***7.450 push rods***
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
www.ls1howto.com has a great install for yella-terras: http://www.ls1howto.com/index.php?article=21
I did not have to use shims in my setup and it took exactly 1 full turn to get from finger tight to wrench tight.
Once the rockers are sitting in the right place, use a 10mm socket and extension but NO SOCKET WRENCH, and finger tighten the rocker arm bolts until both of the bolts get too tough to spin with 2 fingers. You can take your index finger and try to spin the pushrod under the rocker arms as well, and it should have some friction on it and just barely spin, if spin at all. This is called "Zero Lash" and it is where there is no preload on the lifters....the lifter is touching the pushrod, the pushrod is touching the rocker, and the rocker is touching the valve, all without putting any pressure on the lifter.
NOW, get your socket wrench out and attach it to the 10mm socket+extension you were using. Without turning the bolt AT ALL, place the wrench in the 12 o'clock position. What we have to do is count the bolt turns until the instant the bolt gets hand tight. Turn each of the two bolts 90 degrees clockwise, then set the wrench at 12 o'clock and repeat (do each bolt one 1/4 turn, and keep alternating).....each 1/4 turn per bolt seems to equate about 10-12 thousandths preload (this is a very rough guess!).
If you get MORE than 1 full 360 degree turn on each bolt, remove the rockers and install the shims on the bottom of the pedestals and repeat this process to check the new preload. The shims seem to reduce the turns by approximately 270 degrees. You must install a shim on BOTH bolts, not just one or the other. If you got LESS than 1 full 360 degree turn then you are ok to leave the shims out!
Every car will be different so make sure you check this! You want the smallest number of turns you can get, as long as you have at least 1/4 or 1/2 full turn of preload in there once you are all setup. If you get to the point where the bolt is tight yet you can still spin the pushrod (without using shims), then your pushrods are either too short, your valves are too short, or you have some strange valvetrain geometry. You MUST have some preload or it will be OBSCENELY loud and run very poorly. Longer pushrods may fix your issue in this case.
NOW, get your socket wrench out and attach it to the 10mm socket+extension you were using. Without turning the bolt AT ALL, place the wrench in the 12 o'clock position. What we have to do is count the bolt turns until the instant the bolt gets hand tight. Turn each of the two bolts 90 degrees clockwise, then set the wrench at 12 o'clock and repeat (do each bolt one 1/4 turn, and keep alternating).....each 1/4 turn per bolt seems to equate about 10-12 thousandths preload (this is a very rough guess!).
If you get MORE than 1 full 360 degree turn on each bolt, remove the rockers and install the shims on the bottom of the pedestals and repeat this process to check the new preload. The shims seem to reduce the turns by approximately 270 degrees. You must install a shim on BOTH bolts, not just one or the other. If you got LESS than 1 full 360 degree turn then you are ok to leave the shims out!
Every car will be different so make sure you check this! You want the smallest number of turns you can get, as long as you have at least 1/4 or 1/2 full turn of preload in there once you are all setup. If you get to the point where the bolt is tight yet you can still spin the pushrod (without using shims), then your pushrods are either too short, your valves are too short, or you have some strange valvetrain geometry. You MUST have some preload or it will be OBSCENELY loud and run very poorly. Longer pushrods may fix your issue in this case.
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Sorry to disagree, but I thought the 7.425's sounded louder - maybe that's just cause the 7.425 clip of the engine compartment was longrer - however, only real way to correctly determine the needed legnth is w/ a pushrod checker - which I believe you have ordered - also, I've just grown to accept that some sewing machine noise is inevitable and the sound of horsepower - also, also, I think headers amplify the sewing machine sound
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
www.ls1howto.com has a great install for yella-terras: http://www.ls1howto.com/index.php?article=21
I did not have to use shims in my setup and it took exactly 1 full turn to get from finger tight to wrench tight.
I did not have to use shims in my setup and it took exactly 1 full turn to get from finger tight to wrench tight.
Thanks for the LINK...
Burning Brakes
Joined: Oct 2004
Posts: 931
Likes: 35
From: Rowlett, Texas
Sleeper, sorry to hear you are still having problems.
Good luck with the push rod checker. That should eliminate the guesswork.
With the HS rockers, etc; you may well have a pre-load problem of some kind.
Just to recap; remember that the rocker bolts thread pitch is 0.050, and with the 1.7 ratio rockers, one turn of the bolt = .080 preload on the lifter. So most stockers are about 1.25 turns, for approx 0.100 lifter preload. As the guys said, be sure the cam is on the base, be sure the bolts are lightly turned to where the PR just begins to get all the slack out as it contacts the lifter cup (spin it with your fingers, you'll feel it), then turn down, not to 22 lb-ft, but to just where the pedestal is snug, where resistance is first felt. (22 lb-ft just stretches the bolt, but adds no preload after the pedestal snugs down).
If you saw 2.5 turns, as the guys said, you got a BIG problem, or didn't do it just right.
