OK, I just got my oil assay back from Blackstone Labs and they show some
concern about the high concentrations of metals in my sample;
Aluminum 9 vs. 4 universal averages
Chromium 2 vs. 1
Iron 45 vs. 15
Copper 8 vs. 3
Now, no antifreeze or water in the oil, no lead. Everything else was "average"
or below average.
At first glance, high Chromium and Iron would indicate wear from the air induction
system(dirty air filter), but Silicon was 8 v. 9, so it was clean. Aluminum
might be piston scuffing and copper would point to the bearings, but no lead
would negate that. So since I haven't been into these new generation engines
(new to me that is, the '70's 360's were my last rebuild), what else could be
wearing that is iron, aluminum, chromium and copper(or brass) ?
Yep Idwheelthat, now I do recall reading that bit. Just goes to show, this old dawg still remembers babit.
Oh well, now if I could just find out what Federal-Mogul's Al alloy was made of( and the percentages) then
I really might start crying. I've looked, but cannot find a listing for a Mopar crate engine. Short of that,
can the bearings be replaced by just dropping the pan? Assuming, of course that the crank is undamaged.
with the numbers you have, I'd assume camshaft. I don't know if the 4.7L is a roller or flat tappet, but the flat tappets are susceptible to the new oils. I've also heard of random camshaft lobe failures from chrysler products. I do believe the camshafts are cast iron and not steel. More diagnosis is required, if you have a mechanic friend with a borescope to have a look in the oilpan without disturbing anything.
Still doesn't make sense to make bearings out of aluminum and lead when their under pressure and high heat which makes metals soft....
"Both lead and aluminum (both with copper underneath) as bearings are designed for embedability and conformability" to quote my bearing catalogs
which is to say, if small particles get in the oil, the bearings will absorb them without harming the crank/cam surface. Now when cams and cranks are hard chromed, they are ground to a spec. size +/- .0003 or what have you. The bearings can make up for some inprecise grinding with some crush. The same goes for cams/cranks with minisule bends or out of round.
the reason manufacturers have started replacing the lead coated bearings, is for enviromental reasons, and the lead was ending up in the oil, which can cause lead poisoning to us that change our own oils and spill all over ourselves.
More about the on-going saga. Yesterday I changed the oil at 2K miles and
sent a sample off to Blackstone Labs. I have found some disturbing visual
signs, the oil was very red. Inside the oil fill(under the screw-on cap) I
found plated out rust "looking" deposits and upon closer examination it appears
that the contamination is coming from the vent tube. Bizarre. Granted, this
is a used car, with 93K miles but I am at a loss as to where this contaminate
is originating. Damned thing runs great! Sounds great! If, in fact, it is rust
where is the water coming from to convert the iron to rust? Remember no
coolant was found in the oil. Is it possible that there is enough condensate to
generate this much rust? Well, I'll get the oil report next week and relay the
results. Keep your thing caps on.