WTH?!?! Flat Solid valve lash settings last about 5 mins.
Thread Starter
Drifting
Joined: May 2001
Posts: 1,630
Likes: 0
From: Brandywine, Chester and Ridley Valleys Pennsylvania
WTH?!?! Flat Solid valve lash settings last about 5 mins.
Either someone's sneaking into the garage and messing w/ my head when I go upstairs or these rocker arms won't keep the lash adjustment for more than a few revs. It took me a minute of head-scratching to figure it out, they were so far out of adjustment 2 cylinders weren't even firing 
What gives? Do I need to get a set of good rocker arms? Are the stamped steel arms that cheesy that they can't handle the pressure (no pun intended)?
The cam isn't that nutso, .490/.510 lift, haven't taken the new motor over 4000 rpm yet, still soft-pedalling things here.
Eventually a good set of rocker arms was to go on, but that was planned as a winter project, I just want to drive the car for a while before the salt goes down on the roads.
Set the valve lash per SWC Duke's method this afternoon, took the car down the hill not even a mile and let it idle for a bit at my office before shutting it off. Came back 30 minutes later and it went back to missing on some cylinders.
Any ideas????
What gives? Do I need to get a set of good rocker arms? Are the stamped steel arms that cheesy that they can't handle the pressure (no pun intended)?
The cam isn't that nutso, .490/.510 lift, haven't taken the new motor over 4000 rpm yet, still soft-pedalling things here.
Eventually a good set of rocker arms was to go on, but that was planned as a winter project, I just want to drive the car for a while before the salt goes down on the roads.
Set the valve lash per SWC Duke's method this afternoon, took the car down the hill not even a mile and let it idle for a bit at my office before shutting it off. Came back 30 minutes later and it went back to missing on some cylinders.
Any ideas????
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Condition of lock nuts?
Lock nuts still locking? Its hard to see what kind of lock nuts ur using from here in California. 
But the self locking type are really only good for a couple of adjustments on a hyd type lifter let alone a solid. Some mechs will just use a thin locking nut to back-up & lock the adjusting nut. Some better nuts (adjusting nuts) use an allen screw for locking the adjusting nuts. And even these easier to use scews will drive u NUTS. 
Next guess is ur not on base circle of the cam when adjusting with engine off. Or possibly spec is for a warm running engine and ur doing them while eng off & cold.
Hope this can help. cardo0
But the self locking type are really only good for a couple of adjustments on a hyd type lifter let alone a solid. Some mechs will just use a thin locking nut to back-up & lock the adjusting nut. Some better nuts (adjusting nuts) use an allen screw for locking the adjusting nuts. And even these easier to use scews will drive u NUTS. Next guess is ur not on base circle of the cam when adjusting with engine off. Or possibly spec is for a warm running engine and ur doing them while eng off & cold.
Hope this can help. cardo0
Burning Brakes
Joined: Sep 2000
Posts: 1,199
Likes: 1
From: NewCastle IN. USA
are you using your old/used stamped rocker arms?
If you are using them with a new cam then that may be the problem.
stamped steel rocker arms "wear-in" to the cam/lifter/pushrod angle. the pocket where the pushrod contacts the rocker will wear to match the end of the pushrod (giving the most area of contact).
once you put a different cam in (or change pushrod length/angle) say with more lift,, it push's the rocker around farther and contacts a new area in the socket. now your on a edge (where the worn-in area meets previously non-used area), this can cause rapid wear.
I've seen pushrods eat all the way thru stamped steel rockers and try to go thru the valve cover!
It doesn't happen every time, but it can happen. thats why they recommend keeping the valvetrain matched up during teardown/re-assembly, and why they say to replace lifters/pushrods and rockers with a new cam (flat tappet ones anyway).
If you are using them with a new cam then that may be the problem.
stamped steel rocker arms "wear-in" to the cam/lifter/pushrod angle. the pocket where the pushrod contacts the rocker will wear to match the end of the pushrod (giving the most area of contact).
once you put a different cam in (or change pushrod length/angle) say with more lift,, it push's the rocker around farther and contacts a new area in the socket. now your on a edge (where the worn-in area meets previously non-used area), this can cause rapid wear.
I've seen pushrods eat all the way thru stamped steel rockers and try to go thru the valve cover!
It doesn't happen every time, but it can happen. thats why they recommend keeping the valvetrain matched up during teardown/re-assembly, and why they say to replace lifters/pushrods and rockers with a new cam (flat tappet ones anyway).
