5/16 vs 3/8 Pushrod Which Makes More Power

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  • Опубликовано: 6 апр 2025

Комментарии • 103

  • @robertwest3093
    @robertwest3093 Год назад +18

    How this man doesn't have a million subscribers I will never understand! Easily the best, most honest engine tech I've come across on RUclips. Thank you for what you do and I look forward to many more years hopefully! This knowledge is the equivalent of having a secret weapon 👍

    • @WeingartnerRacing
      @WeingartnerRacing  Год назад +4

      I wish I knew why too.

    • @trxtech3010
      @trxtech3010 Год назад +1

      @@WeingartnerRacing It will happen. Just like bussiness...it takes time and word of mouth people will see who you are and stay followers.

    • @111000100101001
      @111000100101001 Год назад +2

      Just like David Vizard’s channel, starting slow but taking off once people experience the tons of knowledge that is being shared in 20 minutes. Best of luck, you have a great channel and your attention to detail is admirable!

    • @1crazypj
      @1crazypj Год назад +2

      I think it's because you need a basic understanding at minimum to know whats going on and a lot of people find this too 'technical' (personally I find it fascinating and also very simple to understand)

    • @Anarchy-Is-Liberty
      @Anarchy-Is-Liberty Год назад +1

      ​@@1crazypj Yep, I agree. I will almost never use most of the information that Eric discovers, because I simply can't afford to build this kind of stuff, but I am a data geek when it comes to race engines, very fascinating stuff. So the "average" car guy probably isn't really concerned about this stuff, but anyone in "the business" I would bet watches his videos and data very, very closely, and would be surprised if they didn't to be honest!

  • @yarrdayarrdayarrda
    @yarrdayarrdayarrda Год назад +4

    For me the evidence is in the last half of the graph. They overlay which tells me both pushrods were more than adequate for the application.

  • @jmflournoy386
    @jmflournoy386 Год назад +3

    Great info Eric couple of vignettes... 292 chevy six has really long pushrods The late Kay Sissel or Mike Kerby had problems with pushrod flex and came up with a bushing at the deck and upper and lower pushrods did make a difference. We noticed early on that the Ford with larger pushrods was more stable than the 440 Chrysler eventhough it has a heaver valvegear.
    There also appears to be a connection with pushrod flex and spring surge/ life Thanks

  • @donaldgrove229
    @donaldgrove229 Год назад +2

    I would say you haven't reached the limit of the 5/16 pushrod. Got to be close. Love the channel.

    • @WeingartnerRacing
      @WeingartnerRacing  Год назад +3

      When the new heads, go on, we may find the limit. They have a much heavier valve train.

  • @Hogiewan1
    @Hogiewan1 Год назад

    Outstanding information. Thank you. Erson is grinding me a cam very close to the specs you suggested. Block is ready, heads are halfway, so almost there. Appreciate the help

  • @Anarchy-Is-Liberty
    @Anarchy-Is-Liberty Год назад

    Hopefully this is one of those things you guys tested during (or are currently testing) the BBC dyno mule tests.
    BTW, thanks for sharing all of this info with the rest of us, you're an awesome guy Eric, don't let anyone ever tell you different!!

  • @jasonfikes9514
    @jasonfikes9514 Год назад +1

    Brunt boots are amazing. Bought a pair in December and absolutely enjoy them more than my red wings.Great video as always. ✌😁

  • @steves759
    @steves759 Год назад +2

    Would be interesting to see how a non shaft rocker played in this testing as well. Thanks for the video.

  • @DSRE535
    @DSRE535 Год назад +4

    I think part of the reason for your results is it’s just a well engineered set up
    to be honest like you said if you had a much heavier spring in there or heavier valves, OR more pushrod angularity from a canted or Hemi valve train I bet you would’ve seen a bigger difference, but I will say that I’m pretty damn surprised I thought the 3/8 pushrods we’re going to make more power!

  • @richardboggs260
    @richardboggs260 Год назад +1

    Very interesting test. Thank you Eric for this video!!

