rocker shaft shims, what are they good for?
#173687
12/23/08 11:47 PM
12/23/08 11:47 PM
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this is what can happen. i'll build a new stand and fix it, but i know my customer wishes he'd never heard of those things.
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Re: rocker shaft shims, what are they good for?
[Re: dirtybee]
#173689
12/24/08 12:36 AM
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the reason that can happen is that the saddle radius is .875". when you put a shim in the saddle, it reduces the width of the saddle by the thickness of the shim. when that happens, it tries to push the edges of the saddle apart when the rocker shaft bolts are tightended. in this case the stand/saddle just couldn't handle that much extra pressure. i can tell this will be a lot of fun to fix.
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Re: rocker shaft shims, what are they good for?
[Re: sixpackgut]
#173692
12/24/08 12:53 AM
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they aren't stock rockerarms. this is a pair of Zeeker heads with Zeeker/Dove rockers and the geometry is terrible. the customer used shims to try to correct it. the rockers are too short and sit almost on the inner edge of the valve, they also didn't clear the 1.625 springs, even though they were already clearanced on the underside. i'll correct the geometry for him without the use of conventional shims under the shafts and make a new stand to replace the damaged one. i'm not sure if anyone cares, but maybe i'll post pictures of the completed repairs.
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Re: rocker shaft shims, what are they good for?
#173693
12/24/08 01:01 AM
12/24/08 01:01 AM
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sixpackgut
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well, i would be interested in seeing the repair and .... the bill
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Re: rocker shaft shims, what are they good for?
[Re: dirtybee]
#173696
12/24/08 05:37 AM
12/24/08 05:37 AM
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493_DART
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yikes---! i think ive got .015 or so shims on mine , and with Dove rockers. isnt that cast--how is that repairable ?
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Re: rocker shaft shims, what are they good for?
[Re: 493_DART]
#173701
12/24/08 09:52 AM
12/24/08 09:52 AM
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Quote:
yikes---!
i think ive got .015 or so shims on mine , and with Dove rockers.
isnt that cast--how is that repairable ?
normally .015 or .030 shims won't hurt anything. these heads had considerably more than that. even though the head is cast aluminum, it is can be welded. the castings are very rough and porous and that doesn't bode well for a good clean high strngth weld. porous cast aluminum can get brittle. fear not, we have the technology.
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Re: rocker shaft shims, what are they good for?
#173702
12/24/08 10:06 AM
12/24/08 10:06 AM
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B G Racing
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Quote:
this is what can happen. i'll build a new stand and fix it, but i know my customer wishes he'd never heard of those things.
Dan,we see that alot with both iron and aluminum heads.Mostly when some one puts a washer under the shaft and trys to fit it by cranking down the bolt or stud nut.Generally we just machine off the stand and make a block with a through hole for the shaft and vertical hole for the hold down stud or bolt.That way we can offset the shaft hole up or down vertically or laterally to correct the geometry.On high lift,high pressure applications we add a locating pin to indicate the block to the head to keep the blocks in place since the holes for the hold downs need to be oversize for relocation and oiling.The block with 100% contact around the shaft and the large seat area(block to head)makes for a stronger attachment for the shaft and allows for unlimited correction capabilities.
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Re: rocker shaft shims, what are they good for?
[Re: boscosis]
#173704
12/24/08 10:38 AM
12/24/08 10:38 AM
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CompWedgeEngines
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I'm addressing that Edelbrock geometry issue with Harland Sharp. They work just fine, but they clearly can be better. A bazillion stes of them out there on Ebrocks and doesnt seem to affect them, but again, cleary can be better.
On the Zeekers, hopefully the customer will ante up for studs on that set up as well. If I re-call he was trying to use bolts to hold it all down too.
RIP Monte Smith
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Re: rocker shaft shims, what are they good for?
[Re: CompWedgeEngines]
#173705
12/24/08 11:00 AM
12/24/08 11:00 AM
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i've made rocker stands before for other heads. the only thing that comes into question on these heads is if there's enough material thickness to drill and tap for a longer stud after milling the old stand off.
Bob, i always put a dowel pin in to locate the stands also.
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Re: rocker shaft shims, what are they good for?
[Re: MR_P_BODY]
#173706
12/24/08 11:01 AM
12/24/08 11:01 AM
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tjmarcus1
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Quote:
The shims I used some years back were thick on the bottom .015 or .030 and thin on the walls, almost 0
ditto! divorak has the correct ones that seem to work.
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Re: rocker shaft shims, what are they good for?
#173707
12/24/08 11:02 AM
12/24/08 11:02 AM
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B G Racing
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Quote:
i've made rocker stands before for other heads. the only thing that comes into question on these heads is if there's enough material thickness to drill and tap for a longer stud after milling the old stand off.
