hlee96

Got 11/12 cam allen bolts inside the cam towers of my 16v 4.5L engine out without any problems, but of course with Murphy's Law, the last bolt in the middle of driver's side cam tower upper bolt has been rounded.

If this happened to you, what would you suggest to remove the bolt? There is evidence of cam gaskets leaking, and this is why I chose to remove the cam towers to replace it with one of Greg's.

BTW, the engine is out and the passenger side cam tower with the lifters are out without problems and bagged.

Thanks-Hoi

MainePorsche

You can try something like this. Hammer it down a little so it 'bites'.

medipedicman

Let me know if you figure it out Hoi. We have a similar situation on I 4.7. The round ball of an Allen head wrench broke off in the bolt. It is a tight fit, and we have tried lots of techniques.
None of them successful.

hlee96

Definitely Brian, I just ordered the Irwin bolt-extractor tool, and I am just afraid that it won't fit into the 17 mm rubber boot opening into cam towers.

Thanks Maine928. Will keep others UTD

M. Requin

The best thing to do is buy the 10 piece SAE/metric set, often the "wrong" one will fit. And BTW I love these things, they have saved me a ton of trouble.

AO

I don't think those extractors will fit in through the opening in the cam tower. I seem to recall I had to grind my 8mm allen head to pit through the hole. I think your best bet is to drill the head off the bolt. If you are very careful, you should be fine and have the head off in less than 5 min.

Find a drill bit that is just slightly larger that the diameter of the threaded portion of the bolt (not the head). The rounded allen portion will act as a guide to center the bit. Just go far enough until the head comes off. At that point the cam tower will be free and can be lifter off the head.

Obviously, you will have metal shavings, so you will need to clean things out really well, but since you have the engine out, there's no issue there. You could try shoving some paper towels in the cam tower to minimize shaving from traveling down, but I'd probably just go to town.

soontobered84

You might also try driving a Torx bit into the allen hole. At best, it will allow you to unscrew the bolt, at worst, you'll just have to remove the Torx bit to drill it.

AO

There is some merit to this suggestion. If you really hammer the Torx in, the shock from the hammering may loosen the bolt.

85euro928

Some may cringe at this but with all the allen head bolts on the engine I give them a good whack or two with a hammer before trying to loosen them. I cut the handles off a 6 & an 8mm tee-handle allen head wrench that were about 12" long and anytime I need to remove an allen head bolt (that I haven't removed before) I just give them a good whack. Works almost everytime.

tmpusfugit

If there is any good news regarding the situation of having rounded out the socket head on these bolts it is that they are quite soft steel and the head can be drilled out allowing the cam tower to be removed with the stud portion still in the head. I originally made an insert to guide the drill into the center of the socket head and trap the metal shavings so they didn't get spread about. It worked fine by the way. Then, I broke the Allen wrench off in the next one (slow learner I guess, but it didn't round it out). The Allen wrench material is too hard to drill with carbide in my case. I ended up machining a hole cutter out of tool steel and cutting the head around the head of the socket Allen. That worked really well. Lessons learned, make certain the Allan is all the way into the socket, make certain you are using a high quality tool, the bolts are really torqued down. Strangely enough after the cam tower was off the bolt stubs came out using my fingers......I also think the engine needs to be out of the car to have enough room to pull the came towers off the remaining studs, guess that is partially dependent upon the location of the problem bolts?

I kept all this stuff just to remind myself not to be quite so ham fisted the next time.

medipedicman

Jim
I know that you said that you machined that particular tool, but are you aware of such a tool that could be bought at retail? I would love to have one for this and future projects.

GlenL

Left-handed drill bit. That's be an extra-long 8mm diameter. Hopefully it grabs and unscrews the bolt. You'll be stuck cleaning the tower for every last shaving but your alternatives are poor.

There's no room for mistakes on those bolts inside the tower. Use top-quality Allen wrenches. I made a long bit by taking a short 8mm socket wrench and replacing the Allen with a cut-off 4" length of an "L" wrench. No ball end as the neck is weak.

tmpusfugit

I don't know of any place to get something like this. I would be happy to ship this one to you if you want to use it. I just checked it and it seems to have remained sharp enough for a few more uses. Drop me a PM with your address and I will send it off to you.

hlee96

Brian, I went to Home Depot and bought a set of Rigid cobalt drill bits for the rounded bolt. It only took 10-15 sec but you will need to take out the camshaft in order to clean out of the shavings. Good luck-hoi

medipedicman

Awesome Hoi, glad it was that simple for you. I hope it turns out as easy for us.