1.7 Rockers
Thread Starter
Race Director
Joined: May 2001
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1.7 Rockers
It's my turn to play like Grumpy does and just paste a link. Unforunately this is just something I wrote. If anything doesn't make sense let me know. I haven't even read back over it yet, no spell check either so I'm sure it's full of mistakes.
http://www.wku.edu/~nathan.plemons/htmls/rockers.html
http://www.wku.edu/~nathan.plemons/htmls/rockers.html
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Joined: Dec 2000
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From: SE NY
Cruise-In II Veteran
Re: 1.7 Rockers (Nathan Plemons)
I think that, in general, it's better to get the lift from a cam than to use the rockers to avoid increasing side thrust on the valve train.
However, for the guys with early L98s using flat tappet cams, 1.7:1 RRs could be used to increase valve lift and effective intensity (lobe slope) beyond the inherent limits of such a cam.
For those of us with roller cams, going to 1.7:1 RRs is a "cheap" (relatively) way to do a cam change.
I wouldn't worry too much about lost power due to increased forces since even a cam change usually means increased spring pressure which, in turn, means more force is needed to open the valves.
BTW, here's a "free edit"; in this line of text "thicker rocker studs will help offset the additional drivetrain stress caused by the higher rocker ratio", I suggest you change "drivetrain" to "valvetrain".
What you have done here is just what I did on my site; put answers to FAQs and other info on my site and place a link to that site in my sig.
However, for the guys with early L98s using flat tappet cams, 1.7:1 RRs could be used to increase valve lift and effective intensity (lobe slope) beyond the inherent limits of such a cam.
For those of us with roller cams, going to 1.7:1 RRs is a "cheap" (relatively) way to do a cam change.
I wouldn't worry too much about lost power due to increased forces since even a cam change usually means increased spring pressure which, in turn, means more force is needed to open the valves.
BTW, here's a "free edit"; in this line of text "thicker rocker studs will help offset the additional drivetrain stress caused by the higher rocker ratio", I suggest you change "drivetrain" to "valvetrain".
What you have done here is just what I did on my site; put answers to FAQs and other info on my site and place a link to that site in my sig.
Team Owner
Joined: Mar 2000
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From: Boston, MA
Re: 1.7 Rockers (bogus)
question... do the 7/16" studs require a retap of the head? or do the threads into the head taper down?
Thread Starter
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: 1.7 Rockers (65Z01)
BTW, here's a "free edit"; in this line of text "thicker rocker studs will help offset the additional drivetrain stress caused by the higher rocker ratio", I suggest you change "drivetrain" to "valvetrain".
Race Director
Joined: Feb 2003
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From: Everyday you must choose between the pain of discipline and the pain of regret. Fredericktown, OH
Re: 1.7 Rockers (Nathan Plemons)
This is a very good write up. I almost started playing around with mixing rocker ratios on a cam that had the same lift on the intake and exhaust side, was going to go up on the exhaust (in my hard core bracket racingt days) as I had heard of several guys who really like the performance gain. As such, you see a lot of split duration/lift cam shafts with higher numbers on the exhaust side.
At any rate, one thing I did not notice specifically in the write up (and it's something I should know). I take it the LT-4 is not using guideplates and therefore not hardened push rods either?
Regardless, you did a very nice job compiling your research and experience. Thanks! :thumbs:
At any rate, one thing I did not notice specifically in the write up (and it's something I should know). I take it the LT-4 is not using guideplates and therefore not hardened push rods either?
Regardless, you did a very nice job compiling your research and experience. Thanks! :thumbs:
Thread Starter
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
Re: 1.7 Rockers (LT-4 CE)
LT4's might have guideplates, factory LT1's in the Vettes did (not the f-body though?) But they are not true guide plates per say. The stock LT4 rockers are self aligning so they are not needed.
