Pushrod length
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Pushrod length
I've got the AFR 195 eleminator heads, TPIS .029 head gaskets and LS7 lifters. I've checked the length with a pushrod length checker using the LS7 lifters with it adjusted at one turn. It looks like the stock length of 7.2 is correct. I'm getting a small mark in the center of the valve stem. Does this seem correct or am I doing something wrong?
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
What valve spring are you using?
If your using the valve springs that come on the head your doing it wrong. The spring will bottom out the lifters plunger travel giving you a false reading and that pattern means nothing.
You must either make a "solid lifter" that won't compress or use a very light checker spring on the valve that won't cause the plunger on the lifter to bottom out.
Will
If your using the valve springs that come on the head your doing it wrong. The spring will bottom out the lifters plunger travel giving you a false reading and that pattern means nothing.
You must either make a "solid lifter" that won't compress or use a very light checker spring on the valve that won't cause the plunger on the lifter to bottom out.
Will
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
What valve spring are you using?
If your using the valve springs that come on the head your doing it wrong. The spring will bottom out the lifters plunger travel giving you a false reading and that pattern means nothing.
You must either make a "solid lifter" that won't compress or use a very light checker spring on the valve that won't cause the plunger on the lifter to bottom out.
Will
If your using the valve springs that come on the head your doing it wrong. The spring will bottom out the lifters plunger travel giving you a false reading and that pattern means nothing.
You must either make a "solid lifter" that won't compress or use a very light checker spring on the valve that won't cause the plunger on the lifter to bottom out.
Will
Drifting
Joined: Aug 2000
Posts: 1,614
Likes: 0
From: Colleyville Texas
I've got the AFR 195 eleminator heads, TPIS .029 head gaskets and LS7 lifters. I've checked the length with a pushrod length checker using the LS7 lifters with it adjusted at one turn. It looks like the stock length of 7.2 is correct. I'm getting a small mark in the center of the valve stem. Does this seem correct or am I doing something wrong?
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
There's a very simple procedure shown on Car Craft's site that doesn't involve all the lifter or spring mods. None of that. Simple, accurate, fast.
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!
Thread Starter
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
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Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
link ?
Will
Le Mans Master
Joined: May 2007
Posts: 8,448
Likes: 27
From: Valparaiso
So its not that accurate then ????
i will need to measure my AFR 195's + LPE 219 Cam pretty soon
i got everything to measure it right :
1- An adjustable pushrod
2- Check springs
3- Mockup Rocker arm
i will need to measure my AFR 195's + LPE 219 Cam pretty soon
i got everything to measure it right :
1- An adjustable pushrod
2- Check springs
3- Mockup Rocker arm
Racer
Joined: Oct 2007
Posts: 478
Likes: 1
....and then there is the mid-lift theory which a lot of the builders use. I have used this method myself and even went so far as to make up a tool using a dial indicator as shown in following link. I was looking for another website that was more graphic but this site will do.
http://74.125.155.132/search?q=cache...&ct=clnk&gl=us
And one more.
http://74.125.155.132/search?q=cache...&ct=clnk&gl=us
http://74.125.155.132/search?q=cache...&ct=clnk&gl=us
And one more.
http://74.125.155.132/search?q=cache...&ct=clnk&gl=us
Last edited by 1989TransAm; Dec 28, 2009 at 06:35 PM.
Pro
Joined: Sep 2004
Posts: 505
Likes: 1
From: Guntersville Alabama
Great thread and very timely.
93cruiser
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Yep, that's the site, but there are plenty of others, like the cam companies, CompCams, Lunati, ISKY, etc. or magazines like GM HIGH TECH PERFORMANCE, ENGINE MASTERS, SUPER CHEVY, on and on.
Guys, don't take something that's so simple to do, then turn it into something complicated. K.I.S.S.
GEEEZZZ!
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!
Guys, don't take something that's so simple to do, then turn it into something complicated. K.I.S.S.
GEEEZZZ!
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!
