DE Oil Change why

[OldTee]

On a DE this WE my oil temps got to the red line, perhaps a little + of the red line. I am installing a oil cooler for the next DE on my stock 79 911SC. The question is should I change my oil after such an event. How soon? The oil has less than 1000 miles on it so the real question is what happens to the oil when it overheats? When it cools how much of its properties does it loose? I know oil cokes and looses lubricity (if there is such a word), and additives burn off, and the engine should be taken off line until it cools, but what then?

[cnavarro]

Wow, it seems no one wants to touch one. Well, there is a long and short answer. I will give you the short. I would replace the oil after prolonged high oil temperatures such as your engine experienced, more so if you are using a conventional motor oil rather than a synthetic. Short of testing the oil after such an event, you don't know what has happened or not happened to the motor oi. Oil and filters are cheap, a rebuild is not.

[1fastredsc]

Originally posted by OldTee
On a DE this WE my oil temps got to the red line, perhaps a little + of the red line.

Have you checked you mixture lately? Even with the stock cooler you should'nt see temps that high, that is rediculous high.

[rlane]

There are a lot of threads in regards to 78 and 79 SC's overheating on the track. Appears to be a combo of:
-trombone cooler being pretty worthless
-lack of airflow to the (pretty worthless) trombone
-the 79 may have the non updated oil sump screen that caused cavitation and lack of scavenging from the case in these cars
-226 vs 245 mm fan-?less cooling
-CIS mixture as fastred points out
My 78 sure overheated , even with a Carrera front cooler until I fixed the oil sump screen (which is NLA..btw)

[OldTee]

Thanks. Noah, co 2.03, H 47, CO2 14.4, O2 0, A/F 13.8, Mileage 140,980 on 3/3/06. Timing checked then. Stock except for SSI. Excursion temps into redline + occured at idle on way to pits and during shut down. Did not measure with pyrometer and guage may be inaccurate. Oil sump to be installed at oil change before next event as will a Carrera oil cooler. Oil is Shell 10/40W. Black bottle. Does this help.

[}{arlequin]

how about when you see these temps?

[304065]

Dave, I thought my engine ran hot, but Sveiks, that's HOT! I'm surprised it didn't seize. G_d bless synthetic oil.

[}{arlequin]

yes, i figure that mobil1 should sponsor me by now

it ran all last season in the 250's w/o a stutter but *this* was the highest i've ever seen. turns out i ran the entire day w/o any advance. timing was waaaaay off. (didn't verify it after i swapped in a new pertronix unit to replace a dead one. )

it caused a knocking sound in the motor.... wish it wasn't terminal but i'm not keeping my hopes up. too bad, i'm gonna miss the little 2.4- i think i'll have to keep it.

[magic930]

Does your era of Porsche have a fender oil cooler? If it does then the thermostat might not be working. If it doesn't then you should get one!

[}{arlequin]

the T never had one but it was in the works for the new motor

[OldTee]

Well, its in. Matt DeMaria called yesterday and said he had a cancellation and did I want to get the job done. It took him 2.5 hrs, some drilling and creative language but no welding. Smooth, I would say.

[Jeff Alton]

Dave, I would be more worried about the lack of oil pressure you have there even though the motor is at 2000rpm........

Cheers

[}{arlequin]

Originally posted by catca
Dave, I would be more worried about the lack of oil pressure you have there even though the motor is at 2000rpm........

Cheers

i'm counting on a faulty sender.... it's at 60 at 4k rpm....

[OldTee]

What did Matt say?

[}{arlequin]

it's dead. noise from the chainbox on passenger side.
not quite dead, 'cause it runs and feels just as powerful
on the street as before, but the noise is there...