Quote:
|
Originally Posted by Blue Bowtie
I also disagree. Did you disassemble, measure, and qualify every wear surface, or are you presuming there are no wear issues since it is still running?
Here's my experience with a 1994 LT1 that was run on nothing but Mobil 1 10W30 and PF52 filters since it had 3,359 miles:
Teardown at 110,000 miles revealed taper wear in the bores. The worst cylinder was #6, and measurements with a telescope gauge, inside mic, and bore gauge (since I didn't believe any of them) revealed 0.0004" taper. That's 4 tenths, not thousandths. And that was over the design tolerances, NOT the wear tolerances. In other words, the design calls fo a 4.0001" finished bore, and the worst bore was worn to 4.0005" at the bottom. Further, the production tolerances allow for up to 4.0005 on a NEW cylinder bore from the factory. It hadn't even worn to that point in 110,000 miles.
Top compression ring gaps were no greater than 0.022". Piston skirs showed only polishing, not scuffing. Main and rod journals had no wear, and the only clearance was due to bearing shells opening to 0.0025" on a couple rods. Standard shells returned oil clearance at the bearings to 0.0018" specs. The timing chain and sprockets, as well as the water pump drive gears were like new. The new replacement timing set went on with the same amount of slack as the one that was removed. Those aren't perceptions or "gut feel", but quantified results - Hard data and facts.
The car was never abused, but never babied. It was regularly driven in so that the "1" lit up on the digital speedometer. It had worn off two sets of tires, mostly on the rear. But it was always at operating temperature before being loaded heavily.
I'm curious how much less wear I could have had if I had used additives. Had I not decided to change the cam and port the heads at that mileage, I'm sure it would still be running just fine on the originals. Now it runs just fine, but only two seconds faster.
As long as the TMT, Slick 50, or other products are not doing any damage, it's probably not a problem. Then again, every ounce of additive in the sump means one less ounce of lubricant.
|
Nope. I don't need a teardown to tell me that it is not common for a 4 cylinder to last over 300,000 miles with no oil control issues...and I have also seen some old cars owned by religious Mobil 1 users that were remakable not only in lack of wear, but internal cleanliness as well, one a 197? Buick Special w/350 at 125,000 miles was in the shop and got the valve cover gaskets replaced, there was nearly no discoloration or varnishing on the rockers, pushrod surfaces, etc...looked like it wasn't hardly broken in....
If I could commit to full syn use exclusively, I wouldn't use anything else, most likely, but sometimes circumstances are such that at oil change time I simply don't have the money for it, so the routine is semi-syn routinely and Slick 50 at reccommended interval...
One time I did note a possible but not suprising effect of S50 use...I had bought a '77 Caprice Estate from an old customer who spared NO expense maintaining that car, and at 80,xxx it ran flawless, truly one of the smoothest running motors (305) I've ever come across...I did my thing 3000 miles after purchase, as he'd just had the oil changed prior to selling it to me...and two days later the timing chain slipped and she wouldn't start...
Once torn down, I noted that the nylon coat cam gear still had teeth, and while rounded, I'd seen them go almost to where there was nearly no discernable teeth before allowing the chain to slide before...could have been a side effect...but that is the only location in a motor and the only condition I can think of where less contact friction could cause a failure....