Back to the future.... Volkswagens final type 1 cylinder head?

[Jon]

In the resent weeks I have enjoyed seeing a lot of skilled people here on lounge producing and modifying their own cylinder heads.
And while they are all works of art, they all seem to follow the norm Volkswagen set. I get the urge to push it forward a bit... only to discover that I was to late... WAY to late.

Ever since that semi hemi discussion, I have been thinking about making a true semi hemi, with cantered valves. In short let the valves move away from the cylinder wall as you lift them.
"WOW how very progressive and cool" I thought...   until I made a quick search...

Volkswagen developed these for the Gol 1300cc (not Golf) in 1980!!






Now, if there only was a double port version  

[Neil Davies]

Those are really interesting. I wonder why VW even bothered to tool up for them when the regular 1300 heads were still available- it must have cost a horrendous amount of money for head castings, the rocker forgings, even the valve cover pressings.

[richie]

Those are really interesting. I wonder why VW even bothered to tool up for them when the regular 1300 heads were still available- it must have cost a horrendous amount of money for head castings, the rocker forgings, even the valve cover pressings.

I know they were designed to run on different fuel from the start,alcohol based if i remember correctly,so maybe a different burn with the fuel required a different chamber design?

cheers richie

[gizago]

Makes you wonder why they went with a single port design.

[wolfswest]

never heard of the "Gol" before so I googled it.  Nice cooling fan system, did you check that out?  911 style 

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[Zach Gomulka]

Makes you wonder why they went with a single port design.

With the valves canted that way it doesn't look like there's room for twin ports.

[Udo]

I knew about that but never saw a picture . a porsche style fan made by VW :-)

Udo

[hotrodsurplus]

A bunch of you might know Russ Arao's 16-valve cylinder heads from a few years ago but I bet not more than two or three people will remember the heads that his dad Ernie did in the '70s. I can't remember the particulars but they were closer to a hemispherical chamber. They had real exaggerated trapezoidal rocker covers, like Porsche 356/912 on steroids. I have the Hot VWs feature. I'll have to scan it if someone doesn't do it first.

I can't imagine any real advantage of that Gol head design. It has all the flow of a single-port head, the combustion efficiency of a bathtub, and the lopsided burn pattern of a wedge. That's a slow-burn head and slow-burning alcohol could've only made it worse. Twin-plug it and it would burn somewhat quickly but I don't know how you'd get around the port design.

It's neat lookin' though.

[richie]

A bunch of you might know Russ Arao's 16-valve cylinder heads from a few years ago but I bet not more than two or three people will remember the heads that his dad Ernie did in the '70s. I can't remember the particulars but they were closer to a hemispherical chamber. They had real exaggerated trapezoidal rocker covers, like Porsche 356/912 on steroids. I have the Hot VWs feature. I'll have to scan it if someone doesn't do it first.

I do remember the early heads,the 1st time i came across them,they were using one as a door stop at a shop opposite Lenny copps place,there was another long block sitting there as well.
And how can anyone forget the most well known incarnation of the later 4v heads

[hotrodsurplus]

And how can anyone forget the most well known incarnation of the later 4v heads

I haven't, certainly not for the lack of trying either. That setup was about as ugly as a sack of armpits.

Ernie was at the Arao Engineering booth during SEMA a few years ago. I cornered him and asked about the early hemi-style heads. He didn't remember much which I took as proof of the design's concept. To be good you have to be different but not all different things are good.

[dannyboy]

there was a guy on vzi a while back selling a load of those gol fan setups

[hotrodsurplus]

there was a guy on vzi a while back selling a load of those gol fan setups

Don't take my word on it but allegedly Thee Jake Raby tested them and deemed them inadequate. Of course he makes his own shroud so trusting his observations may be like trusting rabbits to send carrots.

[MeXX]

Hi

Here are some pix from the Arao 16V heads

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So long MeXX

[dth]

The Gol fan set up was designed to work in a front engined car (good air flow) ,had experience
with them in a bug and always ran way too hot for my liking.

[MeXX]

.

[dangerous]

Very cool MeXX!

I am SUUURE I have seen a dual port Gol head.
I will search my library.

[Jon]

That looks amazing Mexx, how much for two?
And have you done more than drawing it? Very cool!

[andy198712]

the GOL fan works as it is ram assisted being at the front of the car... apparently doesnt work so well in rear engined cars....

