Thought I'd comment on the major automotive surgery I've been working on
with a friend of mine.  (Well, okay, my friend is doing most of the work,
since he knows this engine better than me...)

I recently bought a 1982 VW Vanagon Westfalia Diesel camper.  I love the
Westies...I used to have a 1975 model, but got rid of it eventually because
it was rusting out, and the engine needed more work than I had time to give
it.  Anyway, this one ran great on the test drive, but it later became
obvious there was a compression leak into the water jacket.  (I know. 
Shoulda run it with the cap off and looked for bubbles before buying it.) On
this van that's particularly bad because the radiator is higher than the
engine and filler cap, so the gases tend to collect in it and force the
water out. Bought a new head gasket and a few other assorted pieces,
including a new valve cover gasket.  (The PO had run it for hundreds of
miles with a bad one, and there was oil *everywhere*.) All went well, except
for the usual stuck bolt hassles, until we got the head off.  There were
nasty cracks between the exhaust valves and the precombustion chambers on
two cylinders, no doubt the source of my compression leak.  Sigh...

I got a good enough price on this van that I don't feel too bad about the
expense of a remanufactured head.  And the head is the main weak point on
these engines -- once it's replaced, I can probably expect a good 100,000
miles of trouble-free running.  Still, I'm a bit frustrated.  Right now my
new purchase is in pieces in the parking lot behind my apartment building,
and that's never a good feeling.

Good points:

Gas milage, at least from the amount I've driven it so far, seems to be
excellent.  It's hard to be sure since I haven't filled the tank again, but
I'm estimating about 30 mpg if the gauge is accurate.  Not bad for a 2700
pound brick.

It's not as sluggish as I expected.  The diesel vans have a reputation for
being slow, and in fact the 1.6L, inline-4 diesel is only rated at 52
horsepower.  Top speed is only about 65 mph (limited by a throttle stop on
the injector pump) but it accellerates about as strongly as my 1975
aircooled gas van did.  I had no trouble holding 60 mph on the flat and took
mild hills at 50 to 55.  The final drive ratio is low and there's all kinds
of torque available in 1st gear.

Real heat!  (You have to have driven an aircooled VW to appreciate that
one.)

Interesting stuff:

Apparently car diesel pumps weren't as common in 1982, because this van has
a huge 2" filler neck to accept the high-volume truck nozzles.  I bet that
fills the 16-gallon tank in a hurry!

38 responses total.

Yesterday while cleaning the piston tops we found evidence that they'd
touched the head.  On this engine the pistons protrude *above* the engine
block by a fraction of an inch, and the head gasket sets the clearance
between them and the head, which is flat.  (So are the piston tops; being a
diesel, this is a *very* high-compression engine.) There are four different
thicknesses of head gasket, identified by notches in the edge.  (I assume
this is how VW adjusts for all the stacked tolerances involved.) This engine
had a 1-notch gasket installed when we took it apart, the thinnest one
possible.  We measured a few of the pistons at TDC and sure enough, it
needed a 2-notch gasket.  Back to the parts store for a new
gasket...unfortunately this ate up the remaining daylight, but I'm glad we
noticed it before putting on my pretty new remanufactured head...

I think this may explain some of the cracking of the old head, too, if it
had been repeatedly slapped by the pistons.

Sounds to me like it's pretty amazing the thing ran at all.

That's the freaky thing.  It started easily, ran smoothly and quietly (for a
diesel), and had good power.  Got great gas milage, too.  I can't figure it
out either.

Today we got it mostly back together and running.  (Had to get it warmed up
to complete the head gasket torquing procedure.) The engine warmed up fine
to the thermostat opening point.  I made an attempt to bleed the radiator,
but don't think I got all of the air out -- I'll try again tomorrow.  Flow
was a bit lower than I'd expect from the bleed valve; either the engine
wasn't generating enough heat at idle to open the thermostat fully, or I
have a clog somewhere in the cooling system.

