head/cylinders air cooling question

jan72 · Post by **jan72** » Mon Apr 14, 2008 3:27 am

I would like to keep the water cooling on heads, while the cylinders are air-cooled. For a street engine. With the possibility of heating from the heads.
In theory, the heads produce more heat the the cylinders.
The question is: how much of the cooling capability of both the stock cooling systems (bug fan shroud and vanagon radiator) do the heads and cylinders use? May i decrease the radiator and how much? May i also use a smaller fan and shroud for decreased air volume over the cylinders?

AMBROSIA · Post by **AMBROSIA** » Mon Apr 14, 2008 12:08 pm

Sounds tricky assuming you mean retaining the WBX heads.
You would have to weld up the water holes on the head flat and run coolant through from the front to back.
Without cutting a head in two how can you be sure that you won't get unwanted air pockets where water used to flow

There is also the question of uneven cooling as you say.
I might be tempted to modify the rear of the fan housing to accept a large oil cooler used as a water rad.
That way the engine would look stock and the fan would provide cooling for both. Adding a thermostat would maintain the water temp.
Sounds like an interesting project.

fastback · Post by **fastback** » Mon Apr 14, 2008 2:30 pm

I'm doing this conversion now, but it wont be finisihed until end of summer due to other projects.
I' have welded the unround holes in the heads and plugged the other holes.will also keep aircooling on the heads .
and using 2 small radiators integrated in a modified doghouse with electric 2 waterpumps from Turbodiesel vanagon.
the hot air from these will be routed down and under the engine as the the air from the original oilcooler does.

couple of pic's

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Post by **Piledriver** » Mon Apr 14, 2008 4:43 pm

I have always wanted to do something like this with a 911 fan setup, hot air redirected out of the engine compartment...

Re: The video---
Funny how the absolute fastest, over the top cars "go" with so little drama.

I was at Ennis when the Paradiise Express set some record awhile back:
(Think it ran 200MPH+, maybe 6 seconds?)

Watching the run looked like he was out for a Sunday afternoon drive. Zero drama.

jan72 · Post by **jan72** » Mon Apr 14, 2008 11:49 pm

The upper cylinder tin should be like the one that fastback did, it looks stock, but i don't know about the need of air cooling on the heads, since they're water cooled. I also don't know about using the entire fan shroud, (except for the stock look), but it could be useful by hiding the radiator.
I was thinking of using the stock water pump. Of course, I don't know if there will be air pockets from modifying the heads and i don't know how to find it out without cutting a head (no spares)

.
The question is if one (or maybe two) small radiator or heater core (how small?) is enough to cool the heads. And won't it steal the entire airflow from the left cylinder bank?
I was thinking of using a porsche-style fan, only smaller (from a trabant

, just to cool the cylinders (or maybe a smaller stockish custom-made shroud with a smaller fan) and a small radiator under the rear fender (or somewhere else in the rear) to cool the heads, but your ideas sound better.

Wait a minute, the fan may be used to suck air through the radiator and blow it on the cylinders, which shouldn't dissipate much heat and air at -let's say- 40 C (maybe 50C in the summer) should still "cool" them or at least keep them at a certain temperature. The engine should also warm pretty fast.
Is this stupid?

Oh, most of the water pump goes with the water jacket. I have to think of a water pump.

fastback · Post by **fastback** » Tue Apr 15, 2008 6:07 am

I will modify the fanhouse to also direct cool air to the left head/syl ,by leaving a ~30-40% opening to this an the rest to the small radiators.
My theory is that the "missing" cooling fins, that the WBX heads do not have compared to the type1 aircooled , will be replaced by the radiators.
It'a about cooling area. and the wbx head has some surface area to cool also , that's why i also will have the airflow over the heads.
Maybe the aircooled heads has 2-3 times more area if u lay ot the fins. but i think the radiators have at least the same cooling area as the missing fins.
ALuminium transports heat very well, and water cool's 25 times better than air, so a small airpocket would not be the biggest problem ,most important is constant waterflow.
I was thinking of using oil as coolng also in the water heads, but oil transports heat 3 times less than water and then i would need huge remote cooler. this system hopefully do not need any extra oilcooler. maybe i use the stock vanagon watercooled oilcooler/heater.

time will show

jan72 · Post by **jan72** » Tue Apr 15, 2008 10:52 pm

fastback wrote:... electric 2 waterpumps from Turbodiesel vanagon...

What do those pumps look like? Was the water pump on td vanagon an electrical pump?

fastback · Post by **fastback** » Wed Apr 16, 2008 12:17 am

yes they are small electric ones in addotion to the mechanical one
not on all models though

jan72 · Post by **jan72** » Wed Apr 16, 2008 12:38 am

I searched through Golf 2 and T3 (1,6 TD) manuals and found only mechanical pump. The mechanical one from G2 1,6-1,8 gas engines should of use, it looks like a full single unit that may be attached to any engine. No more type 1 stock look, though.
Are you keeping the oil cooling on this setup? I was thinking that water cooling heads means no need for an oil cooler.

fastback · Post by **fastback** » Wed Apr 16, 2008 9:27 am

i will first try without the stock oilcooler.
The pump is from the vanagon for shure, i have taken several out of these cars. only late TD versions had them.

jan72 · Post by **jan72** » Thu Apr 17, 2008 2:01 am

Ok, i'll try to find such pump(s).
Are you planning to use an individual pump/radiator for each head? Or to connect the heads in parallel?

fastback · Post by **fastback** » Thu Apr 17, 2008 6:18 am

I'm plannign the radiators i series. for ease of plumbing , and two pumps and a tank.

marzano · Post by **marzano** » Sat Nov 29, 2008 4:38 pm

What about use oil to cooling the water heads?

Unkl Ian · Post by **Unkl Ian** » Sat Nov 29, 2008 5:12 pm

marzano wrote:What about use oil to cooling the water heads?

Possible, Suzuki did some oil cooled motors, like the early GSXRs.
But that would put a lot of extra heat in the oil, so you need a bigger cooler.

Suzuki eventually switched to water cooling.