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Technical Valve spring measuring?? - Flathead 8BA

Discussion in 'The Hokey Ass Message Board' started by cederholm, Aug 6, 2018.

  1. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    I'm starting to assemble my 1952 8BA. This is my first flathead rebuild and since the valves are in the block, really my first time installing valves. In the past I've had the machine shop do the OHV on my rebuilds.

    I do not have a valve spring scale (gauge) and they are very expensive for a home shop. What are my options for measuring the springs to see if I need shims? The springs and valves are new.

    Sorry if this is an amateur questions.

    Thanks!,
    Carl
     
  2. I'll be watching for info also.
     
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  3. PINEAPPLE
    Joined: Aug 26, 2012
    Posts: 237

    PINEAPPLE
    Member

    stock rebuild? or performance cam etc? I have used lincoln zephyr springs from reds headers shimmed to 2.0" in a couple engines with reground cams. use one piece keepers. 50 lbs spring pressure is good for flathead. You can get creative with weights and calipers I suppose. Hope this helps a little.
    Matt
     
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  4. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Isky cam, not stock.
     
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  5. tgabbe1934
    Joined: May 20, 2009
    Posts: 64

    tgabbe1934
    Member
    from smithtown

    You could cut a metal rod to the length of the desired assembly height for the spring and use it as a guage. put in the valve, install the lock and retainer and use the guage to see how much clearance you have. pretty much what the machine shops do.
     
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  6. PINEAPPLE
    Joined: Aug 26, 2012
    Posts: 237

    PINEAPPLE
    Member

    I think the zephyr springs shimmed to 2.0 oah will be fine. reds also has the one piece keepers and locks you need.
     
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  7. PINEAPPLE
    Joined: Aug 26, 2012
    Posts: 237

    PINEAPPLE
    Member

    I should clarify a bit. 50 lbs spring pressure was the info I received via. plenty of research when I built my first flathead. I borrowed a spring tester from an engine builder friend. I had heard the zephyr springs shimmed to 2.0 was around 50lbs. I wanted to see for myself, and it was correct information. Engine ran great. I set my clearance to .016-.017 on both intake and exhaust. This was my experience, and is my advice. However I would wait to see what others have to say. I am no expert.
     
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  8. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Aren't I trying to determine and set the springs preload, not clearance?

     
  9. PINEAPPLE
    Joined: Aug 26, 2012
    Posts: 237

    PINEAPPLE
    Member

    yes, the preload should be around 50lbs. installed with the keepers on the guide/valve assembly. the clearance is lifter to stem clearance which would be adjusted if you have adjustable lifters or if you are using solid lifters then the stem gets ground on a valve grinder. Sorry for the confusion, I just added that bit of info.
     
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  10. Truck64
    Joined: Oct 18, 2015
    Posts: 4,056

    Truck64
    Member
    from Ioway

    You're not the first to notice they are spendy. A bathroom scale and a drill press has been used many a time to check for correct spring pressure at the "installed height" specification of the valve spring. This is what the shims are for of course, now you could simply shim each as necessary to get the correct installed height and trust that the springs are within tolerance. You will need the shims, the question is how precise do you want to get. Each cylinder having consistent valve spring pressure is important, the engine will rev no higher than the weakest spring basically.

    So it becomes really important in high performance applications. They'll check each valve and spring combination, and set all of them exactly the same.
     
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  11. akoutlaw
    Joined: May 13, 2010
    Posts: 817

    akoutlaw
    Member

    I believe it was Old Ron over on the Ford Barn had a good thread on doing this years ago. You put a bathroom scale on your drill press table & use the drill press to push down on the valve spring until you reach your desired height measured with a ruler or tape measure, then see what the scale reads for #. You can add shims & re check until you get your desired numbers. Worked for me. Bill Truck64 Sorry, typing at the same time.
     
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  12. sliceddeuce
    Joined: Aug 15, 2017
    Posts: 2,982

    sliceddeuce
    Member

    And if the valves and seats are not ground to the same installed height...…………….
     
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  13. Jimmy2car
    Joined: Nov 26, 2003
    Posts: 1,707

    Jimmy2car
    Member
    from No. Cal

    Truck 64 has it right. Easy
     
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  14. Truck64
    Joined: Oct 18, 2015
    Posts: 4,056

    Truck64
    Member
    from Ioway

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  15. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Really helpful guys. Thanks!
     
