[Vwdiesel] Compression gauge

[Val Christian]

> >So frequent changes, even with a low cost "S" oil, does work, and it can
> >be cost effective.
> >  
> >
> Interesting that using non-C rated oils is not an absolute taboo.

	In my opinion, they are not an absolute taboo.  Certainly,
	a "C" rated oil offers an accepted formulation for diesel
	applications.

	My point is that you should not automatically assume that 
	the engine is trashed, simply because an "S" rated oil is 
	used.

	A second point is that the differences between "C" and "S" 
	rated oils, in some formulations, can be minimal.  For example,
	the lower end Mobil dino oils have traditionally had high 
	detergency, and have good soot retention characteristics.
	They are no longer given a "C" rating. 

	My final point is that I have emphirical evidence, albeit 
	with a very small sample size, that the practice I've engaged
	in does not cause the alledged harm that is often attributed
	to the dreaded "S" oils.  Everyone's mileage may vary.  My
	vehicles are driven a certain way, under certain conditions,
	and tend to receive frequent servicing, including oil changes.
	

	Almost as dreaded as the "C" vs "S" rating, is the viscosity
	ratings.  Again, I can cite emphiracal evidence, with a small
	sample size.  In the early 80's after running VW diesels for
	5 or 6 years, and putting lots of miles on them, I started 
	noticing that I was having sticky rings.  Upon disassembly, 
	there would be substantial carbon buildup on the rings
	(and yes, I was using "C" rated oil all the time at that point).
	My oil practice, consistent with VW recommendation, dealer input,
	and conventional wisdom, was to use 20W50 oil in the warmer
	months, and 10W40 or 10W50 when the temps started dropping
	below 20F.  

	I'll save you the stories, but it remains somewhat surprizing 
	to me today, that the VI was likely the major aggrivating
	factor in reringing a few engines.  The lower VI oils do
	a better job of flowing and therefore washing the ring area.
	I switched to lighter weight oils, and tried to pick oils
	with had more oil, and less VI improver additives.  Since then,
	no stuck rings, and no apparent increased bearing wear. 
	Perhaps the cars are a little easier to start in lower 
	(sub zero) temps, although that has never been much of a 
	problem.  To his day, something in me wants to run 20W50
	oil, but I resist.




> >Let me address your compression issue.  If you are having a problem
> >which could be compression caused, then check the compression.  Harbor
> >Freight has diesel compression gauges for less than $30.
> >
> The HF compression tester is currently on sale for 17.99,  I saw it, it 
> looks ok enough that I may get one and try it when I get to the point 
> that I need to do a compression test..
> 
> >  I don't 
> >have experience with their tool, but the one I use cost less than $100.
> >  
> >
> So what brand is yours?

	I have a KD-tools compression gauge, which I bought in 1978.
	Recently, I aquired a Snap-On gauge, but have not used it.
	It's used, and I have not had a chance to check it with a 
	N2 supply and regulator.

	You will probably find that the HF gauge will serve you just fine.
	Relative readings will help you diagnose problems, and absolute
	readings will help you understand the general wear on the engine.
	In my opinion, and I'm sure there are lots of people on the list
	who will disagree, even if you have a 5% error in the absolute
	reading of the gauge, it will be quite adequate for your 
	purposes.  And that will leave you with more money in your
	pocket so you can buy high end "C" rated oils.

> 
> >If you have the injectors out, or if you're going to pull the head, then
> >check the compression, to get an idea of the condition of the engine.
> >If you simply want to get a metric on how the compression is doing, wait 
> >until you have a few hours ~25 on the engine, so that you get a realistic 
> >reading of the general condition.
> >
> >Should you end up pulling a head, then it's time to ask if you should 
> >be doing the bottom end.  In all my life with VW diesels, I have only 
> >_had_ to rering a couple of engines, and that was with over 300K and
> >over 400K.
> >
> I'm liking these diesels more and more...

	Check out some of the other postings.  Loren sees more of these
	engines than I do, and he reports different findings.  His findings
	are likely more representative of the general population.

	Diesels are different, but after about 30 years of owning and 
	maintaining them, I still think that they are very reasonable
	alternatives, particularily if you're willing to learn things
	that may not be mainstream.

	Val