Rocker Adjustment
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Very debatable subject. I have an old Haynes manual that says 1/2 turn on one page, then a full turn on the very next page! So, you see its a matter of opinon.
Even the Haynes argued with themselves.
Inside the lifter is a plunger. You want the plunger about half way up & half way down in its bore. In laymans terms, it comes out to 1/2 turn or 180* after the pushrod starts to snug up. Placing your ratchet handle at the top position, swing it to the bottom, 180*.
Even the Haynes argued with themselves.
Inside the lifter is a plunger. You want the plunger about half way up & half way down in its bore. In laymans terms, it comes out to 1/2 turn or 180* after the pushrod starts to snug up. Placing your ratchet handle at the top position, swing it to the bottom, 180*.
Last edited by HeadsU.P.; Apr 7, 2018 at 03:09 PM.
Le Mans Master
Joined: Mar 2004
Posts: 7,465
Likes: 1,485
From: Little Rock AR
Its not critical. If you are somewhere in the middle you are fine. The clacking is too loose. Running rough is too tight. The lifter will accommodate at any adjustment in between. Setting them with the engine off is OK but I never use the term "snug". If someone is asking how to do it, "snug" can mean different things.
Engine off - Eliminate any "up and down" loose motion in the valve train plus a half turn would be fine.
Engine off - Eliminate any "up and down" loose motion in the valve train plus a half turn would be fine.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
If your car is factory....I turn them from 3/4 of a turn to one full turn. And I only turn it a 1/4 of a turn at a time and allow the lifter to pump back up by giving it 10-15 seconds...then turn it another 1/4 of a turn and so on.
And I know this may not be the case...but I have had collapsed lifters where the plunger was stuck. And it was not coming back up to the clip that keeps is assembled even when the push rod was removed. Adjusting a lifter when it is in this condition can be quite detrimental to the upper components...such as push rods, rockers, etc.
DUB
Race Director
Joined: May 2006
Posts: 18,692
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there was a similar thread today and Lars suggestion was 1/2 turn.
https://www.corvetteforum.com/forums...ve-78-l82.html
https://www.corvetteforum.com/forums...ve-78-l82.html
Last edited by MelWff; Apr 7, 2018 at 06:03 PM.
Melting Slicks
Joined: Dec 2009
Posts: 3,229
Likes: 656
From: Thunder Bay
I used Howards hydraulic rollers on my engine. They come with instructions that include the range of travel of the lifter piston. Their instructions are to calculate how many turns will place the piston in the middle of its travel. This is calculated from the pitch of the threads on the rocker stud. It would be nice if all the lifter manufacturers would provide this information. By the way IIRC it worked out to about 3/4 of a turn on my engine.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
and know many guys who do it that way....and I also know guys who set them at zero lash. But by adding a bit more of a turn will aid in compensating for wear down the road and and...when parts wear...the lifter will not clack....due to the lifters were adjusted with future wear in mind.And when you stop and think about the travel of the plunger travel...and the fine thread of the rocker stud...and addition 1/4 to half a turn is not a lot...assuming that they are not 'special' lifters that have their own specs for adjustment.
And also taking into account how the person is going to be driving it....and if the engine is old or if it is s new rebuild. So many things that can be considered.
DUB
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Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
there was a similar thread today and Lars suggestion was 1/2 turn.
https://www.corvetteforum.com/forums...ve-78-l82.html
https://www.corvetteforum.com/forums...ve-78-l82.html
I know that thread well. I got Lars paper and it is the best I have seen for doing this. In my case there maybe some dirt in the lifters that is cause the adjustments to be off.
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
For what it is worth:
If your car is factory....I turn them from 3/4 of a turn to one full turn. And I only turn it a 1/4 of a turn at a time and allow the lifter to pump back up by giving it 10-15 seconds...then turn it another 1/4 of a turn and so on.
And I know this may not be the case...but I have had collapsed lifters where the plunger was stuck. And it was not coming back up to the clip that keeps is assembled even when the push rod was removed. Adjusting a lifter when it is in this condition can be quite detrimental to the upper components...such as push rods, rockers, etc.
DUB
If your car is factory....I turn them from 3/4 of a turn to one full turn. And I only turn it a 1/4 of a turn at a time and allow the lifter to pump back up by giving it 10-15 seconds...then turn it another 1/4 of a turn and so on.
And I know this may not be the case...but I have had collapsed lifters where the plunger was stuck. And it was not coming back up to the clip that keeps is assembled even when the push rod was removed. Adjusting a lifter when it is in this condition can be quite detrimental to the upper components...such as push rods, rockers, etc.
DUB
Drifting
Joined: Apr 2010
Posts: 1,857
Likes: 332
From: Cartersville GA
I just finished up replacing the valve seals on my 350 and used Lars papers as well....Easy enough, one thing that I did notice was some of the lifters I could push down and feel the spring while others felt solid.....But as I worked my way thru all the rockers the ones that started out firm I could feel the spring once again....Not sure why.
