You can lead a horse to water, but ...

If you worry about hitting those ubiquitous 2x4s, you should obviously ignore the almost universal advice to remove the tray. Personally, I've yet to run over any significant road debris, but my engine gets pretty hot every time I drive. BTW, your oil temp gauge doesn't measure head temps.

Is the statement that "these cars seem to need (a valve job) every 70k miles due to the CEL/SAI issue anyway" just a baseless quip or is it supported by some study you'd be willing to share with us?

 

FYI, Steve (correct me if I'm wrong, Mr. Weiner) gives this advice not only to himself but to customers far and near, skilled and unskilled. I don't believe his words are directed to those with above average or greater abilities who can readily fix problems caused by a maliciously leaping 2x4.

Do as you see fit. It's your world, boss.

 

"Brother" Phil & "Brother" Mark both posted true Pearls of Wisdom for anyone with questions & concerns on this issue,....

I don't believe I can possibly add anything constructive aside from mentioning that as long as one can afford the financial consequences of leaving the undertray in place, there are no problems with that.

Ultimately, its your car,...................

 

ok, you guys have me convinced about the engine tray.

as for the CEL/SAI remark, i do not have any scientific evidence or study, but based on what i have read here it seems to happen with a greater than expected frequency for a car of this caliber.

 

I took Steve's advice when this topic was discussed two years ago and removed my engine tray. It's taking up space outside my gargage next to the trash cans. Then it happened - debris on the road ahead, nowhere to go but over and hope for the best - kathunk, I cringe and later find that I have ripped a hole in my heater control box hose and crunched the control box flapper ends- ouch was my reaction when I heard that the cost of new replacement parts. But I didn't need new ones, used ones work great and there are plenty of parted Porsches out there. One in particular just happened to be available by our good friend Viper Bob and my new to me heater control boxes were on in a matter of minutes - cheap! (thanks Bob!)

My engine tray is still off.

BTW - I never really noticed a difference in the oil temp guage either way. The high-speed fan override switch makes a night and day improvement and is a must mod in warm weather climates IMHO.

 

I am also very interested in the idea of "ventilating" the engine tray as opposed to removing it completely, is there anyone that has had experience with this or thinks they may know how best to go about doing this? This could be a happy medium for the more timmid 993 owners who are worried about this issue.

 

I do not think you will notice a difference in the temp guage when you remove the tray. Removal is to ensure that air circulates better to avoid valve guide wear. (Bruce Anderson)

 

Has anyone bothered to attached thermocouples to the heads and log some temps with engine cover on & off. If you run a test for, say 1 month with & without, a decent stat analysis of the logged data should tell us the effect of the cover on localised head temps - as I think we all agree that oil temp isn't going to give the data required.

I'm surprised taht OBDI logging doesn't give us head temp data....

 

Wow.... thanks for all the replies and thought provoking comments! As I've been driving the car almost every day here in the Orlando area for a number of years without any apparent heat issues... I think I'll leave it on. And if it's there "just as a noise reducer" I guess I can live with that concept too.

Thanks again!

 

Just removed the tray from my new acquisition.
So much easier than my '90 C2 which seemed to have dozens of full screw fasteners. That tray was significantly more constrictive than the 993. I'd guess that the later one's removal could be questionable but it's off and it's staying off. I was thrilled to confirm that there are no oil weeps or leaks whatsoever!