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EDM is the last resort. We sometimes have to send magnesium 911 cases with broken head studs to the local EDM guy; he is quite good, but you are at his mercy at that point. He charges for however long it takes to get the broken bolts out, as he should, but it easily gets into four figures sometimes . . . .
I can't see the pics of your 3D-printed jigs on that forum, but put me down for some when you are done, I will gladly purchase something like that!
I think you need to log in to garage journal to see the pictures. On the other hand, if you're not on garage journal, you should be. One of my million back-burner projects is to do a metal jig to drill out the tiny little water pump studs. I could print them for testing and then have some CNC'd in aluminum. Interested? For something like this b/s cover bolt, a one-time jig printed in carbon-fiber reinforced nylon would be more than enough. For my "Track Nanny" PSE controller, I printed a jig for the holes in the enclosure and JB welded in bronze bushings so I could use it over and over. I bet I've drilled 100 cases with that one jig...
Or you can go the crude but effective way. After you have the cover off weld a nut to the remains of the bolt (weld inside the nut). Now you have a good place to wrench and you have also heated the shaft of the bolt to loosen it up. works every time I have tried it.
Or you can go the crude but effective way. After you have the cover off weld a nut to the remains of the bolt (weld inside the nut). Now you have a good place to wrench and you have also heated the shaft of the bolt to loosen it up. works every time I have tried it.
That's great. I'll have to see what works. I'll know more once I get the cover off.
Ok, I got 3 nuts, left to pull turbo and then I can pull that bolt out and see if it's broke or what. At this point pulling balance shaft cover will only add 1 year to my 2 year job that started out as a 25 hour clutch job.
A familiar tune on this forum. My motor mount replacement ended up taking about a year.
Ok, here's another idea. Sounds like the banjo bolt was being installed without the oil line fitting and as it was being over-tightened the hollow bolt snapped. The cover is aluminum, the bolt steel. Sort of like the front wheel bearings with aluminum hubs.
What about talking it to a shop that can heat the balance shaft cover in a tank and removing the bolt once the aluminum expands? And, you'll have a clean balance shaft cover. A local shop did that for me with my front wheel bearings and it worked like a charm. Steel bearings easily removed and the new bearings literally dropped in (so they told me). $20 for their help.
Ok, here's another idea. Sounds like the banjo bolt was being installed without the oil line fitting and as it was being over-tightened the hollow bolt snapped. The cover is aluminum, the bolt steel. Sort of like the front wheel bearings with aluminum hubs.
What about talking it to a shop that can heat the balance shaft cover in a tank and removing the bolt once the aluminum expands? And, you'll have a clean balance shaft cover. A local shop did that for me with my front wheel bearings and it worked like a charm. Steel bearings easily removed and the new bearings literally dropped in (so they told me). $20 for their help.
Cheers.
I think you are looking at the wrong bolt. One of the hardened b/s bearing bolts snapped off in the block unfortunately.
To the OP, if there are any threads sticking out, I'd try welding on a nut before removing more parts. Welders are so cheap these days, you're bound to know someone who can haul one over and give it a go. Not much to lose trying, and I bet the bolt will hold a weld better than those near the cooling system (which tend to crumble and fall apart under the weld). If you have to drill and want me to make you a plastic jig, however, send me a PM... I'll add it to my shelter in place list...
I think you are looking at the wrong bolt. One of the hardened b/s bearing bolts snapped off in the block unfortunately.
To the OP, if there are any threads sticking out, I'd try welding on a nut before removing more parts. Welders are so cheap these days, you're bound to know someone who can haul one over and give it a go. Not much to lose trying, and I bet the bolt will hold a weld better than those near the cooling system (which tend to crumble and fall apart under the weld). If you have to drill and want me to make you a plastic jig, however, send me a PM... I'll add it to my shelter in place list...
I found a very similar post on rennlist where someone had the exact same bolt snap in the same way, after removing the cover they were able to unscrew it by hand. I hope that is the case with me, I got all the belts off front of engine, I should hopefully have cover off today.
I had the same issue with one of the bearing bolts on my 87 this spring. It was hands down the worst experience I've ever had working on a 944, and I've done a bunch of unfun jobs on these cars. I found my problem in a similar way that you did. I noticed a drop of oil on the bolt head, and it turns out it was actually broken. There must have been some kind of corrosion between the bolt and the block, because literally nothing touched it. Welding something to it just broke it off deeper inside the block. I drilled it for WEEKS several hours at a time. and eventually broke off an allen tool in the hole, then I drilled some more, and eventually drilled it into the virgin aluminum. the bolt never fragmented or fell out, as if it was monolithic.At the end of the day I decided I was tired of drilling in situ, so I'm going to wait until the next time my engine needs pulled to finish the repair. For now, It's sporting a balance shaft delete kit with one bolt missing, and an ATI crank damper.
Word to the wise, when a balance shaft fails it tends to put a giant hole in the engine block, so you'll want to make sure the bearing bolts are repaired correctly, or stop running the shafts.
If you can get at it and it doesn't spin by hand, you might try grinding a slot in it (Dremel) and using a screwdriver in case it just needs a little extra. Old school mechanics also have a technique for using a chisel and hammer to turn out broken bolts, but I've never been able to do anything other than make things worse that way. If you end up drilling, you should definitely get cobalt drill bits, reverse threaded if possible. With 10.9 bolts, a standard bit will be outmatched and you'll end up like Auto_Werks cautionary tale. It's disappointing to hear he welded on a nut and it just snapped off. That's been my experience as often as not also, but I thought the location of that bolt might help. Guess not.
So it turns out didn't need to pull the front cover of bs to get the housing off. Just two upper bolts of front cover. Turned out there was nearly an inch of bolt sticking out. Gave it a few whacks with a 5# sledge and was able to turn it out by hand. Should I use anti sieze when reinstalling bolts?
Now, should I use standard red locktite, or their fancy gel formula?
So it turns out didn't need to pull the front cover of bs to get the housing off. Just two upper bolts of front cover. Turned out there was nearly an inch of bolt sticking out. Gave it a few whacks with a 5# sledge and was able to turn it out by hand. Should I use anti sieze when reinstalling bolts?
Now, should I use standard red locktite, or their fancy gel formula?
Nice work!
I'd say clean and dry threads, and definitely not Loctite (unless you were joking)! The factory torque specs are assuming clean and dry threads. The problem with using anti-seize is that it will reduce friction between the thread and the bolt as its is torqued, which may seem like a good thing, but it might cause the bolt to stretch beyond its ideal clamping capability, which could cause it to fail again---especially if you are using a torque wrench that is not accurate.
I'd say clean and dry threads, and definitely not Loctite (unless you were joking)! The factory torque specs are assuming clean and dry threads. The problem with using anti-seize is that it will reduce friction between the thread and the bolt as its is torqued, which may seem like a good thing, but it might cause the bolt to stretch beyond its ideal clamping capability, which could cause it to fail again---especially if you are using a torque wrench that is not accurate.
Ahh I should have clarified. Locktite on housing cover. And I got new oring for rear.
04-26-2020, 11:24 PM
One of my million back-burner projects is to do a metal jig to drill out the tiny little water pump studs. I could print them for testing and then have some CNC'd in aluminum. Interested? For something like this b/s cover bolt, a one-time jig printed in carbon-fiber reinforced nylon would be more than enough. For my "Track Nanny" PSE controller, I printed a jig for the holes in the enclosure and JB welded in bronze bushings so I could use it over and over. I bet I've drilled 100 cases with that one jig...