Bob, i always put a dowel pin in to locate the stands also.
Can't speak for the Zeekers,but it workes ok for stock heads as well as Indys.
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Re: rocker shaft shims, what are they good for?
#173708
12/24/08 11:46 AM
12/24/08 11:46 AM
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ok fellows. the shims were made out of soft copper so that it would conform to the pedestal. now these heads needed the rocker shaft raised up .120" the get the roller tip to travel in the correct arc, without them the tip was at the inside of the valve tip and wouldn't even ride close to the center during it's travel. this happened only on the center pedestal which is the tall one, about 3 times taller than the others. when dan did the valve job on the heads he did find the middle pedestal cracked on the other head and repaired it, sharp eye i must say. the pedestal in the pic is the middle one on the unrepaired head , ther was no visable sign of of crack and it broke when i started to torque them and that happened at a mere 20ft.lbs. the other head where dan repaired the pedestal made it to full torque fine. the owner does have a stud kit for the heads and will use it now that the rocker arms are all shimed side to side correctly, even using the studs i have to assume it would have broke anyway. so with due respect to everyone did the heads have the wrong valves in them from the gitgo because the previous owner had ground the underside of the rockers for clearance on the top of the retainers. something was wrong for sure for the pedestals to be .120" too low. the valves seats do not appear to have been sunk excessively, especially somewhere in the .080" range. to correct all this the pedestal will need repaired and the others all raised up .120" to get everything happy. i have full faith in dan's abilities to accomplish this repair.
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Re: rocker shaft shims, what are they good for?
#173709
12/24/08 11:54 AM
12/24/08 11:54 AM
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B G Racing
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Quote:
ok fellows. the shims were made out of soft copper so that it would conform to the pedestal. now these heads needed the rocker shaft raised up .120" the get the roller tip to travel in the correct arc, without them the tip was at the inside of the valve tip and wouldn't even ride close to the center during it's travel. this happened only on the center pedestal which is the tall one, about 3 times taller than the others. when dan did the valve job on the heads he did find the middle pedestal cracked on the other head and repaired it, sharp eye i must say. the pedestal in the pic is the middle one on the unrepaired head , ther was no visable sign of of crack and it broke when i started to torque them and that happened at a mere 20ft.lbs. the other head where dan repaired the pedestal made it to full torque fine. the owner does have a stud kit for the heads and will use it now that the rocker arms are all shimed side to side correctly, even using the studs i have to assume it would have broke anyway. so with due respect to everyone did the heads have the wrong valves in them from the gitgo because the previous owner had ground the underside of the rockers for clearance on the top of the retainers. something was wrong for sure for the pedestals to be .120" too low. the valves seats do not appear to have been sunk excessively, especially somewhere in the .080" range. to correct all this the pedestal will need repaired and the others all raised up .120" to get everything happy. i have full faith in dan's abilities to accomplish this repair.
Bob,as old as these heads are,who knows what they have been subjected to in their past history.I don't think anyone questioned Dan's ability here.
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Re: rocker shaft shims, what are they good for?
[Re: B G Racing]
#173710
12/24/08 12:08 PM
12/24/08 12:08 PM
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Streetwize
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Yeah the thicker shims pry the pedestal apart with the combination of heat cycling, bolt clamping force and the constant stresses of the valvetrain. If you think about it the pedestals themselves are relatively fragile to begin with and ironically the weakest pedestals (the ones that are hollowed for the oil passage) are the ones that are right between the heavier intake valves.... even though they are a lot wider they're not really that much stronger at the cup when you put a thick shim on them. I remember racers in the early 70's were already starting to mill them down for blocks because they didn't want to risk a ton of hours in ported iron heads and expensive valvetrain for a cast pedestal. There was a reason the Race W2's had blocks.
Last edited by Streetwize; 12/24/08 12:16 PM.
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Re: rocker shaft shims, what are they good for?
[Re: B G Racing]
#173711
12/24/08 01:43 PM
12/24/08 01:43 PM
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Quote:
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ok fellows. the shims were made out of soft copper so that it would conform to the pedestal. now these heads needed the rocker shaft raised up .120" the get the roller tip to travel in the correct arc, without them the tip was at the inside of the valve tip and wouldn't even ride close to the center during it's travel. this happened only on the center pedestal which is the tall one, about 3 times taller than the others. when dan did the valve job on the heads he did find the middle pedestal cracked on the other head and repaired it, sharp eye i must say. the pedestal in the pic is the middle one on the unrepaired head , ther was no visable sign of of crack and it broke when i started to torque them and that happened at a mere 20ft.lbs. the other head where dan repaired the pedestal made it to full torque fine. the owner does have a stud kit for the heads and will use it now that the rocker arms are all shimed side to side correctly, even using the studs i have to assume it would have broke anyway. so with due respect to everyone did the heads have the wrong valves in them from the gitgo because the previous owner had ground the underside of the rockers for clearance on the top of the retainers. something was wrong for sure for the pedestals to be .120" too low. the valves seats do not appear to have been sunk excessively, especially somewhere in the .080" range. to correct all this the pedestal will need repaired and the others all raised up .120" to get everything happy. i have full faith in dan's abilities to accomplish this repair.
