Stripped hole in rocker pedestal

[clutch22]

Hey guys. Finally pulled the trigger and bought my first TR(been dreaming for 10 yrs, and lurking here for quite awhile)......love it so far. Even when it's broken! Kinda heavy to push around though:frown: Please help me fix her!

My first disaster is a destroyed rocker shaft. A bolt sheared off in the head and it cut loose. The shaft(solid) is damaged so, since I couldn't find another, I'm going back to a stock shaft with the RJC braces. We removed the broken bolt from the rear pedestal but hit a wall when installing the new shaft.

The center mounting hole(different hole than broken bolt) in the head is stripped out. When we removed the old shaft, I noticed that the center bolt was longer than the others. I figure it was a prior problem and I just destroyed what was left when the bolt snapped and hell broke loose in the valve cover. As soon as torque is put on the bolt it pops right out. These are iron heads.

What are my options? Can I safely tap that center pedestal hole another 1/2" or so? If so, do you think that would be enough?

Thanks guys....all opinions welcome!

-Jeff

 

[bison]

Hey guys. Finally pulled the trigger and bought my first TR(been dreaming for 10 yrs, and lurking here for quite awhile)......love it so far. Even when it's broken! Kinda heavy to push around though:frown: Please help me fix her!

My first disaster is a destroyed rocker shaft. A bolt sheared off in the head and it cut loose. The shaft(solid) is damaged so, since I couldn't find another, I'm going back to a stock shaft with the RJC braces. We removed the broken bolt from the rear pedestal but hit a wall when installing the new shaft.

The center mounting hole(different hole than broken bolt) in the head is stripped out. When we removed the old shaft, I noticed that the center bolt was longer than the others. I figure it was a prior problem and I just destroyed what was left when the bolt snapped and hell broke loose in the valve cover. As soon as torque is put on the bolt it pops right out. These are iron heads.

What are my options? Can I safely tap that center pedestal hole another 1/2" or so? If so, do you think that would be enough?

Thanks guys....all opinions welcome!

-Jeff

Id simply drill and tap for a heli-coil thread insert. Have a friend help with the drilling so you can line it up. Shouldnt be much of a problem since the hole will guide the drill bit. I use grade 8 bolts on those and torque to 25-30 ft/lbs.

 

[jhanson1750]

The problem I see with up-sizing the bolt diameter of the bolt is you also have to increase the size of the hole in the shaft which will weaken the shaft. Unless you find a stepdown stud. I would use a helicoil. Jon Hanson

 

[turbofabricator]

Just try a longer 5/16-18 bolt and see if it engages in threads lower in the pedistal. That's why that had a longer one when you tore it apart. A Helicoil is the best answer, though. With the RJC "caps" you will longer bolts anyway. Not sure if they come with them.

 

[clutch22]

I ran a bolt all the way down.....threads are smoked right to the bottom.

Helicoil it is....Thanks guys. Appreciate it.

-Jeff

 

[MCH86GN]

I'm in the same boat now. I actually had a tap in the sheered bolt on the pedestal. My problem is there is a bolt in there to be drilled out and I'm wondering if I shouldn't pull the head and have a machine shop do it. Because it is very hard try to drill straight and not start angling when you are drilling through metal. I'm not merely taking off threads. I drilling through a bolt. Things are going from bad to worse for me. Since this is the driver's side, I shouldn't to pull the engine to pull the head and then take it to a machine shop and have then do it. Because if I do and it is not lined up It's going to be awfully hard getting my rocker shaft lined up. I have a machine shop at work and I might be able to get one of the people there to do the machining. I'm in uncharted territory here and I'm step away from screwing up another engine.