If it helps, even my teeeny-baby 212/218 cam has a bit of click, and it's "for sure" set at factory specs of 0.100.
Cheers,
DG
Good luck with the push rod checker. That should eliminate the guesswork.
With the HS rockers, etc; you may well have a pre-load problem of some kind.
Just to recap; remember that the rocker bolts thread pitch is 0.050, and with the 1.7 ratio rockers, one turn of the bolt = .080 preload on the lifter. So most stockers are about 1.25 turns, for approx 0.100 lifter preload. As the guys said, be sure the cam is on the base, be sure the bolts are lightly turned to where the PR just begins to get all the slack out as it contacts the lifter cup (spin it with your fingers, you'll feel it), then turn down, not to 22 lb-ft, but to just where the pedestal is snug, where resistance is first felt. (22 lb-ft just stretches the bolt, but adds no preload after the pedestal snugs down).
If you saw 2.5 turns, as the guys said, you got a BIG problem, or didn't do it just right.
If it helps, even my teeeny-baby 212/218 cam has a bit of click, and it's "for sure" set at factory specs of 0.100.
Cheers,
DG
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Sleeper, sorry to hear you are still having problems.
Good luck with the push rod checker. That should eliminate the guesswork.
With the HS rockers, etc; you may well have a pre-load problem of some kind.
Just to recap; remember that the rocker bolts thread pitch is 0.050, and with the 1.7 ratio rockers, one turn of the bolt = .080 preload on the lifter. So most stockers are about 1.25 turns, for approx 0.100 lifter preload. As the guys said, be sure the cam is on the base, be sure the bolts are lightly turned to where the PR just begins to get all the slack out as it contacts the lifter cup (spin it with your fingers, you'll feel it), then turn down, not to 22 lb-ft, but to just where the pedestal is snug, where resistance is first felt. (22 lb-ft just stretches the bolt, but adds no preload after the pedestal snugs down).
If you saw 2.5 turns, as the guys said, you got a BIG problem, or didn't do it just right.
If it helps, even my teeeny-baby 212/218 cam has a bit of click, and it's "for sure" set at factory specs of 0.100.
Cheers,
DG
Good luck with the push rod checker. That should eliminate the guesswork.
With the HS rockers, etc; you may well have a pre-load problem of some kind.
Just to recap; remember that the rocker bolts thread pitch is 0.050, and with the 1.7 ratio rockers, one turn of the bolt = .080 preload on the lifter. So most stockers are about 1.25 turns, for approx 0.100 lifter preload. As the guys said, be sure the cam is on the base, be sure the bolts are lightly turned to where the PR just begins to get all the slack out as it contacts the lifter cup (spin it with your fingers, you'll feel it), then turn down, not to 22 lb-ft, but to just where the pedestal is snug, where resistance is first felt. (22 lb-ft just stretches the bolt, but adds no preload after the pedestal snugs down).
If you saw 2.5 turns, as the guys said, you got a BIG problem, or didn't do it just right.
If it helps, even my teeeny-baby 212/218 cam has a bit of click, and it's "for sure" set at factory specs of 0.100.
Cheers,
DG
I'm on a learning curve. I understand a sewing machine sound will be there..but the "trashing" machine sound I have just isn't normal...
So I'm waiting for the checker to get here and follow the instructions you and others have given on how to do it correctly..
Thanks again
Deno
Last edited by SLPRC5; Aug 22, 2007 at 07:35 PM.
Safety Car
Joined: Apr 2004
Posts: 3,932
Likes: 8
From: Hayward California
As much as I've personally not seen different rockers improving valvetrain noise, if it works for you great. Just do yourself a favor... Since you're buying a p-rod checker, what preload will you be shooting for? The reason I ask is that there are many, many folks (the same ones that say just live with it) that have the .100 preload and are still not stock-sounding. How will you know for sure it will work for you versus a lower/smaller preload?
I would still recommend using shims to find the preload that gets it to a point where it's quiet enough.
Arnel
I would still recommend using shims to find the preload that gets it to a point where it's quiet enough.
Arnel
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Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
As much as I've personally not seen different rockers improving valvetrain noise, if it works for you great. Just do yourself a favor... Since you're buying a p-rod checker, what preload will you be shooting for? The reason I ask is that there are many, many folks (the same ones that say just live with it) that have the .100 preload and are still not stock-sounding. How will you know for sure it will work for you versus a lower/smaller preload?
I would still recommend using shims to find the preload that gets it to a point where it's quiet enough.
Arnel
I would still recommend using shims to find the preload that gets it to a point where it's quiet enough.
Arnel
Lets hope the YT rockers will help out..if not another bad choice and $$ wasted...
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
^ YT rockers are worth the money if only for the fact that you get rid of the needle bearing, failure-prone, oem rockers. The YTs are on trunions and are much more stable.
AlohaC5 gained 9rwhp dyno confirmed on his 383 from only swapping the the YTs. Less friction and less deflection at high lift is a good thing!
