T4 Engine tin: thermal design Options

[914werke]

So seeing a product recently got me thinking about the result of its application & my own observations of how well (or not) the T4 handles air flow, Engine block cooling & resulting oil temperatures. (IMG:style_emoticons/default/smile.gif)

Its somewhat well known that ...in the 914.. the T4 suffers from less than optimal cooling from the front mounted impeller/fan particularly to the #3 Cylinder
& that it is vitally important to seal the tins multiple openings to contain as much laminar air flow front to back over the finned cylinders.
In a gross approach, the goal was to seal the engine compartment "intake" air on top from the eng. heated "cooling" air below the tins.
When a motor is new and all its components serviced & refreshed, the design does, or did, a pretty good job.
After years of use (neglect), elements (oil dirt mice ext) conspire to restrict that air flow.
As well as eng. heat causing hardening of rubber pieces that are intended to help contain that cooling air below.
Now almost 50 yrs on I see fewer & fewer "STOCK" engine configurations which you can guess usually means more heat to deal with.
Jake addressed the cooling air via his(?) DTM solution, but IMO its not very practical for stock or near stock motors (& expensive)

The go-to response to eliminate that heat is usually an additional or a remote oil cooler which comes with its own set of challenges. (IMG:style_emoticons/default/confused24.gif)
How about KISS (IMG:style_emoticons/default/biggrin.gif) Has anyone used any of the Fiberglass based stick-on reflective heat shielding products on the engine-sides of the tin?
Idea being rather than allow heat absorption to all the those steel pieces reflect it back to carried away by the cooling air?

BTW Im not a Porsche engineer...but I did stay in a Holiday Inn last night (IMG:style_emoticons/default/happy11.gif)

[wonkipop]

@searunner

to expand naively on the space shuttle for instance.
and when i say expand, i mean very tentatively, because i ain't no NASA engineer.
but.

you are re-entering the atmosphere.
and you got heated plasma (ie air turning into something else very hot) below the surface of your vehicle, the last thing you want to do is reflect that heat and add to the temp of the plasma........
so you absorb it with black stuff.
thats thick enough to suck it up.
the fabulous tiles. like space age pottery.
they suck the heat up and don't conduct it to the aluminium structure they protect.
which would soften, melt and lead to destruction of the vehicle.

then as the spacecraft slows to less than about 7 times the speed of sound and gets into the lower atmosphere the said tiles can begin to radiate the heat out to the cooler air.
no plasma anymore ( super heated air ). and the equation reverses.

so long as you don't loose any tiles!

i think that is how it worked on the space shuttle in terms of black surfaces.

with a VW engine i think it works by the black tin absorbing engine heat because its being radiated at by the engine, but on the opposite surface the air is cooler so it radiates towards the cooler body, the air and looses the same heat that its absorbing on the other side. in effect it forms a pathway for the enclosed engine to lose some heat out to the surrouding air and also to not reflect the engines heat back at itself, but rather to draw some of that heat away from the engine in the radiant spectrum.

the fibreglass on the 911 engine cooling shrouding probably does a sort of similar job because it does not reflect heat back at the enclosed engine. however it would also not form a pathway for getting the heat out. maybe they didn't need a pathway out for the heat they just worked out they needed a non reflective and non conductive surface.

?

i don't really know. just stabbing a guess at the basics.