The cooling system in this van strikes me as a bit poorly designed.  The
radiator cap is on an expansion bottle in the engine compartment, several
inches lower than the top of the radiator.  They supply a bleed screw on the
radiator to purge out the air.  I don't know why they didn't just put the
cap on the radiator and put a recovery bottle up there.

Incidentally, the head torquing procedure on this engine is *scary*.  It
uses special bolts that can only be used once, and are supposed to stretch
when torqued -- you torque them to a set amount, then give them another 1/2
turn, then warm up the engine and give them another 1/4 turn.  The scary
part is you can feel them give when you do that last 1/4 turn.  I'm supposed
to give them all *another* 1/4 turn after the first 1,000 miles, too.

It must have been *just* touching.  Maybe only when hot/cold?  I suppose
the pistons and such in a diesel would be extra strong too.  Still,
pretty spooky.

I think it's pretty common today to put the cap on the expansion bottle.
Stops people from doing stupid things like removing the cap when the
radiator is hot (and causing a steam explosion when water under pressure
suddenly isn't anymore.) I believe it *is* usual to try to put it
"upstream" - maybe they ran out of room to put it farther up?

The stretchy head bolts is I think not uncommon.  It's a weird design,
but it at least guarantees you're using fresh bolts of known strength.
The older approach was to use studs, and reuse, and reuse, and of course
if you got stripped threads, you were screwed.  What I find disturbing
are aluminum cylinder blocks and heads.  Aluminum deforms a lot more
readily than steel (which is harder and more springy) -- which means
that tightening it is a whole lot more complicated, and if you botch the
tightening, you can easily screw up the head or block.

Yeah, this engine has a big aluminum head on a cast iron block.  They hold
up well as long as you don't overheat them, but one bad overheating episode
will warp the head.

In this case putting the cap on the expansion bottle doesn't really help
prevent steam explosions -- what VW calls the 'expansion tank' is a
plastic tank that's pressurized and has a regular radiator cap on the top. 
This van also has a recovery bottle that collects coolant blown out through
the cap.

Oh!  *That* kind of expansion tank!  Um, yup, that's weird alright.
I've never liked anything that involved plastic and flowing water under
pressure.  I guess it's becoming more & more common.  I suppose that
means the recovery bottle must also have a filler cap.

Yeah, it does.

Working on putting some "real" gauges in the van.  (I don't trust the stock
water temperature gauge, since it has absolutely no calibration marks at
all.) The wiring diagram for this vehicle is, uhm, interesting...VW's
position seems to be "Fuses?  Yeah, we've heard of them." There *are* fuses
for some things, but a lot of stuff is simply connected directly to the
battery side of the fuse panel, or to the ignition switch, which doesn't
have any fuse protection either.  The entire instrument cluster is in this
category.   A lot of stuff seems pretty well thought out on this vehicle,
but the wiring harness does not.

You probably have fusible links in the wiring harness.  I think it's
actually fairly common not to fuse the ignition circuit.  Some Japenese
makers are fond of hiding fuses in 3 or 4 spots, although I can't
imagine VW would do that.

No fusible link, at least not that shows up in the wiring diagram.  My
friend's experience with his '80 Dasher is that in the event of a
serious short, the entire wiring harness becomes a fusible link.

The van's road-ready now, except that it needs an oil change to get any
trash out of the oil that got in while the head was off.  Simple enough,
if I could get the #@$&* drain plug out.  Whoever used to work on this
thing liked fasteners *really tight*.

The entire wiring harness becomes a fusible link?  Must be pretty
spetacular when that goes, not to say expensive afterwards.

Yeah, he had an electrical fire after accidentally shorting out a wire
in his electrical harness.  It started a chain reaction where wires
heated, lost their insulation, and shorted together.  Wiped out nearly
the entire under-dash harness.

