rocker shaft shims, what are they good for?

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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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Those heads are cast aluminum, and can be repaired by welding in a new piece and machining it back to spec.

I'd also love to see the repair

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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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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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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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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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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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The shims I used some years back were thick on the bottom
.015 or .030 and thin on the walls, almost 0

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ditto! divorak has the correct ones that seem to work.

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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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Can't speak for the Zeekers,but it workes ok for stock heads as well as Indys.

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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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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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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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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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The shims I used some years back were thick on the bottom
.015 or .030 and thin on the walls, almost 0

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ditto! divorak has the correct ones that seem to work.

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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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The shims I used some years back were thick on the bottom
.015 or .030 and thin on the walls, almost 0

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ditto! divorak has the correct ones that seem to work.

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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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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