Tim D. Posted April 22, 2017 Report Share Posted April 22, 2017 Just refitted my cylinder head after my torque wrench issue. No water leaks so far!. Anyhow was running the engine with the rocker cover removed and noticed that the pushrods spin when the engine is running. Guessing this is meant to happen as I can imagine that is good for wear on the rockers.. Will deposit a video when I get around to putting it on Youtube... Cheers Tim Quote Link to post Share on other sites
foster461 Posted April 22, 2017 Report Share Posted April 22, 2017 I recall that the cam lobes hit the lifter off-center to make them rotate in the bores so perhaps the pushrods are just rotating with the lifters, Stan Quote Link to post Share on other sites
Nick Jones Posted April 22, 2017 Report Share Posted April 22, 2017 Spinning pushrods are good news - mean that the followers are spinning as they are meant to. Non-spinning pushrods are usually bad news and a sign of damage to the followers and/or cam lobe. Nick Quote Link to post Share on other sites
Waldi Posted April 23, 2017 Report Share Posted April 23, 2017 Always keen to learn: Should they always be spinning, in other words: is non spinning definitely an issue? Quote Link to post Share on other sites
Tim D. Posted April 23, 2017 Author Report Share Posted April 23, 2017 Not all of mine spin.. Have put the video on youtube https://m.youtube.com/watch?v=JxPYJbkx6qE Cheers Tim Quote Link to post Share on other sites
foster461 Posted April 23, 2017 Report Share Posted April 23, 2017 I don't know that it is for sure a problem if the pushrod isn't rotating. It is not directly connected to anything so it is just the drag from the oil that would make it rotate with the lifter. If the lifter isn't rotating the cam will just dig a groove in it over time and I assume eventual lifter failure. Stan (retired IT guy so I could also just be full of it) Quote Link to post Share on other sites
Tim D. Posted April 23, 2017 Author Report Share Posted April 23, 2017 I suspect the pushrod rotation is more driven by rocker geometry. Interesting though.. Cheers Tim Quote Link to post Share on other sites
Waldi Posted April 23, 2017 Report Share Posted April 23, 2017 Thanks for the video Tim. Quote Link to post Share on other sites
Motorsport Mickey Posted April 23, 2017 Report Share Posted April 23, 2017 (edited) I'll give you a clue, in similar circumstances piston rings rotate, if they don't rotate they wear...rapidly, it's what you find in engines when the piston "lands" (the piston material between the piston rings) have collapsed and nip the rings stopping their rotation. Parts in "interference " fit with surrounding surfaces (piston rings, cylinder bores, cam followers, cam lobes, valve stems, rocker tips) if one of the rotating components in the partnership seizes it causes advanced wear in the parts. There is nothing securing these items in one position, of course they turn when exposed to forces, it equalises out the wear. Tim, if we could show you an internal video of your engine when it's running at 3500 revs or varying the revs between on and off throttle I'm pretty sure you would see the components spinning, if they don't there would be wear. Mick Richards Edited April 23, 2017 by Motorsport Mickey Quote Link to post Share on other sites
john.r.davies Posted April 24, 2017 Report Share Posted April 24, 2017 (edited) Not just push rods and piston rings. Valves and valve springs spin too. The video is correct - the conclusions in the captions are not. Valve bounce can be cured by stiffer valve springs, but at the risk of accelerated camshaft/valve train wear. Better is double valve springs, that elevate the natural harmonic frequency of the valve/spring system much higher than the input frequency - as Triumph did. John Edited April 24, 2017 by john.r.davies Quote Link to post Share on other sites
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