Collarless screw studs - not straight..
#1
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Collarless screw studs - not straight..
I have changed to collarless screw in studs on my Vortec heads.
Used the Comp Cams 5306 tap guide, but It didn't turn out perfect.
When I lay a straight edge in the threads close to the top of all the studs, some of them lean app 1/25":
Have I ruined the heads, or will the studs stand the bending forces this create?
Used the Comp Cams 5306 tap guide, but It didn't turn out perfect.
When I lay a straight edge in the threads close to the top of all the studs, some of them lean app 1/25":
Have I ruined the heads, or will the studs stand the bending forces this create?
#2
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Re: Collarless screw studs - not straight..
That's more or less inevitable, given the tolerances of the casting.
It doesn't really cause anything to "bend", as such. Rather, it just leaves the original uncertainty and variability that the factory didn't care about, in the valve train geometry.
Should be OK. If you ever have trouble with it, you still can have the heads drilled & tapped for studs with 7/16" on the side that goes into the heads, in a more precise machine shop environment.
It doesn't really cause anything to "bend", as such. Rather, it just leaves the original uncertainty and variability that the factory didn't care about, in the valve train geometry.
Should be OK. If you ever have trouble with it, you still can have the heads drilled & tapped for studs with 7/16" on the side that goes into the heads, in a more precise machine shop environment.
#3
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Re: Collarless screw studs - not straight..
How's the alignment along the other axis? That is, stud to the valve? If that's off a considerable amount, then the rocker tip won't sit flat on the valve. That could cause some problems.
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Re: Collarless screw studs - not straight..
That's more or less inevitable, given the tolerances of the casting.
It doesn't really cause anything to "bend", as such. Rather, it just leaves the original uncertainty and variability that the factory didn't care about, in the valve train geometry.
Should be OK. If you ever have trouble with it, you still can have the heads drilled & tapped for studs with 7/16" on the side that goes into the heads, in a more precise machine shop environment.
It doesn't really cause anything to "bend", as such. Rather, it just leaves the original uncertainty and variability that the factory didn't care about, in the valve train geometry.
Should be OK. If you ever have trouble with it, you still can have the heads drilled & tapped for studs with 7/16" on the side that goes into the heads, in a more precise machine shop environment.
#6
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Re: Collarless screw studs - not straight..
i wonder if a stud girdle would help straighten things out? maybe something like this howards one or the like?
http://www.summitracing.com/parts/hr...make/chevrolet
http://www.summitracing.com/parts/hr...make/chevrolet
#7
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Re: Collarless screw studs - not straight..
Thanks for all your answers and info. Very valuable, as always.
The heads are already tapped 7/16".
I used a tap like this:
http://www.ebay.com/itm/DORMER-SKF-T...sAAOxy14VRRaMA
My guess is that the misaligment is about the same on the other axis as well. Not more, not less.
Wouldn't a stud girdle put even more stress to the bolts. as they are not 100% aligned?
The heads are already tapped 7/16".
I used a tap like this:
http://www.ebay.com/itm/DORMER-SKF-T...sAAOxy14VRRaMA
My guess is that the misaligment is about the same on the other axis as well. Not more, not less.
Wouldn't a stud girdle put even more stress to the bolts. as they are not 100% aligned?
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#8
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Re: Collarless screw studs - not straight..
Once you have the heads assembled with rocker arms, you'll have the opportunity to check on how the rocker sits on the valve tip. The leaning "in" with respect to the valve wouldn't make much of a difference as was pointed out. That would change the point at which the "sweep" appears on the valve tip when you doing your geometry check. As for the other way, if the difference is slight, the clearances that exist between the stud and trunnion (or rocker ball) and other moving/rotating parts may be sufficient to keep the tip square. Whether that's OK or not is open to argument.
Last edited by skinny z; 05-01-2016 at 02:13 PM.
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Re: Collarless screw studs - not straight..
It may tweak 'em a bit, but, it also distributes the forces the studs have to deal with over a much greater area...... All in all, I think it would be a good compromise. However, it isn't really necessary. So long as rocker to valve geometry is good, you're golden. (unless you want to rev to the moon, then, they are just about a requirement.)
#10
Re: Collarless screw studs - not straight..
It looks like a cut-thread bottoming tap. Despite the tap guide, if the lead picks up at a slight angle the entire hole will be tapped that way. Been there. Even using a tapping table would not eliminate that 100%. If you ever do it again, start with a plug tap to insure a square thread, then change to a bottoming tap if you need full thread depth.
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