valve lash question
Thread Starter
Instructor
Joined: Feb 2015
Posts: 234
Likes: 20
From: Stuart Florida
valve lash question
I have recentlly had Lloyd elliot LE2 head job. Installed Lunati 227/234 .570/.574 cam, Full roller rockers, new Lunati hydraulic lifters...etc.
Lloyd Elliot said to adjust to zero plus 1/4 turn. I've adjusted a lot of valve trains, solid and hydraulic. I just adjusted zero plus 1/4. It just feels too loose, sloppy if you will. I redid it, same feeling. Loyd has been great, and answered my myriad goofy questions. Has any one done a similar setup, and did you tighten more than 1/4 past zero? I was thhinking at least 1/2 or maybe 3/4.It's Saturday night and so I can't contact Lloyd and I want to get this done so I can drive tomorrow. Thanks
Lloyd Elliot said to adjust to zero plus 1/4 turn. I've adjusted a lot of valve trains, solid and hydraulic. I just adjusted zero plus 1/4. It just feels too loose, sloppy if you will. I redid it, same feeling. Loyd has been great, and answered my myriad goofy questions. Has any one done a similar setup, and did you tighten more than 1/4 past zero? I was thhinking at least 1/2 or maybe 3/4.It's Saturday night and so I can't contact Lloyd and I want to get this done so I can drive tomorrow. Thanks
Instructor
Joined: Feb 2016
Posts: 130
Likes: 17
I am putting my 85 engine back together now, and am installing the rockers. My Crane instructions say to tighten 1/2 to 1 full turn after the pushrod snugs up. I have been using 1/2 turn while checking the rockers and this allows the pushrods to be spun by hand after a few rotations of the crank. I am going to experiment with 1 full turn and see how that affects the snugness. I am a novice at this.
Thread Starter
Instructor
Joined: Feb 2015
Posts: 234
Likes: 20
From: Stuart Florida
I am putting my 85 engine back together now, and am installing the rockers. My Crane instructions say to tighten 1/2 to 1 full turn after the pushrod snugs up. I have been using 1/2 turn while checking the rockers and this allows the pushrods to be spun by hand after a few rotations of the crank. I am going to experiment with 1 full turn and see how that affects the snugness. I am a novice at this.
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
I doubt that your Lunati hydraulic lifters have a different adjustment procedure than the factory lifters. Try out this link: There are two techniques addressed here. I've tried both, and like the procedure that uses a 0.0015 feeler gauge to find "zero" lash.
corvetteforum.com/forums/c4-tech-performance/3817181-1984-cfi-rocker-arm-torque-adjustment-specs.html
Let us know how this works out for you!
corvetteforum.com/forums/c4-tech-performance/3817181-1984-cfi-rocker-arm-torque-adjustment-specs.html
Let us know how this works out for you!
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The lifters leak down as you adjust, which really messes up your lash setting. In my opinion the only way to really adjust them correctly is hot and running. That said, I found that setting the (stock) adjusting nut to 0.200" down from the end of the rocker arm stud will get you right where you need to be. With an aftermarket cam you're on your own.
A valve adjusting aid can be helpful to get "hot and running" done without splashing oil all over the place:
A valve adjusting aid can be helpful to get "hot and running" done without splashing oil all over the place:
Instructor
Joined: Feb 2016
Posts: 130
Likes: 17
I doubt that your Lunati hydraulic lifters have a different adjustment procedure than the factory lifters. Try out this link: There are two techniques addressed here. I've tried both, and like the procedure that uses a 0.0015 feeler gauge to find "zero" lash.
corvetteforum.com/forums/c4-tech-performance/3817181-1984-cfi-rocker-arm-torque-adjustment-specs.html
Let us know how this works out for you!
corvetteforum.com/forums/c4-tech-performance/3817181-1984-cfi-rocker-arm-torque-adjustment-specs.html
Let us know how this works out for you!
How do you know if you have collapsed the lifter?
I have been setting the lash, then rotating the crank, and then removing the lifters to check where the roller is contacting the valve stem. Then I adjust my pushrod length and do it over again. Are my lifters bleeding down a little while I am doing this? If so what is pumping them back up?
My new pushrods won't be here for a few days so I have lots of time to think about how I am screwing this up.
