What oil do you guys use?

[Scott Liggett]

I have run nearly everything in my Impala over the last 20 years with the exception of expensive brad penn or royal purple. I am too cheap for that. I typically change the oil every six months no matter how much I drive the car. Though, I have never driven more than 6000 miles in a year. I often buy what is on sale. Or, I buy cheap store brand stuff. I never could tell if one is better than the other.

I am currently running Jiffy Lube 10w30 in the Impala. I have a bunch store brand 10w30:synthetic I bought in a case I add to it often as the rear main seal leaks pretty good. The Caprice has Rotella with Lucas Oil zinc additive. I am told that Rotella and Delvac has reduced zinc levels recently.

[Polyhead]

I have run nearly everything in my Impala over the last 20 years with the exception of expensive brad penn or royal purple. I am too cheap for that. I typically change the oil every six months no matter how much I drive the car. Though, I have never driven more than 6000 miles in a year. I often buy what is on sale. Or, I buy cheap store brand stuff. I never could tell if one is better than the other.

I am currently running Jiffy Lube 10w30 in the Impala. I have a bunch store brand 10w30:synthetic I bought in a case I add to it often as the rear main seal leaks pretty good. The Caprice has Rotella with Lucas Oil zinc additive. I am told that Rotella and Delvac has reduced zinc levels recently.

All domestic oils were forced to reduce zinc levels in 2004 or so. ALL. There is only one caviet to this, oils labelled for "off road only use" typically have the desired 1200-1500ppm zinc levels. Thus why I like the mobil 15w-50, it's labelled as a "race" oil and for "off road use only" and therefore still has a good deal of zinc in it. Now you can get race oils that have similar or higher zinc levels however, those are true race only oils and lack the detergents that the mobil one has. They kept the oil formula exactly the same as it was before the EPA mandate, they just changed the label to get around it!

[Polyhead]

If you're running an O2 sensor in a race car running race gas, what happens to the sensor? Do you have to change it a lot? Do you pull the sensor unless taking a reading? Or is modern race gas low or no lead?

Dan

It destroys them, which is why most of your really harcore race cars don't use 02 sensors for tuning purposes, they use thermocouples for engine tuning. Remember, you can tune an engine via EGT as well. For some fuels, alcohol specifically, EGT is a far more important measurement than O2 level.

[silver_bullet]

We use Mobil One Delvac 5W40 in all of the vehicles and Shell Rotella in the power equipment... Delvac comes on sale at 99 bucks for a five gallon pail with a 60 dollar rebate about twice a year, bringing the cost down to 2.30 per quart after taxes... not bad for a full synthetic with the thermal breakdown resistance and impact load resistance of a OTR fleet oil! we also insist on WIX filters every oil change!

[yellomalibu]

I've been using Rotella in the pickup truck. The 305 seems to be old and high mileage - and when I got it, it was pretty crusty inside. A day before an oil change, for the first couple years, I would add a quart of Marvel Mystery Oil to the engine. When I had the valve cover off one side a couple weeks back, it looked "normal" - not nearly as carbon crusted as it was when I first got the truck, so it seems that using a high detergent oil with the occasional swish of MMO through it has cleaned it up slowly.

My brother once tried to de-crud an engine using either MMO or Seafoam. It worked so well, the chunks of carbon deposits that came free clogged his oil pump pickup.

After changing the timing chain a couple weeks ago, I changed the oil. I got a good deal on Wolfe's Head oil - the 15-40 diesel stuff. It's semi-synthetic and If you read the bottle, it leads you to believe it's the best oil in the world! ...seems to work fine.

