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Rocker stud holes ???????


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Just got the motor primed and ready to start and realized two rocker stud holes are stripped and pretty much egg shaped. This is causing my roller rockers to sit off the the side of the valves. Called the local machine shop and he said he has seen factory heads up to 2/thousands off thats pretty much what mine are. He said dont go any further or I could blow the motor if they let go. What should I axpect for a price to fix this and should I just buy new after market aluminum heads instead of going through the trouble of fixing these ones ? It sucks because this motor was bought as zero miles and I have tons into it.

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as I told you in your PM, a heli-coil I thought was your best option, ask your machine shop if there are rocker studs that you can get with the end going into the head the next size up, then drill and tap them for the larger stud size.

 

if that is not possible, then I would say new heads

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Yeah, I will check on that. The guy working on it said the heads need to come off and I shouldnt bother fixing them. There is a lot of work done to them and they are LS6 heads so I cant see just throwing them out.

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After. I heard it very soon after firing it up though so I caught it before any damage was done. I found a place that sells heads either 1 at a time or by the pair (Clearwater Cylinder Heads) and bought a rebuilt one from them and haven't had a problem since..

www.cylinder-heads.com

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That is an easy fix for a good machine shop. Because of the angles involved with big blocks I would let a machine shop do it, and as Sam said have them helicoiled. Big blocks use 7/16 N/C thread in the rocker stud mounting holes. Most aftermarket aluminum heads have helicoils installed in the rocker stud holes because of the loads on the studs.

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Thanks guys. From what i hear it's more common in rectangle port heads then oval ports. If I go with new ones, I am buying oval ports with a new intake. Right now the car is fiinally running and it sounds nasty. The machine shop i spoke to said he has seen them right out of the factory like this.

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Well, I think that's where the term "Blueprinting" comes from. The factory slaps them together and tolerates some mis-alignment in the process.

Blueprinting is when a machinist measures everything and makes corrections so the piece matches the specs called out on the original blueprint.

 

Just because the head came from the factory that way, and your machinist has seen others like it, doesn't mean its a good thing.

Is it something he can fix, or is he recommending you leave it alone? I would also imagine that a roller rocker would have a tougher time dealing with this problem than a stamped steel one.

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I agree with you. I think your misunderstanding whats I said. I know it's not a good thing at all just becasue they have seen it.

 

It is something that can be fixed but the head needs to come off. I was told today that the guide paltes can actually be cut and welded in order to get it right also. Im not sure what I will do either buy new aluminum heads or get this one fixed.

 

My mechanic says it's not the guide plate. He swears it's the actual hole itself where the rocker stud goes in.

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  • 2 weeks later...
Guest cstraub

What you want is a timesert installed. These are much stronger then the Heli-coils. Not much more different installation technique but MUCH stronger system.

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We actually fixed the problem pretty easy. We cut the guide plates, got the rocker in place dead center and welded the guide plates up. Worked like a charm.

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