Is my 993 C4S overheating?
03-23-2017, 02:08 PM
#16
Drifting
03-23-2017, 02:09 PM
#17
Race Director
This statement lacks even a remedial understanding of physics. Theres a difference between having inadequate lubrication and no lubrication at all. An engine would seize when the power/inertia generated by the system cant overcome the force of friction.
Stick your fist in a Pringles can and vary how hard you clench, then tell me you cant increase friction and still move your hand
Stick your fist in a Pringles can and vary how hard you clench, then tell me you cant increase friction and still move your hand
03-23-2017, 02:15 PM
#18
Rennlist Member
03-23-2017, 05:44 PM
#19
I'll just say in terms of my credentials that I've been working on air-cooled 911's for over 20 years and have built many 911 engines, including 993 engines. Yes, it is true that a few seconds of low oil pressure will not cause a seized engine. But much more than that in either duration or pressure loss and you will spin a rod bearing -- curtains for your engine.
Bearings in an engine, and this goes for rockers/shafts and cams as well, ride on a thin film of pressurized oil. It's why using the right grade of oil and operating the engine in the right temperature range and correct bearing and casting tolerances are critical. Even a few seconds of metal to metal contact spells doom. The post from the yellow submarine guy is evidence of staggering ignorance. An engine in which metal-to-metal friction is occurring would not run long enough to generate extra heat. Do a Google image search for "spun rod bearing" to see what happens next. The idea that an engine will just chug along as metal parts rub against each other generating an overheating problem indicates a total lack of even rudimentary knowledge of engines.
Bearings in an engine, and this goes for rockers/shafts and cams as well, ride on a thin film of pressurized oil. It's why using the right grade of oil and operating the engine in the right temperature range and correct bearing and casting tolerances are critical. Even a few seconds of metal to metal contact spells doom. The post from the yellow submarine guy is evidence of staggering ignorance. An engine in which metal-to-metal friction is occurring would not run long enough to generate extra heat. Do a Google image search for "spun rod bearing" to see what happens next. The idea that an engine will just chug along as metal parts rub against each other generating an overheating problem indicates a total lack of even rudimentary knowledge of engines.
03-23-2017, 07:28 PM
#20
I'll just say in terms of my credentials that I've been working on air-cooled 911's for over 20 years and have built many 911 engines, including 993 engines. Yes, it is true that a few seconds of low oil pressure will not cause a seized engine. But much more than that in either duration or pressure loss and you will spin a rod bearing -- curtains for your engine.
Bearings in an engine, and this goes for rockers/shafts and cams as well, ride on a thin film of pressurized oil. It's why using the right grade of oil and operating the engine in the right temperature range and correct bearing and casting tolerances are critical. Even a few seconds of metal to metal contact spells doom. The post from the yellow submarine guy is evidence of staggering ignorance. An engine in which metal-to-metal friction is occurring would not run long enough to generate extra heat. Do a Google image search for "spun rod bearing" to see what happens next. The idea that an engine will just chug along as metal parts rub against each other generating an overheating problem indicates not just a total lack of even rudimentary knowledge of engines, but an overactive imagination as well. Time to put the bong away in the yellow submarine.
Bearings in an engine, and this goes for rockers/shafts and cams as well, ride on a thin film of pressurized oil. It's why using the right grade of oil and operating the engine in the right temperature range and correct bearing and casting tolerances are critical. Even a few seconds of metal to metal contact spells doom. The post from the yellow submarine guy is evidence of staggering ignorance. An engine in which metal-to-metal friction is occurring would not run long enough to generate extra heat. Do a Google image search for "spun rod bearing" to see what happens next. The idea that an engine will just chug along as metal parts rub against each other generating an overheating problem indicates not just a total lack of even rudimentary knowledge of engines, but an overactive imagination as well. Time to put the bong away in the yellow submarine.
03-23-2017, 07:52 PM
#21
Drifting
Originally Posted by AllanH
This is a community. No need to be a douchebag.
A lot of internet warriors on here that are happy to point out a wrong vs letting things go.
"...let him who is without a mistake throw the first stone"
I think a better idea would be to offer a solution/idea to the OP looking for help. I'm sure he would appreciate the advice during this stressful time.
Last edited by shadow993; 03-23-2017 at 08:17 PM.
03-23-2017, 08:26 PM
#22
Rennlist Member
wow ok...pringles example certainly demonstrates understanding of internal combustion engine and the physics involved. The point of Churchill was that once you lose adequate lubrication (oil starvation) the consequences will seize the engine almost immediately without any heating issues caused by excess friction.
03-23-2017, 08:33 PM
#23
Instructor
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I'm no rocket scientist, but my bet is that one of the earliest indicators of inadequate lubrication would be an increase in friction related heat. It may be fractions of a degree, but I bet it happens.
03-23-2017, 10:28 PM
#26
Drifting
If you have read the earlier posts in this thread, the "inadequate lubrication" was for 2 potential factors, low pressure and wrong oil weight. Since we dont know if OP has actual low pressure or a bad sender unit, the one piece we do know is he was using 0-40W and then switched to 20-50W, as stated in his posts. So yes, no oil will seize an engine quickly, but he has oil as far as we can tell. So the other factor is the likely incorrect oil weight, e.g. inadequate lubrication.
03-23-2017, 10:30 PM
#27
Drifting
Thank you gentlemen. I have just changed the oil to 20W-50 from 0w-40. partial improvement followed with .75 bar of pressure at warmed up idle. Going to take it into the shop. I am thinking maybe the sensor is bad because I hit the gas on it a couple times while driving and was +4 bar above 4000rpm but then returned to the .75 bar at idle...
Heavier oil will cause higher pressure, but .75 is still way too low.
And like quad said, I'm not sure what 285 OBD reading is. When you say gauge is 1/3 from hot, do you mean? 9 o'clock? 10 o'clock? Is this while idling for a while? Or driving?
03-23-2017, 10:41 PM
#28
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Does the pressure gauge move with the ignition on? When mine went bad recently, it would show 2 bar with the ignition switched on, 4 bar cold start, and 1.5 max when warm,. PO had replaced the OE sender with an aftermarket one that went bad after 3k miles.
And yes, access to the sender is a pain....
And yes, access to the sender is a pain....
03-23-2017, 10:48 PM
#30
Race Director