Jabpir8

Hi guys,

Need a metallurgic expert on this one as I just made an engine oil analysis (in a lab) to know if my engine needs full rebuilt or not.

The oil was analysed at 137,000 miles on this SB 350ci L05 and the oil had done 5,000 miles since last oil/filter change.

Results show the following:
- Aluminium (ppm): 16
- Iron (ppm): 62
- Chrome (ppm): 2
- Wear index: 0 (unsure what this means ...)
- Tin/pewter (ppm): 0
- Copper (ppm): 9
- Lead (ppm): 30
(ppm means "part per million" = milligrams in one kilogram for example)

The block being cast Iron it may be not abnormal that there is some iron but is that too much ?
As for the Aluminium I think only the pistons are made of this no !? is that bad ???
Then for the Lead I do not see where it comes from !!! (always using UNLEADED gas)

Any idea and guidance ??

I plan to rebuild the heads with improved valves, springs, FR rockers and a soft cam but was not thinking about changing the pistons and rings ...

torque_is_good

that's awesome that you did it for giggles because it won't tell you if you need a rebuild.

vacuum gauges, leakdown test and compression test are the tools you need


also, if you see smoke blowing out the tail pipe, hear a knocking from the lower end or are consuming oil and or coolant

Jabpir8

Well, you are right but before you smoke blue and knock the oil analysis is kinda cristal ball to tell you if it's gonna fail very quick or not.
Professionals having truck fleets or specific engines use this method to know what they need to do next. It is easy, quick and tell all you need.
Except that I am not expert to tell where those metals come from !!! (is lead in the crank main beaings ???)

My car does not smoke, does not consume much oil (only some through the cyl 1 & 2 valve stem seal). And leakdown test must be done on hot engine, I have headers and this is far from being easy !!! even when cold it is a mess to remove the spark plugs ...

UNCLE TOM

iTrader: (1)

i know many will laugh & joke but oil analysis is often used predict a wealth of engine problems . it is nothing new , it's been around since before most members here were even born . how do i know ? i started as an Air Force acft. mech. in 1956 . (DAMN I'M OLD) and it was just a few years later i became familiar (get ready to laugh) with the "SOAP PROGRAM" . "Spectrometric Oil Analysis Program" it was used throughout my 20+ yr. A.F. career . during the Viet Nam War all fighter acft. had an oil sample taken every flight . (one did not want engine problems over North Viet Nam , most of all if they went downtown) as i continued into civilian aviation i found it as also common . (both in jets & piston acft.) also used by many large fleet vechicle operators . good luck finding your results .

Apeiron

Pistons are aluminum. Piston rings contain chrome. Bearings are tin, lead, copper and aluminum. Iron comes from just about everywhere.

All your numbers are well with normal values.

Jabpir8

Thanks, feel a bit better now !
for info I work for a (civilian) aircraft manufacturer but as we sell brand new aircraft we don't need oil analyses

FNFAL308

iTrader: (1)

Need to do oil analysis on every oil change to get the benefit from it. That way you will see a trend and catch the numbers going up. Tug boats also do that. Not really needed in autos as an engine going out is rarely life threatening

zraffz

Not sure if their is lead in the main bearings but I know a lot of cam bearings have lead in them.

Jabpir8

How do you check cam bearings ? I have a new cam in hands and plan to install it but I did not think of changing the cam bearings (when I overhauled my TH700 2 years ago the bearings were in very good condition !!!)

Apeiron

Cam bearings are loaded lightly. If they don't look all scratched up, they're fine.