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Technical SBC harmonic bal.

Discussion in 'The Hokey Ass Message Board' started by johnfin, Dec 4, 2022.

  1. Dave G in Gansevoort
    Joined: Mar 28, 2019
    Posts: 3,860

    Dave G in Gansevoort
    Member
    from Upstate NY

    It's like shocks. Actually dampers also, but the vernacular has become the norm. Although I suppose if the balancing shop drills the balancer/damper during balancing, we could call it a balancer. Isn't English great?
     
  2. johnfin
    Joined: Apr 11, 2008
    Posts: 283

    johnfin
    Member
    from Florida

    badshifter, are you saying the front of the block to the face of the HB is 3 inches? If so that good. I measured 2.3" from the crank top to the timing chain so that may sound right. Would still be interesting to see what the gap looks like inside the HB after an install. I am guessing at least an inch.
    p.s. I bought the install tool tonight.
     
  3. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 6,063

    2OLD2FAST
    Member
    from illinois

    Some aftermarket crank snouts & hubs may not be sized correctly & may need to be honed so as not to damage either during installation , micrometers are your friends .
     
    Jagmech and tomcat11 like this.
  4. badshifter
    Joined: Apr 28, 2006
    Posts: 3,637

    badshifter
    Member

    I just went over and reread this post. If it takes 140 pounds of torque on a torque wrench to turn your engine over, there is something drastically wrong with your engine build.
    Can you clarify, because there is no way it takes 140 pounds of torque to turn the engine over.
     
  5. Wanderlust
    Joined: Oct 27, 2019
    Posts: 1,093

    Wanderlust

    A poorly installed rope seal can create lots or resistance, ask me how I know :) But more back ground would be helpful, is this a rebuild, refresh or just leak repair?
     
  6. I was thinking the same thing but ***umed he was talking about 140psi for his air tools. Admittedly, that still doesn't make a whole lot of sense either but if his impact isn't adjusted correctly .... I dunno o_O
     
  7. johnfin
    Joined: Apr 11, 2008
    Posts: 283

    johnfin
    Member
    from Florida

    I think it may have been on correctly. I found this pic on the net of an L98 and look where the timing indicator is on the cover in relation to the balancer. Now look at my first posting pic. About the same. There is no way the damper bottoms out to hit the chain. That measurement is over 2 inches from the tip of the crank. That seal mark is around 5/8" and the whole smooth damper shaft is less then an inch. Granted 5/8 is no that much to be on the crank but if the belts align I will run it. And yes, I bought a new damper, $40 Rock Auto.
     
  8. Johnny Gee
    Joined: Dec 3, 2009
    Posts: 14,470

    Johnny Gee
    Member
    from Downey, Ca

    Show and tell! My home made one. C8D5016D-4821-4986-B687-EC2662B0A772.jpeg
     
  9. Roothawg
    Joined: Mar 14, 2001
    Posts: 26,100

    Roothawg
    Member

    Don't be surprised if the new dampener is tight going on. The last few I have bought require polishing, even with the installation tool.
     
  10. 1971BB427
    Joined: Mar 6, 2010
    Posts: 9,870

    1971BB427
    Member
    from Oregon

    The installation tool I own has a thrust washer under the head, so it simply pushes the balancer onto the crank without friction resistance that the bolt and washer will add to it.
    Many decades ago we used to put two washers under the crank bolt, and a good grease on all the washers to help reduce friction, before I broke down and bought the tool. But even the greased washers didn't provide as little friction as the tool with thrust washer has.
     
    Truckdoctor Andy likes this.
  11. johnfin
    Joined: Apr 11, 2008
    Posts: 283

    johnfin
    Member
    from Florida

    I aligned the water pump pulley and sure enough the crank damper only goes on the crank 5/8" for an alignment. Not much and I am not sure what keeps it from stopping but atleast I have a new install tool and damper.
     
  12. Greg Rogers
    Joined: Oct 11, 2016
    Posts: 1,100

    Greg Rogers
    Member

    Yes!!! I still have the ruined crank bolt hanging from a tag on the peg board over my bench. The tag says "SLOW DOWN". I ruined the bolt tightening it- using it to pull on the harmonic balancer. I was able to save the crank by rethreading it though it was damaged. I never used the install tool before and never had a problem until then. I will always use the installer now.
     
    Dan Coburn likes this.
  13. bobss396
    Joined: Aug 27, 2008
    Posts: 18,766

    bobss396
    Member

    I worked with a guy who bought an OT Camaro track car. The PO was not too swift, he hammed the damper onto the big block and bent the front of the crank. Any damper I have installed has gone on without a battle, used or new.

    The crank snout and the damper mating surfaces have to be surgically clean and I use a little white lube for insurance.
     
  14. DDDenny
    Joined: Feb 6, 2015
    Posts: 22,619

    DDDenny
    Member
    from oregon

    This^^^^^^^^^
    Bob knows this but for those that don't, a light brush with a file on the leading edge of the key never hurts either!
     
    bobss396 and Desoto291Hemi like this.
  15. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 6,514

    57JoeFoMoPar
    Member

    BRO. STOP. I JUST WENT THROUGH THIS.

    Except I tore the bolt off inside the crank, and had to pull the crank out of my 0 mile crate engine to have the busted ARP crank bolt machined out. It was a NIGHTMARE.

    Yes, you need the installation tool. HOWEVER, as it was explained to me by Mike and Joe Bontempo at BBC in Linden, NJ, some very experienced machinists and engine builders, new balancers are undersized and intended to be honed to the correct size of the crank. Mine was tight as hell, like yours, and turned out to be .004 under, as opposed to .001 like a proper interference fit should be.

    Check out post #23 in my previous thread and don't make the same mistake I did.
    https://www.jalopyjournal.com/forum/threads/the-consolation-prize-61-olds-super-88.1267254/
     
  16. johnfin
    Joined: Apr 11, 2008
    Posts: 283

    johnfin
    Member
    from Florida

    My new damper came and i noticed there is a relief in the bore thats a few thou to ease ***embly. Only thing thats different from stock is 1/8" lip on damper face which i hope wont kick the pulley out of alignment with the others.
     

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  17. Jagmech
    Joined: Jul 6, 2022
    Posts: 254

    Jagmech

    How many times do you have to tell them, measure snout with mic, measure bore with inside mic or quality dial caliper, . 001" to .0015 interference max. New balancers usually have extra .002" / .004" material that has to be honed.
     
  18. johnfin
    Joined: Apr 11, 2008
    Posts: 283

    johnfin
    Member
    from Florida

    So the tool came and i installed the HB. Did not have a large enough wrench so i used a monkey wrench and pipe(see pic). Looks like a hammer but its not. When the engine started to turn over i checked the belt alignment and it was right on. Give me a mopar any day over a sbc.
     

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    Budget36 likes this.

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