Thread Starter
Drifting
Joined: May 2001
Posts: 1,630
Likes: 0
From: Brandywine, Chester and Ridley Valleys Pennsylvania
SWC Duke- It takes a good deal of torque to turn them, I'm guessing about 25-30 lb/ft. It's a Crower solid 321, .022I/.024E cold (iron heads anyway) This is not good I take it?
cardo0- Good point, they are the cheesey self locking ones...I didn't know they wore out...
olRJ- Yes, it's with the old stamped rocker arms. I guess that is a no-no...
Thanks folks, thanks very very much. At least I might be able to get this thing running soon...
Now, any recommendations on which rocker arms to buy? Crane Gold? Anything cheaper thah that that works well? What about the Jegs rocker arms, they're like 100 bucks cheaper.
cardo0- Good point, they are the cheesey self locking ones...I didn't know they wore out...
olRJ- Yes, it's with the old stamped rocker arms. I guess that is a no-no...
Thanks folks, thanks very very much. At least I might be able to get this thing running soon...
Now, any recommendations on which rocker arms to buy? Crane Gold? Anything cheaper thah that that works well? What about the Jegs rocker arms, they're like 100 bucks cheaper.
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Race Director
Joined: May 2000
Posts: 12,712
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Torque sounds reasonable. Pushrod/rocker arm wear could be a factor! If those are Crower's recommended specs for the cam then they are okay, but keep in mind that both OE and aftermarket cam specs are based on 1.5:1 rocker ratio for SBs. My measurements indicate that actual ratio is about 1.37:1 at the lash point and 1.44:1 at full lift with an approximate 0.3" lobe. That's why I "factor" the OE valve lash recommendations by 1.37/1.5, and I recommend this for all cam manufacturer's lash adjustements when using the OE rockers. If you use aftermarket rocker's with a different claimed ratio, you'll have to make your own measurements.
You might go ahead and change all the nuts. While doing this job, remove the pushrods and inspect both the pushrod and rockers for wear.
Duke
You might go ahead and change all the nuts. While doing this job, remove the pushrods and inspect both the pushrod and rockers for wear.
Duke
Race Director
Joined: Apr 2000
Posts: 17,672
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I had a similar problem turned out the crappy pushrods were wearing down They were the Comp pushrods with the "*****" on the end. Everything in he valve train was setup perfect just these stupid pushrods kept wearing down, took me while to find it because they were brand new, never suspected they would be crap like that, changed them to Comp pro magnum rods and never had a problem after that. 
Burning Brakes
Joined: Sep 2000
Posts: 1,199
Likes: 1
From: NewCastle IN. USA
Originally Posted by TrueBlue ChevyDude
Also, should I get new pushrods along with the rocker arms?
I'd try match marking the nuts to the rocker studs (maybe a scribe mark on each) to see if they are backing off.
I'd also pull one of the rockers off and check the wear on the pushrod/rocker socket area. (not sure what it would look like if bad, maybe two radius's? or galling?).
If the nuts are not backing off then its got to be a wear issue (or the studs are pulling out of the head).
if your using the old style valve train with guide plates (not the self aligning rockers used on later years) then you'll need hardened push rods to keep them from wearing on the guide plates.
which ones to buy?
depends on how much you want to spend!
you can buy the stamped ones again or go roller rocker. both will work, I would stay with a good brand regardless. (cheap parts cost more in the long run, sometimes).
one thing about changing to a different style rocker, you may need a different length push rod. if you stay with the stamped steel rocker the push rod "should" be the same as before.
RJ
Thread Starter
Drifting
Joined: May 2001
Posts: 1,630
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From: Brandywine, Chester and Ridley Valleys Pennsylvania
Simmo- They are screw in studs.
OlRJ- It seems like the nuts are backing off. Even looking at them without scribing them, you can see that they've ridden up the stud a signifigant bit from where they were when installed. This is after just driving for a mile too...
SWCDuke- OK I will change nuts and see if that fixes it. Where to get new nuts? I don't see any in Jegs or Summit??? Thanks for the tip about the 1.37/1.5, I;ve read some posts of yours in the past about this issue and will factor that in once I get things squared away the lash adjustment staying constant. Certainly will check the arms and pushrods for wear.
OlRJ- It seems like the nuts are backing off. Even looking at them without scribing them, you can see that they've ridden up the stud a signifigant bit from where they were when installed. This is after just driving for a mile too...
SWCDuke- OK I will change nuts and see if that fixes it. Where to get new nuts? I don't see any in Jegs or Summit??? Thanks for the tip about the 1.37/1.5, I;ve read some posts of yours in the past about this issue and will factor that in once I get things squared away the lash adjustment staying constant. Certainly will check the arms and pushrods for wear.