oil analysis - lots of silicium ?

Right,

That's exactly what the lab technician told me. He really meant his figure of 149 was the result of a test which separated sand from other silicon compounds. The original figure of Si content in the test was 250.

Thanks,

Peter

Sand is SiO2, but not all SiO2 is sand...There are big differences... Fumed silica is SiO2 and it is light as a feather and not grainy at all. It is used to thicken silicone oils to make silicone grease out of them..

Sodium silicate, from antifreeze intrusion into the crankcase, might also show up as SiO2 on a lab test.

Silicone putties and sealants can have SiO2 in them, sort of like you put gravel into cement to make concrete.

If it were indeed sand, then I agree, it would be quite abrasive.

The plastigauge shouldn't have caused any harm. It is designed for newly rebuilt parts so you can get the 'exact' bearing over or undersize to have an oil film still before doing the final assembly. It is inserted into the gap or friction area.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Aug./05 (More Off Road album links at bottom of the view page)

Thank you. I thought I'd be sure, but it remains to be determined, apparently. Seems like one of those National Geographic episodes of Seconds From Disaster by now ...

I'll have a fresh look into it next week, from a new lab. Now for the commercial ...

Cheers,

Peter

schreef in bericht news:ZModf.12582$ snipped-for-privacy@newssvr21.news.prodigy.com...

Hi,

There were definite scratches/grooves on the crankshaft surfaces. I probably ran into trouble having some sharp and hard particles sticking to the crankshaft. If I would not have turned it around, it might have shown only much later.

Probably it was sand ... Really ...

Thnx,

Peter

"Mike Roma> >

More likely the scratches came from the studs on the connecting rods. I have seen that happen. Some books actually say to put rubber hose bits on the stud ends before getting the crank anywhere near them.

Or it could have been some sand....

The last crank I helped someone install had two rod journals with nasty gouges in them. I think someone was turning the half done job when we weren't looking because we were really careful. I noticed it as soon as the cap got tightened because I had a torque wrench on the main crank bolt to verify the torque after each cap got tightened by someone else.

Mike

peter wrote:

Why bother when the oil analysis doesn't indicate abnormal bearing wear (high levels of copper and tin)!

Do you happen to know what the particle size range is and how this relates to the beta factor for the air filter media you're using?

Unlike diesels, where 'dusting' is usually terminal, the effect on a gasoline engine is more akin to accelerated normal wear patterns. While the event may have taken some miles off the life expectancy it probably hasn't even come close to killing your engine -- and probably not even to the extent that needlessly pulling it apart might do.

FWIW the oil filter should take out smaller particles than the air filter (ie the oil filter media has a higher beta ratio than the air filter), which means that your bearings enjoy better protection than the cylinder bores. This assumes of course that you are using filters from reputable manufacturers -- who normally have no problem supplying specifications like beta factors and efficiency (unlike the dodgy ones).

If it were me I'd be looking to the air filter as a matter of urgency, and have the oil tested again at the end of the oil change period recommended for extreme service conditions (such as a dusty environment).

-- John H

Hi,

Yes, from te lab I Heard that analysis 1 has found particles of

Hi Mike,

No, I had only fitted the main bearings. And had to buy new ones after I found the particles stuck into them, small but nasty. Bad luck no doubt.

Peter "Mike Romain" schreef in bericht news: snipped-for-privacy@sympatico.ca...

Stop top posting you pillock

-- Dave Baker

I admit I got carried away...

Top posting is not really a problem. The responses are a carryover from the old days.

Oh I see. Sorry. Nevertheless, I'll quit talking about other issues ...;-)

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