The van's running much cooler now than it did before putting the new head
on.  If I were more familiar with this particular vehicle, I'd probably have
noticed the problem before buying it, but the stock temperature gauge has no
calibration marks other than a line near the bottom end and a red LED in the
center that flashes if it really overheats badly.  Before it would fairly
quickly heat up to the point where the needle was just past the LED; now it
stops and stays almost rock steady at the line near the bottom end, which I
suspect is intended to indicate normal operating temperature.  My new Sunpro
temperature gauge says this is 210 degrees F, but that may not be entirely
accurate, since I seem to have a fairly high resistance ground connection
from the front of the van to the back.  (Just switching on the headlights
instantly causes the gauge to indicate several degrees higher.) The
thermostat (which I also replaced, while I had everything apart) is supposed
to begin opening at 189 degrees F and be wide open at 220.

I'm starting to realize the Sunpro gauge wasn't the best choice.  With a 189
degree thermostat, only the right third or so of the gauge scale is useful
to me, and that's exactly where it really starts to compress and get
non-linear. :P

Took the van on the freeway, down to Dundee and back.  It ran quite well,
and the temperature stayed rock-solid.  I have a serious voltage drop
problem between the rear-mounted battery and the front of the van, though. 
With the headlights on I'm losing over a volt.  Probably a combination of
corroded connections and undersized wire.

Unfortunately, my patch on the exhaust pipe between the manifold and muffler
didn't hold up, so I'm going to have to give that another try or give up and
buy new parts.

It should be easy enough to find out where the drops are.  If they're
bad enough, you might be able to literally feel them out because they'll
get warm.  The connection between the battery and the engine really
shouldn't have much of any drop under normal circumstances; the starter
circuit has to be capable of sustaining quite a lot of amps for at least
a short period of time -- without so much of a voltage drop that it
fails to run the starter.  That is probably at least 10 times the load
the rest of the car produces, - so I guess I'm arguing that any such
drop in that circuit should be < .2V at any other time than starting.
'Course, I don't know how much of that circuit is shared by the rest of
your car.

Something else to check though -- check your fuses.  There are two
places these can fail -- either the connection between the fuse & the
fuse holder, or *inside* the fuse you can also get corrosion and
eventual loss of conductivity.  The old style glass tube fuses were
pretty good at the latter in time.  Volvoes use a really funky copper
strip system; copper corrodes real good, unfortunately.  I'm not sure
what VW uses -- could be either of those, or the modern style plastic
blade found on most new American cars (GM since about 1978, etc.) I
think the blade style is less vulnerable to corrosion than the older
systems, but I'm sure even it is not immune.

If your vehicle uses a frame ground return system, then ground
connections anywhere & everywhere should be suspect - since the frame is
usually steel, & wires copper, there's built-in electrolytic activity
that guarantees corrosion in time given any water nearby.  You might
find it to your advantage to wire up some copper ground jumpers,
especially if you have parts of the frame that no longer make
electrically good connections to each other.

Re #15: The starter wiring is fine, as is the wiring for the glow plugs --
that's all in the engine compartment, with the battery, so there's very
little voltage drop.  The problem seems to be between the engine compartment
and the front of the van.  I suspect a high-resistance ground, since my
temperature gauge's calibration shifts when I turn on things up front that
draw a lot of power.  I may just make a run of 10-gauge wire from front to
back to connect the main ground points together.  This will also be useful
when I get around to installing an amateur radio transceiver in the van.

Gasoline versions of this van put the battery under the passenger seat.  I
guess for the diesel version they were probably concerned about the voltage
drop during starting, since there's 48 amps worth of glow plugs *and* the
current draw of the starter to support.

Older VW's use those funky fuses with the pointy ends that go into holes in
brass spring strips.  Cleaning them all up is a good idea.  That's not my
main problem, though, since the voltage drop affects *all* the circuits when
I turn on anything up front that creates a heavy load.