Brian
Brian
Le Mans Master
Joined: Mar 2004
Posts: 7,465
Likes: 1,485
From: Little Rock AR
I just finished up replacing the valve seals on my 350 and used Lars papers as well....Easy enough, one thing that I did notice was some of the lifters I could push down and feel the spring while others felt solid.....But as I worked my way thru all the rockers the ones that started out firm I could feel the spring once again....Not sure why.
Brian
Brian
Le Mans Master
Joined: Aug 2017
Posts: 8,336
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From: Cool Northern Michigan
Yes, but only if you can remove the retainer ring in there. Not too many parts to those lifters. You could take it apart, clean it with some brake cleaner, reassemble, then dunk it in a cup of oil for several minutes until the bubbles cease. Re-install, set valvelash knowing the lifter is full and clean.
Or buy new. I think Summit sells individual ones.
Or buy new. I think Summit sells individual ones.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
If you have "dry" lifters, place them [rod-end up] in a tub/container with enough oil to cover them well. Then use one of the push rods to depress the piston in each lifter several times, so that oil is sucked into the lifter (and air expelled).
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,753
From: Charlotte NC
YES...and obviously this means the intake manifold comes off.
I use my drill press and a good sued push rod so I can compress the plunger down and remove the clip...unless the plunger is stuck down and the clip is easily removed.
If the plunger is stuck...in my situation of doing this for a living. I cannot waste hours trying to get the plunger to come out on a part that would obviously cost much less in replacing. So it all depends. I have soaked them and also used compressed air and blew air in on the side hole for oiling and get the plunger to come up.
And I know that this often times does not sit well with my customers...but in seem cases when I remove the lifter...or attempt to remove it...it will NOT easily come out and it has 'mushroomed' and when I get it out and look at the surface where the lifter contacts the lobe of the camshaft. I will stop and call them and let them know that the 'beginning of the end' has occurred on this engine and the top end or the entire engine may need to be rebuilt due to the excessive visual wear on the flat tappet lifter.
DUB
I use my drill press and a good sued push rod so I can compress the plunger down and remove the clip...unless the plunger is stuck down and the clip is easily removed.
If the plunger is stuck...in my situation of doing this for a living. I cannot waste hours trying to get the plunger to come out on a part that would obviously cost much less in replacing. So it all depends. I have soaked them and also used compressed air and blew air in on the side hole for oiling and get the plunger to come up.
And I know that this often times does not sit well with my customers...but in seem cases when I remove the lifter...or attempt to remove it...it will NOT easily come out and it has 'mushroomed' and when I get it out and look at the surface where the lifter contacts the lobe of the camshaft. I will stop and call them and let them know that the 'beginning of the end' has occurred on this engine and the top end or the entire engine may need to be rebuilt due to the excessive visual wear on the flat tappet lifter.
DUB
Burning Brakes
Joined: Jul 2017
Posts: 1,114
Likes: 149
From: Frisco TX
YES...and obviously this means the intake manifold comes off.
I use my drill press and a good sued push rod so I can compress the plunger down and remove the clip...unless the plunger is stuck down and the clip is easily removed.
If the plunger is stuck...in my situation of doing this for a living. I cannot waste hours trying to get the plunger to come out on a part that would obviously cost much less in replacing. So it all depends. I have soaked them and also used compressed air and blew air in on the side hole for oiling and get the plunger to come up.
And I know that this often times does not sit well with my customers...but in seem cases when I remove the lifter...or attempt to remove it...it will NOT easily come out and it has 'mushroomed' and when I get it out and look at the surface where the lifter contacts the lobe of the camshaft. I will stop and call them and let them know that the 'beginning of the end' has occurred on this engine and the top end or the entire engine may need to be rebuilt due to the excessive visual wear on the flat tappet lifter.
DUB
I use my drill press and a good sued push rod so I can compress the plunger down and remove the clip...unless the plunger is stuck down and the clip is easily removed.
If the plunger is stuck...in my situation of doing this for a living. I cannot waste hours trying to get the plunger to come out on a part that would obviously cost much less in replacing. So it all depends. I have soaked them and also used compressed air and blew air in on the side hole for oiling and get the plunger to come up.
And I know that this often times does not sit well with my customers...but in seem cases when I remove the lifter...or attempt to remove it...it will NOT easily come out and it has 'mushroomed' and when I get it out and look at the surface where the lifter contacts the lobe of the camshaft. I will stop and call them and let them know that the 'beginning of the end' has occurred on this engine and the top end or the entire engine may need to be rebuilt due to the excessive visual wear on the flat tappet lifter.
DUB
Can you put a new lifter in place of the bad one without worries about it wiping the cam lobe?
Melting Slicks
Joined: Dec 2009
Posts: 3,229
Likes: 656
From: Thunder Bay
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
Dub must be taking a nap, so the answer is yes.
You can put a new lifter on a new cam.
You can put a new lifter on a old cam.
You can not put a old lifter on a new cam.
You can put a old lifter on a old cam: same position.
Last edited by HeadsU.P.; Apr 8, 2018 at 08:07 PM.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Have answered this to many times. No matter how many times this gets asked the same opinions return. Ultimately you have to sort this out for yourself. Do a search and you can read all night. Study how a hydraulic lifter works and you will learn what controls plunger travel.
My vote is still for 1full turn.
My vote is still for 1full turn.