  • @MrRandy3504
    @MrRandy3504 Год назад +1

    Ive got a pair of brunt boots and they are awesome mine are waterproof comfy and toe protected and light

  • @reason2gether
    @reason2gether Год назад +1

    Great video Eric! I have not used a cam with as much rate as that one you have in your dyno mule. So, it is safe to say, for me anyway, that standard 5/16" pushrods are more than enough. In building engines, it is wise to have margin by using parts that are stronger than necessary, especially in areas where it has no effect on RPM (such as 4-Bolt Mains versus 2-Bolt Mains). When you get into the areas of reciprocating weight however, it does matter more. You have to use the strength level that is needed at the RPM that generates the most stress for that particular component. At the same time, you just want to use the lightest weight possible because anything above that minimum required weight, will be a liability at all other RPMs. That liability will usually be in the form of wasted energy which equals less power, however great or small the difference will be. In the end, because we common folk do not have access to dyno equipment, we try to choose components that are perceived to be "overkill" so that we never run into the hidden failure zone with our engine. Thanks to guys like yourself, we have the necessary information to make more accurate component choices. Thank you for all you are doing for your fellow car enthusiasts. God Bless!

  • @ldnwholesale8552
    @ldnwholesale8552 Год назад +1

    I have always used 5/16 pushrods. Lighter and cheaper. Ballend for preference. Some swedged end gall in the rocker cup. Which is sometimes a problem in itself. I had a well known brand do that to me,,they ended up giving me pushrods that did not. This an engine flat out at 7500. SBC. I have used factory Chev pushrods with no issues on [baby] race rollers.. And on race Holden 6s
    Guide plates can be an issue. Some are not hard! The old Manley plastic ones were good.

  • @pontiac411
    @pontiac411 Год назад +2

    Seem like a lot of Spring pressure for A 2.02 valve at 6500 My 350 with A 2.08 valve, 5/16 push rod and a little over 200 pounds of Spring pressure ran smooth to 7700 on the Dyno and was still gaining power With a .446 lobe lift and a 1.6 rocker stud mounted

    • @WeingartnerRacing
      @WeingartnerRacing  Год назад

      Not really. In this case it seemed happy judging by the numbers with both pushrods.

    • @pontiac411
      @pontiac411 Год назад +2

      @@WeingartnerRacing But if the valve train could still be stable with less Spring pressure that result in more horsepower? I am just thinking about 16 Springs with possibly 50 pounds more than needed per Spring.

    • @1crazypj
      @1crazypj Год назад +1

      pontiac411, is that an overbored 400 or a much modified 389?

    • @pontiac411
      @pontiac411 Год назад +1

      @@1crazypj400 bored .060

    • @1crazypj
      @1crazypj Год назад +1

      @@pontiac411 10-4.
      I have a 1965 Catalina 389 motor for parts, heads look promising as they are small combustion chamber, block is done for as it had water in a few cylinders for ? years and would need liners to be usable
      Have a 76 Formula 400, last year of round headlights and the best looking hood ever fitted with NACA ducts

  • @bobg3034
    @bobg3034 Год назад +3

    Remember the exhaust valve has to open up under pressure!

  • @cfmechanic
    @cfmechanic Год назад

    Great video sir i really appreciate all the info you post.

  • @rtkl13
    @rtkl13 Год назад +1

    The weight difference makes sense to me. Down low less weight, easier to throw around HP climbs quick. Up high, speed of inertia comes along and they both prevail

  • @drivinwithdrew7676
    @drivinwithdrew7676 Год назад +1

    Cool video man, i think the 5/16 is deflecting giving that mid range, but maybe it’s just out of head over 5700, I bet it changes slightly with the next heads like you said, I also learned way more than I want to type from running it to 7k, but that will really help show the gains you’re gonna get on the top end with heads! Great video as always, and thanks for answering my question!

  • @oldguyworks1650
    @oldguyworks1650 Год назад +2

    Great content. Things are looking up as far as the channel goes. Sometimes I think folks are using to much spring rate, maybe. Might make for a good test?

    • @WeingartnerRacing
      @WeingartnerRacing  Год назад +3

      Maybe I will try it. By the way your intake ended being the best one.

  • @shadowopsairman1583
    @shadowopsairman1583 Год назад

    I picked up Chromoly 5/16" diam 7.4" .080" walled pushrods by BTR, they practically the same as TSP, price was determining factor. Stock replacement or mild/moderate builds. The 3/8" rods was thinking rockers and lifters require 3/8" cups

  • @marccres6619
    @marccres6619 Год назад

    Wow peddling shoes. 😂😂😂😂,thanks for the info it is great. I am glad you are so detailed on things it makes it easy. Keep them comming.

