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Join Date: Sep 1998
Location: Brooklyn, NY US of A
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Engine lubrication

I think this topic has been covered here before, which should go without saying. This is most likely a topic that has been covered by every automotive list and magazine at least thrice.
I read the article on Pelican titled 'Everything you ever wanted to know about motor oil'. It opened up more questions for me to consider. I tried to do a search on this BBS on this subject with different keywords but havent come up with anything that would give me substantial information. So what I would like to do is gather the opinion of as many people as possible. If you have a horror story or a high mileage 914 that hasnt given you a hickup since the day you got it I'd like to hear it.
I change my oil every 3000 miles or so give or take 200 miles. I use my car mostly on the weekends, sometimes its in stop and go sometimes its on the open road and sometimes its high rpm high speed highway use. Most likely a little bit of everything. I change my oil filter with every oil change, an extra 5 bucks wont kill me. I use Mobil 1 0-30W and its getting a little cold here in NY. I used 0-30W since the middle of August. I currently live with an elusive oil leak which I will get to the bottom of once I pull the drivetrain to start rebuilding my gearbox. I used to have trouble with my oil light, when on the highway in 'hot pursuit', it would go on and stay on forcing me to abort. More recently since I've switched to Mobil 1 and changed it about 4 times around, it hasnt given me any trouble.
I know idling the car is bad and if it can be avoided it should, but what about cold mornings?. I've heard that one should start the engine let it build up enough pressure and just go and not wait for the it to be warm. Just as long as it isnt abused while it is still cold.
So what do you guys think, should I change my oil more often due to my 'aggresive/semi-aggresive' driving habits?,
Should I change the grade of my oil or the brand?. Whats the general opinion of brands like Redline or Amsoil?.

Thanks
Steve M
Old 10-18-1999, 01:05 PM
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Hi Steve,

I live in the Southeast, more specifically Atlanta, GA. ( >>> GO BRAVES <<<< ) sorry.
I use synthetic 5w-50 grade in my 73 2.0. I change my oil between 5000 and 7500 miles along with the filter.
I think changing the oil every 3000 miles when using synthetic is a little excessive. Your driving style is certainly not aggressive. I drive my 914 daily, hard, and autocross it on the weekends.
After I rebuilt my engine 1 1/2 years ago, I started with conventional 10w-30 oil. I ran that grade/type for the first 5000 miles for the break in period (changing first at 500, then every 1000 miles). During this time (hot 98+ summers) I would experience low oil pressure at idle after a highway run (such as the afternoon commute home). After 5000 miles I changed to synthetic 5w-50. The conventional 10w-30 was getting too thin and losing its viscosity in the heat. The synthetic oils are much more "durable" against viscosity breakdown and heat. I no longer have the low oil pressure problem, even on the hottest of days.
You might consider replacing the oil pump if you are going to have the engine down this winter. The low oil press at high speed is quite concerning to me.
I would NOT suggest that you change you oil more often. I think you are throwing away oil that still is good for another 3000 miles. I am sure that many, though, will dissagree. For the NY area, the 0w-30 sounds like a good choice for the cool/cold seasons.
These are my opinions and experiences on the subject. Your milage may vary.

[This message has been edited by wjdunn3 (edited 10-19-1999).]
Old 10-19-1999, 04:03 AM
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Steve,
I don't have too much experiance, but of what I have I will share.
I had a 1991 Dodge Stealth, I ran 10W-30 in the summer and 5W-30 in the winter. That car ran for 170,000 miles of me driveing it hard (I was 18 when I got it). I changed the oil between 3-4k miles and never had a problem with the engine. At 170k I traded the car in. I used any major brand of oil.
I had a 1967 Mustang with a 1974 351 Windor engine in it. The only oil that would keep oil pressure going in that was 10W-40. Thats all I ran, and that engine worked great. Had other problems though.
My new cars 1999 Explorer and 1998 Escort I run 10W-30 in the summers and 5W-30 in the winter.
I haven't gotten my Porsche to run yet, however I have 0W-30 oil planned to put in it. I plan on this because it is a air cooled engine, and like my moter cycle cools using the oil. Therefor I feel that the thicker oil will help heat travel out of the block and to the oil cooler better then thinner oil.
I do live in Michigan, and will drive my "summer" cars until the first snowfall. Then because of the salt they go in the garage. I'm adding this in so you know that I will drive the car in cold weather.
As far a warming up the car, I don't have much helpful input there for ya, sorry.
Old 10-19-1999, 04:11 AM
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So let me understand something about the different grades. They signify the weight/thickness of the oil or do they signify the ability of the oil to keep from 'breaking down' at certain tempratures?. If both are similar then once an oil is warmed up are they useful at the same temprature and the only thing seperating them is their ability to keep it together at high tempratures?.
The reason I change my oil every 3000 miles or so is because at around mile 1500 the oil starts to darken. At around 3000 it is dark I dont feel safe with oil that has lost its color. Maybe that is a problem also but I'd like to stick to the subject at hand.
Finally I wanted to put in a high pressure pump but I was talked out of it by the guy who rebuilt my engine, I have been considering the high volume oil pump for sometime.
Old 10-19-1999, 06:17 AM
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The grades are indications of Viscosity. From the Tech Article on this site:
"Another way of looking at multi-vis oils is to think of a 20W-50 as a 20 weight oil that will not thin more than a 50 weight would when hot."
"Viscosity is a measure of the "flowability" of an oil. More specifically, it is the property of an oil to develop and maintain a certain amount of shearing stress dependent on flow, and then to offer continued resistance to flow. Thicker oils generally have a higher viscosity, and thinner oils a lower viscosity."

