1. If you have recently registered with a gmail email address, you must contact me, as gmail will not forward our confirmation email to you. Contact me and jim@trishieldperformance.com to complete your registration.
    Dismiss Notice
  2. In and effort to reduce the spam on the site, several years ago I had went to a program where I manually approve each and every new registration. This approval gives you full access to the site, to pictures, and to post, among other things. To be able to enjoy the full potential of the board for you, you need to be fully registered.. and that's easy.. Just send an email to me at jim@trishieldperformance.com and I will verify your registration. This policy will remain in effect indefinitely, as it has completely eliminated the bad actors from our site, who would spam and hack it, once they gained access. Thanks JW
    Dismiss Notice
  3. The "Group Buy" for the 1967-68 Deluxe Steering wheel recasting is now officially "Open". Now is the time to start sending in the wheels. The latest date that the wheels must be received by Kochs is 31 March 2025 The cost for each wheel is $750. The only "up front cost" is your shipping the wheel. If you send in more than one wheel, each additional wheel will cost $700. Shipping and insurance to Kochs and return shipping will be extra. You will be contacted by Teresa to make payment for the wheel(s) and return shipping and insurance when your wheel(s) is complete. The shipping will be factored on your delivery address and insurance. I will be sending the contact information all of you have sent me to Teresa at Kochs. Send in your wheels, horn pad and hardware and paint color sample if applicable. Please include: First and Last Name Shipping Address Phone number email address V8Buick "Member Name" Wheel Color (SEE THE BOTTOM FOR WHEEL COLOR) Pease read the "shipping to Kochs" below. There are two addresses. One for USPS Mailing One for FedEx and UPS shipping You can use USPS/Mail, UPS or FedEx to send in your core. Use the appropriate address depending on what service you use to ship. If you use USPS/Mail ship to: Koch's P.O. Box 959 Acton, CA 93510 Attn: Teresa If you use UPS or FedEx ship to: Koch's 7650 Soledad Canyon Road Acton CA 93510 Attn: Teresa Kochs Contact: Teresa (661) 268-1341 customerservice@kochs.com Wheel Color If you wheel is Black, you can list that in your information you send in with your wheel. For colored wheels, please contact Teresa about specifics for wheel color if you do not send in a color sample to match. Please contact me if you have any questions. Thank you to everyone for your participation in making this a reality. And "Thank You" Jim Weise, for allowing and facilitating this project! Michael .................... to remove this notice, click the X in the upper RH corner of this message box
    Dismiss Notice

Harmonic balancer roundness tolerance

Discussion in 'Street/strip 400/430/455' started by Electra Sweden, Mar 17, 2023.

  1. Electra Sweden

    Electra Sweden Well-Known Member

    So I had the harmonic balancer off and sand blasted it without enough prior reflection. So sandblasted the outer surface that I now realize should mate with the crankshaft front seal :rolleyes::eek:The whole thing had so much gunk on it everywhere so the last thing it looked like was some sort of sealing surface.

    The plan is to put the balancer in a lathe and polish the seal mating surface. Before final assembly I want to put it onto the crankshaft and check the total runout at the seal surface. What is a reasonable tolerance of the total runout at this seal surface? I see SKF specifies 0.005 mm (0.0002 ") for industrial radial seals (see page 80 below). The chances it will get there or ever was there is quiet slim I think :) Many engine builders seem to accept 0.05 mm (0.002") runout at crankshaft bearing surfaces on non-race engines. Which isn't really comparable to a seal surface but anyway, maybe says something about the magnitude of numbers here. I am planning to put a modern radial type shaft seal in. Intuitively it feels a stock rope type seal would handle runout better, but that is just a guess. What do you say?

    https://www.skf.com/binaries/pub12/...SC_220121_EN_linked_18729_1_tcm_12-524179.pdf
     
  2. Electra Sweden

    Electra Sweden Well-Known Member

    Other seal manufacturers seem a bit more relaxed about this.

    Eriks group seem to state round 0.17 m.m. of shaft static eccentricity on a 36 m.m. shaft, reading from their graph:
    https://static.eriksgroup.com/en/oil-seals/brochures/oil seals technical manual/eriks - sealing technology - eccentricity and shaft oscillation.pdf

    GBSA then has similar numbers. I think I read around 0.007" (0.17 mm) in their table:
    https://www.gbsa.com/products/seals/oil-seals/oil-seals-shaft-and-bore-tolerances/

    So 0.17 m.m eccentricity, that is like a cavemen flintaxe precision :) When finishing this sentence I also realize that this number is for the crankshaft. The balancer diameter is even larger and as such has an ever looser tolerance. Should be a cakewalk to achieve. Why is SKF sooo much more pedantic than others then... Maybe they specify general industrial applications and Eriks Group and GBSA refer to oil seals rather.

    Then Parker has some more info.
    https://www.parker.com/content/dam/Parker-com/Literature/Engineered-Polymer-Systems/5350.pdf
    The shaft surface shouldn't be too smooth (section 2-12). Would never have guessed! So what grit of emery cloth is good for the final touch then? Parkers document was the most informative, but they don't specify a number for runout/eccentricity.

    Sorry if I am spamming now, it turned out it was easier to find information than I first thought after figuring out what to search for.

    Conclusion
    A static runout of 0.17 mm (0.007") seems alright for this application, yet to determine is a proper grit for final polishing. Here I haven't found any as authoritative sources as for numbers on shaft eccentricity, but most people on forums seem to stop at somewhere 400-600 grit.
     
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  4. Schurkey

    Schurkey Silver Level contributor

    I've routinely polished the ugly part of driveshaft yokes that slide into trans tailshaft seals, axle shaft bearing and seal areas, dampers, etc. with 180-grit emery cloth, because that was what the shop supplied.

    For my own use, I've gone to 220.
     
    Electra Sweden likes this.
  5. Electra Sweden

    Electra Sweden Well-Known Member

    Aha, there are sleeves. I am thinking, turning down the whole surface area to the next fit on radial seals might be an option too. Will be a bit painful for the next guy to find a seal though.
    EDIT: So it looks we sleeve it without even machining the the harmonic balancer. Well that puts that solution in a completely different light. Didn't realize we can leverage on the looser tolerances on seals compared to bushings bearings. I see there is also this one: https://www.summitracing.com/parts/fel-16203

    Went by your advice, looks like I got a decent surface smoothness.
     
    Last edited: Mar 18, 2023

Share This Page