Rebuilt Small block-zero compression??!!!
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
I take it these are hydraulic lifters?
You're still bottomed out, DON'T LEAVE THEM LIKE THIS!
If you can't get the adjustment right with the engine off, you'll have to adjust them with it running. Get a set of rocker oil clips so you don't spray oil all over the place. Take the valve cover off and with the engine idling loosen the rocker until you hear clacking. Slowly tighten until it is quiet and then (slowly) give it another 1/2 turn.
You're still bottomed out, DON'T LEAVE THEM LIKE THIS!
If you can't get the adjustment right with the engine off, you'll have to adjust them with it running. Get a set of rocker oil clips so you don't spray oil all over the place. Take the valve cover off and with the engine idling loosen the rocker until you hear clacking. Slowly tighten until it is quiet and then (slowly) give it another 1/2 turn.
Melting Slicks
Joined: Mar 2008
Posts: 2,989
Likes: 198
From: Meriden CT
I take it these are hydraulic lifters?
You're still bottomed out, DON'T LEAVE THEM LIKE THIS!
If you can't get the adjustment right with the engine off, you'll have to adjust them with it running. Get a set of rocker oil clips so you don't spray oil all over the place. Take the valve cover off and with the engine idling loosen the rocker until you hear clacking. Slowly tighten until it is quiet and then (slowly) give it another 1/2 turn.
You're still bottomed out, DON'T LEAVE THEM LIKE THIS!
If you can't get the adjustment right with the engine off, you'll have to adjust them with it running. Get a set of rocker oil clips so you don't spray oil all over the place. Take the valve cover off and with the engine idling loosen the rocker until you hear clacking. Slowly tighten until it is quiet and then (slowly) give it another 1/2 turn.
You must have bottomed the plungers inside the lifters.
Le Mans Master
Joined: Jan 2006
Posts: 6,504
Likes: 139
From: Butler Pa
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
Instructor
Joined: Mar 2009
Posts: 187
Likes: 1
From: WA
When the car was cold i adjusted them to zero lash +1/2 turn, car wouldn't start
i then took 1/4 off, still wouldn't start
i then took another 1/4 off, then i could feel and hear the compression, so i was back to zero lash, car started
1 then once hot put a 1/4 back on, car wouldn't start
i then took 1/4 back off, car started
basically i've left it at zero lash and i've got a bad back
i soaked the lifters in oil but forgot to pump them up
i then took 1/4 off, still wouldn't start
i then took another 1/4 off, then i could feel and hear the compression, so i was back to zero lash, car started
1 then once hot put a 1/4 back on, car wouldn't start
i then took 1/4 back off, car started
basically i've left it at zero lash and i've got a bad back
i soaked the lifters in oil but forgot to pump them up
Someone support or shut me down here. I'm afraid he's about to bend some valves. No offense...
Edit: I didn't notice there was a second page and it appears others agree with me.
Last edited by 71_S-Ray; May 26, 2009 at 03:36 PM.
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 845
Likes: 54
From: Bangor, Northern Ireland
i'm aware zero lash is the point where you tighten the rocker to the point where you can't spin the pushrod with your hand.
The car run great now, 2 pumps of the throttle, turn the key and i'ts running and idling within 5 seconds or so, my issue is that i can't even put 1/4 turn on them as i will have no compression, surely i must be able to put at least 1/2 a turn, i'll get her hot and adjust them slowely while it's idling and see what occurs.
I thought hydraulic lifters where meant to make life easier!!
give me solid lifters any day, you know where you stand
The car run great now, 2 pumps of the throttle, turn the key and i'ts running and idling within 5 seconds or so, my issue is that i can't even put 1/4 turn on them as i will have no compression, surely i must be able to put at least 1/2 a turn, i'll get her hot and adjust them slowely while it's idling and see what occurs.
I thought hydraulic lifters where meant to make life easier!!
give me solid lifters any day, you know where you stand
Last edited by aaroncorvette; May 27, 2009 at 09:41 AM.
Le Mans Master
Joined: Jan 2006
Posts: 6,504
Likes: 139
From: Butler Pa
i'm aware zero lash is the point where you tighten the rocker to the point where you can't spin the pushrod with your hand.
The car run great now, 2 pumps of the throttle, turn the key and i'ts running and idling within 5 seconds or so, my issue is that i can't even put 1/4 turn on them as i will have no compression, surely i must be able to put at least 1/2 a turn, i'll get her hot and adjust them slowely while it's idling and see what occurs.
