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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7179 Location: Videbaek Denmark
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Posted: Sun Jul 25, 2021 2:12 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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I do not want to reduce the stem strength that much. It is after all an older construction and the flow improvement is almost non existant. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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earthquake Samba Member
Joined: January 10, 2008 Posts: 3984 Location: SANDY VALLEY, NEVADA
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Posted: Sun Jul 25, 2021 2:51 pm Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Here's a old post I made 11 years ago [damm where does time go] about using Honda Goldwing [1975-79] valves and springs but I never went anywhere with it.
https://www.thesamba.com/vw/forum/viewtopic.php?t=437391&highlight=goldwing
Might give you another option?
eQ _________________ 74 CLASS 11 LOOK-A-LIKE
69 DUNE BUGGY
79 INTERNATIONAL SCOUT II
05 SCION XB SERIES RELEASE 2[#437]
95 Chevy C3500 dually
98 Ford E150
Link to Kelly J. Nolte 3/20/53 - 11/6/08
https://time-zonelabs.blogspot.com/p/about-kelly.html
DEATH TO CHINGERS!
[From a military recruitment poster in the novel "The Stainless Steel Rat" By Harry Harrison] |
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TomSimon Samba Member
Joined: January 13, 2004 Posts: 749
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Posted: Mon Jul 26, 2021 9:41 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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For pistons, take a look at 1000cc iron head Sportster, they have an 81mm diameter (also available in .06" oversize, +1.5mm) a pop up dome close to the right shape to fit in the Okrasa head combustion chamber, and 20.1mm wrist pin.
If JE has a forge mold, you can work with their custom side of the house, and perhaps order the domes unfinished, maybe undersize pin bores as well.
Ball mill a 'kernel pocket' for the spark plug tip to reside?
Just tossing out ideas _________________ 2-time NASA Pro Racing Champion, Bonneville 130 Club and 150 Club Memeber, BRS Pro Gas racer |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7179 Location: Videbaek Denmark
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Posted: Mon Jul 26, 2021 10:29 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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TomSimon wrote: |
For pistons, take a look at 1000cc iron head Sportster, they have an 81mm diameter (also available in .06" oversize, +1.5mm) a pop up dome close to the right shape to fit in the Okrasa head combustion chamber, and 20.1mm wrist pin.
If JE has a forge mold, you can work with their custom side of the house, and perhaps order the domes unfinished, maybe undersize pin bores as well.
Ball mill a 'kernel pocket' for the spark plug tip to reside?
Just tossing out ideas |
I will take a look at those pistons. I need 83 mm bore though. But the pin height is great, maybe even a tad low. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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W1K1 Samba Member
Joined: March 04, 2004 Posts: 4894 Location: Southern AB
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7179 Location: Videbaek Denmark
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Posted: Mon Jul 26, 2021 2:19 pm Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Good idea, but not enough dome for what I´m after when the time comes. The dome on those are about half of what I need.
Also, the domed 83 mm (1500S) pistons are hard to come by. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7179 Location: Videbaek Denmark
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Posted: Thu Aug 19, 2021 9:09 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Soo, Rome wasnt built in a day.
One step further.
New alu bronze seats installed for 37 x 32 mm valves. Chambers machined for 83 mm bore. This is max as you can see we juuust broke though here and there. Nothing serius, but this is it.
Next is getting the ports massaged so we can see if our simulations hold water. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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gimmesomeshelter Samba Member
Joined: May 08, 2004 Posts: 1468 Location: San Carlos, CA
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Posted: Thu Aug 19, 2021 9:30 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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May I ask where you purchased the alu/bronze seats?
I presume the benefit of using this material is head dissipation, yes?
Other than cost, what's what are the downsides of using this alloy?
Cheers,
Paul _________________ "I would rather have questions that can't be answered than answers that can't be questioned."
Richard Feynman |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7179 Location: Videbaek Denmark
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Posted: Thu Aug 19, 2021 10:21 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Not really any downsides that I know of.
We buy a 3 meter rod and cut what we need.
