Adding Cooling Fins to Aftermarket Heads

[neil68]

The problem is NOT really from a lack of cooling air...the stock doghouse fan is more than adequate. I don't think adding more cooling air would help the CE/SF heads become true street/long distance/long durability heads. The problem is the lack of fins on the CE and SF heads.

It's less of an issue with the 044/stock heads, as they already have lots of fins unless you go super high on CR, etc.
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Neil.

Der Kleiner Rennwagens
68 Beetle 2332 cc, 204 WHP
12.5 seconds @ 107 mph
Dynojet Test: https://www.youtube.com/watch?v=M9B_H3eklAo

[1432]

[Jake Raby]

The exhaust port area is the area where the head is hottest, no matter what. Not having fins in this area makes no sense to me. The reason why 911, 4 Cam Carrera, Type 4, Pinzgauer and Corvair heads all have bottom exiting exhaust ports is so the area can be heavily finned for at least 320 degrees of the surrounding real estate at the exhaust port.

Of course in the 1/4 mile what JPM states has more merit, but in a situation where thermal overloading and thermal conductivity matter most, it makes no sense.

Cooling capability is the key and that comes from more cooling surface area as well as fins that are long, thin and properly placed.

Face it, adding fins cost money and lots of it during development.. The more fins the more complicated the mold and the more machine work thats necessary. Thats the reason why the majority of performance heads don't have any cooling fins placed around the exhaust ports. It is a perfect place for some nice heat sinks, though.
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Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell"

[neil68]

Those are interesting comments about exhaust fins. Different heads or engine types have varying characteristics, that's for sure.

I will say this about the JPM heads. They've been available for seven years, in Sweden, Finland, Norway, Denmark, Germany and the rest of Europe. There are numerous users who build high performance engines with these heads and then use them as daily drivers. As I stated above, it is not unusual for some of them to drive 500-700 km across Europe, throw on the slicks, race their 11-second Beetle, and then drive home. They also perform well on the autobahn and some of the HP/TQ readings are very impressive...especially on small displacement motors. Check youtube.com for JPM, if you're interested.

I haven't found anyone who claims to be able to do this with a CE/SF head. Some have done it for a short time, but eventually over-heating problems seem to arise. I will report my results as the miles pile up...
_________________
Neil.

Der Kleiner Rennwagens
68 Beetle 2332 cc, 204 WHP
12.5 seconds @ 107 mph
Dynojet Test: https://www.youtube.com/watch?v=M9B_H3eklAo

[Jake Raby]

I am very familiar with the heads from JPM.. We've put down over 500 RWHP with a set of them on my chassis dyno.

I wonder how many of the countries listed has areas with 92 days in a row with a high of over 90*F? The operating environment that we have in the US is much different than that of the majority of Europe. Its hotter by 0900 in the morning in most parts of the USA during summer than the high temperature will be in the majority of Europe. Remember a few years ago when it hit 90F in London and people were dying of heat exhaustion a dozen per day??

At any rate, I don't believe that there is any substitute for cooling fins and their placement at the hottest portion of the heads is key.
_________________
Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell"

[modok]

There are a few schools of thought on exhaust port cooling

On the one hand, you don't WANT to cool the exhaust port. Cooling the exhaust port is just putting more heat into your cooling system and not helping anything. If you could LET that part of the head run hotter that would be ok, or insulate with an insert in the port that works as an insulator, that is fine, a half dozen engines DO have "port insulators"
Also some engines make the port as short as possible. You don't have to cool the header. Some heads allow the port to project out by itself and minimize the connection to the rest of the head.

But on the other hand, the port by it's nature is connected to the head, and you don't want-
A that area getting so hot it's expansion pulls the rest of the head out of shape and screws it up
B-that area flowing heat into the rest of the head where you don't want it.

So the theory is sound, but your dammed if you do and dammed if you dont

flathead fords warm up fast

[neil68]

[1432]

[RockCrusher]

1432...what you're talking about is just called "Heat Rise" in lab testing parlance. Basically, the oil will rise 'X' number of degrees over ambient temps, say....110* when a given number of BTU's is added to it. SO when it's 50* outside the oil will reach about 160* and if the temp is 100* outside (ambient temp) then the oil will reach 210*. Think of ambient in terms of BTU's and it is simple addition.

That is just a lab type example but in the real world of jetting, engine load, cooling system efficiencies and such those numbers (which I just pulled out of the ambient air ) would vary greatly as you are adding and subtracting BTU's at various rates. The basic idea holds true that increased ambient temps will raise final running temps. It's all about energy and some clever guy said it's all relative.....and it certainly is.

Every bit of this could be figured out mathematically if someone could model the ambient vs mass air flow in the cooling system and BTU change over fuel delivery vs mass air flow thru the engine and much more but who is going to do that....not ME!

RC
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[1432]

RC,
That’s not really what I'm trying to say, my point is more along the lines of the intake cycle ambient air / fuel mixture’s internal cooling effects as it fills the cylinder exclusive of all other external cooling means. A very good example would be the use of alcohol base fuels in extended driving situations. Though gasoline fueled a/c engines will not experience this same degree of cooling influence as alcohol programs the ambient temp air/fuel relationship will still impact net operating temperatures to a measurable degree.

[dawie]

Maybe apply a good thick insulating coating to the inside of the exhaust ports? Think Porsche used ceramic port liners on their last aircooled heads. (993 type).

[yamaducci]

[mark tucker]

mine are coated in the ex ports& chambers,and the face of the intake valves and both sides of the exhaust valve.last time I checked the ex port with an ir gun it was 195 after a nice sunday floging then driving home,and the engine was ideling when checked. the heat was going out the exhaust where it should.but extra fins wont hurt.

[yamaducci]

I am getting closer to completeing a set of heads for testing. So I decided to offer this option for the people who would like to run CE heads on the street without fear of overheat.
This is a "feeler" Ad to gauge interest; as I would need interest to go forward with a water-jetted batch of fins.
http://www.thesamba.com/vw/classifieds/detail.php?id=1199672
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-John Cox
My 2498 Turbo Re-Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?p=5578697#5578697

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[yamaducci]

Multiple fin addition is getting closer.
_________________
-John Cox
My 2498 Turbo Re-Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?p=5578697#5578697

3rd Brake Light Safety Stars- I still have a couple with blue light left. Email me if interested.

[yamaducci]

I am offering this service to those wanting to run Competition Eliminator heads on the street with a lot more over-heat resistance.
http://www.thesamba.com/vw/classifieds/detail.php?id=1199672
_________________
-John Cox
My 2498 Turbo Re-Build Thread: http://www.thesamba.com/vw/forum/viewtopic.php?p=5578697#5578697

3rd Brake Light Safety Stars- I still have a couple with blue light left. Email me if interested.

[baked beetle]

So that one fin drops the cylinder temp by............how much?
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[yamaducci]

[mark tucker]

what about the part of the head under the rocker box?ex ports?or are you just add 2 to the cylinder end?there is a lot of heat on the other side of the chamber where there isant an fins.just a thought.

[yamaducci]