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Rocker contacting top of retainer on vortec heads

32K views 74 replies 11 participants last post by  flyingputz 
#1 ·
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.
 
#3 · (Edited)
Lash caps crossed my mind, AFTER iI already pulled the heads back off of the engine. I hadn't yet used a marker/dykem to see roller sweep across valve tip, but even if I do need longer pushrods, the clearance is nil. I can actually spin the roller tip on one valve stem with rocker installed. Rocker RAIL is resting on the retainer, roller isn't even contacting valve. I WILL use lash caps or Manley LocCaps if I can. The 787 retainers are 7*. Are super 7 locks compatible? I have no lash cap experience, so if this is truly an option someone please let me know. Thanks.
 
#4 ·
Super & locks are actually 8 degree. Will not work correctly on any thing but super 7 retainers.

If your rockers are the self guided rail type. Lash caps won't work. They increase the valve tip diameter to 3/8". Rocker will be too narrow between rails.

Cheapest way out is to go with a +.050 pushrod and lightly trim the rocker rails for clearance. As long as the roller remains fairly centered on the valve you will be ok.
 
#5 ·
I didn't think lash caps & rail rockers would go together, no clearance there. I was just looking at them & realized that. I'm kinda leary about shaving down the rails. I sure don't want to turn 'em into paperweights. Could I switch to guideplates if I remove the rails, or muck 'em up trying to shave 'em down? I certainly don't need any extra expense (new valves) if not absolutely necessary. Thanks for your input.
 
#28 ·
I was looking for that option but got no input on going that route. Too late now, new valves (intake & exhaust) are on the way. $240 later! My NEXT set of vortecs will be MUCH easier!(if I ever use 'em again!) No biggie, I'm opening up spring pockets anyway even though machinist I used said they were good to go. MY opinion differed.
 
#6 · (Edited)
What valves are you using?

Vortec valves have a .290" valve tip for self aligning rocker arms. Standard SB Chevy valves have .250" valve tips. If you use standard SB Chevy valves, self aligning rocker arms will contact the keepers.

I had to use Manley 11863-1 (E) 1.600" and 11860-1 (I) 1.940" valves and self aligning rocker arms. Ferrea does not have SB Chevy valves with a .290" tip. You must use Ferrea valves for a 351-C Ford.

Do not machine the Vortec valve spring pockets. They are too thin, use +.050" keepers to gain valve spring height. My heads have exhaust valve spring rotators which presents a special problem on the exhaust valves. I had to use .075" shims and + .050" locks " on the exhaust valve springs to get 1.750" assembled height. No problem with standard locks on the intake valve springs.

I am also using Comp Cams 26918 beehive valve springs. I enlarged the stock spring seat diameter from 1.250" to 1.320" in order to fit the Comp Cams beehive valve springs. I was even nervous about doing that.
 
#7 ·
Were you able to widen the spring pockets without taking the guide dia. down? I'd also like to widen the pockets a bit as the spring is quite tight/binding in pocket as it sits. The Comp tool takes down the guide (spring locator) as it opens the pocket if I remember correctly. I don't want to do that. Thanks for info. I bought the heads off c-list so I don't know if valves are original. I will measure the groove to tip distance in a bit. I THINK Trick Flow has valves with longer groove to tip?
 
#8 ·
I would have used the 26981 springs and reduced the guide height with the Comp part #4726 cutter for .530 seals. Not alot has to be taken off to give the required retainer to seal clearance.
 
#9 ·
Mousefink,
I pulled a couple of valves, did some measuring, and found some discrepancy. The valve with actual CONTACT with the rocker rail measured .25" groove to tip. The valve WITHOUT contact, but very close measures .29". I don't know if the previous owner swapped some valves or ground the tip down. It looks as if some grinding was done. Tip of valve has machine marks on it. Do I file off rocker rails & install guide plates, or buy new/ longer valves?
 