  • @ChannelZeroOne
    @ChannelZeroOne Год назад +1

    I have had a few pairs of Brunt shoes. The dont last very long if you work in construction FYI> Good to know about the push rod penalty or lack there of.

  • @lamarw9901
    @lamarw9901 Год назад +3

    The test is the test, I expected the 3/8" to has a bit more up top. I'd still take the 3/8 but this makes me question how much better a 3/8 or 11/16 is on a LS with a hydraulic roller. Granteed, I'd still go with the larger pushrod.

    • @davidreed6070
      @davidreed6070 Год назад

      I use 11/16 in my LS engines they do fit and I can't prove any gains but it is ease of mind for me

  • @vehdynam
    @vehdynam Год назад

    Interesting and thought provoking. Thank you.

  • @markgoulette5056
    @markgoulette5056 Год назад +5

    I'll still go by the old adage, put the biggest pushrod you can physically fit in the engine....if you can't get more size, go for wall thickness.....You hurt NOTHING by having a big, thick pushrod, but you CAN have issues with too small of one....

    • @WeingartnerRacing
      @WeingartnerRacing  Год назад +3

      You are correct

    • @1crazypj
      @1crazypj Год назад

      I think you need heavier springs when you have heavier push-rods, so, it will need more power to drive them.
      I remember reading around 1970, use lightest spring rate that gives a safety margin if you miss a shift, of course, that would depend on crank weight and how fast motor spins up.

    • @markgoulette5056
      @markgoulette5056 Год назад

      That's not how it works. Pushrod weight is of little to no significance. Weight on that side of the rocker has little effect on valve control, unless the parts are too weak to begin with. My statement is correct, and is proven by professional builders everywhere. Too weak of a push rod will deflect and cost power.

    • @1crazypj
      @1crazypj Год назад

      @@markgoulette5056 Obviously a 'weak' push-rod will deflect and may cost a complete engine rather than just lose power (if it flexes enough to come out of seating and follower comes out of bore at high rpm) but using a heavy push-rod just because you can is also losing power as it will need heavier valve springs than would otherwise be needed. It's been proven that a heavy valve train costs power by puttig engine on a Spintron. Just because it was done in the 70's and 80's (and earlier) doesn't mean it's done today.

    • @markgoulette5056
      @markgoulette5056 Год назад

      @@1crazypj Yes, a weak pushrod will deflect and can cost power, but additionally it can cause unwanted, uncontrolled valve motion. A heavier pushrod WILL NOT loose horsepower, it will generally GAIN due to less deflection. You do not determine valve spring requirements from pushrod size/weight. As stated, weight on the pushrod side of the valve train has little to no effect on the valve side of the valve train. Yes, heavy valve train parts can cost power, ON THE VALVE SIDE....NOT THE PUSHROD SIDE.....you are incorrect in your assumptions. Lighter weight springs (weight, not RATE), lighter valves, retainers, and locks are very beneficial to the valve train. However, strength and stiffness on the pushrod side are most desirable, and the rule of thumb of using the largest pushrods you can physically fit in an engine is a proven method of stabilizing the valve train. The pushrod acts like a spring, and when it rebounds, it can transfer unwanted motion to the valve. Not good. When there is minimal deflection by the pushrod, there is less the spring has to deal with to maintain control. Then, by adding lighter weight valve components like Ti valves, retainers, locks, and lighter weight springs, allows us to have substantially less valve train harmonics and better control over valve motion. There is no negative to running the largest, strongest pushrods on the lifter side of the valve train. NONE. The spintron data shows this as well. While there may be little gain, there won't be any loss. As stated, weight on the lifter side of the valve makes little to no difference to valve motion unless the pushrod itself is not adequate for the application. Too large of a pushrod has no negatives.

  • @ezmny1387
    @ezmny1387 Год назад +1

    I run 3/8 in every LS engine i do regardless, always best to run the widest pushrod you can.

  • @leekavanagh6549
    @leekavanagh6549 Год назад +2

    It would be interesting to run cam and valve train package on a sprintron to show valve action difference between 5/16 and 3/8. But I suspect the 5/16 is flexing and making the engine think it has a slightly smaller cam.

