Be very careful shimming the shaft up. It has a tendency to crack the sides off the rocker stands. Doug has posted pictures before of stands with a hose clamp around them as a repair.
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| oops. 318 valve miscalculation. https://www.slantsix.org/forum/viewtopic.php?t=18711 |
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| Author: | mopar_nocar [ Fri Jul 21, 2006 6:34 pm ] |
| Post subject: | oops. 318 valve miscalculation. |
well the plot thickens i can't stop messing with this thing. i got the short block put back together, degreed the cam (it is @ 105 centerline, i am waitin for the bushing to come in to put it at 102) and i think...hey! why not put the head on and finish out the long block....well, i forgot to tell ya' i put 318 valves in the head while i had it apart....318 valves are 5.005" long and slant valves are 4.777some odd " long. OOF! can i just get a push rod 9.68" long and be done with it or do i need to come up with some other trick? sb |
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| Author: | Joshie225 [ Fri Jul 21, 2006 7:05 pm ] |
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I would actually space the rocker shaft up .100-.200" if you can to get the geometry closer to original. Otherwise the adjusting screw is going to be angled more than original and put the pushrod to adjuster junction under increased stress. The more agressive the cam and valve springs the more important this becomes. Thankfully slant rockers are quite long so the angular change isn't as severe as say a Chevy. |
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| Author: | mopar_nocar [ Fri Jul 21, 2006 7:21 pm ] |
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yeah, i was thinking of shims also...its a mild cam. total lift at the valve of .435" and 210* duration at 50. i can find oldsmobile rocker shims # jegs, any ideas where to get mopar shims, and are they the same for say a big block? if so, hughes has them in .020 and .040, but that would take lots of shim! what about a piece of 5/32 or 3/16 sheet metal formed to fit and then drilled? sb |
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| Author: | slantzilla [ Sat Jul 22, 2006 4:17 am ] |
| Post subject: | |
Be very careful shimming the shaft up. It has a tendency to crack the sides off the rocker stands. Doug has posted pictures before of stands with a hose clamp around them as a repair.
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| Author: | sandy in BC [ Sat Jul 22, 2006 7:11 am ] |
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Shimming the rockers is in the "do what you have to " category. You can add to that: grinding down the valve stem or grinding down the valve contact pad on the rocker . When I had the same situation after using Chev valves I discovered I had a couple of Intake valves that were problematic. After having a good look at things(cheap and easy) I discovered a couple of rockers that had thicker pads than the non problem rockers(the thinner pads were prolly worn more).......so I ground the thick ones down a titch...so far / so good. We are talking about a very small amount of grinding. There is risk of increased wear if the pad surface was hardened. Your experience may vary....not available in Quebec or Arkansas.....some assembly required. |
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| Author: | Doctor Dodge [ Sat Jul 22, 2006 8:12 am ] |
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Quote: Be very careful shimming the shaft up. It has a tendency to crack the sides off the rocker stands. Doug has posted pictures before of stands with a hose clamp around them as a repair.
Small block Mopar valves are not a good choice for a SL6 head because of their length.Big Block Mopar valves are easer to deal with. If you use shims, grind down the upper edges so they do not act as a wedge and split the rocker shaft towers. Here is that pic, note the shim, hose clamp and the rocker arm's geometry. The push rod should be near straight or a little 'over center' at full lift. Also look at the rocker pad tip to valve stem tip relationship, the contact point should be centered on the tip of the v. stem and not shifted to an edge. With a long valve the contact point tends to move to the inside edge of the stem and it rides on the 'heel' of the rocker arm's contact pad. DD 
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| Author: | mopar_nocar [ Sat Jul 22, 2006 12:07 pm ] |
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ok, ya'll scared me away from shims. so, i figured since the cam is so mild, i would go the route of shorter pushrods....i cut mine down to 9.625" and reinstalled the tips for an overall length of 9.69" it looks ok. geometry may not be ideal, but the rocker rides on the tip of the valve the whole time.... while i was working, my offset bushings came in...so back to degreeing. thanks for all the help. sb |
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