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Beehive valve springs
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gimmesomeshelter
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PostPosted: Sun Dec 09, 2012 6:30 pm    Post subject: Beehive valve springs Reply with quote

Hello-

I would like to install beehive valve springs on my Okrasa repro heads, but so far, I haven't found anything that fits. The stock installed valve height is only 28mm (1.1 inches), and most springs have installed heights of 1.5 inches and larger. So far, the only thing I've found are Yamaha motorcycle springs with an installed height of 1.25, and a max lift of .4 (not so good for my 1.4:1 ratio rockers).http://www.racingsprings.com/Yamaha/sku/145

I suspect I have the following options:

Order custom made springs.

Gain more height by boring into the head.

Gain more height by installing valves (custom?) that have their retainers very close to the tips (btw, stock valves have a ~ 8mm tip. Some valve tips are as small as 2mm).

Comments anyone?

Cheers,

Paul
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Last edited by gimmesomeshelter on Mon Dec 10, 2012 3:07 pm; edited 1 time in total
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Rwoodshvac
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PostPosted: Sun Dec 09, 2012 7:03 pm    Post subject: Reply with quote

Paul

Those springs look nice. You have another option since you will most likely need custom retainers. You. Could have them cupped so that your install height matches the install height of the springs You will still have plenty of valve spring stem with lash caps to get good geometry
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48 Aluminum Case drilled tapped, Full Flow Filter
Porsche 356 B Crankshaft 74mm
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Shasta Cylinders with JE Pistons 80mm
WW Okrasa Heads worked by Ron Chuck
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34 Pbic Carbs rebushed by Mr Okrasa
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Last edited by Rwoodshvac on Sun Dec 09, 2012 7:05 pm; edited 1 time in total
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modok
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PostPosted: Sun Dec 09, 2012 7:03 pm    Post subject: Reply with quote

1.1 inches? Sorry but I do not believe you. Measure again.
Some snap gauges will not fit, so try this; grind a piece of welding rod/coat hanger to the size that bridges from retainer to seat, then measure that.
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Beetspeed
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PostPosted: Wed Dec 12, 2012 1:36 am    Post subject: Reply with quote

I just measured my stock 36hp heads roughly and they came out to 33,8mm which is about 1.33".
Nothing suggests WW Okrasa heads having a different installed height as stock.

Then, with custom valves with higher placed retainers, I think you can win 4-5mm at the valve head, making the installed height approaching stock type 1.

IF you're considering beehives, your getting serious about a good valvetrain and if so, replcing that stock ancient valve locating method is the first thing to get rid of.
Getting custom valves also opens the road to much better valves, so you can use even lighter parts (valve, retainer etc).

I don;t think you can or should do this half-way. Either use the stock WW parts or make it all custom. 'Custom' is not neccesarily a high $$ one-off set of parts, but can can also mean using other make stock parts and/or modifying those Twisted Evil

I think you're on the right track Paul Very Happy

Regards,
Walter
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modok
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PostPosted: Wed Dec 12, 2012 10:12 pm    Post subject: Reply with quote

Perhaps i was too sharp in that answer.

Just in general a valve spring for this kind of engine should be expected to have approx .150 wire, and 5-6 coils. If we do the math
With some margin away from bind the full open height should be no less than .900"

With modern tech we can bend these rules and make shorter more powerful springs, but okrassa did not have such stuff. Surely there is something wrong, either with your measurement, or with the reproduction heads!

I'd be looking to the ford "modular" beehive springs. They are both common and very good, and available from several manufacturers and a few levels of strength.
To mount the top of the spring above the top edge of the keepers is possible, but only if the top diameter of the spring is large enough to allow enough section for the retainer to have enough strength. If the top diameter is too small, you will have to use different valves, as said, to move the keepers up.
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gimmesomeshelter
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PostPosted: Wed Dec 12, 2012 10:52 pm    Post subject: Reply with quote

Hello-

BTW, the only information I have about the valve springs comes from the '52 - '57 workshop manual. It indicates that the valve spring free length is 43 mm (1.69") and the loaded length is 28mm (1.10). My heads are bare (no springs, seats, etc.) so I can't really measure anything. They're going to the head porter tomorrow, and I ask him about this when I drop them off.

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Cheers,

Paul
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modok
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PostPosted: Thu Dec 13, 2012 12:03 am    Post subject: Reply with quote

ah, ok
The manuals only say with certainty that 28mm is a "checking height" for pressure.

It may also be the open length, I always thought it was, but I have no proof Smile
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