Safety Car
Joined: Sep 2004
Posts: 3,953
Likes: 550
From: Mission Viejo CA
Since you are familiar with this procedure, you'll recognize what I call "pushrod rattle". When the rocker is very loose, the pushrods are loose (rattle) in the spherical pocket of the rocker. As you tighten the adjustment of the rocker, the "rattle" disappears, but the pushrod can still be rotated. If you continue to tighten the rocker, the pushrod will get very difficult to turn. It's at that point you have collapsed the lifter, and you are starting to compress your valve spring. That takes a few more turns on your adjuster.
The internal spring in the hydraulic lifter extends the lifter to its maximum height when you relieve pressure on the lifter.
I have been setting the lash, then rotating the crank, and then removing the lifters (rocker arms?) to check where the roller is contacting the valve stem. Then I adjust my pushrod length and do it over again. Are my lifters bleeding down a little while I am doing this? If so what is pumping them back up?
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Thread Starter
Instructor
Joined: Feb 2015
Posts: 234
Likes: 20
From: Stuart Florida
This link mentions that you can collapse the lifter while adjusting the lash and then your adjustment will be off. This seems like a big problem for setting the lash.
How do you know if you have collapsed the lifter?
I have been setting the lash, then rotating the crank, and then removing the lifters to check where the roller is contacting the valve stem. Then I adjust my pushrod length and do it over again. Are my lifters bleeding down a little while I am doing this? If so what is pumping them back up?
My new pushrods won't be here for a few days so I have lots of time to think about how I am screwing this up.
How do you know if you have collapsed the lifter?
I have been setting the lash, then rotating the crank, and then removing the lifters to check where the roller is contacting the valve stem. Then I adjust my pushrod length and do it over again. Are my lifters bleeding down a little while I am doing this? If so what is pumping them back up?
My new pushrods won't be here for a few days so I have lots of time to think about how I am screwing this up.
Do this:
Wipe the top of the valve stem off, where it touches the roller on the rocker. Then mark the entire top with a black sharpie. Install an adjustable pushrod. Install rocker, adjust rocker to zero lash and rotate crank 360 degrees. The sharpie mark should be rubbed off across the middle of the top of the valve stem if your pushrod length is correct. If the pattern is shifted to intake side of valvestem, the pushrod is too long. If the pattern is shifted towards the exhaust side of the valvestem, the pushrod is too short. Go .050 longer or shorter as you need and repeat. Order pushrods accordingly. On my 1994, stock pushrod is 7.2" With reworked heads and valvetrain, and .026 head gaskets, I needed 7.0" pushrods for proper geometry.
Instructor
Joined: Feb 2016
Posts: 130
Likes: 17
I think you meant removing the rockers not lifters?
Do this:
Wipe the top of the valve stem off, where it touches the roller on the rocker. Then mark the entire top with a black sharpie. Install an adjustable pushrod. Install rocker, adjust rocker to zero lash and rotate crank 360 degrees. The sharpie mark should be rubbed off across the middle of the top of the valve stem if your pushrod length is correct. If the pattern is shifted to intake side of valvestem, the pushrod is too long. If the pattern is shifted towards the exhaust side of the valvestem, the pushrod is too short. Go .050 longer or shorter as you need and repeat. Order pushrods accordingly. On my 1994, stock pushrod is 7.2" With reworked heads and valvetrain, and .026 head gaskets, I needed 7.0" pushrods for proper geometry.
Do this:
Wipe the top of the valve stem off, where it touches the roller on the rocker. Then mark the entire top with a black sharpie. Install an adjustable pushrod. Install rocker, adjust rocker to zero lash and rotate crank 360 degrees. The sharpie mark should be rubbed off across the middle of the top of the valve stem if your pushrod length is correct. If the pattern is shifted to intake side of valvestem, the pushrod is too long. If the pattern is shifted towards the exhaust side of the valvestem, the pushrod is too short. Go .050 longer or shorter as you need and repeat. Order pushrods accordingly. On my 1994, stock pushrod is 7.2" With reworked heads and valvetrain, and .026 head gaskets, I needed 7.0" pushrods for proper geometry.
I was marking the tops, sorry that's what I meant when I said I was checking the contact point. I ordered a new set of pushrods after I checked using the adjustable pushrod.
Thanks, so when I remove the tension on the rocker nut any lifter bleed down is restored by the spring.