Broken rocker stud

[sheboyganjohn]

Was tearing down one of my 140's (1973) and one of the rocker arm studs twisted off. Figured no big deal there is plenty sticking out, just remove and thread a new one in, but it appears that this is a press in stud. Is this something that can be repaired at home or do I need a machine shop.

 

[alldodge]

Re: Broken rocker stud

Was tearing down one of my 140's (1973) and one of the rocker arm studs twisted off. Figured no big deal there is plenty sticking out, just remove and thread a new one in, but it appears that this is a press in stud. Is this something that can be repaired at home or do I need a machine shop.

http://www.boatfix.com/merc/Servmanl/13/13A3R2.PDF

Start looking on page 21, it will show you what needs to be done and you can determine if you have the equipment needed.
Best of luck

 

[sheboyganjohn]

Re: Broken rocker stud

I read that in the manual 1. It tells you all the tools but I could not figure out exactly what it was doing. It appears that to pull the stud you basically screw down the stud with a spacer under it, thus pulling it out. I am fuzzy on the install. The tool I found searching on line with the part number just looks like a guide collar, I am guessing it to set them to the correct depth. Do they get pressed in with a press or pounded in with a deadblow.

 

[Watermann]

Re: Broken rocker stud

You need a rocker arm stud puller and alignment tool for putting it back in. You should have the head off before trying to repair that stud. It would be much easier to do on a bench. I would tap out the hole and put in a screw in replacement stud rather than another press in. Reason being that boss hole is going to let go sooner or later and the stud will lift. They do make over sized boss end of the studs for this reason but you would be better off doing the tap and screw in replacement.

 

[sheboyganjohn]

Re: Broken rocker stud

Well I guess since I have the head off and one bad stud, might as well change them all over to screw in studs. Any particular trick to make sure you tap the hole perfectly straight.

 

[04fxdwgi]

Re: Broken rocker stud

Well I guess since I have the head off and one bad stud, might as well change them all over to screw in studs. Any particular trick to make sure you tap the hole perfectly straight.

Replacing press in studs with screw in ones is smal block Chevy hot rodding 101. Can be done easily on any engine w/ press in studs and is actually a piece of cake to do. There are jigs readily available (try Jegs or Summit Racing) that ensure the hole for the tap is drilled 100% straight. There is a 99.999% chance the tap will go perfectly straight into the drilled out hole, so there is no need to take any special actions to ensure this.

Go to some of the hot rodding sites and you will get a blow by blow description on how to do it correctly.

Here is one article that shows what needs to be done:
81 Malibu -Performance Therapy project: Grassroots Motorsports forum: Grassroots Motorsports Magazine


Needed to do the job correctly:
Jig to make sure new hole is drilled straight.
A good drill bit of the proper size for the tap and drill motor (prefferably, a drill press).
A good quality "standard tap" for major part of the threads, not a cheap one.
A good quality "Bottoming Tap" to finish the tapping job to the bottom of the hole.
A tapping fluid or light oil to lubricate the tap while it's cutting.
Compressed air to blow everything out nice and clean.
Spray degreaser to clean everything up before inserting the stud.
More compressed air to clear out hole again.
Locktite Red (you can use Blue also. Easier to remove, but not as strong) to hold the stud in place.

A six pack at the end to help enjoy what a fine job you did and fact that studs won't pull out again.

Or.................. Take head to an automotive machine shop and they'll be happy to do it for you for a reasonable price, and correctly.

 

[sheboyganjohn]

Re: Broken rocker stud

Thanks for the link. I think I will just take it into a local machine shop and let them do it. If it was just drill and tap I may have tackled it on my drill press, but having to mill down parts of the head I think I'll pass.