OK if you
have lifetime battery warranty, but the time and inconvenience add up. Wife
thinks Vanagon has failed again.
My solution: I built a thermal shield around the battery to minimize thermal
transfer. The barrier seals to the engine cover and vents to the wheel well.
The air flow from the side scoop ventilates the battery compartment. No loss
of battery capacity since install several years ago.
Fourth and last comment on statements about miserable engine mounts for the
factor diesel mount cage (50 degree offset) vs. the Kennedy/Fast Forward 15
degree mount. Balderdash say I. The vibration spectrum of the diesel makes
that of its gas counterpart pale in comparison. From low frequency to high
the amplitude and power spectrum of the diesel far exceeds the gas. Of
course, the gas engine can spin to rates which would lead to piston/con rod
extrusion through block events on the diesel (lots of short term vibration).
The mount technology used by VW of passive vibration isolation through a
rubber adsorber/isolator bonded to metal has about the same acoustic
impedance for all I-4 VW engines. The compliance is different on the VR6 and
TDi engines given the torque impulse characteristics. As far as I know,
no-one has adopted the proven vibration isolation technology pioneered by
Porsche (liquid filled rubber mounts) or Citroen (coupled liquid logic rubber
mounts). Therefore the reported I-4 vibration problems are not a function of
mount angle and are not solved more effectively by an aftermarket solution
as compared to the factory one. Afterall, the block mount points are the
same, the engine cradle is rigid and there is no evidence to suggest that the
possible difference in frame mount location is tuned to different resonances.
Note, the factory mount is through one rubber set to the cradle, then the
cradle mounts to the frame through two sets of rubber isolators. The front
transmission mount is common to any system. Many of the aftermarket mounts I
have seen are hard mounted to the frame and coupled to the engine through a
single compliant mount. Vibration resonances are (in my experience) due to
poorly mounted exhaust systems.
Sorry for the length, hope this helps someone.
Frank Grunthaner