Reasons for clean oil?

[GasSavers_maximilian]

Originally Posted by theholycow

maximilian, I'd say you're a prime candidate for oil analysis. Send a sample of it off to be analyzed before changing it.

Oil analysis? There's got to be some weird geek bragging rights involved with doing that! I'll take a look.

[theholycow]

Oil analysis:
http://bobistheoilguy.com/index.php?...d=50&Itemid=56
http://bobistheoilguy.com/forums/ubb...Board=3&page=1

[bobc455]

Originally Posted by theholycow

So, an engine built with 1962 technology and manufacturing processes failed prematurely (how long were engines expected to last in 1962?)

Before you get all happy bashing my pride and joy, keep this in mind- there have been virtually NO changes to engine technology, manufacturing & design principles outside of fuel delivery since 1962. The same principles that were used 40 years ago are virtually the same with regards to piston design, ring gaps, bearing design & clearances, cylinder wall preparation, engine oiling, balancing, sealing, camshaft design (excepting moving the cam overhead, but the principles with regards to valve lift & timing are the same), and so on. The only major difference is the fuel delivery. So if you took that same engine today and treated it the same way, it would probably still die after 67k miles. And like I said, I know of many of these engines that were built in 1969-ish but have still never been opened and still run well.

The primary differences between today's engines and 1960's era engines are the size & typical RPM. If you really think about it, most of the improved MPG of today's cars are thanks to overdrives, lockup converters (on automatics), aerodynamics, weight, and less HP/pound. The engine principles are still quite similar, if you were to design a smaller, higher-revving engine for today's car.

Yes, it was about as severe as you could get. But engine failures like this do happen, even if not at 67k miles.

-BC

[Jay2TheRescue]

You are right, the basic engine, manufacturing processes, and tolerances really haven't changed in the past 30 - 40 years. What has changed is the quality of oils we put in our engines. I would not hesitate to say that the worst quality oil on the market today is probably at least twice as good as the best oil available 40 years ago. I think this is the biggest difference in cars lasting longer. Plus, nowadays we flush brake fluid, transmissions, power steering, fuel systems, etc. Back then most people didn't do anything to their brake fluid but top it off if it was low. People regularly drove their automatics without ever flushing the transmission fluid, so the transmissions died right around 100,000 miles.

People are more conscious of maintenance, and the quality of the lubricants and fluids is much higher than was previously available.

-Jay

[theholycow]

Between 1967 and now, materials, manufacturing processes, and manufacturing tolerances have changed a lot. There are probably other differences too.

There's no question that a modern engine lasts a lot longer than 50 year old technology did. It could partly be attributed to higher gears = fewer revolutions per mile, but I remember 100,000 miles being the expected lifetime of an engine, and now you'd be silly to think that's all you're going to get out of an engine.

Edit: Jay, I thought it was common knowledge that tolerances were awfully sloppy and tighter tolerances were one of the major reasons that Japanese cars were so much more reliable in the 1980s than American.

[Jay2TheRescue]

Take my truck. A 1998 GMC Sierra. It has a 350 in it. That engine was made for decades. Would I still be having the same like new operation and trouble free performance if I was using lubricants designed and manufactured to the same specs as the 60's? I don't think so.

My 1980 Pontiac Bonneville wagon gave us 13 years and 190,000 miles of trouble free service. When we sold it the car still got an average of 16 MPG/tank, and didn't burn any oil. Dad always used whatever oil was on sale (except for Quaker State), and changed it every 5,000 miles. We never even took the valve covers off the car in 190,000 miles. How's that for trouble free operation? I think the tolerances were fine. I admit the finish quality of the paint sucked. Dad took it back to the dealer, and they repainted 1/2 the car. He should have just let it be. The half they repainted looked really bad when the car was 10 years old.

[GasSavers_maximilian]

I've heard tires are a lot better now as well. Is that true?

[bowtieguy]

Originally Posted by theholycow

After 10,000 miles, it comes out black but not sludgy, gritty, or inconsistent.

i would at the very least change the filter half way then.
_______________________________
we've talked about this before(dino oil vs synthetic) and no one will ever convince me that dino is acceptable in my vehicles. like Jay eluded to, it's convenient to do oil changes on an annual basis, besides the better lube and temp tolerances.

maybe it's the heat/humidity in florida, but i've seen lots of sludge and leaky seal issues. and engine failures are not rare here either. that might be attributed to over heating tho, but synthetic can help w/ that as well.

in regard to manufacturer recommendations...think of Toyota's sludge issues, GM's coolant issues, and the vast array of after market improvement designs over the years.

recap:
longer change intervals...dino, no; synthetic, yes
better temp tolerances...dino, no; synthetic, yes
oil seal conditioner...dino, some types; synthetic, yes
cleaning properties...dino, no; synthetic, yes

[GasSavers_maximilian]

How do longer change intervals relate to the humidity getting into the oil issue? Since I'm more time than mileage limited, this counts for me more, right?

[theholycow]

Originally Posted by bowtieguy

i would at the very least change the filter half way then.

I'm not worried. I'm complying with the manufacturer's service schedule and specifications, and I don't intend to keep the car past 45,000 miles anyway.