#11 ·
My machinist used a Comp Cams 4716 cutter to enlarge the valve spring seats for the beehive valve springs and reduced the O.D. of the inner spring locator boss. The tool cuts 1.320" O.D. valve seat x .630" valve guide boss. The Comp Cams 26918 valve springs are 1.310" O.D. x .885" I.D. at the base. The engine builder may have used Goodson tools but they cut the same dimensions as the Comp Cams cutters. I talked to the machinist about reducing the O.D. of the inner spring locator boss and he seemed to think reducing it to .630" O.D. for the .885" I.D. valve springs would not create a problem. The cutter provides spring clearances of .005" outer x .128" inner in order to register the valve spring properly on the head. That stabilizes the valve spring and prevent "dancing" (oscillation).

The valve guide itself was cut for Comp Cams 518 Viton metal body seals for 11/32" stems (.530" guide x .575" O.D. seal) using a Comp Cams 4726 guide cutter. I think the machinist removed about .150" guide height for .060" minimum retainer to seal clearance. He used the Comp Cams Viton metal body seals on the intake and exhaust valves. The Comp Cams seals are .575" O.D. and were pushed down on the .530" guides. That places the seals .060" from the ledge of the .630" O.D. guide boss.

IMO, there is no way to avoid cutting the inner guide boss when machining the spring pockets for larger O.D. valve springs.

As I recall, the machinist may not have used the Comp Cams 614 +.050" valve locks on the exhaust valves. I gave him a set to use if he needed them after eliminating the exhaust valve rotators. I recorded most of the engine assembly data on my computer for future reference in case my memory fails me.
 
#13 ·
flyingputz,
It may make some food for thought, but I don't think it will solve your problem.
I noticed that the top of the seven degree retainer seems to be higher than the top of the seven degree locks(on the left in the pic), vrs the same dimension using the ten degree locks/retainers on the right.
However it also seems that the 10* locks are closer to the tip of the valve like the +0.050" standard locks do, so no benefit.
You might look at the locks that have the recess for lash caps(pn611,or614). They might help? I don't know if you can run them without the caps? Probably not a good idea.
Personally I would use the standard 7* locks, and machine the top of the guides down about .070", and live with the increased seat load(130lbs@1.8" vrs 146lbs@1.75" installed height). I assume your using the roller cam/lifters the springs are designed for. If you consider that the conventional springs for roller cams typically use more force to control the valvetrain(seat load and over the nose) than behives do, your not hurting the valves, lifters, or cam IMO. Also if you may consider that many people install 1.6:1 rockers which increase the load on the valvetrain similar to increased spring pressure, but use the same springs as if they were 1.5:1 rockers, and have no detrimental effects. JMHO
FWIW,
ssmonty
 

Attachments

#14 ·
I suggested Comp Cams 10* Super Locks for lash caps to gain a little clearance for the self adjusting rocker rails. I bought a set of those locks and trial fitted them with a rocker arm, valve and 10* retainer and did not gain enough clearance, even with the 10* locks and retainers which are wider than the 7* locks and retainers. I decided to purchase, prepare and install a set of Manley valves with .290" tips, even though they are about twice the cost of Ferrea valves. BTW, my engine builder used Comp Cams 795 10* retainers and Comp Cams 613 10* locks. I called him at home and he said he did not use the +.050" locks. He said he shimmed the exhaust valve springs enough to eliminate the valve rotators without using +.050" locks. All valves have 1.750" height and the train works perfect.

Parts:
Comp Cams 26918 beehive springs
Comp Cams 795 retainers 10*
Comp Cams 613 locks, 10*
Scorpion 1073BL rocker arms, 1.5:1 self self aligning, narrow body.
ARP 134-7104 rocker studs, 3/8"-24 x 7/16"-14 with Time Serts.
Alex's Parts shims, 1.255" O.D. x .875" I.D. hardened
Comp Cams 7940 push rods, 7.200" chromemoly, .080" wall
Comp Cams 15850 hyd. roller lifters, REM finish, short travel, .005" pre-load.

When I was trying to determine what valves to use, I finally called Ferrea and their representative suggested using the Ferrea Ford 351W valves with .395" tips. I am sure those would provide more rocker arm clearance than necessary but I thought the extra long tips may cause a problem with the rocker arm, rocker stud and push rod geometry. I purchased Manley Vortec valves with .290" tips. I believe those valves were designed with self-aligning rocker arms in mind.
 