Last edited by JAKE; Dec 29, 2009 at 01:46 AM.
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
What I don't get - is if your going to do it WRONG, why bother to do it at all?
When the lifter plunger compresses it happens in the first .200ish of cam LOBE lift... Since most hyd camshafts are only a .350ish lobe your only measuring 1/3 of the rockers TRUE travel thru the range of lift at the valve.
That is why your rocker pattern on the valve stem will always look really small/narrow when you do it this way. Its always going to look good when the rocker only moves 1/4 of the distance (vertically and horozonally) it's soposed to.
The above applies to whatever method of valve train geometry you subscribe to. MILLER's "mid lift" theroy or the old "minimize scrub across the valve stem" system.
It's really easy to intall and use a checker spring. Takes about 10 seconds to switch the valve spring out.
If you want to do it the hard way or just don't like taking the valve spring assy apart for some reason, it takes all of 20 mins to take an old hyd roller lifter apart and grind some 1/4" washers down to fit in the lifter body (under the plunger assembly) to make it solid.
Will
When the lifter plunger compresses it happens in the first .200ish of cam LOBE lift... Since most hyd camshafts are only a .350ish lobe your only measuring 1/3 of the rockers TRUE travel thru the range of lift at the valve.
That is why your rocker pattern on the valve stem will always look really small/narrow when you do it this way. Its always going to look good when the rocker only moves 1/4 of the distance (vertically and horozonally) it's soposed to.
The above applies to whatever method of valve train geometry you subscribe to. MILLER's "mid lift" theroy or the old "minimize scrub across the valve stem" system.
It's really easy to intall and use a checker spring. Takes about 10 seconds to switch the valve spring out.
If you want to do it the hard way or just don't like taking the valve spring assy apart for some reason, it takes all of 20 mins to take an old hyd roller lifter apart and grind some 1/4" washers down to fit in the lifter body (under the plunger assembly) to make it solid.
Will
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Since there are SO MANY DIFFERING, unorthodox and, yes, down-right "bad" views floating around on the net, covering just about anything we do to these engines, the VERY FIRST decision for me is to determine on whose recommendations and advice to rely.
In my case, it first boils down to the valve train gurus, like Godbold at CompCams or Billy (?)Knight, I believe at Lunati. There are a few more, but those two are REALLY 'Heavy Hitters' when it comes to the valve train.
Then I use our "Library Of Congress", high reader mags, like GM High Tech Performance, Engine Masters, Super Chevy, Corvette Fever, Vette, on and on.
Then, when I need to, I get feed-back from really reputable guys, those with excellent track records, like ShoeBox, GrumpyVette, SpeedyGonzales, just to name a few.
Finally I fall back on my years of experience (and since I'm 64 I've got lots of those in building both street and full-race engines) of screwing on these suckas.
Your choice. Bottom line, whomever you choose, choose wisely.
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!
In my case, it first boils down to the valve train gurus, like Godbold at CompCams or Billy (?)Knight, I believe at Lunati. There are a few more, but those two are REALLY 'Heavy Hitters' when it comes to the valve train.
Then I use our "Library Of Congress", high reader mags, like GM High Tech Performance, Engine Masters, Super Chevy, Corvette Fever, Vette, on and on.
Then, when I need to, I get feed-back from really reputable guys, those with excellent track records, like ShoeBox, GrumpyVette, SpeedyGonzales, just to name a few.
Finally I fall back on my years of experience (and since I'm 64 I've got lots of those in building both street and full-race engines) of screwing on these suckas.
Your choice. Bottom line, whomever you choose, choose wisely.
Jake
West Point ROCKS! Nation's TOP COLLEGE per Forbes Magazine!! Graduation Day Parade 20 May 2010!!!
Racer
Joined: Oct 2007
Posts: 478
Likes: 1
Let me just say the least amount of sweep by the rocker arm means more motion is available for the opening of the valve. With what I will call the mid-lift method you can get the sweep down to .030" - .040". That will transfer the most cam lobe lift to the valve.
