Shaft mount, on the street
11-08-2007, 07:40 PM
#1
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Shaft mount, on the street
The thought of switching to shaft mounted rockers crossed my mind, when a buddy of mine and i were discussing it..Would you be able to run Shaft mounts on the street? Not as a DD, but on the weekends, car shows,etc? And could you do it all on a HR motor..
11-09-2007, 07:24 AM
#5
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Just to elaborate a little. The spirng pressures and valve accelerations you see with even an aggressive HR cam simply don't warrant shafties. Good quality rocker studs and rockers will be just fine. So, it would simply be a waste of time and $$$ to install shaft mounts.
Another advantage of shafts, which does not apply to a hydraulic setup is that the alternative when something more is needed than just rockers and studs is a stud girdle. The stud girdle/good studs/good rockers combo works quite well. However, it is a PITA when it comes time to adjust the valves, especially the first time where you have to adjust, install the girdle, recheck and adjust, tighten the girdle back up, and reapeat a couple of times. I have the stud girdle setup on my bracket car (~250# seat, 700# open) and it works fine. Luckily, I only need to adjust valves every month or so. But it is kind of a pain. If you are starting with a clean slate, shaft mounts aren't too much more than a girdle setup. But most people aren't starting from zero and already have at least the rockers.
Rich
Another advantage of shafts, which does not apply to a hydraulic setup is that the alternative when something more is needed than just rockers and studs is a stud girdle. The stud girdle/good studs/good rockers combo works quite well. However, it is a PITA when it comes time to adjust the valves, especially the first time where you have to adjust, install the girdle, recheck and adjust, tighten the girdle back up, and reapeat a couple of times. I have the stud girdle setup on my bracket car (~250# seat, 700# open) and it works fine. Luckily, I only need to adjust valves every month or so. But it is kind of a pain. If you are starting with a clean slate, shaft mounts aren't too much more than a girdle setup. But most people aren't starting from zero and already have at least the rockers.
Rich
11-09-2007, 08:01 AM
#6
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I look at the stud-girdles as treating the “symptom” of the problem (rocker stud flex) and is the old-school approach. Whereas, shaft rockers eliminate the issue of stud flex and often provide some degree of mechanical efficiency (quicker opening) over standard RRs. Additionally, they eliminate the requirement for pushrod guide plates.
WD
WD
11-09-2007, 09:53 AM
#7
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I look at the stud-girdles as treating the “symptom” of the problem (rocker stud flex) and is the old-school approach. Whereas, shaft rockers eliminate the issue of stud flex and often provide some degree of mechanical efficiency (quicker opening) over standard RRs. Additionally, they eliminate the requirement for pushrod guide plates.
WD
WD
11-09-2007, 10:37 AM
#8
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I upgraded over 2 years ago from Comp rockers arms to Jesel SS shafts. My valvetrain is whisper quiet now. I did notice a SOTP difference going to the shafts, and I run a hydraulic roller. On a SBC, the shafts correct the rock arm pivot length. They have been dyno proven to give 20 to 25 HP over stud mounts on a dyno. Cost wise, by the time you buy a stud mount rocker, studs, poly locks, guide plates and a girdle; you are almost at the price of a set of shafts.
Nick
Nick
11-09-2007, 11:29 AM
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The only place I see the need for a shaft mount setup would be with very high rpm engines...the place where the stock PCM does not go.
The only if I had shaft mounts would because the heads came with it already done...if not, stud girdle the thing (which again is questionable on low rpm engines).
The cost of getting quality shaft mounts (because you can get $200 china knock offs) and the machining work...pulling the heads, new gaskets, blah, blah....simply is not worth it.
Take that money and put it in your suspension or drivetrain.
The only if I had shaft mounts would because the heads came with it already done...if not, stud girdle the thing (which again is questionable on low rpm engines).
The cost of getting quality shaft mounts (because you can get $200 china knock offs) and the machining work...pulling the heads, new gaskets, blah, blah....simply is not worth it.
Take that money and put it in your suspension or drivetrain.
11-09-2007, 12:53 PM
#13
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Originally Posted by WS6T3RROR
I'd also like to add mine are whisper quiet, cant hear a thing under the valve covers.
Originally Posted by NJLT1SS
I upgraded over 2 years ago from Comp rockers arms to Jesel SS shafts. My valvetrain is whisper quiet now.
11-09-2007, 01:15 PM
#14
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Heres a karl ellwein page with some visuals so you can see what is involved and why. I had my heads done for this while i was building my spare engine on the stand, because i was just sick of hearing the rockers in my daily driver, with which i had tried every lash setting under the sun and when they were as quiet as possible i still couldnt stand it.
http://www.karl-ellwein.org/350Y2003/350Y2003.htm
11-09-2007, 06:44 PM
#15
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I was curious. But with shaft mounts on a solid roller cam set up. Do you need to ajust the valves still? And if so how do you exactly do that with a shaft mount set up? Might be dumb question but I dont know much about them either and am interesting in knowing more.