worf928

And about what I expected.
I would assume that the silicon is from the cylinder bores too?

At least that puts to bed anyone claiming that Mobil 1 15w-50 doesn't have enough ZDDP in it.

When I saw the car for the first time(*) it was obvious that it was running 40 or even 30-weight oil. So a new filter and 15w-50 went in. That was 1200 miles ago. (Note that the mileage numbers in the report are KM not miles.)

Even better news. Not.

There was. When the oil was changed the first time there was a 'pea-sized' drop of very very fine metal on the magnet. This time - with the very fresh M1 - when I took the analysis there was the same 'pea-sized' drop.

Yup. That's the next step I guess.

I'm going to think on these results while waiting for Doc Brown to opine too.

(*) The first time I saw this car, it had a punctured pressure regulator diaphram and was sucking tons of fuel into the intake. That was another really good reason to change the oil. I, of course, corrected that along with all the stuff on top that had been destroyed (vacuum lines, elbows, breather hoses, etc.)

It seems, perhaps, that that overly-rich condition had been present long-enough and washing the bores long-enough to kill the bores and rings? It cannot have helped.

GregBBRD

And even quicker and a whole lot less of a mess, with a filter cutter.

http://www.summitracing.com/parts/sum-900510/overview/

(Now I know what to get Jim for Christmas....don't tell him!)

worf928

That's good to know. I will definitely give them a call tomorrow.

worf928

Ordered

jcorenman

That seems to make sense. The traditional sources of silicon in an oil analysis are holes in the air filter (dust and fine sand finding its way into the oil) and silicone sealer that finds its way into the oil (e.g. gasket sealer). But if the bores are being eaten then aluminum+silicon makes sense.

Seems to. And that's a higher zinc level than an analysis that I had done a few years ago (2008), which was zinc=1100.

That would be iron, nothing else is magnetic. And iron was also very high in Blackstone's report. Where is it coming from? Piston coating?

Ouch! But wouldn't that take a lot of fuel? How did the engine run? Or only moderately-rich combined with a poor oil choice??

simos

Found this document some time ago.

Engine bearing failure analysis guide from Clevite

http://www.studebaker-info.org/tech/...CL77-3-402.pdf

If looking the failed bearing pictures seen in this forum, the oil starvation is very much the number uno reason for seeing those.
Perhaps someone has seen other reasons, but detonation is causing usually so called fatigue to bearings. This is what I have seen also on other documents.

There is also instructions of howto install bearings, any comments on that?Perhaps quite straight forward except using only plastigauge for measuring the clearance

John Speake

So what knock control system does the MS offer ?

Tom. M

Adam's MSIII has knock sensing built in.... I'm not sure what is it or how effective it is..but it's there and should be running soon...so we'll find out. My MSII doesn't have built in knock sensor capabilities, thought about adding it..but since it's on a track car...the tune will be be set for the track (eg. on the richer end)..so I'm not too concerned at this stage....


edit..here's a link to the MS knock sensor...

http://msextra.com/doc/ms3/knock_module.html

mark kibort

amsoil!!! hitting rev limiter........ hitting high oil temps!!! (260F on occasion) and always 5 bar oil pressure or greater. all stock no mods, no early pan or pick ups.

put new glycols in there, plasticine it up to see if it is the right clearance. and you are good to go.

(as long as the pieces of rod bearing havent clogged up somethings.)

worf928

It's been a while. For closure purposes....

I talked to 'Alex' at Blackstone. In summary:

There's not enough copper and lead in the mix to suggest that the bearings are a primary source. Likely, the copper and lead - while definitely from bearings - is a result of all the iron in the oil accelerating wear of the bearings. (Basically, this motor is pumping liquid sandpaper around...)

After reminding/informing Alex that we're dealing with an Alusil block his focus was on cylinder walls.

I asked him... "so, if I look at the walls with a borescope and see nothing horrible what's your next, best, guess for a culprit?" And he didn't have an answer. Not surprising that.

I did a compression check. Two cylinders are down by 20 and 10 psi respectively. The other six are close-enough. Borescope does not show a horror show. There are a couple of scratches on the walls. But, the scratches are more-or-less what I've seen on plenty of cylinder walls with motors that were not machining themselves.

Had both cam covers off. No smoking gun. Time to put the thinking cap on...

Ad0911

ooh, this is good. Thanks for sharing

jcorenman

I missed the "closure" part

This continues to get more mysterious. I keep going back to the iron as the major clue, on the magnet (as fine powder) and in the Blackstone report. So where is the iron coming from??

Pistons are ferrous coated, but I would expect damage there to also show up as damage to the bores. Is the alusil surface hard enough to wear down the piston coating without being damaged itself? (This assumes inadequate lubrication or a poor choice of oil at some point, which sounds possible).

Was there any difference in bore condition for the two cylinders with the lower compression? Did you rotate the engine to get a look at the full length (at least what is visible at BDC)?

Cams and lifters are iron & steel, but if the lobes were shedding then that would be obvious with cam covers off. And in my experience (not with 928's) you see flakes as well as powder.

The crank is harder than anything else it touches, bearings are presumably lead and copper (which showed up) with a steel backing, but they would have to be very far gone for the crank to start grinding steel...

Oil pump? Gears are steel but I can't see that as a primary failure.

What is the next step? Teardown?

worf928

The 'closure' is that the oil analysis and subsequent conversation with the folks at Blackstone suggest that bearing wear is a by-product of something else. Thus, the discussion of this engine (probably) has nothing to do with the subject of this thread.

You're tellin' me.

Yup. My question to blackstone (above) seems either prescient or just good risk management practise..

I bought a better borescope and took another look at the two suspect bores. I also compared them to a 'known good' engine and didn't see any differences (to my eye) that looked significant.

Short of pulling the heads on the 'bad' motor I have no better way to determine the health of the walls.

I have no idea. I've never tried to 'scratch' a piston. I do know that the bore surface is pretty tough.

I did all the 'scopeing at BDC. Nothing super-interesting. But, the view from the borescope leaves something to be desired.

Nothing interesting to see under the cam covers. The cam lobes have a bit of pitting but it's more-or-less what I would expect to see.

Oil pump seems to be the next thing to look at. In my mind it *could* be responsible for both low oil pressure and shedding metal. However, I have no idea (yet) of how the pump system could be so screwed up as to cause both 'mobile machining' and low oil-pressure.


The next step is to test oil pressure with an external guage and then to replace the pistons and springs that modulate oil pressure. I expect my external guage to confirm low hot oil pressure. I do not expect replacement of the oil thermostate and bypass components to 'cure' the pressure problem. However, those are the last 'low hanging fruit' components that might cause low hot oil pressure.

After that... removal and dis-assembly of the engine would seem to be the next step. But, I don't know if that is in the cards.

I've given the owner of this motor the 'homework' task of trying to determine what was done (and why) to this motor when it was pulled. (And I *do* know that it was pulled and extensively 'touched.')

Chris

Well how about this?



Interesting in that the engine ran like this for a number of years before I got curious (read bored) one Winter as I thought the idle oil pressure was lower than it should be. Guy who reground the crank said that looked like someone did not flush the oil cooler lines after an engine let go, as this car has a replacement engine that may well be the case.

Sorry if this went a bit of topic Tom

GregBBRD

Yep, those are bad.

And have seen bad main bearings, when people are stupid. Just not "normal" stuff. These engines will toss a connecting rod right out of the side and have normal looking main bearings.