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  #46 (permalink)  
Old 01-10-2013, 10:08 PM
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Quote:
Originally Posted by flyingputz View Post
I didn't go any deeper, just opened 'em up tp 1.350" with Comp tool #4721. The 'updated' Comp 26918 beehives are 1.310 seat diameter and were binding in areas where seat had casting ridges. Like I said, I'll definitely go a different route on my next set of vortecs. This first set was quite a learning experience. Things would have been much easier had I chosen a cam with a little less lift.
To confirm, the rockers are hitting the retainers, not the split locks, right?

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Old 01-11-2013, 04:11 AM
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With rocker centered over valve tip it contacts lock, but if rocker is slid across tip 'til the rail stops its lateral movement the opposite rail WILL contact the retainer. I've got Comp #787 7* retainers for the beehive springs. I trimmed down the tops of a set of the +.050 locks to see if I could skate by, but no go. MOST of the locks are FLUSH with the retainer. On the few where the lock actually sat higher than the retainer this theoretically might have worked. However, trimming ANY material away from such critical components is probably not a good idea. I'd rather spend a bit more money and play it safe than gamble catastophic failure. My initial objective was to upgrade these heads without doing ANY machining (other than screw in studs). Easier said than done! There are a LOT of misleading articles out there on vortec head upgrades which supposedly require no machine work.
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Old 01-11-2013, 04:44 AM
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I don't recall, what rockers are you using? Agree on misleading info. But there's something that is somehow different about your set up that is causing the problem; there are a lot of guys using everything from stock retainers to the same set up you have to going back to the early-style valves and retainers (less damper) that all work w/SA rockers. So my theory is there is (at this point, anyway) the rocker arm might be the fly in the peanut butter.

Last edited by cobalt327; 01-11-2013 at 04:50 AM.
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  #49 (permalink)  
Old 01-11-2013, 07:23 AM
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Quote:
Originally Posted by cobalt327 View Post
To confirm, the rockers are hitting the retainers, not the split locks, right?
The first pair of heads we installed were equipped with Ferrea 5000 Series valves with .256" tips. I am using Scorpion 1.5:1 SA narrow-body rocker arms for center bolt valve covers. With that set up, the alignment rails on the rocker arm roller tips actually rode ON the Comp Cams 10* locks (not the retainers) and did not even touch the valves. We switched to Comp Cams 10* locks designed for lash caps but did not use lash caps. Those keepers provided about .005"- .010" clearance between the rocker rails and the keepers. The rocker rails sit in the lash cap cavity but would pinch against the locks and eventually fail. Not good enough.

I drove it for about 4,000 miles using the lash cap keepers but I checked the keepers and rocker rails regularly. I prepared a better set of heads and this time I used Manley Race Master Series valves with .290" tips and used regular Comp Cams 613 (10*) keepers. Now the rocker rail to keeper clearance is .035" - .040" which is the way is should be and the way the SA rocker clearances were designed by GM.

It does not matter whether you are using beehive valve springs and retainers or straight springs and retainers, the clearances or lack thereof are the same. You must use valves with .290" tips with SA rocker arms. I preferred to use Ferrea 5000 Series valves but Ferrea does not offer Chevy valves with .290" tips, at least not in the 5000 Series. So you must use Manley Race Master Series valves with .290" tips and they cost twice as much.

The alternative is to get a flat bastard file and go to work.
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  #50 (permalink)  
Old 01-11-2013, 12:29 PM
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My c/n 062 heads have plenty of clearance and the tips are not 0.290- which is supposed to be only on the exhaust, anyway. I suspect the valves were resurfaced and this caused the tip lengths to be shorter than 0.260" intake/0.290" exhaust. The rockers clear them just fine. So the tip length is not ordinarily a problem.

If this was a universal problem, there would be thousands of reports of this being a problem. But there aren't- because it isn't a universal problem. There's something peculiar about HIS set up that is causing the problem, I believe it's the rockers he's using, or the geometry of the valvetrain (which hasn't been addressed AFAIK).
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Old 01-11-2013, 02:43 PM
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The O-ring groove was eliminated on the 1996-2000 062 and 906 Vortec valves and a different retainer without a shield was used.

The 906 Vortec heads were equipped with hardened exhaust seat inserts which resulted in a increased valve seat margin compared to the intake seats. The increased exhaust valve margin made the exhaust valve sit lower in the head. It was corrected by making exhaust valves with longer tip lengths. The keeper groove was the same distance from the valve seats.

