The stock and stock replacement heads don't leave a lot of room. It's likely you won't get the pattern centered without also using an offset fulcrum rocker like Crower makes. Jim (IQ52) may have some additional recommendations though.
EQ heads, Chevy rockers and what studs?
- Thread starter dusterdoug
- Start date
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As I stated in the N.A.C.C.B.P.P. EQ360 thread, I moved the stud as far as I felt safe. I wasn't comfortable with the strength of the stud boss after going with solid roller valve springs, a 7/16 stud and moving it towards the intake manifold. So I decided to make sure and go with a stud girdle and tie everything down solidly. It is explained in the EQ360 thread with pictures. I am comfortable with what I have now.
Bobzilla
Well-Known Member
My question appears out of order because you posted while I was taking too long to correct my terrible attempt at spelling. Sorry about that. Your thread is a great help on this. Thanks again.
I cannot say THANK YOU enough to everyone! First AND LAST Magnum I'll do. I had sold this motor, before completion and now run into this. I'll let the new owner decide what to do, including a full refund of his deposit if he chooses as I think he was "set" on that solid cam. Oh well, if I'm stuck with it, the EQ heads will be for sale and back to LA style we go.
Wait! One more question if you don't mind. Opinions on a OE stamped Magnum rocker tolerating a Comp 26995 beehive spring: 125 closed/305 open, or am I looking for trouble there too?
nm9stheham
Well-Known Member
How much lift are you going to? And what peak RPM is anticipated? Those springs have a low rate relative to the standard 'hi-po' straight springs. So while closed seat pressures are certainly higher than stock, the open spring pressures are not super high like often is the case with the really strong straight valve springs.
As an aside.... I have been curious why folks don't use flat steel shims between the base of a stock Magnum pedestal and the rocker boss to raise and lower the fulcrum to set lash on a solid. (Not adressing any geometry issues at the moment, of course....) It wouldn't be quick to set up, but there have been lash adjustment systems that were worse. (I can recall some Fiat or Audi systems with discs that were pretty horrid.)
As an aside.... I have been curious why folks don't use flat steel shims between the base of a stock Magnum pedestal and the rocker boss to raise and lower the fulcrum to set lash on a solid. (Not adressing any geometry issues at the moment, of course....) It wouldn't be quick to set up, but there have been lash adjustment systems that were worse. (I can recall some Fiat or Audi systems with discs that were pretty horrid.)
nm9stheham
Well-Known Member
Nice.... looking at the 2nd-to-last pix in the instructions, it appears like the height and orientation of the valve axis to the center of 'shaft' may be pretty good for geometry. (Assuming the pix are accurate and I am seeing them right...) Imagine a line from the center of the shaft to the roller-tip contact on the valve tip; if it is perpendicular to the valve stem's axis at mid lift, that is the best you can do for the height of the shaft.
http://www.hughesengines.com/Upload/productInstructions/HUG1555new.pdf
http://www.hughesengines.com/Upload/productInstructions/HUG1555new.pdf
Problem solved. Thank you Hughes for what appears to be a great product!!
nm9stheham
Well-Known Member
Awesome!
Yeah those rockers are a bowl fulla badassary, but for those without the funds for them, Crane makes the stud kit to get the job done otherwise.
Crane Rocker Arm Guideplate Conversion Kits 36655-16
Crane Rocker Arm Guideplate Conversion Kits 36655-16
Bobzilla
Well-Known Member
What kind of pattern are you getting on the valve tips with those Hughes rockers?
Also, please post a picture from the front or rear showing how they sit while camshaft is on base circle, and at full lift. Been curious about these.
Also, please post a picture from the front or rear showing how they sit while camshaft is on base circle, and at full lift. Been curious about these.
Wyrmrider
Well-Known Member
I was thinking of the Crower backset trunion rockers as a fix
or there are studs with 1/2 inch lower thread which could offset without welding- have not tried it in a magnum but have used for repairs elsewhere
I'll have to check out the Hughes and Crane suggestions
I usually use + length valves in SBM and Pontiacs and others with shot spring heights
or there are studs with 1/2 inch lower thread which could offset without welding- have not tried it in a magnum but have used for repairs elsewhere
I'll have to check out the Hughes and Crane suggestions
I usually use + length valves in SBM and Pontiacs and others with shot spring heights
I set up a set of the Hughes Magnum rockers for member Matts440 when I did his Eddy cylinder heads. With a solid roller that has a fair amount of lift, the rockers still had to be raised a bit for proper geometry. Anything with less lift would need more correction. A longer valve would make it even worse, and just using a stud conversion just puts you back where the OP started from. Overall though, the Hughes are probably the easiest to correct, at least on a Magnum head, and they use a cup style adjuster.
I’ll get some additional pics when I see the motor again next weekend.
These are definitely application specific. I don’t think I’d trust them with a big solid roller and big spring pressure. But I think the Allen head 5/16 fasteners should be enough with my moderate lift solid cam and 125/325 spring pressures. Hughes said I was “plenty safe” with my springs.
These are definitely application specific. I don’t think I’d trust them with a big solid roller and big spring pressure. But I think the Allen head 5/16 fasteners should be enough with my moderate lift solid cam and 125/325 spring pressures. Hughes said I was “plenty safe” with my springs.
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