I wire ham transceivers directly to the battery, both - and + (with fuses
in both wires). Just as easy since if you can run one wire to the battery
you can run two, and this avoids some interference problems. 

Yup, if I go ahead and do this I figured I'd run two heavy-gauge wires to
the front as long as I was underneath the van anyway.

Are you just measuring the available voltage at the front and back, or
are you measuring the difference in ground potentiality between the
front & back?  The former will only tell you've got a problem somewhere,
the latter should tell you if should be looking at your ground or hot
wire distribution side.  The voltmeter's current draw should be
infinitesimal, so even wimpy magnet wire (with nice aggressive alligator
clips, or one or more willing and able assistants to hold things) should
suffice should the voltmeter's leads be too short to reach front to
back.  Thicker wire would make it easier to establish good contact
though.

I haven't measured the actual ground drop, yet, but I plan to.  It may very
well be both.  I'm suspicious of the ground side, though, because the
temperature gauge I installed moves upscale when I turn on the headlights,
and back down when I turn them off.  Its sender is ground-referenced.  It's
possible the gauge just has poor voltage stabilization, and the voltage
change itself is what's affecting it, though.  At any rate, on a 20-year-old
vehicle it'd be worth my time to clean and tighten all the major grounds. 
The '75 van I used to own cranked sluggishly until I did that, and
afterwards it cranked like it was on city power.

I still need to figure out how to mount the sender for my oil pressure
gauge.  I have a tee and nipple to connect both it and the idiot light
sender to the stock location on the block, but the sender for the gauge is
heavy and I don't think I want it just hanging there.  I know I'll be taking
this van on rough dirt roads from time to time, and I'm afraid the weight
and vibration will snap off the brass nipple.  I'm thinking of seeing if a
hydraulic hose shop can make me a short hose with an 1/8" NPT male
connection on each end, so I can mount the senders to the firewall.  I've
seen grease gun hoses with connectors like this, but I'm not sure if they'd
stand up to hot engine oil.

I don't know that I would try that -- the engine is likely to vibrate
and move quite a bit relative to the firewall (especially on rough
roads), which means anything between is going to be undergoing a torture
test, hot or not.  And, if it does break, you're going to have a nice
oil leak (and I hope your exhaust isn't anywhere nearby).  I'd recommend
looking for some way to secure your sender to the engine block instead
-- if there's nothing obvious nearby and no way to bend it to secure it,
perhaps you can make a bracket? If you do decide to go the flexible hose
route, there is definitely flexible hose made that's suitable for hot
oil.  Um -- whatever they use for oil coolers would work for you.

Yeah, I figure a hydraulic shop would know what to use.

I'll investigate securing it to the engine, but there's very few attachment
points on the cylinder head (which is where the oil pressure sender is) and
I'm not about to start drilling holes in it. ;) My friend has a similar
setup with the gauge sender hanging off a brass tee, and it has snapped off
once or twice, so I'm risking an oil leak no matter what I do.  The sender
is nearly half a pound of brass, much larger than the idiot light sender
that's normally in that location. :P  I really feel like I need it, though,
because the stock oil pressure warning light really only tells me anything
at idle.  The sender is calibrated to turn on the light if the pressure dips
below 7 psi; normal running pressure at highway RPM is more like 25.

Friday I tinkered with the refrigerator a bit, and got it to light on
propane on about the fifth try.  I let it run for an hour and it was
definately getting cold inside.  I still don't fully understand how you can
make stuff cold by burning propane, but as long as it keeps my beer chilled
on trips I won't worry about it. ;)

Could a very strong magnet be used to hold the sender to the head?

See http://www.nh3tech.org/absorption.html for how an ammonia absorption
refrigeration cycle works. 

Re #23: Nope.  Aluminum head.