I thought hydraulic lifters where meant to make life easier!!
give me solid lifters any day, you know where you stand
The car run great now, 2 pumps of the throttle, turn the key and i'ts running and idling within 5 seconds or so, my issue is that i can't even put 1/4 turn on them as i will have no compression, surely i must be able to put at least 1/2 a turn, i'll get her hot and adjust them slowely while it's idling and see what occurs.
I thought hydraulic lifters where meant to make life easier!!
give me solid lifters any day, you know where you stand
Zero lash is when there is zero clearance on the push rod. Not when you can't turn it anymore.
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Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
For what it's worth, here's a quick way to rough in valve settings. Crank the nut nown until there are 4 threads showing above the top of the nut. An old Chevy mechanic gave me this tip. When I went back and checked them the "standard" way, sure enough, 4 threads. If you have more than 4 showing then you have the lifter bottomed.Gary
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 845
Likes: 54
From: Bangor, Northern Ireland
thanks guys,i've got roller rockers with polylocks, perhaps i'm not explaining myself right,
i adjusted the rockers as follows- spin pushrod with one hand and tighten rocker gently until it grips pushrod and i can't turn it any more, thats it
if i slackened the rockers off 1/8th of a turn they would be claking, i haven't adjusted them down so far that they have 'bottomed out', i.e tightened the rocker so much the lifter is squashed in, i've taken care with this build, unless by 'bottoming out' you guys mean something else
i'll adjust them slowly once warm tomorrow, cheers
i adjusted the rockers as follows- spin pushrod with one hand and tighten rocker gently until it grips pushrod and i can't turn it any more, thats it
if i slackened the rockers off 1/8th of a turn they would be claking, i haven't adjusted them down so far that they have 'bottomed out', i.e tightened the rocker so much the lifter is squashed in, i've taken care with this build, unless by 'bottoming out' you guys mean something else
i'll adjust them slowly once warm tomorrow, cheers
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
Forget the notion that zero lash is where you can't spin the pushrod. I've adjusted valves on hydraulic cammed engines where you can still easily spin the pushrod with the valve at full lift!!! Rattle the pushrod up and down, zero is where it won't move up and down any more with the valve on the seat. Then tighten it down 1/2 to 3/4 turn.
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
Forget the notion that zero lash is where you can't spin the pushrod. I've adjusted valves on hydraulic cammed engines where you can still easily spin the pushrod with the valve at full lift!!! Rattle the pushrod up and down, zero is where it won't move up and down any more with the valve on the seat. Then tighten it down 1/2 to 3/4 turn.
....absolutely correct.....
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Whew - lots of different approaches.
L88's right - but the "spin" method still works. Zero lash is the first time you feel ANY "drag" when rolling the pushrod between your fingers. Loosen the valve, start to tighten it down and you'll feel that spot where it's clearly not spinning 100% freely any more.
It's one of those "feel" things that's very hard to describe, but a huge "Ah-HAH!" when you actually do it.
L88's right - but the "spin" method still works. Zero lash is the first time you feel ANY "drag" when rolling the pushrod between your fingers. Loosen the valve, start to tighten it down and you'll feel that spot where it's clearly not spinning 100% freely any more.
It's one of those "feel" things that's very hard to describe, but a huge "Ah-HAH!" when you actually do it.
Instructor
Joined: Jul 2008
Posts: 100
Likes: 0
From: Long Jetty NSW
I've been caught out on the "spin the pushrod 'til it tightens" approach before. I now use a 1 & one half thou feeler gauge. As soon as I feel the slightest amount of pressure on the gauge, I call that "zero", then do the half turn bit. Seems to work for me.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Not questioning, as there's a million ways to skin this cat - but curious.
Team Owner
Joined: Jan 2007
Posts: 53,648
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From: Southern Cal Ca
St. Jude Donor '22
Instructor
Joined: Jul 2008
Posts: 100
Likes: 0
From: Long Jetty NSW
Hi Billa, caught out because I spun the pushrod until it would spin no more and assumed that was the "zero" point. Just like the originator of this thread, I ended up with no compression on some cylinders. As someone else has pointed out, some pushrods can be turned even when the valve is open. The feeler gauge is just my method of determining when there is zero lash. Because its only 1 & 1/2 thou, I doubt it effects the adjustment or end result much.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
I think that's the big misunderstanding - is that it's not about turning the pushrods...it's about feeling for contact/drag.
Everyone should find someone that knows how to do it to show them