peter_jansen

My engine tray sits on my garage floor directly under my engine. Better than cardboard. I feel that this is the best use of the piece and what Porsche truly designed it for.

bricem13

Everybody shall make his thoughts on this point.

Personally I agree with Adrian in this thread https://rennlist.com/forums/964-foru...it-or-not.html (see posts 18-42 as well as 26). Removing the foam is to do definitively.

Duck

Would this experiment work? I cannot do it since my engine is being rebuilt.

Using a diagnostic tool, read the cylinder head temp of a car with the tray and then without the tray. Would need to have about the same ambient temps and run for similar conditions (idle, similar route, etc.). Would something like this give at least some evidence if the tray increases head temps? Also I am sure someone more knowledgeable could set up a more scientific experiment.

GBX

I'm very new to this debate and am planning on removing mine the next time it's up on the lift (I did buy a car with the tray installed...didn't concern me one it, but only time will tell I guess).

What I don't get is that if there really was such a flaw in the design by having a tray, the why was it still on 993's? Don't you think that if the tray caused issues, Porsche would have eliminated it on the 993???

bricem13

Don't forget that the rear fan shall come into operation at key off if engine temperature is too high: http://www.bergvillfx.com/porschehvac2.html (look at rear fan operation). On the side note, I am sure everyone here is convinced that engine warm up shall be slow to avoid any issues, tray will ensure reasonable cool down duration.

dhc905

The flaw in all of this "logic" is positing that no matter what higher engine temps are worse than lower temps. This is not true, and I have a hard time believing the engine tray will be the reagent for engine damaging temps. Like I said, our engines driven under normal circumstances at normal temps will not overheat. There is a lot of cooling capacity built into them that driving on a Sunday morning on a non-trafficked highway at legal speeds, you will not reach a temp to damage your engine, engine tray or not.

If you are racing, do whatever you see fit, but for 99% of the folks here, this is silliness that will only lead to problems down the line.

gfunk

Why bring facts into an emotional debate

Duck

Sorry, I am not sure what I was thinking. I must have been .

Navaros911

I've left it off and have it on now.
To my eye I had no difference in oil temp on the dash - unlike the mod for earlier high speed fan operation on the oil cooler, search for the thread if you want it.

All I noticed is longer warm up periods for the oil with the tray removed. I'm not going to assume this is the same as having higher engine temps.

So, who is right here... only data will tell. So I'm for the scientific approach... that happens to be missing from either side.

My subjective opinion is: it doesn't matter on the life of the engine. Oil changes and how you drive it do.

J richard

From Porsches own tech bulletin the whole purpose was sound:

DobermanDad

To me, if it doesn't need to be there, it's going. Just one more part in the way when I want to work on my car. Mine was off when I bought my 964, as well as all the foam.

J richard

The issue of heat is not what you read on the temperature gauge but the localized internal buildup of heat in the cylinder head around the valves, specifically the exhaust valve. And sitting in traffic with the AC going and low airflow from the fan is harder on the engine than running at speed.

Prior to the 3.2 a 911 motor would easily go 200,000 miles without a hitch. But the change in valve guide material and additional heat from the larger displacement taxes the cooling of the head. The result even with ceramic liners is premature valve wear. So compaired to the previous generation if you've had to have your top end rebuilt before 175,000 due to valve guides you have just experienced premature guide wear.

Anything you can do to reduce trapped heat, and heat soaking around the cylinder head will extend the life of the engine. (The only exception if you live in an area that never allows the engine to reach operating temp)

This is not about emotion, bad science or voodo, it's practical experience. Talk to anyone who builds these motors and you'll get the same answer.

C4inLA

Mid 1990's spent few days visiting J. woods and B. Anderson in San Jose. Their observations suggest leaving off. I took the advice.

tcsracing1

anybody have a decent picture of the undertray along with the mounting assembly and associated heat sheilds?

I am trying to piece together my heat sheild from boxes given to me by previous owner but it appears i am missing items....

Steve Weiner-Rennsport Systems

Porsche used the same material from 1978 to the present.

We do all of our machine work here in-house and have processed well over two thousand sets of heads for others as well ourselves and the (poor) guide material hasn't changed since the introduction of the 3.0 engine all the way to the latest version of the Mezger GT-3 engines.

There are two issues at work here (exacerbated by cylinder head heat): lousy guide material and loose (out-of-spec) fitment right from the factory. We've addressed the former by making our own guides (using a superior material) since 1979 and the latter by honing guide bores more precisely and to factory spec.

I've seen worn/poorly fitted guides in engines with as little as 3K miles so one knows they left the factory in that state. Some engines were assembled very nicely (inside factory spec) and those can go the distance before requiring replacement depending on operating conditions and maintenance.

The valves used in 3.6 litre engines have hard-chrome stems so they really outlast their predecessors.

I've just very briefly touched on this subject here, but I hope this helps maintain some clarity so people stay correctly informed.