There should be brackets and screws *somewhere* on that engine.  The
traditional method of securing the alternator, a/c compressor, and other
outboard components is via brackets screwed on *somewhere*.  There may
be other screws that secure components such as cables, fuel injection
rail, intake throttle components, etc.  If there's no place convenient,
it might make sense to mount the oil sensor on some *other* part of the
engine and run a line (could be either flexible steel wrapped, or steel)
to wherever you can solidly attach the sensor.  By keeping it all as one
unit that moves in one piece, you should be able to reduce tension & the
risk of breakage.

The propane refrigerator is using a trick of thermodynamics, it's using
the heat flow "downhill" from the very hot propane flame to the
relatively cool out-of-doors, to pump a small amount of extra heat
"uphill" from inside the refrigerator.  It's not actually very efficient
(the ordinary mechanical compressor is actually better for this), but it
has very few moving parts so is cheap to make and reliable in operation.

That's how your home refrigerator works. It is using the very hot burning
of fuel to generate electricity, which runs your refrigerator, which
exhausts low-level heat to the surroundings. It's all heat running "downhill".

Well, sort of, but the "very hot burning fuel" in that case is almost
certainly not located in your refrigerator, and if it's "solar power",
burning is not really a very accurate description of what's happening
inside the sun.  On the other hand, if the electricity came from nuclear
power (which is true of some % in michigan), while "burning" is no more
accurate, that is one of the few forms of energy available on earth that
isn't ultimately derived from solar energy.

Actually it is, as radioactive elements were created in stars. 

Nuclear physicists and engineers use the term burning for spontaneous
nuclear reactions. See, for example,
http://casswww.ucsd.edu/public/tutorial/Nukes.html

I suppose they're going to start pronouncing "nuclear" with 3 syllables
next.

? Why not? Nucleus is. 

I think we should all start using the G.W. Bush pronounciation, "nukyaler". 
If we don't, the terrorists win.

The URL Rane quotes doesn't seem to cover nuclear decay (a "spontaneous"
nuclear reaction), but may cover nuclear fission (which may be either
"spontaneous" (ie, various natural nuclear reactors found at the earth's
surface, or the really big one at the earth's core that some people
allege must exist), or "planned" (ie, commercial nuclear power, or also
fission bombs.)  In the sense used there, "burn" may be intended to
describe only controlled or at least stable reactions, or it may not; in
chemistry "burn" is not usually used to describe the sudden dissolution
of an explosive such as nitroglycerine, and a distinction is usually
made between this and the "fast" burn that occurs in an automobile as
gasoline is rapidly combined with oxygen generating a blue flame and
much additional pressure.  In any event, I assume the use of "burn" to
describe solar nuclear reactions is a holdover from an older theory that
held the energy of the sun came from a really *really* big coal fire.
(This theory was cast into doubt when calculations showed that this was
incompatible with the calculated age of dinosaur bones then being
discovered.)

I agree that it is a holdover. But that happens to words, when new
possible uses arise. 

I suppose nuclear decay, then, is just smouldering.......

Just a quick note on what's been happening:

Van's running great.  No overheating problems at all since the head job.  In
a few hundred more miles it'll be time to do the final torquing of the head
bolts.  (An extra 1/4 turn on all of them.)

Gas milage is running around 25 mpg, mixed city/highway.  This compares
favorably to the 17 mpg my gasoline VW got.  It would probably be even
better if I set the timing properly, but that requires a $120 dial gauge and
holder that I haven't purchased yet.  I know it's "close", but best power
and economy on these engines requires very precise timing settings.  (The
valve timing, which I *have* set properly, is so critical that the camshaft
sprocket has a taper instead of a key, so you can make adjustments of less
than one timing belt tooth.)

Had a minor oil leak which turned out to be the valve cover gasket.  Easy
fix.

Still haven't dealt with the voltage drop problem, but I plan to do that
soon because I want to install my 10 meter transceiver.