Plus they're dead sexy
AlohaC5 gained 9rwhp dyno confirmed on his 383 from only swapping the the YTs. Less friction and less deflection at high lift is a good thing!
Plus they're dead sexy
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
^ YT rockers are worth the money if only for the fact that you get rid of the needle bearing, failure-prone, oem rockers. The YTs are on trunions and are much more stable.
AlohaC5 gained 9rwhp dyno confirmed on his 383 from only swapping the the YTs. Less friction and less deflection at high lift is a good thing!
Plus they're dead sexy
AlohaC5 gained 9rwhp dyno confirmed on his 383 from only swapping the the YTs. Less friction and less deflection at high lift is a good thing!
Plus they're dead sexy
Thread Starter
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Melting Slicks
Joined: Jul 2006
Posts: 3,356
Likes: 1
From: Chesapeake Va
The bigger shaft would make them stronger, and add zero weight to the valvetrain.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I just set up a set of YT's last night. Used a dial indicator and checking springs. I found that the as installed wipe pattern was off center towards the intake and the provided shims are necessary to obtain a correct wipe pattern. You should check this during installation. Also, use a pushrod checker to verify your length.
Didn't you pay a local shop to do this work?
Didn't you pay a local shop to do this work?
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
^ Not according to the directions that came w/ my YTs. It says nothing about adjusting for wipe, it only speaks of pre-load.
It tells you to firs test w/o shims, if it takes over 1 full turn to get from finger tight to wrench tight then you need the shims.
I still have the paper at home for the exact wording.
It tells you to firs test w/o shims, if it takes over 1 full turn to get from finger tight to wrench tight then you need the shims.
I still have the paper at home for the exact wording.
Burning Brakes
Joined: Oct 2004
Posts: 931
Likes: 35
From: Rowlett, Texas
Well, Sleeper, the plot thickens!
This is fun, gets my old Retired Engineer juices flowing.
Shimming the pedestal will certainly affect the wipe pattern a bit, as the fulcrum point of the rocker arm is changed. Maybe it's not much, but many of the guys on the Forum have discussed it in relation to the various after-market rockers. I can see it possibly making noise if off a bit. Certainly the wear/stress issue is real if it's not correct.
I guess if it was me, I would first shoot for a verified 0.80 - 0.120 lifter pre-load to start. If in that range, the lifters should be pretty happy.
Then, take a close look at the valve stem wipe pattern to insure it's good.
Others with more experience on the LS1 can correct me, but
on the old engines, we marked the valve stem with a Sharpie, and tried to get the most centered "rub spot" on the valve stem as the rocker arm moved the valve fully up and down.
If I remember correctly, I don't think PR length or lifter pre-load has any affect on wipe pattern; only pedestal ht, cam base circle, and head design/geometry will change these. (and of course, rocker arm design/geometry, if different from stock.)
SON OF A GUN, YOU CHANGED ALL OF THESE!
So, better check that wipe pattern.
Check Comp Cams web site, lots of good "wipe" info there.
So, if the wipe is good and centered on the valve stem, then leave the pedestals alone (or try the pedestals on one set and see how the wipe changes.
Pick the wipe/pedestal combo that looks best.
Then,
Pick the lifter preload you want. (my guess, .100-.120 will be quietest - no flames please.)
Do the math and select the proper PR.
If none of that works, well, re-install the old LS6 cam - ha!
Keep us informed on progress - interesting project.
Cheers,
DG
This is fun, gets my old Retired Engineer juices flowing.
Shimming the pedestal will certainly affect the wipe pattern a bit, as the fulcrum point of the rocker arm is changed. Maybe it's not much, but many of the guys on the Forum have discussed it in relation to the various after-market rockers. I can see it possibly making noise if off a bit. Certainly the wear/stress issue is real if it's not correct.
I guess if it was me, I would first shoot for a verified 0.80 - 0.120 lifter pre-load to start. If in that range, the lifters should be pretty happy.
Then, take a close look at the valve stem wipe pattern to insure it's good.
Others with more experience on the LS1 can correct me, but
on the old engines, we marked the valve stem with a Sharpie, and tried to get the most centered "rub spot" on the valve stem as the rocker arm moved the valve fully up and down.
If I remember correctly, I don't think PR length or lifter pre-load has any affect on wipe pattern; only pedestal ht, cam base circle, and head design/geometry will change these. (and of course, rocker arm design/geometry, if different from stock.)
SON OF A GUN, YOU CHANGED ALL OF THESE!
So, better check that wipe pattern.
Check Comp Cams web site, lots of good "wipe" info there.
So, if the wipe is good and centered on the valve stem, then leave the pedestals alone (or try the pedestals on one set and see how the wipe changes.
Pick the wipe/pedestal combo that looks best.
Then,
Pick the lifter preload you want. (my guess, .100-.120 will be quietest - no flames please.)
Do the math and select the proper PR.
If none of that works, well, re-install the old LS6 cam - ha!
Keep us informed on progress - interesting project.
Cheers,
DG