In order to maintain equal valve stem heights , the O-ring groove, O-ring seals and oil shields were eliminated on the Vortec valve stems and the retainer lock grooves were relocated. The tip lengths were changed from .250" intake and exhaust to .289" on the exhaust valves and .260" on the intake valves. The valve face and seat angles should be ground in order to establish the valve margins at .050" intake and .080" exhaust to allow for the difference in valve tip lengths.
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  #52 (permalink)  
Old 01-11-2013, 05:38 PM
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Quote:
Originally Posted by flyingputz View Post
I don't mean to beat a dead horse, but here's my dilemma. I thought I had this ALL figured out. I've got the #906 vortec heads, Comp 26918 springs(recommended installed height 1.80") 787 retainers and +.050 locks. This gave me my necessary height and retainer to seal clearance, with NO machining. I don't like the idea of taking away that much material from the guides and seat, especially since the guide is ALSO the spring locator. I don't even know if ANY material can be taken away from seat to increase installed height? Now my rockers are contacting on many of the retainers. If I put the standard locks in place plenty of valve tip is available, however, that takes away my retainer to seal clearance AND increases my seat pressure to approx. 144 lbs. I feel my only option is +.100 longer valves. I will take up any extra height with -.050 locks OR shims. I know I'll have to keep the geometry correct at final assembly via pushrods. BTW, cam is 222-230 dur. .509/.528 lift @ .050 with 1.5 rockers. I'll be using Comp 1.52 rollers(self aligning). Screw in studs are already in place. As stated, I already have ALL these parts. Any thoughts or suggestions greatly appreciated.
I have to admit that after 4 pages of this I'm getting lost.

So if you still have the problem let me state my understanding, or lack, of it.

I take that you have self guided roller rockers and the self guiding guides that are like washers located to either side of the roller which contacts the valve stem are themselves touching the spring retainer. Is this correct?

The other choice open to interpretation is that the body of the rocker contacts the spring retainer. Is this what's happening?

Neither situation is desirable, nor acceptable, but the causes and solutions of each are different.

Neither of these problems have much to do with the installed height of the valve, not that this can be ruled out but for the valve to be sitting deep in the seat from an exuberance of seat grinding to the head or valve, or both, would have to be very extreme to have such a huge effect on the angle of how the rocker address the valve stem as to put parts of the rocker into contact with the spring retainer or the locks. Sinking the valve seats (head and valve) forces the stem to ride higher in the guide. This moves the lock position (thus the retainer) further from the spring seat resulting in the installed length of the spring to be longer than specification which in turn relaxes the spring reducing the forces it will generate toward keeping the valve train following the cam lobe and holding the valve in the closed position. Typical flat rate shop work for this situation would be to shim the spring between the spring pocket and spring is the usual solution toward making the effective length of the spring shorter so the correct spring length is established between the bottom of the retainer and the top of the shim. The valve tip is often ground to restore the installed height of the stem to the valve spring pocket to restore the rocker angle and position to the stem tip. But this shortens the clearance distance between the lock grooves and stem tip; thus also ,where the retainer positions from the stem tip, this can get you into clearance problems between the retainer and rocker or in the case of self guided rockers the lesser distance could put the guiding bosses or washers into contact with the retainer. As an aside this is a common problem with older Ford SBs where rocker tip and stem tip wear closed the clearance till the rocker guides rubbed on the retainer, which risks pushing the retainer low enough to allow the locks to pop out dropping the valve into the cylinder.

Obviously trying to avoid shortening the Vortec's tall guide boss to provide additional lift clearance between the assemblage of the retainer, stem seal, and stem guide by sinking the valve deeper in its seat is not the way to solve this clearance problem as it gets you into the problems I describe above. When I read your comments through this; I get the feeling that this approach could be involved. Did you do this?

It is always possible that the lock angle of 10 degrees or 7 degrees does not agree with the interfacing angle of the retainer. This would cause the retainer to sit improperly as a position to the stem tip and affect spring installed length. Did you check these parts to be sure they have matching angles?

Roller rockers especially cast ones tend to be fatter than stampings; it is not unusual to have to grind a clearance into their body to clear the retainer especially where oversized springs are used.

The angle the rocker makes with respect to the retainer can also be an issue; if the studs are too short there usually isnít enough bite for the studís threads into the retaining nut which can result in thread failure. Solution is a longer stud which for sure will force a longer pushrod. Or if the pushrod is too short because the valve stem sits higher than designed then the rocker sits at a low position with a sharp angle between the push rod and stem tip that can get it into contact with the retainer. The solution is a longer push rod.