#15 ·
SSMonty,
I used Crane machined steel +.050 locks (look a bit beefier than the stockers) and most are flush with the retainer. A couple locks are even a tad higher than the retainer( probably not even measurable). I just remembered I have a set of bad vortecs(cracked) laying around. I'll see if I can use the valves from the bad set. They have about 240,000 miles on 'em, but mavbe they'll clean up. I'll measure the rest of my valve tips and make sure that's the issue. I appreciate all the input guys.
 
#17 ·
Tomorrow I'll measure ALL the valve tips on my old, bad set of #906 castings. I KNOW all those valves are the original parts. Sometimes I think "The General" just uses whats available! Especially if it was assembled on a Friday afternoon! BTW, the (my) short-tipped valve HAS the backcut. What I DO know is that for MY particular application I need the .290" tips. The carmakers sure don't make it easy, do they? Oh, and Happy New Year!
 
#18 · (Edited)
It's not as bad if you need intake valves bigger than 1.94".

BTW, if you use stock diameter springs you might want to use the stock Vortec retainers- they're made to have plenty of clearance for self aligning rockers.

BTW II, all I have been able to find regarding replacement Vortec valves (or more correctly, valves used w/self aligning rockers like Vortec and LT1/4, etc.) is:

Intake- 0.260" groove to tip length
Exhaust- 0.289" groove to tip length

Why exhausts are longer I cannot say, but the first time the intake valve tips are reground, that extra 0.010" is all but gone. And as I said earlier, this is not like my Vortec valves- they're standard length tips. So take it for what it's worth- all I can say is a stock 0.250" tip is plenty for use w/the stock valve train.
 
#19 ·
It is the keepers, not the retainers, that interfere with the self aligning rocker arm rails or nubs when using valves with .250" tips.

I furnished my engine builder with the Ferrea 5000 Series SBC valves with .256" tips and later found the problem with the keeper to rocker rail interference. After discussing the problem with my machinist, he told me the Chevrolet heads that use self aligning rocker arms have valves with .260" tips (int.) and .289" tips (exh.). He recommended Manley Race Master Series SBC valves with .290" tips, intake and exhaust. Manley Race Master Series 11863-1 and 11860-1 valves with .290" tips provides .035" clearance between the10* keepers and the self aligning rocker arm rails, when using beehive valve springs. I am using 10* keepers which are wider across the tip of the valve than 7* keepers. When trial fitting the Scorpion self aligning roller rocker arms with the Ferrea SBC valves that have .256" tips, the self aligning rocker rails actually rode on the the 10* keeper and not on the valve!

The beehive retainers are smaller in diameter (1.055" O.D.) and sit lower on the valve stem than standard valve spring retainers and do not present a problem with self aligning rocker arms.
 
#20 ·
Well, I pulled, cleaned & measured all the valves off my bad set of vortecs and here's what I found. ALL intake valves are a bit shorter than the exhaust valves. 4.88" vs. 5.91". The lock groove to tip is ALSO shorter on the intake valves. .260" vs. .290". Looks like I can use all the exhaust valves but will have to purchase new Manley intake valves. I wonder what the reasoning was for the valve variation? This would make the valve FACE to lock groove identical. Hardened tip inserts, perhaps? :confused:
 
#21 ·
I used Manley Race Master Series SS valves that have .290" tips and are 4.951" long.

I used those valves with Comp Cams 26918 beehive valve springs, 10* keepers and retainers. We equalized the beehives at 1.750" with 144 lb. seat pressure and 330 lb. at .500" valve lift, according to a Rimac spring tester.
 
#22 ·
Just a thought I emailed one of the guys at comp to see what I needed to give me more lift on my 906's and he hooked me up with a parts list of what I needed that handles .600 lift with no machining. I know u said youy already had parts but if you cant figure it out this is another option.

Good luck
 
#24 ·
Comp parts gave me what I needed as far as lift and retainer clearance. It DIDN'T give me my needed rail rocker to lock/ retainer clearance. Make sure you check this if you go that route! It probably wouldn't have been an issue with use of guide plates and NON self- align rockers.
 