[Stripped66]

the GOL fan works as it is ram assisted being at the front of the car... apparently doesnt work so well in rear engined cars....

The GOL fan works because the engine runs on ethanol.

[hotrodsurplus]

The GOL fan works because the engine runs on ethanol.

That's not exactly the case. Ethanol (and methanol) has lower BTU than gasoline for sure but that doesn't account for thermodynamics. It takes a certain amount of power to push a car down the road at a given speed and that's regardless of fuel. It's just that an engine running a high-BTU fuel like gasoline will consume less fuel than an engine running a low-BTU fuel like ethanol. In other words, the alky car will just consume more fuel to produce the energy needed to push the car down the road. That's one of the reasons we have to alter the jetting to run alcohol-laden fuels. Here's another thing to ponder: if the presence of alcohol made a difference in how cool an engine ran then our engines would theoretically benefit from the 15-or-so percent ethanol content in most domestic US fuels. That's not much less than the 20-or-so percent that Brazil used at the time. Sad to say that my cars don't run any cooler on alky blends than they did on straight gasoline.

Also the engine's displacement wouldn't have any bearing on things either. Say it takes 25 horsepower to push a car down the road at say 60mph. It will take the same power and heat to move the car down the road at 60mph regardless if the engine is 1,200ccs or 2,200ccs. 

If that fan shroud design did actually work for the Gol it was likely for less reason than fuel or any sort of air pressure from facing the fan towards the front of the car. For any sort of ram effect you'd have to maintain a pressure differential and I doubt the Gol developed a significant positive pressure at the nose of the car or negative pressure underneath. And even that would require damming the area around the engine so the positive pressure would follow the path through the fan shroud and under the car rather than just around the engine. 

I'm thinking the shroud design was viable because of the vehicle's aerodynamics and intended use. It can't help but be more aerodynamic than a beetle and that reduces power/BTU requirements. Also, I'm betting that those cars were intended more for low-speed local use than highway commuting.

[neil68]

I checked out the Gol shroud a couple years ago at a nearby shop.  IIRC, they were using them in buggies and they worked fine.  Here's a pic:



Regarding the front engine design, I don't really think that the air rushing into the fan affects cooling much differently than a Beetle or Porsche cooling system.  The fan can only suck in a certain amount of air, and the front intake works well, but it's not "supercharged" or "forced air intake" to the shroud, as I see it.

[Stripped66]

That's not much less than the 20-or-so percent that Brazil used at the time. Sad to say that my cars don't run any cooler on alky blends than they did on straight gasoline.

The E20 or so blends in Brazil were the mandated ethanol blends for gasoline. E100 has been available since 1979, and the majority of cars sold in Brazil from the early to late 80's ran on E100 (with the ethanol shortage of 1990 effectively killing the sales of E100 cars).

...but that doesn't account for thermodynamics.

FWIW, our aircooled engines run significantly cooler on E85 than gasoline. And several folks have used methanol on the street with no cooling system at all. There's no violation of the laws of thermodynamics; alcohol burns slower and cooler than gasoline. Heat flux requires a temperature gradient. So, assuming two engines each producing the same HP, each having the same efficiency, and each containing the same heat of combustion, the alcohol having a lower combustion temperature will transfer less heat into the cylinder head due to the lesser temperature gradient than the gasoline (with gasoline's higher combustion temp and greater temperature gradient).

[Airspeed]

FWIW, our aircooled engines run significantly cooler on E85 than gasoline. And several folks have used methanol on the street with no cooling system at all. There's no violation of the laws of thermodynamics; alcohol burns slower and cooler than gasoline. Heat flux requires a temperature gradient. So, assuming two engines each producing the same HP, each having the same efficiency, and each containing the same heat of combustion, the alcohol having a lower combustion temperature will transfer less heat into the cylinder head due to the lesser temperature gradient than the gasoline (with gasoline's higher combustion temp and greater temperature gradient).

Neat explanation!
I having a little trouble translating your term 'heat flux' into my native language in this context. Could you clarify that some more?

Same for heat gradient. Though I see and agree upon the combustion temps differences, where does the 'heat gradient' come into all this? Do you refer to the gradient of the inner most part of the combustion being hottest and gradually the temperature gets lower towards the edges where it gets cooles from touching the cylinderhead chamber walls? That gradient or is it meant otherwise?