It is natural for oil to darken with usage. The question is, at 3000 miles of service, is your oil still transparent or has it gotten so dark that it is opaque? At 5000+ miles, mine is somewhat darker than new oil but very much still transparent.
If your oil is getting opaque, then it is sheering and burning (in the tech article this is where the "ash" comes in). This would indicate that the oil is too thin for your application / heat range.
0w-30 is a thinner oil than a 10w-30, not thicker.
As for change interval:
"Synthetics can be run two to three times the mileage of petroleum oils with no problems. They do not react to combustion and combustion by-products to the extent that the dead dinosaur juice does. "
Old 10-19-1999, 06:48 AM
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Thinner, thicker... I knew what I ment

Sorry about any confusion that caused, I typed the oposite of what I was thinking.

Before you asked about warming the car. I talked to a couple friends of min, and here is there input;
If you warm up a car for say 15 minutes, what are you doing? Pretty much nothing more then warming the engine and getting lubecants flowing, and heating the interior of the car. So the engine is at the correct operating temp during your drive, everything is functioning to spec.
If you start the car and drive without warming it up, and you only drive say 5 minutes and the car does not reach the proper temp, then we have condensing issures, alternators that start struggleing and so forth. So according to them its best to make sure then when you drive your car that it reaches the correct operating temp at some point during the drive.

Hope some of this helps
Old 10-19-1999, 04:34 PM
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Yes it does, warming it up and the thinner/thicker oil I should be using.
So is 50W thicker than 30W? and 10-30W thicker than 5-30W?

Thanks
Steve m
Old 10-20-1999, 12:08 AM
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Steve wrote:
"Yes it does, warming it up and the thinner/thicker oil I should be using.
So is 50W thicker than 30W? and 10-30W thicker than 5-30W?"

Yes and yes.

A 10w-30 oil is a 10 weight oil that will not thin any more than a SAE30w oil would at 100c.
A 5w-30 oil is a 5 weight oil (slightly thinner than the 10w oil) that will not thin any more than a SAE30w oil would at 100c.

The 5w-30 will flow better cold (at start up for instance)and in engines enginneered with fairly close tolerances.
Old 10-20-1999, 04:06 AM
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Condensations issues are something that I never considered.
How does that affect the longevity of the engine?
My thinking was along the lines of this, the metal to metal friction that is created when cold causes microscopic particles of metal to chunk off. Once the engine warms up the metal becomes softer which helps friction. Even though the pistons expand so to do the cylinders. But even though I've been told that idling any car for long periods of time I dont know why. For instance a diesel generator that sits and produces current is run at a constant RPM for extended periods. Their maintainence intervals are judged by the amount of hours spent operating.
So my next question is why is idling a warmed up engine bad?

Steve M
Old 10-20-1999, 07:16 AM
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Condensations issues are something that I never considered.
How does that affect the longevity of the engine?
My thinking was along the lines of this, the metal to metal friction that is created when cold causes microscopic particles of metal to chunk off. Once the engine warms up the metal becomes softer which helps friction. Even though the pistons expand so to do the cylinders. But even though I've been told that idling any car for long periods of time I dont know why. For instance a diesel generator that sits and produces current is run at a constant RPM for extended periods. Their maintainence intervals are judged by the amount of hours spent operating.
So my next question is why is idling an engine that has already been warmed up bad?, when in reality the engine is acutally running at a constant RPM. So doesnt that mean less stress on the engine and not more.

Steve M
Old 10-20-1999, 07:17 AM
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Well, for what I know, and I will dare to say it... If you maintain proper engine temperature, change the oil when it needs it, and supply gas, you should be able to idle an engine forever. There are 3 reasons I can think of that idleing an engine is bad.
1) If it is air cooled, then there is a chance that you will not be able to maintain proper engine temp and over heat.
2) Since it takes longer for the engine to heat up, you expose yourself to longer amounts of condensation in the engine. Also since there is not as much warm air traveling through the exhaust, the air will cool quicker causeing condensation and corrosion of the exhaust system (This does not affect the engine)
3) Some older carbs will not automatically kick off the choke. This will cause the engine to get warm, then when warm the RPM will be well above idle, and create extra heat, causing a posible overheating.
So all and all, if your driving a modern day F.I., electric fan operated, water cooled car you should be able to idle forever.
Old 10-20-1999, 08:38 AM
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