#27 ·
Would it not be more cost efficient to install the guide plates under your screw in studs and swap out the rockers rather than redesign your intake valvetrain? I'm assuming this would be easier than the swapping valves and locks and keepers. Are your current pushrods hardened? If so this route would cut back greatly on labor as well. Another thing comes to mind is the center bolt valve covers vs. the sbc style as he non self allinging Are narrower to allow for clearance on the vortec bolt patterin.
 
#29 ·
I used 10* Super Locks designed for lash caps on my first pair of heads with SA rockers and they provided additional clearance for the SA rocker arm rails. I put about 4,000 miles on them with no problems. I did not use the lash caps, just the locks.

I replaced those heads recently and used regular 10* locks and Manley SS valves with .290" tips. That is the proper way to do it. The .290" tips provide .035" clearance between the locks and the SA rocker arm rails.
 
#31 ·
your seat pressure is of little significance here, what is your open pressure? If you have enough clearance between your retainer and seal with standard locks at peak lift then your best solution (and the free one) is to just use standard locks. I'm betting the .050" difference on the compressed height and pressure of your spring isn't going to make a bit of difference (provided you have clearance).

I hate to say this but the $240 you just spent on valves was over nothing.
 
#33 ·
The problem being discussed is:
The clearance between the self aligning rocker arm rails and the valve lock (aka, keepers). The + .050" locks does nothing to provide more clearance. The + .050" locks will lengthen the valve spring by .050", provide .050" clearance between the retainer and the valve seal and will reduce valve spring pressure. .050" x spring rate per inch.

The Manley SS valves for Vortec heads have .290" tips and will solve the problem of self aligning rocker arm to valve lock clearance. The .290" tips provide .040" clearance whereas the 1955-1995 SBC valves with .250" tips provide .000" clearance. Using 1955-1995 valves and self aligning rockers can toss the self aligning rocker arms off the valve stems, or worse.

When you are using self aligning rocker arms:
1. Must use valves with .290" tips.
2. Must avoid valve float at all costs.
3. Must use hydraulic lifters.
 
#34 ·
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.
 
#35 ·
Spring pockets on Vortec heads:
1. Enlarge pockets to a maximum of .100" for valve springs that are 1.350" diameter.
2. Do not machine the spring pocket depth in order to increase valve spring assembled height.
3. In order to increase spring height, use + .050" locks and/or + .100" long valves.

If there is another way to use Vortec heads, please advise.
 
#37 ·
I know exactly what the OP was "trying" to say. I have been there before. Sometimes people get locks and retainers confused as the OP did in this case.

You cannot set the lash using a feeler gauge with a solid lifter camshaft if you have self aligning rockers. The gauge will not fit between the rocker and the valve tip.

Self aligning rockers are difficult to use with Comp Cams 875 or 15850 short travel hydraulic lifters. Those lifters set a .005" pre-load. I am using CC 15850 lifters and can set them with a "flick of the wrist" without a feeler gauge which is 1/16" to 1/8" pre-load.
 
#39 ·
Southern engineering will not solve the problem. If it would I would grind my own camshafts with a wood rasp.

When using self aligning rockers, the rocker MUST be pre-loaded (in contact) with the valve tip at all times or the rocker arms will be tossed off the valve. That eliminates the use of a solid lifter camshaft that may set from .015" to .030" valve lash.
 
#42 ·
Hydraulic lifter valve train must always maintain contact between the valve tip, rocker arm, push rod, lifter and camshaft lobe. That is why they call it "pre-load". If pre-load (contact) is lost due to valve float, valve bounce or lifter loft, you can have possible destruction of the engine. High lift camshafts increase the possibility of valve float if the valve springs are not strong enough to maintain the pre-load. When you reach a certain spring load, you must switch to solid lifters and self aligning rockers are designed for mild camshafts with valve lifts less than .525".

A camshaft with more than .525" valve lift require valve springs with no less than 150 lb seat pressure and 350 lb. open pressure along with full roller rocker arms. IMO, that is too high for regular production hydraulic lifters. I used Comp Cams 15850 short travel restricted oiling lifters because my Comp Cams 26918 beehive valve springs were set up at 144 lb. seat pressure at 1.750" and 330 lb. open pressure at .500" valve lift. No valve train noise and no sign of valve float at 5,500 RPM.
 
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