Valve Spring Reference

vibrac

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VOC Member
If I said my gold star valve springs that I fitted years ago on the Egli twin were set to 120 lbs would my memory be correct?. I still have my wooden valve spring tester and spring balance I may see what standard springs read..
 

davidd

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VOC Member
If I said my gold star valve springs that I fitted years ago on the Egli twin were set to 120 lbs would my memory be correct?. I still have my wooden valve spring tester and spring balance I may see what standard springs read..

I think so. I shimmed my Gold Star springs for 110 lbs. opening pressure which should be well within that range.

When I selected a beehive spring replacement for the Gold Star springs on the racer I did not choose any of the springs listed by Bruce. I chose one that had 90 lbs. opening pressure. The tough part is selecting all the other pieces to work with the springs: retainer, locks, top valve guide and valve. It is relatively easy for a racer because the stock valve locks and valve would not necessarily be the first choice. If you have to custom make those two items, you might as well go to beehives. The reduction in mass of the beehive system is impressive. Much of the reduction is in the valve itself as I had to reduce the stem diameter to 5/16" to match the available retainer and locks. Also, to adjust the spring pressure properly (and the valve clearance) you have to move the shoulder on the valve higher.

I have been making valves to get a final valve design, but I have not been able to find a local machinist capable of doing the finished valves, which has stalled the project.

The benefit of using the beehives is primarily in the ability to use higher revs without valve float. Seeing that with the Gold Star springs the single can rev to 8500 without float to begin with, this would make running in that area a little more reliable. I thought being able to rev high for a short period would help in competition and at Bonneville. On a twin, unless you have a 9,000 rpm crank there is not much competitive benefit, but reliability may improve a bit at higher revs.

One of the side benefits of beehive spring is that the components are quite high quality and very inexpensive. The springs are about $12 and the titanium retainers are about $15. That helps when you have to pay for a custom valve.

David
 

passenger0_0

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Non-VOC Member
The beehive springs in the Indian LSR bike were set to 75 lb seated pressure and no valve float with 0.500" lift at 6,000 rpm. I am considering using these in my Rapide (if it ever wears out).
 

david bowen

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Valve spring warning there was a batch of valve springs in the system that inside diameter was wrong check that they fit over the lip on the ET40.
 
D

Deleted member 3831

Guest
David,
the Gold Star springs referred to need to be identified by maker and part number before any sensible comment is possible, likewise the beehive springs latterly mentioned. The details released by spring manufacturers permits a reasonable guess as to the possibliity of fitting, but little else.
Spring rates and seated poundages can have little or no relationship to the valve train or the cam profile, and in a high performance application it is essential to know the natural harmonic frequency of the spring (s).], something that is impossible to establish- from the manufacturers data tables.
If the Gold Star springs mentioned are from the same manufacturer who supplied springs to Eddie Dow for his BSA Gold Stars, they were from S and W springs in the USA (Sparks and Witham). Both Art Sparks and Tim Witham are long deceased, but the company continues as RD Springs.
Why would one want to discover the natural harmonic frequancy of the spring(s) ?
Because if this frequency should happen to coincide with that of the engine at a particular engine speed, serious oscillation can occur within the spring coils, resulting in loss of control of the valve train, and even component failure if the situation persists. Now add the natural harmonic frequency of the pushrods into the mix, and the end result could be trouble with a big T !
To avoid such a situation, the general tactic is to select components whose natural harmonic frequencies are outside of the engines normal operating range, but selecting springs from a manufactures list one can only hope that the spring chosen will do the job, and not bring with it any problems of the above mentioned kind.
Phil,
the big single that finished the Classic TT with beehive springs, would you enlighten us a little and reveal what the engine was ?
 

davidd

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VOC Member
the Gold Star springs referred to need to be identified by maker and part number before any sensible comment is possible, likewise the beehive springs latterly mentioned. The details released by spring manufacturers permits a reasonable guess as to the possibliity of fitting, but little else.

I get my springs from RD.

The beehive springs seem to have been used for decades in Vincents, so I have take a leap of faith that they will work in my engines. My time is up on the spintron.

Pac 1223 Spec.JPG


Manufactured by PAC for the Ford 32 valve engine.

DSCN0413.JPG


DSCN0423.JPG


Bruno Leroy ran the IOM with Patrick Godet's new engine. I do know a little about what is inside, but Patrick prefers a non-disclosure agreement with the info he sends, so I will have to defer to Patrick.

Although I am way down the ladder, I am happy to share anything I have tried.

David
 

BigEd

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VOC Member
VOC Forum Moderator
I get my springs from RD. ......................................

Although I am way down the ladder, I am happy to share anything I have tried.

David

Dear David,
Your modesty is admirable.
"Way down the ladder" possibly but I suggest you are several steps higher than many.
Thank you for sharing what you are able.
 
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