I ended up replacing most of the exhaust system, with a combination of new
and used parts. It's still noisier than I'd like on the highway.  Some of
this is probably normal, but I'm suspicious that it may be partly due to the
fact that I'm missing part of the intake system.  There's supposed to be a
fairly long snorkel on the air cleaner, but it's missing.  Since this is a
diesel, that means the only thing between the intake valves and the outside
is the intake manifold and the air filter.  Not much sound muffling there,
and I've learned from experience that, at least on gas engines, an unmuffled
intake can contribute a surprising amount of engine noise.  I think I've
tracked down a used snorkel assembly and will hopefully be putting that on
soon.  Even if it doesn't help the noise much, it'll be better for the
engine to not be inhaling hot air from the engine compartment.

If you can't get "the right" part for the snorkle, it strkes me there
ought to be a ton of alternative "kludges" that should work fine.  A
bent piece of the right size auto exhaust might be a simple fix...

Yup.  I've got a line on at least part of a used snorkel, but your
suggestion is my 'plan B'.  I'd rather use the 'right' part because it
has some nice features, like a cyclonic water separator.  (Water in
high-compression engines is Very Bad.)

The valve cover gasket sprung a leak again in the same spot.  Gotta make
sure the cover isn't bent and then see about doing a better job putting
the gasket on.  It's an awkward design.  The gasket comes in two pieces,
a flat cork gasket that covers most of the sealing surface and a rubber
strip that goes over the cam arch.  You have to glue the two parts
together with RTV.  Naturally, it's leaking at the cam arch.

I changed the transmission lube a week or so ago.  What came out had
very likely been in there for 21 years and 150,000 miles -- VW has *no*
oil change specification for their manual transmissions.  It was solid
black and had a bit of water in it.  Managed to spill some, and I can
say this stuff is a nightmare to clean up -- 80W90 gear oil, in 70
degree weather, is the consistancy of warm honey.  Imagine trying to
wipe up spilled honey, except it's slippery instead of sticky, and you
get the idea.  Found the normal collection of steel filings on the
magnetic drain plug but nothing worrisome.

I got the upper part of the snorkel yesterday.  I'm still missing the
water separator/elbow and some other connecting pieces, but I bought a
piece of 3" aluminum flexible duct at the hardware store and cobbled
together a connection to the air cleaner.

Wow!  What a difference!  The engine noise at highway speeds is half
what it was before.  I had no idea so much racket could come out of an
intake.  At least some of the noise now is probably engine vibration
being transmitted to the body by the aluminum duct, too -- I haven't
made any attempt to isolate it yet.

Intake noise was apparently the dominant noise source from the engine at
highway speed -- so much so that patching two major exhaust leaks hadn't
changed the noise level noticably.  Hooking up this snorkel is what
finally made a difference.

Took the van down to Milan tonight to pick up an exercise bike from another
Grexer.  On the way down and back it started behaving oddly.  It was running
slightly warmer than usual, and when I had to idle at a stoplight the
temperature would slowly increase.  It would slowly go down once I reached
highway speed again.  Now, this van has a huge radiator for the size of its
engine, and normally in this weather the temperature *drops* when idling. 
This was not normal behavior, and it worried me.  Shortly after parking the
van, it peed out a small puddle of coolant.  Uh oh.

Fearing the worst, I opened the engine hatch.  I noticed the top of the
expansion bottle was wet, and then realized the pressure cap was crooked.
It turns out when I'd checked the coolant level earler, I hadn't gotten the
cap back on straight.  It wasn't sealing, so the cooling system couldn't
pressurize properly.

The root problem here is bad design by VW.  The pressure cap is the usual
sort, a metal radiator cap with two tabs that hook into a lip on the
expansion bottle neck.  Unfortunately, the expansion bottle neck is plastic. 
I failed to put enough force on the cap to fully compress the spring, and
one of the tabs carved a new "thread" into the lip.  This is probably why
they only used this design for one year -- the expansion bottle I have is a
1982-only item.

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