Thanks,
Walter

[Fastbrit]

I can vouch for the fact that my 2332 motor ran way cooler when I shipped the car to SoCal than it did in Europe, even with far higher ambient air temperature. The only difference was the heavily ethanol-based fuel, although you could argue that as i didn't change the jetting to account for altitude correction, it was running richer in the USA than over here.

[BeetleBug]

I can vouch for the fact that my 2332 motor ran way cooler when I shipped the car to SoCal than it did in Europe, even with far higher ambient air temperature. The only difference was the heavily ethanol-based fuel, although you could argue that as i didn't change the jetting to account for altitude correction, it was running richer in the USA than over here.

Perhaps that also explains why cars always seems to go a lot faster and engines produce a lot more power over there as well?

 

[Stripped66]

FWIW, our aircooled engines run significantly cooler on E85 than gasoline. And several folks have used methanol on the street with no cooling system at all. There's no violation of the laws of thermodynamics; alcohol burns slower and cooler than gasoline. Heat flux requires a temperature gradient. So, assuming two engines each producing the same HP, each having the same efficiency, and each containing the same heat of combustion, the alcohol having a lower combustion temperature will transfer less heat into the cylinder head due to the lesser temperature gradient than the gasoline (with gasoline's higher combustion temp and greater temperature gradient).

Neat explanation!
I having a little trouble translating your term 'heat flux' into my native language in this context. Could you clarify that some more?

Same for heat gradient. Though I see and agree upon the combustion temps differences, where does the 'heat gradient' come into all this? Do you refer to the gradient of the inner most part of the combustion being hottest and gradually the temperature gets lower towards the edges where it gets cooles from touching the cylinderhead chamber walls? That gradient or is it meant otherwise?

Thanks,
Walter

Heat flux is the rate of heat transfer. Regarding the gradient, heat and temperature are not the same. Heat is the amount of energy that is in a given amount of matter (it considers temperature and mass, and the specific heat of the matter). Temperature is just a measurement of that heat. The temperature gradient is the difference in temperature across a distance or between two different mediums. The temperature gradient drives the transfer of heat, and although a heat gradient may exist, it does not have to exist. For example, if you had a container that was separated into two compartments, one containing a liter of water at 100C and the other 10 liters of water at 100C, they both have the same temperature. The 10 liters compartment of water has 10 times more heat than the one liter compartment, but there is no temperature gradient between the two compartments, so no heat is transferred between the two. If the one liter compartment was at 100C and the 10 liter compartment was at 10C, each compartment would have the same amount of heat, but the temperature difference would drive the transfer of heat from the one liter compartment to the 10 liter compartment.

The difference between the combustion temperature and the head temperature is what drives heat transfer into the heads. If the combustion temperature and the head temperature were the same (heaven forbid), there would be no temperature gradient and no transfer of heat. The example you provide is certainly true, as the temperature gradient across the distance of the combustion chamber drives the transfer of heat from the point of combustion across the chamber.
 

[hotrodsurplus]

The E20 or so blends in Brazil were the mandated ethanol blends for gasoline. E100 has been available since 1979, and the majority of cars sold in Brazil from the early to late 80's ran on E100 (with the ethanol shortage of 1990 effectively killing the sales of E100 cars).

Good point. E100 may have been available since '79; however, the Gol wasn't always (if ever) an E100 car. My hunch was based on those gigantic CR-killing chambers. But the ad in the following link confirms that at least this particular model Gol was designed to burn a gasoline-based fuel.
http://www.autoblog.com/photos/vw-gol/full/#photo-2487414

Here's that same basic design on a 1980 model. 


So just because E100 was available doesn't mean everything ran it. Case in point, I know E85 exists in the US but even though I've been to about half the states since it's been out I've never seen an E85 pump. Few cars run it.

Now I've seen photos of Gol engines that have twin carburetors and very pronounced preheat tubes that use exhaust gases ala the VW single manifold. Here's a 1985 example.
http://bimg1.mlstatic.com/volkswagem-gol-bx-1985-motor-a-ar_MLB-F-3647726358_012013.jpg

I take that as proof that particular engine ran at least great levels of ethanol if not straight ethanol as the latent heat of vaporization is a big issue on intake tracts on alky. I mean we've all proven that manifold preheat isn't required on gasoline. I don't know how I got on that tangent but it was fun.

