Switched to synthetic oil and have a question.

I just switched over using from conventional Chevron brand motor oil in the road runner to 20w/50w Royal Purple's full synthetic type as I got a good deal on some.

So I drove the road runner about 20 miles and then rechecked the oil and went from a nice clean color to really dark color in that short amount of usage.

Just wondering if this normal when switching to a full synthetic?



Thanks
Stu

That's not been my experience but I use Mobil 1 and I have only switched over modern EFI engines.

I haven't switched a carb'ed engine.

Kevin

Maybe it grabbed all the dirt of the internals right away?? That was my first thought?

That's likely exactly what happened. Your new oil probably has more/different detergents than your previous oil.

How'd yer 'old' oil look???

I always change the oil once a year and as usual it was just getting sort of dirty looking. Usually it stays pretty clean for most of the year. I would guess i put on about maybe 1000 miles to 1500 miles between oil changes.

I know Mobile1 does that real quick in lots of engines, not sure about RP.

So this is normal i guess? Wonder if i should change it again right away if its full of contaminates now?

I wouldn't.

Also if you change it every year at approximately 1500 miles, then synthetic is a waste of money for you. Use regular oil or extend your oil changes to like 7500 miles to make synthetic worth while. IMO

I only used the Royal Purple as i got a deal on it from a friend so it was going to be the same cost as regular. The car sits so much that i feel changing the oil every year is worth the few $$.

Isint that Royal Purple uh Purple? IIRC it is dark to begin with.

I remember royal purple didn't stay purple for long. been a while though.

I also agree. I change my oil once a year too. 30 bucks in oil and filters once a year is cheap insurance, for as little as I drive mine.

I wouldn't worry about changing it early just for a color change.
oil sample tests are as expensive as a change, so I probably wouldn't bother with that either.

Agreed...

I would be real careful using Synthetic in old muscle cars with flat tappet cams. Flat tappet cams REQUIRE an oil with Zinc in it. You really need a racing oil with Zinc, for instance, VR1 Valvoline, or Amsoil Dominator racing oil, Joe Gibbs racing oil. They have taken all the Zinc out of oils because it plugs up Catalytic Converters. I learned the hard way. At least put an additive with Zinc in it.

This might be an interesting read.
https://540ratblog.wordpress.com/

There are synthetic oils that have high anti-scuff additives (zddp/zinc or others).

"Amsoil Dominator racing oil, Joe Gibbs racing oil." are synthetic.

Big thread on this guy on the corvette forum.Film strength test being taken as gospel without wear and other factors taken into consideration.One guy chellenges him pretty strongly.I will provide a link if anyone is interested.

Superior heat protection, no doubt...

But, regarding viscosity, I'm on the fence...

The Royal Purple oil i used has the added ZINC in it.

Change the filter and add a quart. Using a high quality filter helps extend the life of synthetics, but you are not doing many miles anyway.

Unless I missed it somewhere....I did not read where you used an engine flush before switching over to synthetic....?? When I switched my diesel engines over from conventional to Amsoil, I was told to use the engine flush that Amsoil sells to help clean up the cylinder walls and all from the contaminants.

They said to pour the flush in with the conventional oil and run the engine for either 20 or 30 minutes (cannot remember) and (do not drive with the flush in the engine) but after the run time, drain the engine and then put the new synthetic oil in and my engines always looked clean when checking the oil.

One main thing I remember when I switched was that the engine temp. always seemed to run about 5° cooler with the synthetic over the conventional oil......

I would like to read that. The logic this guy is presenting, to a layman like myself, seems to make perfect sense.

I was told you could not run Zinc in full synthetic, that's why Spector makes semi synthetic with the zinc added in...

Bullpoop. The three most dangerous words are, "I was told".

Synthetic lubricants probably require different additive packages than petroleum based oils, that's true. But there are several brands of engine oil with high levels of zinc in a pure synthetic base stock.

R.

If anyone is concerned about zinc and phos in a synthetic, here is a Blackstone Labs used oil analysis for Shell T6 (synthetic Rotella) off of a BMW forum.

12,500 miles on the oil.

Kevin

Wow. Since I've had the motor in my car, I've used only Mobil 1 15w-50 along with one bottle of Comp Cams break in lube. In 5 years, I've changed my oil once. Just checked it yesterday, and it's still pretty clear. On average, I'll drive about 600 miles/year. To be fair though, the first several years it wasn't really driven at all. 2012 was the first year I started driving it more than just back and forth from a shop/garage. And that was late 2012, so I'll say 2013 for all intents and purposes.

I too would be interested in reading the other discussion.

I agree, if you're changing oil every year at 1500 miles, synthetic is a waste. That said, I wouldn't go running to change it now, I would just run it for the year as-is.

Also, out of curiosity, why are you running 20w50? Were you getting low oil pressure with 10w30 or just jumping on the "old cars need thick oil" bandwagon?

http://www.corvetteactioncenter.com/tech/oil/oil_camwear2.html

Here's a good article on zddp, even though not what the OP was was about, it came up in the discussion.

You all could have a bit of a look at service intervals on every car ever produced in the last 50 years, I have yet to see one based purely on mileage - there is a time factor in there too, this is because various parts of the oil start losing their effectiveness when exposed to heat/air/contaminates, I think 6 months OR 3000 miles is more appropriate than a year - its not like its a huge $$ thing to protect your $howevermuch to replace motor

A few thoughts,

I wouldn't stress over the appearance of the oil in such a short time. Motor oils have heat activated additives that change appearance with normal use. Nothing to be concerned about. Here's a video from GM which I find helpful in showing folks it's very difficult to judge motor oil useful life based on color alone. I'll start the video at 1:05min to avoid the marketing on GM's OLM system. -> https://youtu.be/oi_J4SZUlSo?t=1m5s

I also agree with others that 20W-50 may be overkill. Don't know the specifics of your build, but as I recall, the general rule is 9-to-10psi per 1,000rpms. You may be able to accomplish that with a decent 10W-30 and free up a pony or two in the process.

Also, plenty of full synthetics with lots of Zinc in them. I'd also agree that in a seasonal driven muscle car application, synthetic may not provide a meaningful advantage. There's lots of good options commonly available. With an old school cam grind, I'd consider a 10W-30 Rotella or even a Quaker State DEFY 10W-30. With a newer fast-rate flat tappet I'd go with the specialty muscle/race oil.

Also, there is one area I can think of where a top tier PAO synthetic may be advantageous in a muscle car application. That is PAO synthetics have shown an increased ability to stay within their viscosity grade when fuel dilution is a potential occurrence like for example in carbureted engines. But you won't really be able to tell you'r degree of fuel dilution without used oil analysis testing.

Good Luck

Who do you think came up with those oil change intervals? Scientists working in a lab for the good of mankind? Or was it oil companies/car manufacturers who make money every time you come in for an oil change?