Stage 2 question
Tourer
Joined: Jun 2020
Posts: 290
Likes: 67
From: Fairfax, Va
Originally Posted by Tampa Fatboy
If done correctly, they do the job. Now if you wish to pull the top end for perfection then you should do the jug upgrade.
Removing the rocker covers and rocker shafts isn't even remotely similar in time, complexity, or expense to pulling the top end (heads).
Road Master
Joined: Dec 2018
Posts: 913
Likes: 322
From: St. Louis
I have read about the weight difference in adj. pushrods vs non. Some say it doesn't matter in modern engines some say it does. Potato pahtato. The biggest disadvantage with the adj pushrods comes from the potential of flex. Even that is mitigated by going with a reputable company, and unless you are doing crazy hp/tq numbers, which you are not, you will be just fine.
HDF Community Team
Joined: Oct 2018
Posts: 4,347
Likes: 3,392
From: Seattle
I have read about the weight difference in adj. pushrods vs non. Some say it doesn't matter in modern engines some say it does. Potato pahtato. The biggest disadvantage with the adj pushrods comes from the potential of flex. Even that is mitigated by going with a reputable company, and unless you are doing crazy hp/tq numbers, which you are not, you will be just fine.
I got the Wood 22X cam kit from fuelmoto in my wishlist, and it comes with the fuelmoto adjustable push rods. Combined with Feuling's lifters, I really don't think I have any reason to worry about em on a stage 2 build.
I'm far more concerned about blowing apart the compensator than a pushrod.
HDF Community Team
Joined: Sep 2013
Posts: 2,373
Likes: 2,342
From: Wisconsin
Adjustable pushrods exist for only one reason - for mechanics who are in too much of a hurry to do a proper job by removing the fuel tank and rocker covers. Some cams do require shorter push rods which are available in a one piece design as well.
Tourer
Joined: Jun 2020
Posts: 290
Likes: 67
From: Fairfax, Va
The laws of physics doesn't care if the engine architecture is modern or not. In regards to this application it could well be that the valve springs are stiff enough to control the extra mass of the heavier push rods at higher RPM's but I've not seen anyone confirm, in writing, that that is the case.
Flex is definitely a potential issue. Reputable company or not, there is only so much they can do within the tight confines of the push rod tubes. They can't makes the PR's much fatter because the adjusting nut would then have to be larger and then wouldn't fit in the tube. They can heat treat them, and they do, but that makes the PR's more brittle. They have to make them smaller diameter, but with much thicker walls to accommodate the threads, which makes them heavier. Trade off's.
The valve train doesn't care about Hp/Tq numbers, it isn't under any additional stress as power levels rise. The only thing the VT has to manage is the mass of the components that comprise it, at the reciprocating speeds it must run.
Flex is definitely a potential issue. Reputable company or not, there is only so much they can do within the tight confines of the push rod tubes. They can't makes the PR's much fatter because the adjusting nut would then have to be larger and then wouldn't fit in the tube. They can heat treat them, and they do, but that makes the PR's more brittle. They have to make them smaller diameter, but with much thicker walls to accommodate the threads, which makes them heavier. Trade off's.
The valve train doesn't care about Hp/Tq numbers, it isn't under any additional stress as power levels rise. The only thing the VT has to manage is the mass of the components that comprise it, at the reciprocating speeds it must run.
HDF Community Team
Joined: Sep 2013
Posts: 2,373
Likes: 2,342
From: Wisconsin
The laws of physics doesn't care if the engine architecture is modern or not. In regards to this application it could well be that the valve springs are stiff enough to control the extra mass of the heavier push rods at higher RPM's but I've not seen anyone confirm, in writing, that that is the case.
Flex is definitely a potential issue. Reputable company or not, there is only so much they can do within the tight confines of the push rod tubes. They can't makes the PR's much fatter because the adjusting nut would then have to be larger and then wouldn't fit in the tube. They can heat treat them, and they do, but that makes the PR's more brittle. They have to make them smaller diameter, but with much thicker walls to accommodate the threads, which makes them heavier. Trade off's.
The valve train doesn't care about Hp/Tq numbers, it isn't under any additional stress as power levels rise. The only thing the VT has to manage is the mass of the components that comprise it, at the reciprocating speeds it must run.
Flex is definitely a potential issue. Reputable company or not, there is only so much they can do within the tight confines of the push rod tubes. They can't makes the PR's much fatter because the adjusting nut would then have to be larger and then wouldn't fit in the tube. They can heat treat them, and they do, but that makes the PR's more brittle. They have to make them smaller diameter, but with much thicker walls to accommodate the threads, which makes them heavier. Trade off's.
The valve train doesn't care about Hp/Tq numbers, it isn't under any additional stress as power levels rise. The only thing the VT has to manage is the mass of the components that comprise it, at the reciprocating speeds it must run.
Thread Starter
|
Advanced
Joined: Aug 2018
Posts: 94
Likes: 14
From: California
Thanks for all the info and varying options. I talked to FM and they did say they use a ton of adjustable pushrods even in big bore builds. I will be using the S&S ones. Looks like I will be purchasing fueling lifters as well. Seems the consensus is to change them.
Road Captain
Joined: Feb 2020
Posts: 615
Likes: 209
From: California
Thanks for all the info and varying options. I talked to FM and they did say they use a ton of adjustable pushrods even in big bore builds. I will be using the S&S ones. Looks like I will be purchasing fueling lifters as well. Seems the consensus is to change them.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Seasoned HDF Member
Joined: Feb 2012
Posts: 13,456
Likes: 10,452
From: Sunshine State
The "job" they are designed to do is to make cam swaps easier which, coincidently, helps drive product sales. Marketing, being what it is, touts the benefits of the product, but almost never does it point out the potential risks. Everyone makes their own cost/benefit analysis based on the information they have, or may not have. For me, I'd really rather not risk floating the valves or having an adjustable push rod come loose.
Removing the rocker covers and rocker shafts isn't even remotely similar in time, complexity, or expense to pulling the top end (heads).
Removing the rocker covers and rocker shafts isn't even remotely similar in time, complexity, or expense to pulling the top end (heads).
Like I suggested earlier, if you wish prefection, go the extra mile and do the friggin jug upgrade while youre there, Mr join date June 2020.
My previous comment was a little positive input. There is a 11:1 piston kit fit those jugs and give it more performance if you have the time and money. Have to choose a different cam tho, the torque cam only allows 10:1 pistons.
Last edited by Tampa Fatboy; Oct 20, 2020 at 04:30 PM. Reason: typo