16 Valve Heads

Wally · Post by **Wally** » Thu Apr 22, 2004 1:09 am

theo_m24 wrote:I wondering how much more possible HP a 16 Valve head would make???

I looked up your original question in one of the publications of Ludwig Apfelbeck:

- A two-valve OverHeadCammed head on a 1600cc type 1 engine would be able to make 160 hp (=100 hp/liter). He made prototypes of such a head and there is one picture of it in his book. That picture is also s/where on the Samba.com (scanned from the book).

- A three-valve OHC head on the 2 liter type 4 engine would be able to make 230 hp (=115 hp/liter).

These figures are probably on the conservative side and are to be seen in an application for track/endurance racing (Formel (super) V), so durability is essential.

A 4-valve (OHC) head would need watercooling...IMHO, at least for a street application.

greetings,
Walter

cj011 · Post by **cj011** » Sat Apr 24, 2004 9:01 pm

what sohc heads were adapted to aircooled motors?

Brian Murray · Post by **Brian Murray** » Sat Apr 24, 2004 11:01 pm

cj011 wrote:what sohc heads were adapted to aircooled motors?

I'll be damned If I know.

Stroker 40 horse · Post by **Stroker 40 horse** » Sat Apr 24, 2004 11:30 pm

Bet I could put AZ600 heads on a 40 HP...

Lots of aircooled motorcycles have S/DOHC heads. They are also highly tuned and have no forced air cooling.

Wally · Post by **Wally** » Sun Apr 25, 2004 8:35 am

cj011 wrote:what sohc heads were adapted to aircooled motors?

As mentioned above: Ludwig Apfelbeck made SOHC heads for both type 1 and type 4 engines. He described both in his book (still available, the book).
The type 1 heads were 2 valve per cylinder. The type 4 heads were 3 valve per cylinder. Do a search on the type4rum for apfelbeck. I made two posts there I believe (with some pictures).
There have been no records that we know of of an existing working engine with those heads, but we are trying now.
I hope you are as exited about it as I am.

Best regards,
Walter

Brian Murray · Post by **Brian Murray** » Sun Apr 25, 2004 8:47 am

I've got a DOHC set of heads in the works... but then thats gonna be a LONG way down the road, especially considering that in order to make them I'll need a TIG welder and some training as well as a few junk heads and a couple of cams.

Pablo · Post by **Pablo** » Sun Apr 25, 2004 9:27 am

Stroker 40 horse wrote: Lots of aircooled motorcycles have S/DOHC heads. They are also highly tuned and have no forced air cooling.

The first motorcyle DOHC heads-to-Type I adaptation that I saw was in 1985. They were quite successful.

roo · Post by **roo** » Sun Apr 25, 2004 2:27 pm

i was referring to the Apfelbeck heads as well as the 911 head swap. what i had in mind was adapting a variable cam timing setup similar to the new sohc 3 valve ford setup. it uses and actuator to vary the the oil pressure to the cam timing acuator wich varies the cam timing. i'm not familiar with the honda system does it use a mechanical actuator like a motorcycle powervalve or does it do it electrically? the problem with the ford setup is the need to run a pressured oil line to the actuator. i'm sure there are simpler systems that someone can chime in on. another question for you guys is if you could vary the cam timing at will would it be varied linearly with rpm of would it be nonlinear? just throwing this out not actually going to attempt this by the way. a completely self contained electrical system on a cam gear that was tunable would be ideal.

cj011 · Post by **cj011** » Sun Apr 25, 2004 7:45 pm

was Ludwig using motorcycle heads? can you share some info in regards to the motorcycled headed t1's? this post may end up me getting back into vw's.

Wally · Post by **Wally** » Sun Apr 25, 2004 11:01 pm

cj011 wrote:was Ludwig using motorcycle heads?

Nope, he made his own heads which were specially designed for the type 1 and type 4 (two different set of heads, but both SOHC).
The ones for the type 1 were never seen again, but as I mentioned before, the moldes of the heads for the type 4 were preseved and aquired by a friend of mine, Roberto (also a STF member here). It may take a year or so to have an engine running with them.
But imagine: no clearence problems with large strokes in a type 4 because of the OHC!!
For example: Two 38mm intake valves, one 46mm exhaust valve, hemi-style combustion chambers, two spark plugs per cyliner, flow like hell on a 103x86 (2866cc) type 4.
It would give drag racing a type 4 a new meaning....

Regards,
Walter

cj011 · Post by **cj011** » Sun Apr 25, 2004 11:35 pm

dear god, i could only imagine that size motor hooked up to a turbo

Cam · Post by **Cam** » Mon Apr 26, 2004 10:34 pm

A common misconception surrounds the original Porsche flat 4 quad cam motor. These were infact 8 valve motors with two spark plugs. one valve (per chamber) per cam.

I would love to see an aircooled VW motor running bike heads. I was talking with my Dad about this conversion. He is a bike rider and doesn't think there are any bike heads that will allow large enough bores to be able to be adapted to VW motors.

MASSIVE TYPE IV · Post by **MASSIVE TYPE IV** » Tue Apr 27, 2004 5:06 am

Cam is correct.... AND until you have worked on one, you just don't understand the meaning of difficult!

Cam · Post by **Cam** » Tue Apr 27, 2004 5:08 am

Yeah, I've messed with one. Cyanide was looking attractive after about 6 hrs.

Long time since I've been here, you got yourself a 912 Jake?

Nice move dude.

Searoy · Post by **Searoy** » Tue Apr 27, 2004 7:24 am

The Harley Davidson EVO heads are large enough. Finding a set of 4 valve heads for those is hard though, as is finding an overhead cam head is equally hard.

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16 Valve Heads

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