If everything is dimensionally correct and the witness marks on the stem show the roller to be properly positioned on the stem sweep but the guide washers are riding on the retainer then one can consider several possibilities are causing the stem clearance distance to be incorrect:

- This can be a result of the lock's location of the tang being other than what you expect; there are locks that move the tang up or down .050 inch being typical from the OEM position. These are often relieved for lash caps which will allow their use with roller tipped rockers. You also need to be sure the locks are the proper diameter for the valve stem. Between .310, 8mm (.3150), .3437, .375 inches there's getting to be things that are close but not necessarily correct for what you're using, so you've got the check stuff before using it.

- The distance between the lock groove and the stem tip is insufficient. Typically the SBC valves come in a .225, .250, or .290 inch clearance. Don't go by what documentation says should be there use what provides the needed clearance. Often the overall length is held at a constant and this clearance is moved by relocating the lock groove, this is done to play with spring length as a means of adjusting pressure between the weight differences of intake and exhaust valves. More engineering refinement than is probably necessary for anything short of a race engine. Use this to get the rocker correctly positioned. Keep in mind that longer valves does not mean the relationship between the lock groove and stem tip changed but is just moved further from the valve head and seat. Some heads are .1 or .2 inch taller between the seat and the spring pocket and need an overall longer stem to restore the spring length to retainer relationship. This doesnít change the groove to stem clearance aside from placing that relationship further from the valve head. This will require longer pushrods because it changes the rockerís position from the head deck (makes the engine taller is at were) but does not necessarily change the dimensions between the bottom of the spring retainer and the top of the spring pocket, I mean it can, but doesnít have to. The production Vortec head should require this kind of messing around unless youíre trying to get space for more lift without grinding down the guide. In that case you get into a lot of problems not unlike where youíre at. Did you do this?

- The guide washers are too large, given the quality issues I see almost everywhere anymore it could be that the guide washers are bigger than needed, I guess I could say grind them down, but I wouldn't do that except as a last resort after checking and adjusting everything else first.
I know itís hard to believe, but Iím out of words and will be out for the weekend. So good luck with this.

By the way, a hydraulic lifter will chase any gap that opens up in the valve train parts till the plunger runs into it retainer (bail or clip). This is what a pumped up lifter is all about. A space appears between the parts for any reason, the lifter closes it. If it was adjusted properly there's about a .020 to .030 gap between where it's running position is and its retainer. When it closes that space the next time the valve goes to close it can't, it's hanging .020 to .030 off its seat till the lifter bleeds down and returns to its normal preload clearance.

Bogie
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  #53 (permalink)  
Old 01-12-2013, 04:22 AM
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Quote:
Originally Posted by MouseFink View Post
The O-ring groove was eliminated on the 1996-2000 062 and 906 Vortec valves and a different retainer without a shield was used.

The 906 Vortec heads were equipped with hardened exhaust seat inserts which resulted in a increased valve seat margin compared to the intake seats. The increased exhaust valve margin made the exhaust valve sit lower in the head. It was corrected by making exhaust valves with longer tip lengths. The keeper groove was the same distance from the valve seats.

In order to maintain equal valve stem heights , the O-ring groove, O-ring seals and oil shields were eliminated on the Vortec valve stems and the retainer lock grooves were relocated. The tip lengths were changed from .250" intake and exhaust to .289" on the exhaust valves and .260" on the intake valves. The valve face and seat angles should be ground in order to establish the valve margins at .050" intake and .080" exhaust to allow for the difference in valve tip lengths.
Thanks for the info, I have not seen this tip/seat info here previously. If it can be verified (not doubting you; got any links?) I will include it in the wiki.

My heads are 062 w/induction hardened exhaust seats. It may be that standard Vortec tip valves were used in non hardened insert Vortec applications; there's no sense in using a too-long tip to correct for a problem that doesn't exist on non hardened insert-equipped heads- this would be as bad as using a too-short tip on an insert-equipped head.

However I believe discontinuing the O-ring/metal shield was unrelated to going to a single groove stem; the O-ring/metal shield simply isn't needed when using the Vortec valve stem seals. I believe they opted for the better seals for emissions and cost savings as much as anything, secondarily for any other reasons.
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Old 01-13-2013, 12:27 AM
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Well, after much thought heres what I've decided to do. I'm gonna ditch the +.050 locks in favor of standard locks. This gives me plenty of valve tip to work with. I'll machine the guides down a bit to give me the necessary retainer to guide clearance, and live with the slightly increased seat pressure( up from 130# @ 1.80" installed height to 145# @ 1.75" installed height). I'll still be safe from coil bind and my open pressure will be in line(342# @ 1.20") A guide cutter and new seals is a helluve lot cheaper than the new valve order I cancelled. That and I had just gotten a valve job done on them a month or so ago. The proverbial "fly in the ointment" was the +.050 locks. They just won't work with .25" valve tips and self aligning rocker arms. Dare I ask, anyone see issues with this or does it seem the logical thing to do?