  • @leonardfoster6252
    @leonardfoster6252 Год назад +1

    Good job Eric!

  • @mohanperformance.enginerd.1308

    Orcourse as stated. Every engine is unique in its valvetrain behaviour. But still I did not see this result coming. Very interesting.

  • @AlanRoehrich9651
    @AlanRoehrich9651 Год назад +3

    If you make the pushrod stuff enough you take one spring to control out of the equation. I've never seen a pushrod too stiff, and weight is not a big concern.

  • @jodysmith3662
    @jodysmith3662 Год назад +3

    One other comment. There used to be a company that claimed swapping over to titanium valves is worth a tenth in ET. Cannot remember the company but always wondered if there is power to be had there.

    • @ldnwholesale8552
      @ldnwholesale8552 Год назад

      Ti is expensive and has a short service life. Will help the engine rev a little more free. Us budget racers will use good stainless as the gains are not worth the extra cost

  • @reedsilvesan2197
    @reedsilvesan2197 Год назад

    I've been watching you alot lately, enjoying it.
    Do you ever run beehive springs?
    Also, I would like to have you flow one of my heads. How can I get this done?

  • @ThirteenTwentyRepair
    @ThirteenTwentyRepair Год назад +1

    Makes me curious about running 5/16 chromoly intake pushrods for less weight, and 3/8” exhaust for less deflection against cyl pressure 🤔

  • @JalopyTechnology
    @JalopyTechnology Год назад +2

    I use 3/8 in my SBM....the PR angle kills lift with a smaller PR

  • @donaldhalls2189
    @donaldhalls2189 Год назад

    The results may be the same because there wait differences may not be enough to register, our Australian engines push rod's are fairly straight up and down, thanks for sharing, all the best to you and your loved ones

  • @bryanw.3076
    @bryanw.3076 Год назад

    Thank you for the update and information

  • @tjrobison3267
    @tjrobison3267 Год назад +1

    I expected the 3/8 would make slightly 5-10hp more at 6000 plus and the same down low as the 5/16. Cool test even if it can't be directly applied to every combo.

  • @aarongrattafiori617
    @aarongrattafiori617 Год назад +3

    Interesting. Seems worth it to go bigger because it's stronger / less deflection....?

  • @rossmason4434
    @rossmason4434 2 месяца назад

    Im curious what the comparison is from 1800-6000 .
    Very nice heads !
    Nice boots too .

  • @PeggyParrow
    @PeggyParrow Год назад

    When the pushrod is offset you loose lift because it is going in 2 directions at once instead of a straight line.😊

  • @bobstitzenberger1834
    @bobstitzenberger1834 Год назад +2

    Just off the top of my head, seems the 3/8 with the thinnest wall would be best.

    • @1crazypj
      @1crazypj Год назад

      That was my thought.

  • @YouCantSawSawdust
    @YouCantSawSawdust Год назад +1

    Could the 5/16 add a little power by lofting the valve?

  • @Errol.C-nz
    @Errol.C-nz Год назад +1

    Ive not work much with pishrod engines other than bmc mini's.. same engineering applies for competition just different scale of hp.. engine harmonics plays a huge roll & the pitch harmonics of these rods vs any critical resonance rpm harmonics from the engine are going to be bigger factors than static load stiffness of the respective rods.. thinner & thicker wall sections would be a better option to look into to change the harmonic frequencies of valve trains vs all up recipro weights or critical individual component weights.. "strongest" can still have a critically short life vs lightest.. as can firing order or ignition event timing (cylinder bank angles create different combustion harmonics that feed back through all the machine in different ways).. a flat plane v8 will have many of the harmonic problems in valve gear that flat plane 4s have.. cylinder bank angles & stroke interfere with those harmonics a lot! valve gear included..
    Excellent artical.. food for thought thanks.. loving the channel.

  • @yodawunn6700
    @yodawunn6700 Год назад

    Good info, and I need a new pair of boots too.

    • @WeingartnerRacing
      @WeingartnerRacing  Год назад +1

      Thank you

    • @yodawunn6700
      @yodawunn6700 Год назад

      @@WeingartnerRacing So I've always used air die grinders but after I watched one of your videos (can't remember which) I got a Foredom SR. That thing is awesome.

