Billet heads on Samba

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Adam Wright
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Re: Billet heads on Samba

#16 Post by Adam Wright »

C J Murray wrote:
Adam Wright wrote:so you could really be the Head King!
I don't think I want to be known as the Head King.
Yeah, that might not go your way...
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Bill Sargent
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Re: Billet heads on Samba

#17 Post by Bill Sargent »

The billet heads Joris saw at the Strahle swap meet last weekend are made by a gentleman named Pit Schweiger from Switzerland. He is in the aircraft industry and has a second business making performance parts for 356. I met him at Rennsport Reunion and then spent some time with him at Jacques place the week after. Great guy. His contact email is jpsaircooled@gmail.com.

He has a stock version and a performance version of the heads. He has a Facebook site where you can see photos of the heads and rockers. Search on "Pit JPS Aircooled". I do not think he has finalized pricing yet.

The gentleman selling billet heads on the Samba is someone else.
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Re: Billet heads on Samba

#18 Post by Dan Epperly »

C J Murray wrote:
Adam Wright wrote:so you could really be the Head King!
I don't think I want to be known as the Head King.
:D

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Ron LaDow
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Re: Billet heads on Samba

#19 Post by Ron LaDow »

Several (more?) years back, scheming, sketching, doing clay mock-ups, etc, and pestering my CNC guys, it became obvious that the tooling required to produce the modified engine tin (and other peripherals) was the major cost involved in any design of a really modern chamber for 616 engines in CNC-machined heads.
At best, it looked like, with some real careful dimensioning of the rocker gear and valve location, a wedge chamber might be possible, keeping the carb manifolds, stock tin, muffler, and heating system, but any really modern chamber ran afoul of tin dimensions, exhaust port cooling, not to mention requiring a total redesign of the muffler/heating system.
At the time, a CNC wedge-chamber-head penciled out at a price which I never considered salable, to which you had to add flat-top pistons, valves-springs-keeper-guides, finding (you'd hope) some rocker gear which worked, providing a rocker box. Maybe more, if that wasn't enough, like development costs...
And then (from memory) the compromise between the plug location (that damn tin) and the C/R really didn't work (theoretically); the plug location looked like it needed too much advance for a C/R which could only be lowered by killing the quench clearance. Given the projected costs, I gave it up on it before finding a solution that that issue among others.
I have no problem with CNC'd 'stock' heads; you can probably get a reliable chamber volume. And if they are willing to move the plug location a bit, you might get a decent quench area.
But I doubt you can get any really good chamber into the engines cheaper than buying one of Dean's 4-cylinder 911 clones.
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Re: Billet heads on Samba

#20 Post by C J Murray »

Ron, starting with A or B heads, if the ports and squish area were made more like C/SC heads by CNC machining do you think that would be "affordable"? This assumes that the basic casting of A/B heads has dimention to do that.
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Vic Skirmants
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Re: Billet heads on Samba

#21 Post by Vic Skirmants »

I have B heads cut all the time for the 30 degree angle. Problem arises from the fact that the 31mm exhaust valves are WAY closer to the piston.
New seats for 34mm valves, installed at the correct depth, should take care of that. And then you have to open the exhaust port up.
A heads have very shallow sides for the valve spring pocket; you'd end up with shims overflowing the pocket. Not recommended.
Recently saw two C heads advertised as just needing some machining. Photos showed the high-lighted cracks at THREE spark plug holes.
I think welding might also be required.

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Jacques Lefriant
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Re: Billet heads on Samba

#22 Post by Jacques Lefriant »

Hi
if new cast heads were to be considered the sparkplug could be changed to 3/4" rather than 1/2" this should help with cracking in that area. I don't know if the volume is there to do a run of premiant mold fully machined replacement heads so I think the billet heads should be embraced and the price should come down to an affordable level if there are enough performance oriented engine builders out there. The budget minded ones out there can keep dreaming.
j
 

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Re: Billet heads on Samba

#23 Post by C J Murray »

Vic, yes, my machinist made a 30* tool to cut my 22* heads and that is easy but I wonder if a head with smaller ports could be ported to be better than even a modified SC head. I don't know if the smaller port heads have enough meat to move the ports to where they would be better. Often heads "wake up" by putting epoxy into the port in the right places. I have been told that the best way to get the best out of a port is to saw the head apart at the port and see what the options are. You can either do that just for research or you can make the desired modifications and weld the head back together. Honda and BMW both did that with their Superbike Championship winning bikes. They might have spent more on those projects than we have available. :wink:
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Re: Billet heads on Samba