FWIW, our aircooled engines run significantly cooler on E85 than gasoline. And several folks have used methanol on the street with no cooling system at all.

I can believe it on E85. There was even one on the cover of HVWs in the early '80s that didn't run a shroud. The points you made are valid, including your following explanation of heat transfer. There's also the issue of latent heat of vaporization cited earlier in this post that causes blowers and injector hats to frost up on fuel cars while staging. That too will reduce cylinder-head temperature.

But that assumes that the Gol ran really high concentrations of ethanol or even ran straight e100. At lesser concentrations I don't think ethanol fuels reduce engine operating temperature to such a significant level. At 85 and 100 percent, yeah but that would be a different story.

So, assuming two engines each producing the same HP, each having the same efficiency, and each containing the same heat of combustion, the alcohol having a lower combustion temperature will transfer less heat into the cylinder head due to the lesser temperature gradient than the gasoline (with gasoline's higher combustion temp and greater temperature gradient).

Well that gets back to the point I was making. Let's make the comparison between engines designed to run straight gasoline and straight ethanol. An engine designed for gasoline will run on straight ethanol but will not run very well due to the lesser thermal capacity of the ethanol (and other dynamics). And yes, very little heat would transfer to the heads making that engine run exceedingly cool--too cold--compared to how it would run on gasoline. But a straight-ethanol engines don't maintain the same parameters as a gasoline engine.

For one, to compensate for the lesser thermal capacity of ethanol engines designed to burn it usually maintain significantly greater compression ratio. Compression translates to heat--you're balling up potential energy in a much more confined space among other things. So you may be starting with a fuel that has lesser potential energy but then you're packing it into a much smaller space. To a lesser degree the greater CR also expedites the burn rate. Also, the ethanol may burn slower but the smaller chamber area also reduces the time it takes for a flame front to sweep across it. 

Of course you're not going to reclaim all of the heat lost by cranking compression but I'm inclined to believe that an engine designed to run on straight ethanol will approach the operating temperature of a gasoline-fired engine. But I don't think we can claim that ethanol was the reason the Gol cooling system worked properly. After all, we have advertising proof that at least one Gol model ran on gasoline or at least a gasoline blend.

And that gets us back to another issue, whether the Gol system really is inadequate. I know someone who many claim is an authority said so but I'm not going to take that on blind faith. I did that once and as a result made the chambers in a set of perfectly good heads look like the ones in the Gol head. 

[Airspeed]

Thanks 'Stripped'!

Regarding the Gol running on E20 or E100: it could not have run on both because it still has carbs: the tune is so different with those radically different amounts of ethanol, it had to run on either one of them.

[modnrod]

The head and chamber may have been made by VW to suit both ethanol and petrol. It's not unheard of for a manufacturer to save costs where they can.
I can run 87 octane in a stock 1600, but I can also throw in VP100+ if I so wish, it will still run fine. A hemi chamber designed to run on petrol with 8:1 will still run happily on ethanol or methanol, not optimised, but it will happily run once you have the correct jetting. This is an early-80s design, not a 20-teens Euro3/4 motor.

As for the fan setup being good or not, ALL fan setups have a capacity limit. If the Gol fan was airflow or capacity limited, then VW Brazil would be HP limited in the car to make it last acceptably. An acceptable mileage is one customers would expect. For all I know cars in Brazil with 60000km could be completely trashed from the road conditions and climate, and be 10 years old, and considered acceptable. I know my cars here NEED a new suspension after 40-50K km, because it is complete mush by then.

Back to the head though, I like it. Whether the physics involved says it should work better or worse than a more usual bathtub chamber is irrelevant if the thing does the job in application. If it doesn't work then adjust some other parameters and it will be fine. If your outcomes are cooler running temps on the street and good street-revs torque, it has been my experience that open chamber heads are great, while closed chambers seem to work better for high revs and high DCRs.

If VW Brazil developed a head that optimises street cooling capacity over a wide range of fuels, on an engine that is really only expected to rev to 4000 stock by its customers, why wouldn't they make the head run even cooler again, and have even more throttle response off idle by using a well accepted single port design? Canted valves would just make the open chamber swirl more, being yet more "street efficient again.

[Udo]

Found this on facebook. that fan design looks perfect

Udo