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WV hillbilly
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781 Posts
Discussion Starter #1
Well it finaly happend to me, I have been upholding the Brand PTL for quite awhile, several sets without a flaw, and now? Here is whats going on, Im running a 1.550 roller spring, 7/16 studs and a set of Comp Cams pro comp magnum rockers, they are supposed to clear, they dont, at first I thought it was the rockers, but not to lame blame so quick I checked everything... I found that one head (rocker stud to retainer clearance) was .070 tighter than the other side...and the head that has the most clearance there is enough room for the rockers to go one the rocker stud but not enough clearance to clear the body of the rocker...

I even tried 3/8 studs and rockers, they still hit! I have an idea for a solution but I need an expert evaluation, drill out the rocker stud bolt holes and insert heli coils or./...get a new set of heads...what do I need to do here?


Im not a PTL hater I like the heads, but with problems like this I see why now, people are skeptical of this brand...
 

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3,532 Posts
I had the same problem on my Sportsman II heads. A friend of mine put heavier springs on, but didn't upgrade the stock retainers and keepers. The valves began to pull through the retainers. If they pull all the way through the valve will fall into the piston. Check and see if your keepers are worn down. You can't tell when the springs are installed.
 

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what you need is rockers that are relieved on the spring side to clear the retainers with the larger springs. or have yours machined out to clear, i think i payed about $ 60 bucks the last time i had this done.
 

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WV hillbilly
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781 Posts
Discussion Starter #4
hmm, all the parts are new, so are the castings, this engine has never been fired.....I was installing the pro mag rockers getting ready to lash the valves when I came accross this problem, neither my machinest or I could ever imagine to check the rocker arm studs for proper alignment, we checked just about everything else, new heads are a concern to me due to the amount of time and money I have in these due to the portwork, see I had another set of rockers that wouldnt clear and thats the reason I just spent money on a new set of rockers, 262.59 to be exact, no one imagined the rocker studs themselves (or the angle they were machined) would be the problem...


I could possibly use 3/8 studs and a smaller diameter spring and get the rockers to clear, I doubt that would cure the problem as I feel Rocker geometry problems would definatly arise...

either the heads were cast wrong or they were simply drilled and tappet wrong....I cant say for sure... the castings at thier present state are no more that very expensive paper weights and for sure Im not real happy at the moment... :(

I may just have to put my project on hold to save up for another set of heads...I feel Dart Pro 1's will be on my wish list (as soon as I can save the money...) these PTL casting has put a definate hault to my budjet...
 

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E.T. divided by $ spent= Speed
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Just an idea from a cobbler.But if your sure the rocker studs are to close to the springs(and not the valve spring pocket in the wrong spot)can't you have the studs removed,fill the holes with aluminum weld(there aluminum right??),then machine the area flat and redrill the holes for the studs??
 

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look on the box and paper work that they came in it will say that you my need to grind them a little. I DID. i am making 550 hp. just make sure you dont take any out you dont have to becouse that weekens it and it will break. so be careful.
 

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Hotrodders.com Moderator
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a couple of options. If the cam profile would allow it go to a 1.44 diameter valve spring/retainer setup. Howards makes a 200# @1.75 roller spring. The other, which is the one I'd do is to do as you originally mentioned and drill the rocker stud holes at the correct angle, re-spotface, and put in heli-coils. Sounds like the angle is just off a couple of degrees.
 

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WV hillbilly
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781 Posts
Discussion Starter #8
Yeah I know its not as big as deal as I let on, I was just really upset last night, and I have never ran accross a set of heads that were off by this much, I dont mind a lil grinding on the rockers, but im telling you there is no way I can cut that much off a rocker and make it work, and I suppose I'll go ahead and see what I can do with them, now my only problem is finding a source (a geometry correct 23* head to go by..) I'll let you guy's know how it go's
 
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