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)

[Superhawk996]

@wonkipop

You are correct.

Black is indeed the best color both for absorption and emission of radiant energy and why the OEM tin is black. Black on the inside to absorb as effectively as possible. Black on the outside to emit as effectively as possible. All about letting the radiant energy pass in & out as easily as possible to get it away from the engine. Likewise, you’ll notice any of the thermal dispersant coatings are black.

Having said that, I still had one set of my tin powder coated in red - cause’ ya’ know, it adds 10hp right? (IMG:style_emoticons/default/happy11.gif)

Ideally, I would have had it masked so that it was black inside, red outside. But that probably also tips my hand about how worried I am about radiant cooling contribution on an otherwise stock engine. (IMG:style_emoticons/default/biggrin.gif)

[wonkipop]

@wonkipop

You are correct.

Black is indeed the best color both for absorption and emission of radiant energy and why the OEM tin is black. Black on the inside to absorb as effectively as possible. Black on the outside to emit as effectively as possible. All about letting the radiant energy pass in & out as easily as possible to get it away from the engine. Likewise, you’ll notice any of the thermal dispersant coatings are black.

Having said that, I still had one set of my tin powder coated in red - cause’ ya’ know, it adds 10hp right? (IMG:style_emoticons/default/happy11.gif)

Ideally, I would have had it masked so that it was black inside, red outside. But that probably also tips my hand about how worried I am about radiant cooling contribution on an otherwise stock engine. (IMG:style_emoticons/default/biggrin.gif)

incorrect. at least 20 hp. (IMG:style_emoticons/default/beer.gif)

i think red is sort up there heading towards black anyways.
or purple. (IMG:style_emoticons/default/biggrin.gif) going with the 70s.
white or silver would be kind of not what to do.

yeah. i figure the radiant performance is more to do with cool down after running.
and its kind of negated a bit by that magnesium fan casting that just sucks up everything from the crankcase etc via conduction and turns itself into a mini nuclear reactor for 20-30 minutes after shutdown. boiling your fuel lines. that was always porsches problem with the vapor lock syndrome. the mag fan shroud. the conventional VW type 4s didn't really have that problem since the fan shroud casting was hanging out the arse and having a whose hotter contest with the muffler. but at least all the heat could sort of get away. they were really testing things going mid engined. but it kind of worked ok really. certainly a lot better than most italian super cars of the same time - at least in a joint like australia.

[searunner]

@wonkipop

You are correct.

Black is indeed the best color both for absorption and emission of radiant energy and why the OEM tin is black. Black on the inside to absorb as effectively as possible. Black on the outside to emit as effectively as possible. All about letting the radiant energy pass in & out as easily as possible to get it away from the engine. Likewise, you’ll notice any of the thermal dispersant coatings are black.

Having said that, I still had one set of my tin powder coated in red - cause’ ya’ know, it adds 10hp right? (IMG:style_emoticons/default/happy11.gif)

Ideally, I would have had it masked so that it was black inside, red outside. But that probably also tips my hand about how worried I am about radiant cooling contribution on an otherwise stock engine. (IMG:style_emoticons/default/biggrin.gif)

incorrect. at least 20 hp. (IMG:style_emoticons/default/beer.gif)

i think red is sort up there heading towards black anyways.

Only one NOTE on Black used on 914 for radiant cooling

911S 2,4 1972 engine was painted in RED
911T 2.2 1972 engine was painted in GREEN
Was one simple immediate eye distinction System??
I don't remember if the interior color was different
https://photos.app.goo.gl/LC5eWJzzKMfDSVmq5
https://photos.app.goo.gl/veb7yo2yVwMd8y4z9

My opinion for the TWO deflector underside is that Porrshe prefers to have the Air free for cooling the central OIL CUP

[moto914]

My opinion for the TWO deflector underside is that Porrshe prefers to have the Air free for cooling the central OIL CUP

Good additional thought. Thanks