Bob,as old as these heads are,who knows what they have been subjected to in their past history.I don't think anyone questioned Dan's ability here.
this statment is a non-issue here because no one is questioning it and i truely feel dan is the man to fix this problem.
Last edited by bOb shingler; 12/24/08 06:12 PM.
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Re: rocker shaft shims, what are they good for?
[Re: tjmarcus1]
#173714
12/24/08 03:06 PM
12/24/08 03:06 PM
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tjmarcus1
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Quote:
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The shims I used some years back were thick on the bottom .015 or .030 and thin on the walls, almost 0
ditto! divorak has the correct ones that seem to work.
i would not doubt dan's skill level, and am not into bashing him. if my post was interpreted as such, then i humbly apologize. dan is the man
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Re: rocker shaft shims, what are they good for?
[Re: BradH]
#173715
12/24/08 03:08 PM
12/24/08 03:08 PM
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BDS871Cuda
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Just a question for Dram, How good are Zeeker heads? Like flow and stuff. Edelbrock RPM's or Indy SR's ? Is this Dan Zeeker were talking about?
Snap your neck, mega G-force launch, is all I want!
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Re: rocker shaft shims, what are they good for?
[Re: tjmarcus1]
#173716
12/24/08 03:30 PM
12/24/08 03:30 PM
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MR_P_BODY
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Quote:
Quote:
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The shims I used some years back were thick on the bottom .015 or .030 and thin on the walls, almost 0
ditto! divorak has the correct ones that seem to work.
i would not doubt dan's skill level, and am not into bashing him. if my post was interpreted as such, then i humbly apologize. dan is the man
I dont think anyone was. I have never seen anyone go as much as .120 but I dont see a ton of heads, the most I have gone was .045 with the shims mentioned above
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Re: rocker shaft shims, what are they good for?
[Re: MR_P_BODY]
#173717
12/24/08 03:36 PM
12/24/08 03:36 PM
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Bob_Coomer
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Let me ask the machinist/builders this If the rocker stands are off that much .125 doesn't this get multiplied times the rocker ratio etc? case in point would equal to .1875 and as much as .200+ with higher rocker ratio's. I was thinking so, this would be a mile off in reality...
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Re: rocker shaft shims, what are they good for?
[Re: BDS871Cuda]
#173718
12/24/08 04:20 PM
12/24/08 04:20 PM
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Joined: Feb 2004
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WadeMetzinger
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BDS871Cuda, the Zeekers are the predecessor to the Indy 440-1, they take the same rockers, valves, etc. Indy bought the mold from Zeeker to make the -1s they can flow about the same as a fully ported set of -1s. That's what I ran all last year and they made good power and I didn't have any issues with them. If you ever order HS rockers for -1s you'll notice the part number has a Z in it, it's because they were designed for the Zeeker heads. Mine didn't have the porosity issues that some sets had, didn't have to use shims or anything special.
Mine already had the rocker shaft pads cut down and use square blocks that mount flat to the Head shaft pedestals. Here is a pic of the HS rockers and the blocks.
Wade Metzinger 918-809-0987 71 Cuda 9.28@145 -1s, Pglide 68 Cuda 10.64@124 1.45 60's 318->390 eddys Moparts discount code on WIX - moparts www.Filter1.com
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Re: rocker shaft shims, what are they good for?
#173722
12/24/08 07:33 PM
12/24/08 07:33 PM
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Ouchy!!! Wouldnt studs help that problem?? And also I have never heard of using any shimms thicker than a few thou. It also puts extra side to side stresses on the bolts the farther away the threads are from the head. In this case it was nasty bad. I am going to stud my rocker shafts. I have done that in the past on Higher RPM circle engines, and it has always worked fine.
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Re: rocker shaft shims, what are they good for?
[Re: MR_P_BODY]
#173723
12/25/08 03:54 PM
12/25/08 03:54 PM
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Quote:
The shims I used some years back were thick on the bottom .015 or .030 and thin on the walls, almost 0
I have that same type of "tapered" shim on my Charger's 440. Bought them 20yrs. ago from Mancini I believe? I have never been able to find them since?
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