#24 Post by Larry Brooks »

C J Murray wrote:Vic, yes, my machinist made a 30* tool to cut my 22* heads and that is easy but I wonder if a head with smaller ports could be ported to be better than even a modified SC head. I don't know if the smaller port heads have enough meat to move the ports to where they would be better. Often heads "wake up" by putting epoxy into the port in the right places. I have been told that the best way to get the best out of a port is to saw the head apart at the port and see what the options are. You can either do that just for research or you can make the desired modifications and weld the head back together. Honda and BMW both did that with their Superbike Championship winning bikes. They might have spent more on those projects than we have available. :wink:

I wonder how long it going to take before I stop chuckling whenever I see one of your posts after Adams suggestion that you could become the "Head King"?

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Re: Billet heads on Samba

#25 Post by Ron LaDow »

C J Murray wrote:Vic, yes, my machinist made a 30* tool to cut my 22* heads and that is easy but I wonder if a head with smaller ports could be ported to be better than even a modified SC head. I don't know if the smaller port heads have enough meat to move the ports to where they would be better. Often heads "wake up" by putting epoxy into the port in the right places. I have been told that the best way to get the best out of a port is to saw the head apart at the port and see what the options are. You can either do that just for research or you can make the desired modifications and weld the head back together. Honda and BMW both did that with their Superbike Championship winning bikes. They might have spent more on those projects than we have available. :wink:
OK, but other than trial and error (ignoring obvious problems), how do you gain any idea which port form is better?
The Pre Mat 36mm Zenith manifolds worked well by keeping the head surface port at whatever diameter that is, which meant shrinking it from the 36mm at the carb, the theory being the charge velocity was kept up by decreasing the area. But I have no idea whether that was optimal or just a part which was better than a file-job on the stock manifolds.
BTW, for those with some machining capabilities, it is a Saturday project to make a 30* chamber cutter:
30 degree cutter 001 cropped.JPG
It's a HSS lathe cutting tool, captured by set screws in a fab'd holder and sent to the sharpening guy for an edge. Never used it to alter 22* heads, but used it always to match the conical cut to the bore size.
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Martin Benade
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Re: Billet heads on Samba

#26 Post by Martin Benade »

Is the shaft nice and big so it doesn't want to chatter too badly?
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Re: Billet heads on Samba

#27 Post by Ron LaDow »

Martin Benade wrote:Is the shaft nice and big so it doesn't want to chatter too badly?
I've got a Bridgeport knock-off and the biggest collet is a 3/4", so that's the shaft size. And it is run snug up to the head, raising the table against a locked quill.
As a single-blade cutter, it gets pretty slow running speeds and a lot of kerosene (WD40); it is cutting aluminum. You have to keep an eye on it since it doesn't exhaust chips well, but it tells you when it needs to be cleaned it out. As such, 'chattering' only happens if you let it load up.
Since measuring the edge of that cone is so difficult, I end up making the final cuts by shutting off the machine, reaching up and 'driving' the pulley by hand; sort of treating it as a hand reamer. Hard to get a better finish than what that gives you.
For a second iteration, I'd add a second edge and angle them WRT the C/L, but this one makes for a satisfying Saturday afternoon, getting all four chambers to the correct diameter.
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Re: Billet heads on Samba

#28 Post by John Brooks »

It also talked to Pit at Rennsoprt, for an hour or so and went over is CAD/CAM drawings and 3D models of the new heads. I was impressed over all. Made from 7075T6 billet, larger valves with wider intake angle. Much stronger but lighter rockers. Valve train should be good for at least another 1K RPM.

He has CFD for the air flow, quench and pretty much all the aspects of the fluid dynamics on the design. Pit has works at Pilatus for 20 years. Very skilled and well trained for what he has done here. The only thing is the cost. It takes about 20 hours to carve out the head. Machine time is expensive. But it's a solid design.

I will probably buy a set this spring and see how they work.
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Jacques Lefriant
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Re: Billet heads on Samba

#29 Post by Jacques Lefriant »

Hi Pit is planning on bringing them to the upcoming lit meet.
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Re: Billet heads on Samba

#30 Post by C J Murray »

Jacques, Pauter has VW racing heads that I thought were billet but are actually castings that they have made and then machine. Could that be done for 356 heads and make a less expensive quality head vs the billet heads?
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