[redneckjoe69]

i've been using VR1 50 weight for years with no problem. i have to let my car warm up anyway since i dont have a choke. its supposed to have plenty of ZDDP.

heres an oil test/info if anybodys bored. http://speedtalk.com/forum/viewtopic.php?f=1&t=35731

[Polyhead]

i've been using VR1 50 weight for years with no problem. i have to let my car warm up anyway since i dont have a choke. its supposed to have plenty of ZDDP.

heres an oil test/info if anybodys bored. http://speedtalk.com/forum/viewtopic.php?f=1&t=35731

The thing is with those tests is that he doesn't mention what temperature he tested the oils at. With multigrades, their film strength can be altered drastically with temperature. It should also be said that film strength isn't the end all be all for how well an oil will protect an engine. He is right in one thing though, in an ideal world no place in the engine would exceed the oils film strength and then you wouldn't need zddp. Unfortunatley, due to dynamic loads on cam shafts, it's very difficult to have an oil that is both easy to pump and would have high enough film strength. In fact the only oil that is going to do that are flourine based synthetics and unless you want to spend $200 a quart for your motor oil, it can't be done. So, some metallic additive that can take over once the oil film has failed is the smart sollution.

The tests do confirm what others have said (mopar action specifically) is that too much zddp reduces the performance of the oil. This makes perfect sense when you think about it. Oil film strength is maintained because the long hydrocarbon chains get sort of "stuck" on each other causing them to link up and make long strands. Kind of what you get when you make a fabric. Now if you introduce contaminants they get in the way of the oil molecules linking up and you reduce the film strength. This is why detergents are so important in motor oil! It's not just to keep the engine clean, it's to keep the contaminants from being able to blend into the oil and spoil it's film strength. This is also why you change oil because eventually there is just so much in the way of contaminants that the film strength just can't be maintained. But now you introduce a chemical that isn't contained by the detergents and interferes with the friction modifiers on the oil.... bad juju.

[yellomalibu]

Truthfully, I haven't given much deep thought to oil. I used what is suggested by peers, being attentive to zddp for flat tappet camshaft break-in, and using synthetic later if the engine doesn't leak.
Film strength; cohesion... This last oil change in the pickup truck after the timing gear/chain swap had about two months on it. It was Rotella. One highway trip to North Carolina and back, and several hundred miles of towing my small work trailer locally. Perhaps two thousand miles on the oil. I waited and waited and waited under the truck for it to stop running out of the drain plug hole and to "drip" (which is how I usually know when to put the drain plug back in). It didn't drip. It continued to "run", even though the stream became extremely small.
Is this a visual example of "film strength" and oil that has not "broken down"?

[Polyhead]

Truthfully, I haven't given much deep thought to oil. I used what is suggested by peers, being attentive to zddp for flat tappet camshaft break-in, and using synthetic later if the engine doesn't leak.
Film strength; cohesion... This last oil change in the pickup truck after the timing gear/chain swap had about two months on it. It was Rotella. One highway trip to North Carolina and back, and several hundred miles of towing my small work trailer locally. Perhaps two thousand miles on the oil. I waited and waited and waited under the truck for it to stop running out of the drain plug hole and to "drip" (which is how I usually know when to put the drain plug back in). It didn't drip. It continued to "run", even though the stream became extremely small.
Is this a visual example of "film strength" and oil that has not "broken down"?

sure can be. although it could just be an example of viscocity as well. Friction modifiers that get used these days make it impossible to judge and oil visually, almost impossible anyway.That said, oil that that will have that level of cohesion is certainly a good thing! That means it's sheer strength is high, which as far as the friction bearings in the bottom end of the engine are concerned is the most improtant thing. The rotational speed of the main bearings puts increadible sheer loads on the oil. Just kind of try to visualize what the oil is doing when pressed between a stationary object and another object spinning at 6000rpm. Its a hell of a thing. Now throw in the dynamics of the power pulses slamming the crank around inside the bearing clearances. It pinches and pulls that oil with forces in the nairborhood of tens of tons.

[BigAL]

Royal Purple in the performance cars and Rotella in the diesel.

[Lee Stewart]

10W-30 from March to September and 5W-30 from September to March. I only change my oil twice a year because I only drive around 3000 miles a year.