Switched to the Mobil 5W-50 today
11-11-2010, 07:32 AM
#122
I had to use that oil when I had my M-roadster... That stuff was running $12-14 per quart. It was more expensive to do an oil change on that car than on my 996TT... And I have no clue how much better that oil is or isn't...
Mike
Mike
11-11-2010, 07:40 AM
#123
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I've heard of folks who don't use their car much, but just get in and start it up once a week.
That is the worst: Wait a week to ensure everywhere that oil can drain from has done so, do a cold dry startup so the valvetrain spends as much time dry as possible, produce the acids, produce and circulate the accumulating water, repeat..
Joe
How long does it take for an engine to drain off enough oil to be considered in a position for a "dry start"? A week, a day?
Post storage startups (as you described above) can be helped a little bit by disabling the fuel pump or ignition, cranking the car over on starter only (lower RPM's than an idle condition) and waiting for full oil pressure to build up. Enable the fuel pump or ignition and the car should start up in a 'wet' condition.
Initial starting conditions are always the worst for an engine.
11-11-2010, 10:05 AM
#125
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In a 996 Turbo Coupe, I believe it is fuse C4?
You have to check the little white "cheat sheet" that is on the inside of the fuse panel door.
I pull it every spring when it's time to wake up from storage. I put a small piece of masking tape on it to make it easier to find.
It is surprising to note how long it takes cranking the car before full oil pressure builds up, but again, you are cranking the engine slowly while waiting for oil pressure to build up in the engine rather than starting the engine and idling at a higher RPM waiting for oil pressure to build it.
You have to check the little white "cheat sheet" that is on the inside of the fuse panel door.
I pull it every spring when it's time to wake up from storage. I put a small piece of masking tape on it to make it easier to find.
It is surprising to note how long it takes cranking the car before full oil pressure builds up, but again, you are cranking the engine slowly while waiting for oil pressure to build up in the engine rather than starting the engine and idling at a higher RPM waiting for oil pressure to build it.
12-12-2010, 03:15 PM
#128
I avoid all additives....if I were to use one, I'd do it driving to my mechanic as I was about to change my oil...
Gas today has a lot of stuff in it to keep the injectors clean. Key thing is to avoid lousy gas...no name gas stations in the middle of nowhere or gas that is just too much cheaper to make sense raise my radar..... I stick to 93 octane if possible too. My favorite is Amoco (BP, I know).
Jeff
Gas today has a lot of stuff in it to keep the injectors clean. Key thing is to avoid lousy gas...no name gas stations in the middle of nowhere or gas that is just too much cheaper to make sense raise my radar..... I stick to 93 octane if possible too. My favorite is Amoco (BP, I know).
Jeff
12-12-2010, 04:38 PM
#129
Race Director
In a 996 Turbo Coupe, I believe it is fuse C4?
You have to check the little white "cheat sheet" that is on the inside of the fuse panel door.
I pull it every spring when it's time to wake up from storage. I put a small piece of masking tape on it to make it easier to find.
It is surprising to note how long it takes cranking the car before full oil pressure builds up, but again, you are cranking the engine slowly while waiting for oil pressure to build up in the engine rather than starting the engine and idling at a higher RPM waiting for oil pressure to build it.
You have to check the little white "cheat sheet" that is on the inside of the fuse panel door.
I pull it every spring when it's time to wake up from storage. I put a small piece of masking tape on it to make it easier to find.
It is surprising to note how long it takes cranking the car before full oil pressure builds up, but again, you are cranking the engine slowly while waiting for oil pressure to build up in the engine rather than starting the engine and idling at a higher RPM waiting for oil pressure to build it.
The starter cranks the engine at a very low rpms. 75 to 150 rpms is what I recall. The oil pump is not very efficient at low rpms. (Hot idle of around 700 rpms the oil pump manages just 1.5 bar to 2.0 bar while at 3K rpms the same oil and temperature of oil can be 4 bar or higher.)
As a result, the oil pump takes time -- as you have noted to build pressure -- at this low operating speed.
However, all main/rod bearings in the engine are hydrodynamic and rely not only on supplied oil pressure but speed of rotation to create a thin layer of oil between the metal bearing surfaces.
By following a normal start up the engine cranks a moment or two then starts and rpms climb in just a moment to a fast idle. This does several things: It gets the oil pump operating in a more efficient rpm range and at the bearngs gets them spinning so what oil is there is formed into a hydrodynamic bearing oil film.
The load upon the engine's internals at start up is minimal just the normal loads associated with an idling engine so this perceived lack of oil and the absence of full oil pressure is of little consequence.
The only time I applied full oil pressure to an engine before starting it was after a rebuild and in these cases I arranged to drive the oil pump without turning over the engine to supply full oil pressure to all locations/bearings.
Then the engine was started.
Sincerely,
Macster.
12-12-2010, 07:06 PM
#130
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I crying BULL**** on the recent post 129...
Anyone that has pulled the fuse and actually watched the oil pressure gauge will see the oil pressure rising as you crank the starter!
