Exhaust valve rotators

Discussion in 'Cams, Heads and Valve Trains' started by anderson3754, Nov 28, 2009.

  1. anderson3754

    anderson3754 Member

    Exhaust valve rotators in ref to BBC heads 049 781 etc

    Is there a general guideline that would apply as to cam lift and or valve spring pressure when they should be replaced with Exhaust Valve Rotator Eliminators

    I fool around alot with BBC, but only have experience with smallish cams .540 or less lift, single valve springs with dampners on street cars, that rarely even touch 5500 rpm. :? :)
  2. grumpyvette

    grumpyvette Administrator Staff Member

    Ive always asked the cam manufacturer if I needed different springs, and in most cases once you exceed about .500 lift on a bbc the answers going to be yes that you'll want to upgrade, the valves train, removing the rotators reduces weight and upgrading the springs, and going to lower weight retainers allows the valve train to rev freely ,if you ask several different cam manufacturers and they all suggest you need to upgrade springs with cams having a similar lift & duration its a fairly safe bet that the stock springs won,t work, most bbc engines don,t have the rotators so its not mandatory that they be used, what is mandatory is maintaining enough oil flow over the valve springs and rockers to keep them cooled down,and checking the valve train geometry and clearances, and IVE always suggested you carefully checked clearances, and replaced the springs and retainers with lighter weight components of better quality when I swapped to the valve springs that are suggested to be used by the cam manufacturer or to something similar in load rate in a bee-hive design valve spring.
    MY advice on performance engine builds is to use lighter weight retainers and better quality valve springs with the required matching machine work to significantly increase your valve clearances, lighten the valve train and increase the engines durability, in many cases upgrading to BEEHIVE springs with their smaller and matched lighter retainers is a big PLUS
    ID suggest you talk to your cam manufacturer, and take their tech departments, technitians advice to heart, in most cases their goal is to have your engine run trouble free and produce more hp, so they don,t want you having problems and telling your friends THEIR cams SUCK, as a result they generally will try to give you good basis advice if asked
    but you will occasionally find your talking to some guy, on a tech desk that has little too zero practical knowledge, or experience, who reads answers off a telle-prompter flow sheet.
    exhaust rotators tend to extend the life of the valve seats, and exhaust valve seal, removing the rotators lowers valve train weight and normally tends to increase the engine rpm band a bit, ESPECIALLY if you upgrade to lighter retainers and better springs
    keep in mind hardened exhaust valve inserts were designed and used when non-leaded fuels and leaner f/a ratios were introduced, to lower emissions, and catalytic converters were mandated. that had the effect of significantly lower ability to lubricate the valve seats than the leaded fuels
    hardened exhaust valve seats tend to last longer

    so read thru these threads & links



    http://www.enginebuildermag.com/Article ... dures.aspx


    http://www.gesslerheadporting.com/membe ... enDocument





    recessed valve seat
    hardened exhaust valve seat inserts
  3. anderson3754

    anderson3754 Member

    Thanks :D for the info

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