sbc Valve Spring replacement?
Thread Starter
Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
sbc Valve Spring replacement?
79 L82 w/ 80k miles, i plan on installing some umbrella seals on the valves stems on the car.(burning a little oil on start up), would it be wise to replace the valve springs and locks with new oem ones or just reinstall the old ones. i didnt know if it would cause any problems with the camshaft, i am also replacing the pushrods and oem rocker arms with roller tip rockers. just need some thoughts. thanks.
Drifting
Joined: Jul 2005
Posts: 1,623
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From: The Netherlands
If not mistaken, the new rocker arms will allow for more lift. I'd check if the current spring can handle that. On the other hand, if you are making such an investment and taking them off anyway: new springs aren't really that expensive...
Le Mans Master
Joined: Mar 2004
Posts: 7,507
Likes: 1,513
From: Little Rock AR
New springs are cheap BUT if the old ones were still within specs you might consider reusing them. You have put the current set on a long term QC test and they have passed. New springs are going to be fine 9 times out of 10 but why roll the dice?
No real "right" answer here but maybe this helps in some way.
-Mark.
No real "right" answer here but maybe this helps in some way.
-Mark.
Melting Slicks
Joined: Mar 2006
Posts: 3,342
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From: Connecticut
Le Mans Master
Joined: Sep 2001
Posts: 7,739
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From: Unreconstructed, South Carolina
Respectfully, In this case I disagree on reusing old springs ... nearly 30 years old & 80Kmiles ... lotsa cycle time ... they may be fine, maybe not. Under those conditions and since they're gonna be loose anyway, I'd fit new springs. BTW ... I'm not a fan of rollertips ... & IMHO, unless you're changing rockerarm ratio from stock 1.5:1 ... simply having rollertips ain't worth fooling with anyway. An OE or better quality set of replacement VSprings can be had for about $25 - $30 / 16. I'd go with an OE replacement or equivalent spring ... nothing more.
-edit-Pretty sure stock OE replacement spring for '79 from sealed power is P/N VS-677 ... while a stronger "Z-28 spring" is VS-739R .
-edit-Pretty sure stock OE replacement spring for '79 from sealed power is P/N VS-677 ... while a stronger "Z-28 spring" is VS-739R .
Last edited by jackson; Oct 26, 2007 at 05:16 PM. Reason: moinfo
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Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
-edit- ... unless there is a lotta rocker arm side play at valve tip ... you wouldn't want roller to run off the tip of valve ... guideplates too much trouble ... so if you have alotta sideplay then self-aligning may be correct for you.
Last edited by jackson; Oct 26, 2007 at 05:26 PM.
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
And then theres the standard Roller tip rocker which can cause side loading problems if the pushrod holes in the head casting are not exactly in line with the valve stem tips.
I had this problem with a set of RHS heads and the Comp Cams non aligning roller tips which you can see in the last picture.
Comp Cams Roller tip
RHS heads geometry problem with Comp Cams roller tips.
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Look at this comp cams catalog page:
http://www.compcams.com/technical/Ca...106-07/269.pdf
Look at the upside down rocker at page bottom right ... it's circled in red.
See the rails or nubs that are on either side of the tip-roller? That's a self-aligning rocker arm. Those rails/nubs are what distinguishes a self aligning rocker from non-self aligning ... nothing else ... has nothing to do with trunnion. BTW ... stock OE stamped shoe "NON roller self-aligning is similar ... has rails/nubs extending on either side of sliding surface ... captures valve tip & centers it. Comp also has same thing in rollertip but without roller trunnion.
http://www.compcams.com/technical/Ca...106-07/269.pdf
Look at the upside down rocker at page bottom right ... it's circled in red.
See the rails or nubs that are on either side of the tip-roller? That's a self-aligning rocker arm. Those rails/nubs are what distinguishes a self aligning rocker from non-self aligning ... nothing else ... has nothing to do with trunnion. BTW ... stock OE stamped shoe "NON roller self-aligning is similar ... has rails/nubs extending on either side of sliding surface ... captures valve tip & centers it. Comp also has same thing in rollertip but without roller trunnion.
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Now that I look at it I guess I was wrong about trunnion keeping it aligned.
I have also seen rockers with the flat washer type guides on both sides of the roller that keep them on the valve stem.
I think the most important issue with self aligning rollers is having the proper clearance in the pushrod holes
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Jack, are you saying that the trunnion is just there for smoother movement?
Now that I look at it I guess I was wrong about trunnion keeping it aligned.
I have also seen rockers with the flat washer type guides on both sides of the roller that keep them on the valve stem.
I think the most important issue with self aligning rollers is having the proper clearance in the pushrod holes
Now that I look at it I guess I was wrong about trunnion keeping it aligned.
I have also seen rockers with the flat washer type guides on both sides of the roller that keep them on the valve stem.
I think the most important issue with self aligning rollers is having the proper clearance in the pushrod holes
Trunnion (point at which rocker articululates up-down at rocker stud) is a ball&fulcrum on our OE C3 ... and on magnum rockers. But it's a needle bearing on late LS motors (LS still has a sliding non-roller tip) and on PRO magnum rockers. Yep, comp has Aluminum rockers with washers on either side of tip-roller to self align ... me thinks the washer type self align is a poor design. There's alot more friction reduction found in rollerizing the trunnion than in tip (tip negligible) ... look at all GM LS motors ... including hi-po LS7 ... roller trunnion w/ NON roller tip. I've seen evidence roller tip simply slides across valve tip and not rolling across.
There's alotta variation amongst heads' pr holes ... dang near impossible for anyone to say with absolute certainty exactly what's best without having the particular head & valvetrain in front of them.