We make the seats ourselves. (Westspeed that is) I´m not that good with a cnc. In fact I am worth very little _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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earthquake Samba Member
Joined: January 10, 2008 Posts: 3984 Location: SANDY VALLEY, NEVADA
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Posted: Thu Aug 19, 2021 12:05 pm Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Can you use a surface gap plug for your spark plug problem?
eQ _________________ 74 CLASS 11 LOOK-A-LIKE
69 DUNE BUGGY
79 INTERNATIONAL SCOUT II
05 SCION XB SERIES RELEASE 2[#437]
95 Chevy C3500 dually
98 Ford E150
Link to Kelly J. Nolte 3/20/53 - 11/6/08
https://time-zonelabs.blogspot.com/p/about-kelly.html
DEATH TO CHINGERS!
[From a military recruitment poster in the novel "The Stainless Steel Rat" By Harry Harrison] |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7179 Location: Videbaek Denmark
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Posted: Thu Aug 19, 2021 2:18 pm Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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To recess the spark plug? I most likely could. But at this stage we are working from the point of view that we will make pistons which protrudes into the chamber, leaving as much as possible of the outer squish and make the center part "356 look alike" This way I can get a little of the benefits of wedge chambers and not suffer so much from the Hemi shape. Sort of like this _/ \_
if you catch my drift.
It will be a while until I get the next step done. I have gotten a new work contract with assisting in setting up a new Mazak cnc for cylinder honing 20 to 250 mm which will restrain me from working so much on engines for a while. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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FritzCP Samba Member
Joined: October 23, 2005 Posts: 463 Location: Wisconsin
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Posted: Fri Aug 20, 2021 12:38 pm Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Would an AC.net Super Squishy Piston top design work well with the okrasa (or stock 36hp) head chamber design? _________________ Fritz Custom Products
Fritz 10 - Tin Screw Torquer
Fritz 124 - Crank Pulley Puller
Fritz 70 - 6306 Bearing Puller
Fritz 44 - Dizzy Puller |
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JeeWee Samba Member
Joined: February 05, 2011 Posts: 120 Location: Garijp, the Netherlands
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Posted: Mon Aug 23, 2021 12:04 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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I love this topic~! Great work and awesome you do share the results! _________________ 1192CC WW okrasa
48,2 DIN PS (58SAE HP)@4430rpm - 83Nm@3610rpm |
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chris fryer Samba Member
Joined: November 12, 2017 Posts: 82 Location: Australia
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5500 Samba Member
Joined: October 16, 2020 Posts: 112 Location: Cape Cod
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Posted: Sat Dec 04, 2021 8:53 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Hello Alstrup. Wondering if you've done any more with these heads? |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7179 Location: Videbaek Denmark
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Posted: Sat Dec 04, 2021 8:57 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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No. I´m swomped with work, so I have very little time to do VW stuff. I expect to make progress during the Christmas hollidays. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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RWK Samba Member
Joined: June 24, 2009 Posts: 1337 Location: S.W. MI
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Posted: Sun Dec 05, 2021 7:16 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Here is some info on the copper (bronze) alloy seats, guides and other components.
I use their material extensively in plastic tooling, this company started out with the alloys for industry and branched out into engine components.
One of the benefits of high copper alloys is that it work hardens, good for seats.
As Alstrup says you can purchase the material and cut your own.
http://www.performancealloys.net/MotorsportApplications.htm _________________ 73 Type 181
63 Type 113
63 Type 261- 428 071
62 Type 241-378 025 178 530 |
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sled Samba Member
Joined: February 16, 2005 Posts: 6171
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Posted: Tue Apr 12, 2022 2:48 pm Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Hi Torben, any updates on this monster?? _________________ drive your split. |
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Alstrup Samba Member
Joined: July 12, 2007 Posts: 7179 Location: Videbaek Denmark
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Posted: Wed Apr 13, 2022 9:44 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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No. I got some issues I needed to adress, so the winter have been very non productive. But I am gearing up to start working on them again. _________________ https://www.thesamba.com/vw/forum/viewtopic.php?t=435993 |
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Matthew Samba Member
Joined: January 29, 2004 Posts: 1760 Location: Eastern Tennessee
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Posted: Fri Apr 22, 2022 6:11 am Post subject: Re: The making of cylinderheads for an Okrasa engine on steroids |
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Alstrup wrote: |
Soo, Rome wasnt built in a day.
One step further.
New alu bronze seats installed for 37 x 32 mm valves. Chambers machined for 83 mm bore. This is max as you can see we juuust broke though here and there. Nothing serius, but this is it.
Next is getting the ports massaged so we can see if our simulations hold water. |
Are you planning to use modified 40hp 83mm cylinders? _________________ 1965 Beetle sedan
Click to view image |
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