Anyone ever drilled out a rocker shaft bolt while still in the engine?

[Tippy]

Made a rookie mistake and put the two rocker shafts backwards next to the chain housings (#1 exhaust and #4 intake rockers) intentionally due to my back up allen wrenches being too long. So now, I cannot tighten them the correct way since the 5mm side, I do not have enough travel.

I guess I am going to have to drill the rocker shaft bolt now to R&R.

Has anyone done this or is there another technique?

I assume others have had to do this once a bolt has stripped.

I thought about using a really long burr on a die grinder to get in there. My fear is the burr chattering and catching the rocker shaft bore. Then it will be game over!

TIA
Cory

[Flat6pac]

Take them out and turn them around. I have a cut 5mm that I made because there has been engines opened in years gone by that were done wrong
Bruce

[Tippy]

Originally Posted by Flat6pac

Take them out and turn them around. I have a cut 5mm that I made because there has been engines opened in years gone by that were done wrong
Bruce

I assume you are using a ratchet and getting one click at a time? I can't see a 1/4" ratchet fitting in that tiny access area, only an allen which does not have enough travel.

How exactly did you do it? Thanks Bruce.

[cgarr]

Get 2 or 3 5mm and put some bends in them so you can get the travel you need to loosen it up also may have to grind them shorter to fit in there.


Sent from my iPhone using Tapatalk

[304065]

I just did this using an electric drill and a 1/2" bit, followed by a 1/4" bit.

The most important thing is to not get any chips in the engine. You should stuff copious clean-room wipes in the cavities to prevent any from falling in. Then once they are full, cover the outside one with a thick layer of grease or assembly lube- this will cause any chips to stick and not fall between the wipe and the cam box. Have a helper position a shop vac next to the bit as you drill.

It seems like an extreme measure but it's actually quite simple.

[Tippy]

Originally Posted by cgarr

Get 2 or 3 5mm and put some bends in them so you can get the travel you need to loosen it up also may have to grind them shorter to fit in there.


Sent from my iPhone using Tapatalk

I like that idea, Craig! Thanks.

Originally Posted by 304065

I just did this using an electric drill and a 1/2" bit, followed by a 1/4" bit.

The most important thing is to not get any chips in the engine. You should stuff copious clean-room wipes in the cavities to prevent any from falling in. Then once they are full, cover the outside one with a thick layer of grease or assembly lube- this will cause any chips to stick and not fall between the wipe and the cam box. Have a helper position a shop vac next to the bit as you drill.

It seems like an extreme measure but it's actually quite simple.

Yes, there will not be a single shaving going into the motor. It'll be 95% masking time, 5% drilling/grinding!

Thanks for the bit sizes.

[Tippy]

What do yall think about this combo? I'm not around to see or try the actual combo of tools but maybe one of you will know one way or the other.

1. 7/16" ratchet wrench (not sure the head will fit inside the access hole)
2. 3/8" male to 3/8" male adapter drive
3. Shortened 5mm allen socket

The ratchet wrench 7/16" side will fit over the 3/8" male to male drive on one end and the other end will have the allen socket.

This combo should only be about 3/8" longer than the allen socket itself due to the thickness of the ratchet wrench.

[elflamo]

Cory, I did the drill method (extensions on extensions etc) and the problem was the wobble of the entire assembled 'drill'. Very hard to not make it touch the bearing area's of the other rockers. I would not recommend it if you don't already need another camhousing for other reasons. Will probably only work if you have one single drill of sufficient length.

[Tippy]

I was going to use a solid burr bit on a die grinder.

I'm assuming you were using an extension on a drill bit?

[elflamo]

Yes indeed, it worked, but too risky

[Flat6pac]

Trimmed 5mm allen

Bruce

[Tippy]

Bruce, on the #1 exhaust rocker, the access hole in the housing is not very big hindering making any movement with the 5mm allen wrench.

I've already did what you've done to my allen.

The #4 is not too bad on the intake side - it is a lot wider regarding the gap.

[Tippy]

Another thought:

1. Take the piece I cut off the allen wrench
2. Put the piece in a 5mm wrench box end.

Tape it to keep in place somewhat.

I think this will work if only I can find the piece I cut off on the ground..........

[304065]

You don't need a long drill bit all the way through the other rocker bores. Just hold a 1/2 bit at an angle so you don't hit the valve cover mating surface.

All you are doing is removing enough metal from the screw head and expander to weaken it and allow you to get the smaller bit in. This will then remove the remainder of the head and you can drive the screw out the other side.

[Tippy]

Originally Posted by 304065

You don't need a long drill bit all the way through the other rocker bores. Just hold a 1/2 bit at an angle so you don't hit the valve cover mating surface.

All you are doing is removing enough metal from the screw head and expander to weaken it and allow you to get the smaller bit in. This will then remove the remainder of the head and you can drive the screw out the other side.

Yep.

I think I am going to get the roughly 1/2" long piece I cut off the 5mm allen wrench and use a 5mm box end wrench around it. This will give me plenty of axial room.

Then, once I hit the cam tower, I'll stop, pull it out and index the cut allen wrench piece one notch on the 12-pt box end and turn what I can over and over again until loose.

I am a little too scared to drill/grind in case of damage.

[Eagledriver]

Is there no way to take the bolt out (with shortened wrenches) and put it in the right way? It seems like alot of trouble to drill it out. And by the way you can tighten it from either end. It's just a bolt and nut. Turn the nut if you have to.

-Andy

[304065]

I just went back and re-read completely your original problem.
There is no reason to drill anything.
The reason I drilled was that I destroyed the internal wrenching feature of the screw once clamp load was already applied.

I guess what I'm having a hard time visualizing is why you can't loosen the front end (the end toward the flywheel) with an M8. You claim your difficulty is that you installed the rocker shafts with the M5 internal wrenching feature toward the pulley. Why not loosen up the other end? I mean, you aren't supposed to torque these things down by turning the M8 end, but if you hold the M5 end and turn the M8 you should be able to get it loose enough to remove the M8 expander and then remove the whole shaft.

Maybe a photo would help?

[Tippy]

I couldn't get the 8mm side to bite enough to loosen. Of course, I used Allen wrenches, not an Allen socket.

[boyt911sc]

Originally Posted by Flat6pac

Trimmed 5mm allen

Bruce

Bruce,

These are my special 8-mm tools very similar to yours. The short piece that was cut off is used with my ratchet wrench to facilitate the removal after breaking it loose.


Tony

[Walt Fricke]

Tipppy

1) I'm glad you have dropped the notion of drilling/grinding etc. That's just plain ugly, and really only has a role when tearing down a motor and finding stripped Allens, or perhaps ones which have been tightened so much (and the shafts have perhaps broken) that the bolt end protrudes so far into the nut end that the wrench can get no purchase, but the nut is slipping.

2) Are these shafts properly aligned? One end roughly flush with the "short" part of the housing bore? If so, why not just tighten them (assuming you didn't get them tight in the first place)? Which way to install the bolts is a matter of convenience (as you have found out) for interim work. If you do a full teardown you can take off the chain boxes/oil cooler to get needed access.

If not tightened, just tighten, using the schemes you are contemplating, which are the logical ones.

Of course, if you don't have the proper alignment, which is why you started down this path, well then it makes sense to swap ends once you have things loose.

I always install with the bolt end toward the flywheel. It lets me use a torque wrench with various extensions, rather than torquing by feel. But that's on my engine stand.

For a field install (as after replacing a broken rocker), just do whatever is easiest for the end rockers - bolt ends facing inward. I don't think many of us have a 1/4" torque wrench with a head small enough to fit in there anyway, so we compromise at that point.