There are SAE white papers that state that MOST of engine wear occurs on "cold" engine start up.
We have a dual stage oil pump. The engine case must be full of oil to start the first stage, at the same time the suction part of stage 2 will pull the oil from main oil tank. This requires "time"
When you start the engine without a pre-oil (fused pulled) you will see the engine idling with zero to low oil pressure for a few seconds.
Anyone that has pulled the fuse and actually watched the oil pressure gauge will see the oil pressure rising as you crank the starter!
There are SAE white papers that state that MOST of engine wear occurs on "cold" engine start up.
We have a dual stage oil pump. The engine case must be full of oil to start the first stage, at the same time the suction part of stage 2 will pull the oil from main oil tank. This requires "time"
When you start the engine without a pre-oil (fused pulled) you will see the engine idling with zero to low oil pressure for a few seconds.
12-12-2010, 07:24 PM
#131
Thank you Kevin. Some of the dis-information in this category has got to stop... Between this thread and the nonsense in the discussion about oil change intervals, it's enough to stop posting all together...
Lewis you gotta stop the madness with these boys...
Mike
Lewis you gotta stop the madness with these boys...
Mike
Last edited by Mikelly; 12-12-2010 at 08:01 PM.
12-13-2010, 02:19 PM
#132
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I've heard of folks who don't use their car much, but just get in and start it up once
a week. That is the worst: Wait a week to ensure everywhere that oil can drain from has
done so, do a cold dry startup so the valvetrain spends as much time dry as possible,
produce the acids, produce and circulate the accumulating water, repeat. Oh, and they
also use a 'good thick oil to improve the pressure and protect things', which really just
ensures that the delicate parts run dry longer at startup till that thick stuff finally gets
warm (and therefore thin) enough to flow well into all the crannies.
Joe
a week. That is the worst: Wait a week to ensure everywhere that oil can drain from has
done so, do a cold dry startup so the valvetrain spends as much time dry as possible,
produce the acids, produce and circulate the accumulating water, repeat. Oh, and they
also use a 'good thick oil to improve the pressure and protect things', which really just
ensures that the delicate parts run dry longer at startup till that thick stuff finally gets
warm (and therefore thin) enough to flow well into all the crannies.
Joe
IMO, I dont see much difference in starting up your car once a week and taking it for a good drive (20+ miles) vs starting it up every other day and taking it for a good drive - other than less miles......
12-13-2010, 02:31 PM
#133
I agree with that. I would just imagine that the people who are not really using the car,
but just trying to keep it ready-to-run, would not be starting the motor every day. I just
chose once a week as an example of a likely period someone might be doing to 'maintain'
their not-in-use car. You are right that the amount of oil left is probably about the same
between 24 hours and 1 week. The absolute worst behavior would be to start a cold motor
for some very short period, but long enough to do some inefficient combustion (20 seconds?),
then shut off and wait till completely cold, then repeat... Sort of like Glen Close with the
light switch in Fatal Attraction...
but just trying to keep it ready-to-run, would not be starting the motor every day. I just
chose once a week as an example of a likely period someone might be doing to 'maintain'
their not-in-use car. You are right that the amount of oil left is probably about the same
between 24 hours and 1 week. The absolute worst behavior would be to start a cold motor
for some very short period, but long enough to do some inefficient combustion (20 seconds?),
then shut off and wait till completely cold, then repeat... Sort of like Glen Close with the
light switch in Fatal Attraction...
12-13-2010, 02:54 PM
#134
Burning Brakes
I crying BULL**** on the recent post 129...
Anyone that has pulled the fuse and actually watched the oil pressure gauge will see the oil pressure rising as you crank the starter!
There are SAE white papers that state that MOST of engine wear occurs on "cold" engine start up.
We have a dual stage oil pump. The engine case must be full of oil to start the first stage, at the same time the suction part of stage 2 will pull the oil from main oil tank. This requires "time"
When you start the engine without a pre-oil (fused pulled) you will see the engine idling with zero to low oil pressure for a few seconds.
Anyone that has pulled the fuse and actually watched the oil pressure gauge will see the oil pressure rising as you crank the starter!
There are SAE white papers that state that MOST of engine wear occurs on "cold" engine start up.
We have a dual stage oil pump. The engine case must be full of oil to start the first stage, at the same time the suction part of stage 2 will pull the oil from main oil tank. This requires "time"
When you start the engine without a pre-oil (fused pulled) you will see the engine idling with zero to low oil pressure for a few seconds.
12-13-2010, 03:32 PM
#135
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Paul, I would pull the fuse if the car sat for 1 month.. With my own garage queen's I will bar over the crankshaft (turn it over by hand) every month or two. With my 930 and 993TT I know that the engine oil has rose in the case.
Again, pull the fuse if you are changing the oil, pull the fuse if you are putting your car back into service (from winter storage)... You will have to charge the battery.
Again, pull the fuse if you are changing the oil, pull the fuse if you are putting your car back into service (from winter storage)... You will have to charge the battery.