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Old 07-16-2008, 03:29 PM
oldbogie oldbogie is offline
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Quote:
Originally Posted by piniongear
Being the original poster I can say;
(1) I have the magnetic drain plug and have never seen any metal attached to it.

(2) This is a vehicle driven almost daily, but not in cold weather for the most part. But I would never plug the bypass on my engine.

(3) Again, the Pennzoil 30-5W oil and Fram filter get changed every 3000 miles. I cannot do more than that.........pg
Ahh, 5W-30, I'd stay away from that stuff. It just doesn't offer enough protection for hard working engines, those that tend to find life is low on RPMs and high on loading.

Now a series of "experts" are gonna come outa the wood work when I say what I'm gonna say; but that watered down oil just isn't good enough except in little ole lady driven vehicles. A lot of folks will jump on "watered down" and go on about the oil is rated at a 5 weight at some large sub zero degrees and a 30 weight at 212 degrees so that nothing really changes. Yet, I have never put that stuff into an engine that it didn't show a loss of oil pressure, primarily at low RPMs where I've always felt that GM engines were marginal to start with. My long standing concern has been engines that pull hard at low revs just don't have adequate protection in the crank bearings for the loads they're seeing. The problem is not so apparent at high RPMs, even in racing engine because by then the pump's delivering a lot of oil and pressure is up on the bypass valve. But when you're expecting the engine to grunt against a 6000-8000 pound load at 2000-3000 RPM there just isn't enough oil pumping thru the bearings to hold a good hydro-dynamic wedge and cool the interface. You will note that your bearings show the heaviest wear in the zone of heaviest loads right where I'd expect high loading to blow the oil wedge out. High load occurs twice a stroke; coming down under the power stroke to BDC and going over the top at the end exhaust stoke where it wants to keep going out the top of the engine as there's noting to buffer its acceleration so as the crank comes over TDC the rod get one heck of a jerk in the opposite direction to where the piston is flying toward.

Now a previous entry I speculated as to whether the failed cam and lifter may have put in the gunk that caused a situation where the rod bearings failed, or whether the failed rod bearings put in enough gunk to fail the cam lobe and lifter. I also stated that either could be related to neither. This seems to have set off a great exploration of filter mania. All that aside, the relationship between these failures is probably the 5W-30, again, this stuff doesn't have the Extreme Pressure (EP) element is sufficient quantity to protect a sliding tappet lifter and cam, this situation is compounded by low RPMS because it extends the time of loaded contact. This is a situation where the maximum load is present for a long duration of time, permitting the lubricant time to escape from the applied load and also generating a lot of local heat. In this situation the weak link will give up. Lots of people think that high loads and heat come with excessive RPMs, this isn't a singular truth. These are also common to situations where the speeds are too slow for the applied loads. The specific cause of the failure will be somewhat different, but the result will look a lot the same when you pick thru the wreckage.

The apparent lack of ferrous material collecting on your pan bolt magnet shows the filter was doing its job and the amount of material accumulated in 3000 miles was so small as to go un-noticed by your visual inspection. The failed bearing material would not be magnetic thus would not show on the magnet till the copper was worn thru to the steel backing. The bearing material would have been well mixed with the oil, if the filter didn't get it first, to where it would be hard to see, especially if you didn't know what to look for which would have been faint metallic streaks in the drain oil.

The only thing I'll recommend, is that you don't use any of that 5W-XX swill in your next engine, save it for grandma's Sunday goin' to church Buick. I can't tell you the number of engines all the manufacturer's have had to warranty with that stuff in 'em. It's there to get their "Corporate Average Fuel Mileage", as tested to government rules, up as high as possible, no other reason than that to reduce the power used for internal pumping losses. This is passable for motors that don't work too hard. If you expect them to do work in the day to day world with these mini weight oils in them, you've got to expect some bearing failures and certainly if you're running a flat tappet can some lobes and lifters are going to eat it. Fill the crankcase with a good 15W-40 or 20W-50 and save the bearings, lobes and lifters and forget the sellers and recommenders of "skim" oil.

Bogie
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