Originally Posted by xsboost90

lifters have springs in them but also fill with oil pressure/oil during operation and "self" adjust tension onto the cam/valves. When they wear out they tend to not pump up anymore hence "collapse". I had a ticking lifter once but it ended up just being a spun rod bearing.

Originally Posted by Doug Hillary

Hi,

This Oil Condition Report (Used Oil Analysis - UOA) is the eighth and final. It may be of interest to those who have followed the previous seven reports over the past almost two years
The oil and filter were NOT changed at this point as ExxonMobil's Lab. report OK'd the oil for continued use. It will be changed about one month from now at Porsche's prescribed maximum time limit of twelve months or sooner if the distance covered exceeds 12k miles

This is the fourth UOA on Mobil's Delvac 1 5w-40, a fully synthetic commercial "mixed fleet" HDEO (heavy duty engine oil). This oil has both the highest diesel/petrol ratings and is the latest API "CI-4/SL" rated "mixed fleet" diesel engine oil. It also exceeds ACEA's A3 and B3 ( E3, 4, 5 & B4) ratings. It is suitable for high performance petrol engine vehicles and meets the 928's viscosity and quality requirements stated in the Owners Handbook

Details:

Car - MY89 - 928S4 Auto
Speedo - 84557 miles (136163kms)
Oil - Mobil Delvac 1 - 5w-40 full synthetic - API rated as "CI-4/SL"
Oil/filter change date - 09/20/03 (OEM "MANN" filter used )
Distance since oil/filter changed - 11848 miles (19079kms)
Time since oil/filter changed - eleven+ months
Oil used since oil/filter change - nil (still near "FULL" mark)
Date of this sample - 8/23/04
Distance since last UOA - 1545 mile(2488kms)
Time since last UOA - approx. four months
Use in this period (approx) - 10% town, 13% urban, 77% hiway
Avg speed in period - 44 mph (70km/h)
Fuel economy in period - 20mpg US (11.8ltr/100km) (24 mpg Imp)
Ambient in this period - from 35c high to -3c low Humidity in this period - 88% (highest)

Oil Condition - "use" factors;

Viscosity OK - 92 (excellent)
Water OK - 0.0%
Soot Index OK - 0.00
TAN OK - 3.7. (excellent) - Start 1.00 & Max allowed 8.9

Lab. Report Summary

ExxonMobil's rating now - "Normal"
Status-Excellent for continued use
Last Report - "Normal"


Elemental (& wear metal) Analysis;

Detail of the Elemental columns are:
Col 1 = this UOA (my comments in brackets)
Col 2 = averages of all eight UOA's
Col 3 = Oil Industry's "acceptable" max. wear rates (rounded) & not 928 specific

Iron 10 ( excellent ) [8] (( >100 ))
Aluminium 6 ( excellent ) [4] (( >30 ))
Chromium 1 ( excellent ) [<1 ] (( >30 ))
Copper 4 ( excellent ) [4] (( >50 ))
Lead 11 ( excellent ) [6] (( >100 ))
Silicon 5 ( excellent ) [8] (( >30 ))
Sodium 6 ( excellent ) [4] (( >10 ))

Note:
The elemental/wear metal rates are very low. All are around the previous averages and well below the Auto Industry's "acceptable" figures. This indicates that the rings, pistons, bores, cams, bearings and other major components are wearing at a very very low rate indeed
This is another "technical analysis" of why the 928 engine is so durable in normal use when using the Porsche recommended (or better) lubricants that are changed at Porsche's recommended servicing intervals

Oil Condition Summary:

The lighter 5w-40 viscosity oil has now been used for almost 12000 miles (19079kms) over about eleven months. During this time the car was driven above 100mph(160km/h) for some long periods in 30+C and at below freezing temperatures
This very high quality oil has contributed to the overall lowering wear rate trends and has caused the wear trend averages to fall accordingly
The oil will be changed in September according to Porsche's time - maximum 12 months use - recommendation, but the maximum distance may still be reached!

RENNLIST's 928 owners now have a very good baseline of UOAs from which to measure their own engine's wear and oil degradation rate trends. This will also assist those persons who race our engines.
A number of Labs. in NA do UOAs - but it is always better to use one that is well known

Regards