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  16. CNC-Dude
    Joined: Nov 23, 2007
    Posts: 854

    CNC-Dude
    Member

    You'll also need a height Mic to measure what the actual installed height is in the block for each spring. Some things just aren't DIY friendly if you don't have the tools of the trade.
     
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  17. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Those I have. Thx

     
  18. tgabbe1934
    Joined: May 20, 2009
    Posts: 64

    tgabbe1934
    Member
    from smithtown

    Yes exactly, you are mearing the space between the retainer and the spring seat. isky should give you the specs for the assembled spring height, set your gauge to that distance and you will see how much shimming you will need shims.
     
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  19. jimmy six
    Joined: Mar 21, 2006
    Posts: 6,358

    jimmy six
    Member

    Bought this tester from Jegs yrs ago and made the length testers from PVC pipe. Not much into it and used for many engines. I use my bench vice for the test. Can use the drill press too. image.jpeg
     
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  20. Truck64
    Joined: Oct 18, 2015
    Posts: 4,056

    Truck64
    Member
    from Ioway

    I'm no expert but found the whole routine really interesting. Until I did a valve job had no idea that .010" one way or the other made any difference. Valve springs are one of the most stressed parts of the engine, and neglected. Crane or somebody had an interesting article and claimed that the domestic OEM at one time purposefully installed soft valve springs, to cut down on warranty service from "overenthusiastic" drivers. The valve springs acted like natural rev limiters, preventing much of anything happening above 4000 or so.

    The general idea is measure, and record, each individual valve seat & retainer height on every cylinder. Determine the valve with the shortest seat to retainer distance. This is your standard for the rest of the valve springs, shim as necessary to achieve this same installed height. Now they are all exactly the same.

    Even if you're not tuning for performance or using stock springs, the reward is quick cold weather starts, better compression and smooth idle etc. You'll notice the difference. If they made a valve spring micrometer that actually fit on stock Y block heads I'd have bought one. There's other ways to get there, but none quite so slick and fast.
     
    Last edited: Aug 7, 2018
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  21. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Ah, I've seen those but they didn't make sense at the time. It's much clearer now after this tread - thanks for the pic.

     
  22. sunbeam
    Joined: Oct 22, 2010
    Posts: 4,849

    sunbeam
    Member

    One more thing you need an old valve to chuck up in the drill when shimming springs check for coil bind good rule of thumb .035 between at least 3 coils. at max lift.
     
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  23. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Another silly question...
    Are all spring shims created equal? IE can I buy a shim pack off ebay or are they engine specific?

    Thanks!
     
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  24. Truck64
    Joined: Oct 18, 2015
    Posts: 4,056

    Truck64
    Member
    from Ioway

    I think for "standard" run of the mill springs like SBC or SBF they gotta be pretty generic. They are hardened, come in three different thicknesses. Flatheads, not sure.
     
  25. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Thanks, and diameter? This is for the flathead?

     
  26. Truck64
    Joined: Oct 18, 2015
    Posts: 4,056

    Truck64
    Member
    from Ioway

    Yeah, sorry I had to think about that I don't speak Flathead. Spring diameter is different? If you dig around on the parts sites they should have some part #s listed. think I paid about as much for the shim set as for the springs. They don't give them away, and you won't need all that many.

    edit: $29.47 for shim kit, $36 for spring set
     
  27. Truck64
    Joined: Oct 18, 2015
    Posts: 4,056

    Truck64
    Member
    from Ioway

    If you search online, it looks to me like they are generally available in a .060" set of 16 and .030", Flathead spring pressure is pretty low, maybe it's not necessary to get too precise. They aren't offered in the sets of three different thicknesses like SBF and SBC. Were it me, I'd want to talk to a flathead guy and see what the deal is, so I'll shutup ;)
     
  28. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Thanks Truck64, appreciate the help!
    ~ Carl

     
  29. Joe H
    Joined: Feb 10, 2008
    Posts: 901

    Joe H
    Member

    Spring shims come in .015" hardened, .030" standard, and .060" standard. There are lots of diameters, https://goodson.com/collections/valve-spring-booster-shims Goodson also has the tools to check them. With lower rpm engines, it's not necessary to dead on accurate, close is usually good enough.

    When using the drill press and scale, use a heavy steel plate on the scale to spread the load across the whole scale, one spring in the center could bend the scale and give false readings. Use a wood block or gauge blocks for set height standard to compress to.
     
  30. cederholm
    Joined: May 6, 2006
    Posts: 1,621

    cederholm
    Member

    Thank you Joe! Very helpful.

    ~ Carl

     

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