  • @rustygehl
    @rustygehl Год назад

    Awesome!!!! I'm building a moderate Jeep 258 (with Edelbrock 4.0 head and cam) and many have said to get thicker rods. I really didn't want to, lol. They're non adjustable rockers, and rare, so it would be an expensive part. Glad to see it really isn't worth it in the end.

    • @WeingartnerRacing
      @WeingartnerRacing  Год назад +4

      They are worth it. It is never a negative for thicker pushrods.

    • @rustygehl
      @rustygehl Год назад

      @@WeingartnerRacing Yeah, but they would probably have to be made custom- non adjustable rockers. I don't race it or anything strenuous. Just don't think the squeeze is worth the juice in such a build.
      Wait till I get bored, then I'll end up buying them, lol. It's never ending....

    • @DSRE535
      @DSRE535 Год назад +1

      @@rustygehl
      I can’t imagine you’re turning much rpm of the street six even with a really good cylinder head

    • @shadowopsairman1583
      @shadowopsairman1583 Год назад +1

      The more spring rate I'd say a stronger pushrod required, 5/16 for moderate builds at most depending on the alloy and wall thickness.

    • @shadowopsairman1583
      @shadowopsairman1583 Год назад

      ​@@WeingartnerRacing when you have 3/8" pushrods, do you require 3/8" cups on rockers and lifters?

  • @jodysmith3662
    @jodysmith3662 Год назад +1

    Be nice to see it at 8000 with a supporting camshaft.

    • @leftyo9589
      @leftyo9589 Год назад +2

      an aggressive ramp on the lobe would be better to show if push rod flex is a factor.

  • @alltherpm
    @alltherpm Год назад

    Nice work

  • @daveperry6793
    @daveperry6793 5 месяцев назад

    did add 3/8 pushrods but also added an oldstyle rev kit to help offset the weight of the pushrod-thoughts please reply

  • @jeffdyer8541
    @jeffdyer8541 Год назад

    Great information.

  • @cgarris8674
    @cgarris8674 Год назад

    Good stuff!

  • @shanerorko8076
    @shanerorko8076 Год назад

    I'm at 9:22 that tells me if the 3/8 is much cheaper then use it, I know there is an older guy on yt that would make out that gain is the difference between a fool and a pro. But we won't go there....

  • @db1988
    @db1988 Год назад

    IDK The 516th might weigh less so will that make it revmore? But then 3/8 does it deflect less meaning does it Basically not bend as much creating more a lift I guess I'm about to find out

  • @MsKatjie
    @MsKatjie Год назад

    thanks for your hard work. i used 5/16ths on an LA 370 , when i changed my rocker ratio. Wouldn't weight on a fulcrum point be less significant?

    • @WeingartnerRacing
      @WeingartnerRacing  Год назад

      Weight on the pushrod side is not near as bad as it is on the valve springs side.

  • @musclebone7875
    @musclebone7875 Год назад

    3/8 for me 😆

  • @kevinwest3689
    @kevinwest3689 11 месяцев назад

    Steve morris" ever hurd of him? He states that one thing you can't over do. Are push rods, and fuel pump. When someone like Steve, or Nelson, tells me something. I don't need to over think it.

    • @WeingartnerRacing
      @WeingartnerRacing  11 месяцев назад

      I’m just showing test results. Do whatever you want. I’m not advocating small pushrods.

    • @kevinwest3689
      @kevinwest3689 11 месяцев назад

      @@WeingartnerRacing My comment is for the comment section. Thought provoking. Your doing a fine job 👍

  • @kularace7351
    @kularace7351 Год назад

    you know this but ill say it. Its not all about power when it comes to a happy valvetrain.

  • @Airman..
    @Airman.. Год назад

    Subed

  • @Thumper68
    @Thumper68 Год назад

    No difference beyond average deviation between tests.

  • @teddjordan582
    @teddjordan582 Год назад

    Good info but tough to watch. Everything is out of focus.

    • @toomanymodz
      @toomanymodz Год назад +3

      Video looks clear to me. Possibly it's your internet connection or computer that is causing youtube to downgrade the resolution. I watch it at 1080 HD.

    • @jacobnorth8642
      @jacobnorth8642 Год назад

      Looks clear to me and I'm into the lower deck on a 30 pack...

  • @I_like_turtles_67
    @I_like_turtles_67 2 месяца назад

    Literally ordered the trick flow 7.800 for my engine build. 5/16