911 engine (all) run whitout FAN? how many minutes/seconds?

[dan67]

hi/ciao
how many minutes / seconds, the engine can run fanless? (run contitions = oil 90° temp air 20°)
It seemed to be reading from old textbooks that for a certain period by carefully controlling the temperature of oil could travel.....

[Spumato]

Where you driving? The whole purpose behind the fan is to pull air across the cylinders to help keep them cool. Without out it, the engine will heat up very quickly. You are more concerned with the internals not cooking, and these temps are different from actual engine temperature. Best advice is shortest time possible. When driving and the red alternator light illuminates, pull the car over and turn the engine off to prevent any damage.

[woland]

Hi!

In his nice book "The gold plated Porsche", Steve Wilkinson refers of a client who shredded the fan belt during a race, finished the race and the engine while open resulted in perfect shape.
911 can run without fan because with his 12 liters results pratically "oil cooled"

From where, in Italy?

[tctnd]

If it's under load you could ruin it in less than a minute; if idling down the block you might might go two. I wouldn't do it under any circumstances short of life threatening.

regards,
Phil

[gshiwota]

In an effort to track down a strange chirping noise coming from my engine once I drove around the block with the fan disconnected (process of elimination). I just kept my eye on oil temp and drove it easy. Nothing dramatic happened as a result. It can be done but just be careful.

[NYNick]

My 89 Targa (since sold) was snapping belts like crazy. It happened again on a Sunday evening, several miles from my Porsche specialist. Alternator light was lit, of course. I pulled over on a busy highway, saw the broken belt and decided there was no way in hell I was going to sit there and wait for a tow truck.
I started her up and drove, slowly, with hazards flashing, carefully watching the temp gauge. It got hot, but not dangerously so, or at least it indicated such. It got me to the P-shop no problem, but I would never do such a thing if I wasn't watching the gauge carefully.

[dan67]

.. I run on motorway for 5 min on 5° gear at minimum gas...oil temp normal...currently no problem....
(911 always takes you home)

(sorry for idiom)
4 woland
ciao, sono dall'altra parte delle Alpi....provincia di Cuneo.

[RedCoupe]

Personally, I would only run the engine without the fan long enough to get it off the road into a safe parking place. Many years ago my family had a couple of Corvairs with their air-cooled flat sixes. In the middle of a Phoenix summer, one family member broke a fan belt on one Corvair and decided he could make it the couple of miles home. Although it started pinging badly before he got all the way home, after it cooled off and the belt was changed all seemed okay. Unfortunately, an exhaust valve seat came loose a couple of days later and held the valve open so there was a piston-valve collision and an expensive mess to fix. Now, I'm not saying that something similar would ever happen to a 911 engine, but I still remember having to change the head, exhaust valve and piston on that old Corvair, so I wouldn't risk anything similar with either of my Porsches.

[DRACO A5OG]

Just remember the temp gauge is much lower than the actual temps on the heads/towers. For diagnostic, 1-2 minutes max.


When I broke my Conti belt on the road. I saw my alternator light come on and my temp started to riise. I pulled over and swapped with my back up right away. Lesson here, keep a spare belt, pulley tool, proper socket and for A/C, a 13MM wrench. Go home and properly torque the nuts/bolts.

[Spumato]

As stated earlier, the engine may be oil cooled, but you still need to draw air over the engine to assist in the cooling. If the fan were not important, the engineers at Porsche would not have included it in their timeless design. Also, I would not advise putting the engine under load or even operating it without the fan. If you have done such and it has not caused problems, consider yourself lucky. Rolling the dice, just to troubleshoot an issue or for any reason will not measure up to an expensive engine rebuild when you reduce the engine to a paperweight! Use the fan! Watch out for the alternator light during operation, and check the tension on the belt periodically.

[quattrorunner]

I once had a belt break and pulled off the road. I was I. A massive rush so I decided to do the quick poor mans aproach to belt replacement. See in this video. It works. Not optimal but way better than driving with no fan!!
https://m.youtube.com/watch?v=BQhfcdQf1QA

[LEAKYSEALS951]

Wasn't there a Grady Clay post on disconnecting the fan and spraying water over the engine to get more HP for short runs? I can't remember.

[pors1968]

OIL temp and P/C temp big diff 1or 2 minute for test is ok.

[woland]

If the fan were not important, the engineers at Porsche would not have included it in their timeless design

No one reccommends running for long time without fan, but think at a 12.000 rpm two stroke AC engine (I had for long time Puch, Ktm, Ossa, Simonini dirt track bikes before liquid cooled engines exist): you could cover chilometers uphill in 1st and 2nd gear with a ridicoluos amount of air flowing through head and cylinder but you seized the piston in seconds without oil in the fuel.

This is what i meant: oil comes for first

[winders]

Originally Posted by woland

No one reccommends running for long time without fan, but think at a 12.000 rpm two stroke AC engine (I had for long time Puch, Ktm, Ossa, Simonini dirt track bikes before liquid cooled engines exist): you could cover chilometers uphill in 1st and 2nd gear with a ridicoluos amount of air flowing through head and cylinder but you seized the piston in seconds without oil in the fuel.

This is what i meant: oil comes for first

If we were discussing two stroke engines, you would have a stronger point. But, we are not.

Oil cooling is critical for the engine. But, the air cooling is also critical. This is especially true for the heads and cylinders. Non-water-cooled 911 engines must have the fan functioning or they will be damaged after a brief while. It doesn't matter how many quarts of oil are in the oil system.

[quattrorunner]

Originally Posted by winders

If we were discussing two stroke engines, you would have a stronger point. But, we are not.

Oil cooling is critical for the engine. But, the air cooling is also critical. This is especially true for the heads and cylinders. Non-water-cooled 911 engines must have the fan functioning or they will be damaged after a brief while. It doesn't matter how many quarts of oil are in the oil system.

Exactly. Think of those aircooled motorbike engines with a shroud covering the fins and no air going over them and that's what our engines have without a fan. But worse because the engine also heat soaks with more mass that's hotter and no airflow for relief.

[woland]

Ok!

Let's assume that until oil temperature and engine temperature remain under the red bandl I can (carefully) proceed.

Let's assume instead that with oil warnig flashing I have to stop ISTANTLY
This is what i meant

[dan67]

...hi...after 2/3000 Km after the (my) problem at the pulley....NO problem!

my engine was naturally used when I bought the 911 (i suppose 100/200.000km) ... now I have more than 100000km without problems ... is perfect ... but tired after a few days of downtime in the first ... 10/20 sec departure is irregular. ..there will be oil in the valve seats ... it's normal ... for now everything works perfectly .... the problems will be when the unmount)))

thanks All/grazie a tutti

[winders]

Originally Posted by woland

Let's assume that until oil temperature and engine temperature remain under the red bandl I can (carefully) proceed.

Bad assumption.

First, you don't have an engine temp gauge. You can cook your heads well before the engine oil temp gauge shows a problem.