engine oil

[Ron in Quincy]

I have been using Castrol GTX 20-50 for over 35 years and have had good results. Any good brand of oil should be OK. I prefer a detergent oil rather than non-detergent.

Ron

[Paul from Maine]

Originally Posted by 1931 flamingo

Paul: I don't understand why on a freshly re-built engine the oil is getting "dirty" so fast??
Paul in CT

My standards are pretty high since the rebuild. I consider any oil that is not completely golden and clear to be "dirty." Before the rebuild, I considered any oil that was not completely black to be "clean." I am probably being way too picky, but oil is cheap compared to a rebuild. Before the rebuild, I would go 600 miles or so before I changed it. I was burning so much and leaking so much, that it eventhough it was black in 20 miles, I figured it was still doing the job since I was always adding oil.

[MrTube]

I would like to once again bring up the point of zinc NOT being necessary in the "A" due to weak valve springs.

[ford1]

some oils just get dark quick and people think its dirty, another thing is there may be ring sealing problem letting combustion gases get into the engine pan and contaminate the oil, its a new engine so it may get better as the rings seat

[MrTube]

Originally Posted by ford1

some oils just get dark quick and people think its dirty, another thing is there may be ring sealing problem letting combustion gases get into the engine pan and contaminate the oil, its a new engine so it may get better as the rings seat

Agree 100%.

In my modern vehicles I run Mobil 1 and usually change around 8000 miles and the oil is pretty dark, yet still sort of transparent. Of course this is also on two engines running quality Mobil 1 / K&N or PureONE filters and both engines have very little blowby.

More blowbly = change oil more often, including on an engine which is not broken in yet as ford1 stated.

[sphanna]

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I do exactly as msmaron does. I want the zddp in Rotella 10-30

[columbiA]

Between the weak valve springs & steel cam shaft & low RPM,zink is certainly not needed in the A engine.Also, changing the oil every 500 miles is a waste of oil & money.I change mine every 1,000 miles-no filter,and it barely changes color between changes.At work,we changed oil in Cat loaders,Kenworths etc every 250 engine hours & the oil would look black shortly after changing.It wasnt uncommon for the engine to still be running well after 25,000 hours.

[Dick Deegan]

I use Mobil 1 10W30 year round and have done for several years. I change the oil every 1500 miles or so and have a full flow filter. Don't know whether I need the filter or not.

I think that the only down side of synthetic oils is the small increase in leakage from the rear main.

Dick

[theHIGHLANDER]

Interesting, throwing away something that's still doing it's job. Here's an oil story that I'll swear on my 41 Packard 160 is dead-on-balls true. I drag raced in the 90s. I ran a 454 punched .100 over with a .714 roller cam and 14.11:1 compression. In the begining I ran Kendall "Nitro 50" on the recommendations of some of the top engine builders here near Motown. The car ran well, consistant, and was a lot of fun. Leaving the line at 5500RPM, and crossing the stripe at 7800RPM is something that takes a bit of a toll on parts, especially in a car that weighed in at a heafty 3545#. Every 3rd weekend it would use a qt of oil. Too much oil on the crank is not a good thing so I never worried about keeping it full, just added that qt. Once I got cylinder leak numbers in the high 90s where I wanted them (96 and 97%), I switched to 20-50 Amsoil. Now I went into this with info learned 2 yrs prior as to which synthetics actually worked, actually made power vs standard mineral oil. Interestingly, Mobil 1 was the worst offender in regard to parasitic drag, worse than std mineral oil! The top 3 were Red Line, Torco, and Amsoil, and all 3 (within a couple HP) actually made over 50HP in a 1000HP naturally aspirated race engine. As proof the test engine went back to mineral oil and settled in to within a couple HP of it's original reading on min oil.

Back to my engine, while I may have had some dillusions of power I could feel, I was confident in my choice. The car was .05 quicker and 2MPH faster in every condition I recorded. It also stopped burning that qt of oil every 3rd race weekend and always looked new when I pulled the stick. Having a "spare bullet" in the shop, I took a risky position. I left that oil in there for over 150 passes down the 1/4 mile. Worried a bit, I swapped out the filter and added a qt, and I cut the filter apart for inspection. It was like new inside, my oil mods were doing their job (modified dist housing, lifter gallery mods), and the engine was reading 97 and 98% in a leak down test. All in, I ran that oil for over 400 passes with 1 filter change. When the #6 cylinder developed a crack (common issue), a complete tear down revealed bearings that looked maybe a week old. I saved the oil and threw it in my high mileage F-250.

So what's the point? Top grade synthetics don't burn like mineral oil. They have superior lubrication qualities, and in independent testing seem to prove their worth. The burning of engine oil at the rings is one of the biggest factors in why it turns black. Let it go on long enough, and the soot, microscopic as it may be, is what colors it. After thousands of miles it will eventually sieze the rings, load up on the valve stems, and clog passages. Use an oil that doesn't burn there (many synths burn at much higher temps and burn cleaner), that issue is reduced. As silly as it sounds, oil doesn't ever truly break down. Their additive packages go away (burn away), they get loaded with soot (abraisive), and then it's off to be recycled and refilled with the additives. Throwing away dark oil after 350 miles? You'll spend 1/2 of that $3500 in around 30K miles, maybe less. Now if you only drive the car 500 miles a year it'll take a while. But what fun is that? FWIW, an air filter is a big help in keeping the crankcase clean. A filtered case vent helps too.

That's been my experience with oil experiments. I run Amsoil in my 170HP snowmobile too. Had a lean burn down in my other Amsoiled sled once, and after 5500 miles of abuse the inside of that engine was like new as well. I trust it, but anyone thinking about switching needs to consider going up a grade or 2 from what their engine likes. Yeah, this is like building a clock for someone asking the time, but I thought I'd share.

[john in illinois]

Like Dick Deegan I use mobil 1 10W30,change about 1500-2000 miles with a full flow filter.I have 13,000 miles on the engine and it does not use oil. I drove a 4,000 mile trip to Montana last year and used less than a quart. I really did not need to add any,but I keep it full to the mark.

I think any good oil is ok. It is personal preference.

John

[30modelA]

Originally Posted by 1931 flamingo

Paul: I don't understand why on a freshly re-built engine the oil is getting "dirty" so fast??
Paul in CT

especially with synthetic