Steve (Thanks for the tip) - A HA!  I found it: http://www.vwdieselparts.com/forum/viewtopic.php?t=1747&postdays=0&postorder=asc&start=45

(Wow, these forums look pretty similar to vwdieselparts's.  Even the "look and feel".  Hmmm... hey even the users there look familiar! )

May I recommend an oil temperature gauge? I generally put one on anything that's driven hard. It tells you SO much more than a water temp gauge can.

Marcel

Already got one.  Thanks for all the info, I don't have anything new as a yet to report but will post up here again as soon as I do.

I've heard good things about leak down tests.

This is just a guess, so take it as such. I would think that doing a wet compression test on any diesel would not be a good idea. Obviously the fuel is off, but could it not theoretically try to start on the oil. Also having the oil in the cylinder would reduce the volume of the combustion chamber. It has been my experience that a leak down test will usually give the best answers, but I have only ever done them on gas engines.

 Also Jake, it is my understanding that the engine requires 600 or so RPM for starting purposes, so I would think it would deem neccessary to reach the same speed during a compression test also. Somebody correct me if I'm wrong, but 190 RPM seems way to slow.

Hey guys - you bring up some good quesitons.

Regarding wet compression test - no bentley does not state you can't do it.  In fact, it explicitely states you can.  According to my bentley (covering '77-'84 Rabbit / Jetta Diesel) it states: "To determine whether the piston rings are causing low compression squirt a small quantity of SAE 40 oil into the low-reading cylinder(s) through the injector hole(s), and repeat the compression test. ..."

Furthermore, also in the VWoA service manual distributed to dealerships titled "Four Cylinder Diesel 1977-83 / ProTraining" (someone uploaded it here: http://www.vwdiesel.net/phpBB/viewtopic.php?t=321 ) gives compression test procedure on page 53, stating "A low reading can be rechecked by adding 1 tablespoon of engine oil through the injector hole..."

Also more about the wet compression test, the way I measured the quantity of oil to add was found a good spoon to use, then measured that 3 spoonfuls of water was equivalent to 1 tablespoon.  If I put in 3 full spoonfuls, a bit of oil would get up into the compression tester.  If I put in 3 light spoonfulls, not oil would get up into the compression tester.  But I would imagine it would be  thrown around inside the combustion chamber and no doubt, would add some to the compression ratio.  The compression tester I used did it's measuring through the injector hole.  It is very similar to the one pictured in the Bentley manual referenced above, on page 10.  The glow plugs were left installed.

Moonstone - Regarding adequate cranking RPM - 600rpms is way above what is required for our motor and what our starter motors are capable of without any cylinders firing to assist.  See same source referenced above (Protraining), where it states to check for adequate cranking speed on page 25: "Cold cranking speed must be at least 150rpm."  (This is referring to standard cranking speed where all four cylinders have resistance during compression of course, not speed during compression test when only one cylinder has full compression loading, however I didn't really notice the RPMs seeming to be much different between the two.)  I just can't see there being a problem with my motor's cranking speeds.  The way I measured cranking rpms during the compression test was by counting the number of "puffs" on the compression gauge in a 10-second period, and multiplying that number times 12 to get the RPM of the crankshaft.  16 puffs in 10 second period x 12 = cranking speed of 192 RPM during the compression test  (give or take 12 RPMs.)

Mark the Miser - on a leakdown test, to rule out the rings, engine oil is added.  But unlike the compression test, the pistons are not moving up and down, it's just the rate of air leakage that is being measured, so the oil would definitely stay down around the rings where gravity would make it go.  It would only help seal the rings.  It would not get splashed around inside the combustion chamber by moving pistons and could not possibly help seal valves.  It would indeed be more definitive test than a "wet compression" test.

I am thinking that based on my compression test, I've got some problem that's definitely not starter, electric, or fuel injection related.  I'm thinking about the only thing I might think about doing is double-checking the cam timing before taking the head off.  Although the evidence that I do have seems to be pointing to rings.  I have not had bad sealing valves before so I don't know if they would be even or not.  Keep in mind this is a freshly rebuilt head.  Common sense says if the machinist screwed up the valve job, it wouldn't be exactly even on all cylinders.  But at the same time, it is possible...

So anyway, I'm thinking next steps I should do are first double check cam timing, since it is easy to check.  And then, I'm not sure... I'm debating between checking / changing valve clearances, or just taking the plunge and pulling the head off for testing.

Mark the Miser - on a leakdown test, to rule out the rings, engine oil is added.  But unlike the compression test, the pistons are not moving up and down, it's just the rate of air leakage that is being measured, so the oil would definitely stay down around the rings where gravity would make it go.  It would only help seal the rings.  It would not get splashed around inside the combustion chamber by moving pistons and could not possibly help seal valves.  It would indeed be more definitive test than a "wet compression" test.

 :twisted: Thats not to say that the air would not also show up poor valve seating at the same time(hissing in inlet or exhust at TDC compression (stroke) :twisted:

I am thinking that based on my compression test, I've got some problem that's definitely not starter, electric, or fuel injection related.

 :?: Two points here are causing conflict with my  (sometimes)logical thinking..
Earlier on you mentioned observed change in cranking speed with 'three injectors out and four in...Is this right? I'd expect a doubling of cranking speed [ish] although your 190rpm sounds reasonable in itself [3 rev per sec]
The second point is your reference to 'fuelling must be good' WHY?
I'd loosen one injector line and under end of line do a fuel collection for a few cranks (GP's off) :?:

 

Common sense says if the machinist screwed up the valve job, it wouldn't be exactly even on all cylinders.  But at the same time, it is possible...

:wink:  Ah do you put all your money on a single number in roulette?  
Mark-The-Miser-UK