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Sunday morning bench race - Valve springs and rev kits - pros and cons?

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  • Sunday morning bench race - Valve springs and rev kits - pros and cons?

    I was flipping through some old magazines the other day and saw a rev-kit installed on some v8 of a brand I can't specifically remember. I started wondering about valve control and it seemed like a better idea if the goal was to reduce valve / spring package weight for better valve control.

    I'm just bench racing this in my head but I'm curious why this didn't become more prevalent? I must be missing something other than the obvious unit cost. Would it make sense on something seeing 7000-75000 to use a smaller valve spring like a beehive and a rev kit? It seems like it would be a lot nicer to the cam and less work to operate the valvetrain as the combined spring pressures shouldn't necessarily have to be as high.

    what do you guys and gals think?

  • #2
    Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

    timing on the cam can do anything except fix a weak spring or too strong..
    and then iron is different than aluminum...seats and no seats...
    is the kit a gimmick?

    the run down the middle is the casual stuff.

    seeing btdc of 40 degrees is a killer.. no matter what one does.

    I noticed on my forr cyl it is just 3 degrees, more than ironic to be helping it along, going on its 25th year, no rebuild, crazy revver (buries 8k tach).

    some of my 8s drove me nuts with the heat slug...its the cams more thn any other part for revs.. and oil.

    my 2cents.



    Previously boxer3main
    the death rate and fairy tales cannot kill the nature left behind.

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    • #3
      Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

      I think they are costly for what they are and engines with very heavy valvetrain can't use them( haven't see any for a bbc)
      and the cost of the "kit" that ADD'S more parts. can be used for valvetrain parts that are light enough not to need the kit..
      they are only adding more parts to break and check.. and is it cost effective to have to replace 32 springs and any wearing parts over 16 good light weight gear..

      the + don't out weigh the -

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      • #4
        Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

        I don't think it's a gimmick... Seems like you could run a lighter spring pressure to control the lifter and a lighter spring package on the valve since you're not having to control the lifter with the valve spring?



        sbc example - 110.00

        TR - I see what you are saying, but if you reduce the work each spring has to do, seems like they would last longer?

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        • #5
          Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

          TR - that's exactly what I was thinking the benefit would be. Reduce the valvetrain weight, Including the spring..


          150.00

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          • #6
            Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

            ran a rev kit , still ate valvesprings , but thats cool

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            • #7
              Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

              Without a spintron I'm not sure how you'd be able to tell what's going on when you mess around with the spring rates. I had asked comp about them once and they seemed to hint that on properly designed and matched valvetrain the lifters wouldn't go ballistic in the first place so at best, they're band-aid insurance against lifters leaving the lobe, and at the worst, they're an unnecessary horsepower loss.
              Cheap, slow, half-assed: Pick three

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              • #8
                Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

                Originally posted by milkovich

                they're band-aid insurance against lifters leaving the lobe
                X2, Thats the answer I was always told. BIG solid flat tappet cams of a by-gone era (for the most part) liked these kits. Like Jim said, it wasn't a cure for breaking valve springs though. I've read there is some harmonic cancelling effect aswell.

                Rollers, Bee-hives, SOHC,DOHC, computer designed cam profiles seemed to have replaced the Rev-Kit idea IMO.
                Jeremy George in Windsor NY

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                • #9
                  Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

                  Why so expensive though? They seem dirt simple, like any competent machinist could whip up a kit.

                  It'd be neat to see beehives on both the top and underneath in the rev kit too... wonder if that'd work on a BBC 2.x-big" valve.
                  Yes, I'm a CarJunkie... How many times would YOU rebuild the same engine before getting a crate motor?




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                  • #10
                    Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

                    Tony, that's kind of where I was going with my thoughts.. but milkovich stomped on my dreams with reality. lol. Need a dyno and somebody else to pay me to do stuff like this. Maybe if I just got off my butt and did it, then went to the track it would help, but I hate wasting money on a guess. :o

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                    • #11
                      Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

                      if it was worth it..
                      some one with a dyno and money to burn opps I mean test with
                      would have

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                      • #12
                        Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

                        dohc ? I don't think so

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                        • #13
                          Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

                          Originally posted by SpiderGearsMan
                          dohc ? I don't think so
                          you mean Doh!!!!!!!!!!!!!!!!c ;D

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                          • #14
                            Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

                            uh, where did you guys get DOHC from a pushrod conversation?

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                            • #15
                              Re: Sunday morning bench race - Valve springs and rev kits - pros and cons?

                              Originally posted by Tom Slick
                              TR - that's exactly what I was thinking the benefit would be. Reduce the valvetrain weight, Including the spring..


                              150.00

                              From your link....
                              In some endurance and most oval track applications, it is necessary to use a rev kit for the lifter to precisely follow the profile of the cam. This ensures that in the event of push rod breakage or rocker arm faillure, the lifter will not come out of the bore. Fits Comp Cams fill round body lifters.
                              As for less valvetrain weight the rev kit adds to it and you still run the recommended springs for the cam. Remember the valve spring keeps the valve closed the rev kit has nothing to do with that.

                              And yes I run a Crower rev kit in my 406. ;)

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