Synthetic Oil = Trashed Lifters? Doubt it...

["Al Powell" <apowell@agcom.tamu.edu>]

Re - the comment about synthetic oil having ruined some 
lifters....there is something unknown here.  It just does not make 
sense.

1)  MUCH more likely that the lifters were weak but had 
deposits which caused the problem not to be evident.  Synthetic is 
highly detergent and may have made the clicking audible by breaking 
the deposits loose.

2)  As an aside because of the amount of discussion we've had 
about lifters at one time or another, note this.  (The following 
comment is from memory - times and revs are approximate; please 
correct me if I'm a few seconds or revs off...)  Lifters are not 
considered to be "clicking" in the I-5 engine unless they do so AFTER 
the engine has been run at 2K RPM or more for at least 30 seconds.  
Many lifters are audible when the engine is started but *not* after 
being run as per the above spec.

3)  I have used Mobil 1 and Amsoil in the following cars since 1977:

1977 Chevy Monza Spyder, 305 V-8
1980 Plymouth Duster Turismo 4-cyl.
1982 280ZX
1983 280ZXT
1985 Audi 5KT
1990 Audi 200
1985 Chevy C-10 Pickup, 305 V-8

In that 20-year period, the ONLY lubricated engine part which has 
failed on ANY of the above cars was a turbo on the 1983 280 ZXT, 
which went out about 4K miles after I bought at 49K miles.  I believe 
this was the fault of the previous owner not maintaining the turbo.

4)  All of the above cars has been run at least 10K miles between 
oil changes; filter changes have been done at 3K mile intervals.  I 
have also used synthetic gear oil and automatic transmission fluid 
in all the above vehicles.

5)  Of the information I have received and researched about sythetic 
oils (including that sent to me by the estimable Avi Meron) I have 
never seen HARD data indicating that synthetic oil - and for that 
matter, synthetic gear oil and ATF - do not OUTperform conventional 
oils. 

6)  Based on the above, I do not think synthetic oil was the problem. 
Nor do I believe that most mechanics know their butt from a hole 
in the ground when they discuss synthetics.  Most of them are so 
tied to tradition that they have never studied the subject.

Disclaimer:  

The small but real differences between today's admittedly excellent 
conventional oils and synthetic oils may NOT justify the extra 
cost for the synthetics - to you.  To me, is it a slam-dunk in favor 
of synthetics, especially on a turbocharged automobile.  I would not 
use conventional motor oil in a turbo engine under any circumstances 
when synthetic is available.

The above is offered as observation and opinion, not as advice.


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Al Powell, Ph.D.                 Voice:  409/845-2807
107 Reed McDonald Bldg.          Fax:    409/862-1202
College Station, TX 77843      
Http://agcomwww.tamu.edu/agcom/satellit/alpage.htm
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