Announcement

Collapse
No announcement yet.

Roller lifters

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Roller lifters

    So, modern pushrod car engines pretty much all come with roller lifters.

    Why the heck are they still round????? Thereby necessitating additional hardware to prevent them from rotating in the bore???

    Just my dilemma of the day.

    Carry on.
    Last edited by BBR; November 28, 2018, 12:41 PM.
    Life is short. Be a do'er and not a shoulda done'er.
    1969 Galaxie 500 https://bangshift.com/forum/forum/ba...ild-it-s-alive
    1998 Mustang GT https://bangshift.com/forum/forum/ba...60-and-a-turbo
    1983 Mustang GT 545/552/302/Turbo302/552 http://www.bangshift.com/forum/forum...485-bbr-s-83gt
    1973 F-250 BBF Turbo Truck http://www.bangshift.com/forum/forum...uck-conversion
    1986 Ford Ranger EFI 545/C6 https://bangshift.com/forum/forum/ba...tooth-and-nail

  • #2
    Because someone would try to put a square peg in a round hole.

    Okay, just guessing here but:

    1. Stress risers

    2. Round is easier and cheaper to machine than anything with an angle.

    3. Easier to adapt pre-existing tooling.

    4. Pushrods are antique aritifacts anyhow, so why not make 'em as familiar as possible.
    Last edited by Gateclyve Photographic; November 28, 2018, 11:10 AM.

    Comment


    • #3
      Could it have anything to do with parasitic loss

      Comment


      • #4
        My guess (and it IS a guess) is that it's an issue of machining. Making - say - oval lifter bores and lifters would be a trick and making the clearances work would even add to it. Besides, most roller lifter engines started life back when they were flat tappet engines so the bores and lifters are sort of carry-overs. Next time I see Wayne Jessel I'll ask him.

        Dan

        Comment


        • #5
          My thoughts were predominantly aimed at LS and G3 Hemi. These were designed from the ground up to use roller lifters. You'd think square lifters would work fine.
          Life is short. Be a do'er and not a shoulda done'er.
          1969 Galaxie 500 https://bangshift.com/forum/forum/ba...ild-it-s-alive
          1998 Mustang GT https://bangshift.com/forum/forum/ba...60-and-a-turbo
          1983 Mustang GT 545/552/302/Turbo302/552 http://www.bangshift.com/forum/forum...485-bbr-s-83gt
          1973 F-250 BBF Turbo Truck http://www.bangshift.com/forum/forum...uck-conversion
          1986 Ford Ranger EFI 545/C6 https://bangshift.com/forum/forum/ba...tooth-and-nail

          Comment


          • #6
            Making that same not round shape in the block would be difficult too.

            Comment


            • #7
              Originally posted by BBR View Post
              My thoughts were predominantly aimed at LS and G3 Hemi. These were designed from the ground up to use roller lifters. You'd think square lifters would work fine.
              You can probably get by with a cheaper grade of assembly robot / UAW member with the current configuration . . . . Nearly everything eventually comes down to price when you're making millions of something every year . . . .

              . . . Recalling the ancient "Mail for McMcCahill" joke in Mechanix Illustrated:

              Dear Tom, Why is it that my $6,000 new car has a lousy $1.00 bumper jack?

              Tom McCahill: Because they ran out of 50-cent ones.

              Comment


              • #8
                How you going to "bore" a square hole in the block.....this is where it won't work ?

                Comment


                • #9
                  You just need to rethink the lifter 'bore". Open slots with a bolt-on cover piece would be easy-peasy.

                  Quickie not-to-any-sort-of-scale-whatsoever drawing.

                  Click image for larger version

Name:	SnipImage.JPG
Views:	71
Size:	34.8 KB
ID:	1222754
                  Life is short. Be a do'er and not a shoulda done'er.
                  1969 Galaxie 500 https://bangshift.com/forum/forum/ba...ild-it-s-alive
                  1998 Mustang GT https://bangshift.com/forum/forum/ba...60-and-a-turbo
                  1983 Mustang GT 545/552/302/Turbo302/552 http://www.bangshift.com/forum/forum...485-bbr-s-83gt
                  1973 F-250 BBF Turbo Truck http://www.bangshift.com/forum/forum...uck-conversion
                  1986 Ford Ranger EFI 545/C6 https://bangshift.com/forum/forum/ba...tooth-and-nail

                  Comment


                  • #10
                    Where did you go to engineering school?



                    It's a neat idea...but hey, it's not difficult to keep lifters from turning, and it's a heck of a lot easier to machine round things.

                    My fabulous web page

                    "If it don't go, chrome it!" --Stroker McGurk

                    Comment


                    • #11
                      ease of machining
                      round never jams
                      lubrication

                      those are the ones that spring instantly to mind.
                      Doing it all wrong since 1966

                      Comment


                      • #12
                        Don't most modern roller lifters also have a hydraulic component? So.... they still need to be fed oil pressure requiring a seal. So for the same reason pistons are round to make it easier to create and maintain that seal.
                        My hobby is needing a hobby.

                        Comment


                        • #13
                          Love the drawing (Reminded me of an early video game for some reason). But "me-seat-o-de-pants" suggests that square lifters would be heavier, have more service area, and be tougher to seal-up the internal juicy part . . .

                          As it turns out, some purported real engineer-types came to similar conclusions when evaluating square pistons . . . . (see link, infra)

                          (Of course engineers came up with such "hits" as the Tay Bridge Disaster (1879), The Titanic (1912), St. Francis Dam flooding (1928), The Hindenburg (1937), Tacoma Narrows Bridge collapse (1940), Cleveland East Ohio Gas Explosion (1944), Hyatt Regency Hotel walkway collapse (1981), Challenger explosion (1986), Chernobyl disaster (1986), Concorde Air France Flight 4590 crash (2000) , Columbia disaster (2003), not to mention the VEGA and Iron DUKIE lumps, the Oldsmobile Diesel, the 301 Pontiac . . . . )

                          I hope this isn't piling on at this point . . .

                          Comment


                          • #14
                            However if you want to think outside the circle consider this, a Honda motorcycle engine that could turn 20K on 8 valves per cylinder.

                            Click image for larger version

Name:	NR_engine_preview_featured.jpg
Views:	77
Size:	47.1 KB
ID:	1222767
                            My hobby is needing a hobby.

                            Comment


                            • #15
                              Heck, look up oval pistons (see Honda's NR750, and I think there was an F1 motor also).

                              Round stuff expands uniformly as it gets hot and has no corners to jam into the block if it's trying to rotate. As I recall, the oval-piston engines weren't really oval, they were more shaped like an oval track (a circle with two sides having aspirations!). They had one hell of a time with the machining and heat expansion issues--mostly on the rings, I understand). The benefit was it allowed them to make an engine that qualified as a four-cylinder under the rules, but that had what sure looked to be V8 heads on it (i.e., 32valves on four pistons). It was written out of the rulebook right fast and in a hurry.

                              Edit: Beaten to the punch by a few seconds!
                              Last edited by AndyB; November 28, 2018, 03:14 PM.

                              Comment

                              Working...
                              X