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Alstrup Sun Jul 25, 2021 2:12 am

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.

earthquake Sun Jul 25, 2021 2:51 pm

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

TomSimon Mon Jul 26, 2021 9:41 am

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

Alstrup Mon Jul 26, 2021 10:29 am

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.

W1K1 Mon Jul 26, 2021 1:30 pm

what about some type 3 1500s domed pistons?




Alstrup Mon Jul 26, 2021 2:19 pm

Good idea, but not enough dome for what Im 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.

Alstrup Thu Aug 19, 2021 9:09 am

Soo, Rome wasnt built in a day. :roll:
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.

gimmesomeshelter Thu Aug 19, 2021 9:30 am

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

Alstrup Thu Aug 19, 2021 10:21 am

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) Im not that good with a cnc. In fact I am worth very little :roll:

earthquake Thu Aug 19, 2021 12:05 pm

Can you use a surface gap plug for your spark plug problem?

eQ

Alstrup Thu Aug 19, 2021 2:18 pm

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 :shock: which will restrain me from working so much on engines for a while.

FritzCP Fri Aug 20, 2021 12:38 pm

Would an AC.net Super Squishy Piston top design work well with the okrasa (or stock 36hp) head chamber design?

JeeWee Mon Aug 23, 2021 12:04 am

I love this topic~! Great work and awesome you do share the results!

chris fryer Sat Aug 28, 2021 3:50 pm

So impressed with you sharing the infiormation and your knowledge, thumbs up.

5500 Sat Dec 04, 2021 8:53 am

Hello Alstrup. Wondering if you've done any more with these heads?

Alstrup Sat Dec 04, 2021 8:57 am

No. Im swomped with work, so I have very little time to do VW stuff. I expect to make progress during the Christmas hollidays.

RWK Sun Dec 05, 2021 7:16 am

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

sled Tue Apr 12, 2022 2:48 pm

Hi Torben, any updates on this monster??

Alstrup Wed Apr 13, 2022 9:44 am

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.

Matthew Fri Apr 22, 2022 6:11 am

Alstrup wrote: Soo, Rome wasnt built in a day. :roll:
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?



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