1957 Euro Semaphore/Ragtop Vintage Speed Project

[Rwoodshvac]

I guess in every engine build you need to decide on the compression ratio. This Engine Calculator has been very handy.

http://www.cbperformance.com/enginecalc.html
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57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[Rwoodshvac]

Here is the closest tolerance in my engine .088. This with 74mm stroke so it looks possible to increase stroke another 2mm or so. Not sure it would be worth the money>

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57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[Rwoodshvac]

One of my goals i wanted to accomplish on this engine build is not having to use any shimms between the cylinders and the case to get the compression ratio i want. I have decided on a CR of 9 to 1

With the use of some Porsche 356 1500 pistons i was able to mock up the engine with my cylinders . The Porsche pistons had a deck height of .004

A VW stock piston in comparison

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57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[Rwoodshvac]

So i sent the piston off to have an copy made less .036 in compression height and no valve cut out.
My new pistons should give me a deck height of .040

With a deck height of .040 and 41 CC's in my heads the compression ratio should be on the money with out using cylinder spacers.

My stock Okrasa heads are 46 CC's so they will not require much boring at all maybe .030 or .040 i will let my head guy do the math on that.

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57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[gimmesomeshelter]

Hello-

[grueni]

in fact of the chamber of an okrasa head you could told your piston guy just to cut the enge so that you can use the little dome . maybe you will need no or just less cutting on the heads. with a dome 1mm and 60mm diameter what will fit you are at 8,7:1 with a dome that fit in the camber you are at 9:1

and you messured not deck height...you messured dome to cylinder edge that is easy to see on the pic "piston into cylinder"

if you let made some pistons do some really modern ones. small modern rings and much less in weight + a less weight pin...short pin i would say all together pistons+rings+pin arround 350g. that is the best what you can do for your crank, mearings and also the case.


buuut. with such an engine it would be the same if you just cutting the top end of your existing pistons. your engine will not need the other expensive stuff. just a beer for the local guy on the mill or on the lathe.
you will not hurt you pistons by doing cut a 1mm ring on them.

my 2 cent
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1960 1584cc turbocharged, 35,5/32 (11,117s 1/4mile )

[Rwoodshvac]

Grueni

You are the second person to tell me that i could shave the top of the Porsche pistons down. I have never done that and didnt quite believe that they would hold up. Have you done that? If so i will do just that. I have a lathe and it would be easy to cut them down 1mm or .036.
Just measure the cc's in the valve cut out and cut heads accordingly.

Thanks for your input

PS. I just mailed a piston off today to have it measured and the new ones priced. so i can use the ones i have if it is safe to shave them.
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57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[Rwoodshvac]

Paul
My son used to be involed in motorcycle racing . And i have a inside conection to Ross Racing Pistons However if it pans out to shave the Porsche pistons down i may just use what i have.
_________________
57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[Rwoodshvac]

Grunei

I mesured from the top of the dome to the top of the cylinder. I had the studs in the case with a deck height tool torqued to specs when i took the measurements and from the top of the dome to the top of the cylinder it is .004 The picture was taken before i did the measuring without the tools in place
_________________
57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[grueni]

[Rwoodshvac]

Ok very nice. You have opened my thinking. I will go with what i have. I weighed the pistons and they are 314g without pins. I think with Titanium pins and machining them to fit my heads and cc ratio i could have a total weight of 355 to 360 g per piston.

And like you said with less money spent
And less machining on the heads
Thanks for your input
_________________
57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[grueni]

the samba is to help.
but forgett about titan pin. titan is in that case not for longlife.
but you can machine the original pin with cones on the end.
in your engine it is not needed to have superlight pistons, with cour cam and co it will not spin that high.

keep on posting.

wishes from germany
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1960 1584cc turbocharged, 35,5/32 (11,117s 1/4mile )

[oval56]

flattop porsche pistons, no problem, to machine em down wit a lathe..

did it on mine 0,6mm had no picture availible at the moment, webserver crashed down... tomorow i think i'm able to find that picture and post it up
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www.oval56.com

1956 Oval, 2364ccm typ4
1957 Oval Ragtop 1584ccm singel port modified
1950 Hebmüller, 1584ccm okrasa modified

DBK Germany!!!!!!!!!!
www.dbkvw.com

[oval56]

_________________
www.oval56.com

1956 Oval, 2364ccm typ4
1957 Oval Ragtop 1584ccm singel port modified
1950 Hebmüller, 1584ccm okrasa modified

DBK Germany!!!!!!!!!!
www.dbkvw.com

[Rwoodshvac]

Oval 56
Wow that is a very nice job. How long have you been running those pistons? What kind of HP?
I will do the same to mine.

Thanks for sharing
Rick
_________________
57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[Rwoodshvac]

After reading a few posts on how to CC heads I built myself a Head CCing kit. It takes only four items to get good results.

Plexiglas disc with hole to insert fluid
Syringe in ml a 50 to 60 ml works great for VW heads
Sparkplug that you are going to run in the head
White grease

To make the Plexiglas disk use one of your cylinders for a sizing tool. After marking the Plexiglas with a sharpie I used a band saw to cut it out.
For best results the placement of the fill hole should be at the extreme edge See photo. I beveled the hole but it is not necessary
Put a very thin layer of white grease on the ledge in the head where the disc will rest while measuring this will make a seal
Do two or three measurements for accuracy.
Any fluid will work I like antifreeze

I found thru trial and error to tilt the head at a 45 degree angle with the fill hole at the top gave the most consistent results.

_________________
57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[oval56]

[Rwoodshvac]

88 HP I bet that is a blast to drive. Are those 82.5s Have you had any sealing issues cylinder to case?

Thanks again
_________________
57 Ragtop Semaphore Sedan
48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
Porsche 356 B Rods
Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
Speedwell Ratio Rockers 1.25
Dual Valve Springs w/Lash Caps
Blackline Racing Lifter Inserts, Manton Push Rods
34 Pbic Carbs rebushed by Mr Okrasa
Custom Okrasa Intakes enlarged to 34mm
Gene Burg Sump
Fram bypass Filter with Okrasa Oil Cooler

[oval56]

[oval56]