rocker shaft shims, what are they good for?
#173687
12/23/08 11:47 PM
12/23/08 11:47 PM
|
Anonymous
OP
Unregistered
|
Anonymous
OP
Unregistered
|
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.
|
|
|
Re: rocker shaft shims, what are they good for?
[Re: dirtybee]
#173689
12/24/08 12:36 AM
12/24/08 12:36 AM
|
Anonymous
OP
Unregistered
|
Anonymous
OP
Unregistered
|
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.
|
|
|
Re: rocker shaft shims, what are they good for?
[Re: sixpackgut]
#173692
12/24/08 12:53 AM
12/24/08 12:53 AM
|
Anonymous
OP
Unregistered
|
Anonymous
OP
Unregistered
|
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.
|
|
|
Re: rocker shaft shims, what are they good for?
#173693
12/24/08 01:01 AM
12/24/08 01:01 AM
|
Joined: Jun 2003
Posts: 9,225 Charleston
sixpackgut
Drag Week Mod Champion
|
Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
|
well, i would be interested in seeing the repair and .... the bill
Gen 3 power 6.22@110, 9.85@135 Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
|
|
|
Re: rocker shaft shims, what are they good for?
[Re: dirtybee]
#173696
12/24/08 05:37 AM
12/24/08 05:37 AM
|
Joined: Jul 2004
Posts: 4,384 Worst Weather USA
493_DART
master
|
master
Joined: Jul 2004
Posts: 4,384
Worst Weather USA
|
yikes---! i think ive got .015 or so shims on mine , and with Dove rockers. isnt that cast--how is that repairable ?
|
|
|
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
|
Anonymous
OP
Unregistered
|
Anonymous
OP
Unregistered
|
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.
|
|
|
Re: rocker shaft shims, what are they good for?
#173702
12/24/08 10:06 AM
12/24/08 10:06 AM
|
Joined: Mar 2006
Posts: 9,910 Eighty Four, PA
B G Racing
master
|
master
Joined: Mar 2006
Posts: 9,910
Eighty Four, PA
|
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.
|
|
|
Re: rocker shaft shims, what are they good for?
[Re: boscosis]
#173704
12/24/08 10:38 AM
12/24/08 10:38 AM
|
Joined: Nov 2004
Posts: 3,544 Syracuse,NY
CompWedgeEngines
master
|
master
Joined: Nov 2004
Posts: 3,544
Syracuse,NY
|
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
Your work is a reflection of yourself, autograph it with quality.
WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.
|
|
|
Re: rocker shaft shims, what are they good for?
[Re: CompWedgeEngines]
#173705
12/24/08 11:00 AM
12/24/08 11:00 AM
|
Anonymous
OP
Unregistered
|
Anonymous
OP
Unregistered
|
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.
|
|
|
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
|
Joined: Nov 2004
Posts: 2,119 sc
tjmarcus1
top fuel
|
top fuel
Joined: Nov 2004
Posts: 2,119
sc
|
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.
|
|
|
|
|