BTW Cobalt, the stamped rockers were contacting locks/ retainers also
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Old 01-13-2013, 04:15 AM
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The +.050" locks will shorten the effective valve tip length.

If you do not want to go to the expense of purchasing valves with .290" tips, use locks designed with a recess for lash caps...... but do not use the lash caps. The lash cap recess will proved a little more clearance for the self aligning full roller rocker rails. I ran those type locks for about 4,000 miles with Scorpion narrow body, self aligning, full roller rocker arms before I installed better heads with Manley SS valves that had .290" tips. I inspected the locks and rocker arms regularly because I realized that was not the best way to solve the problem. Unfortunately, lash cap locks will not help if you are using stock self aligning rocker arms. The alignment nubs on the stock self aligning rocker arms are too large.

I would probably have still been using the Comp Cams 10* Super locks designed for lash cap locks if I had not installed the better heads I had prepared with Manley valves. I replaced the 10* lash cap locks with standard 10* Super Locks and have .035" clearance between the rocker rails and the locks. .

Last edited by MouseFink; 01-13-2013 at 04:41 AM.
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Old 01-13-2013, 08:31 AM
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Quote:
Originally Posted by flyingputz View Post
Well, after much thought heres what I've decided to do. I'm gonna ditch the +.050 locks in favor of standard locks. This gives me plenty of valve tip to work with. I'll machine the guides down a bit to give me the necessary retainer to guide clearance, and live with the slightly increased seat pressure( up from 130# @ 1.80" installed height to 145# @ 1.75" installed height). I'll still be safe from coil bind and my open pressure will be in line(342# @ 1.20") A guide cutter and new seals is a helluve lot cheaper than the new valve order I cancelled. That and I had just gotten a valve job done on them a month or so ago. The proverbial "fly in the ointment" was the +.050 locks. They just won't work with .25" valve tips and self aligning rocker arms. Dare I ask, anyone see issues with this or does it seem the logical thing to do?

BTW Cobalt, the stamped rockers were contacting locks/ retainers also
Still wondering what rockers you're using.
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Old 01-13-2013, 11:47 PM
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I've got the Comp pro magnun chromoly self aligning full rollers. #1317 if I remember correctly. These went out of production some years back but I found a set of NOS at a reasonable price.
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Old 01-14-2013, 07:30 AM
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The Comp Cams 1317 rocker arms have the alignment tabs on the rocker arms rather than on the roller tips. That makes them about .020" wider between the alignment tabs. That will cause the rocker arm alignment tabs to contact 7* retainers rather than the locks. The alignment tab location and not being narrow body for center bolt valve covers were the reasons they were taken out of production. They are rebuildable but apparently that was not a good selling point.

If you use 10* locks with a lash cap recess (and 10* retainers), the 1317 alignment tabs would fit inside the lash cap recess and may offer a bit more clearance. That is not the best way to get more clearance but it is cheaper than buying a set of Manley SS valves with .290" tips or buying a new set of aluminum, narrow body, self alignment rocker arms.

I used Scorpion 1073BL full roller, self alignment, narrow body, aluminum rocker arms. Those rockers have the alignment rails on the roller tips. They measure 0.350" between the alignment rails and better fit SB Chevy 0.343" (11/32") valve stems with negligible (0.0035") side to side movement. I am using Manley valves with .290" tips. The rocker arm alignment rails have .035" clearance from the 10* locks.
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  #59 (permalink)  
Old 01-14-2013, 08:06 AM
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For comparison sake...

Quote:
Originally Posted by flyingputz View Post
I've got the Comp pro magnun chromoly self aligning full rollers. #1317 if I remember correctly. These went out of production some years back but I found a set of NOS at a reasonable price.
The 1317 seem to still be in production. They are mentioned by Sallee specifically as an option for the production Vortec heads:



In any event, those rockers have wider alignment rails compared to a rocker like the Comp p/n 1015:

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Old 01-14-2013, 02:29 PM
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After I shave the guides down to .530" should I use the Comp #503 PTFE .530 seals or the #529 viton .530 seals? Or #518? I read somewhere that the PTFE (teflon) seals require a crimping tool? Does one seal have a lower profile than the other?

Last edited by flyingputz; 01-14-2013 at 02:42 PM.
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