Cracked engine case or normal casting flaws?
10-29-2016, 04:05 PM
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Cracked engine case or normal casting flaws?
I'm getting pretty close to the end of the tear down phase of my engine rebuild, head studs are all out except for the three that broke very close to the case. While working out a plan of attack for them I started with a thorough cleaning of the area surrounding each one. In doing so I noticed what appear to be cracks in the engine case coming from the stud holes. The attached pictures show what I'm talking about. Inspecting further I have found the same thing near just about every stud on the motor. So what's the deal here? Are my cases junk or am I looking at typical casting flaws that I don't have to worry about?
10-31-2016, 02:55 PM
#3
Burning Brakes
Steve - thanks for the interesting tip on Zyglow. I did a quick youtube search to see how that worked, and also came across the following, thanks to the genius of youtube recommendations. That stuff looks pretty amazing. And for the OP, it may be something you can use to test for yourself on this and any other item as carefully as you want to do it.
10-31-2016, 05:03 PM
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Given everyone's comments, I agree that the marks are not troubling. That said, a cracked case is far more concerning to me than a few broken studs at this point. It will take some work for sure, but I have no doubt that I will get those out and continue on. Had the case(s) been cracked though, that would have me thinking very hard about the pros/cons of having to weld up the cracks prior to rebuilding vs doing a complete motor swap.
At this point all attempts to get a tool on the studs have failed, there's just not enough sticking out to grab onto them well enough to make them turn. I tried welding a nut to one and a bolt to another one but both twisted off with little effort (I'm an ok welder, nothing to brag about). My next attack plan is to drill and left hand tap them then thread in a left handed bolt as an extractor. I might even go nuts and try welding the bolt once it's threaded in just to give it a bit more strength beyond the threads. Honestly not sure how well it will work, the studs may prove too hard to tap but if that's the case I will re-evaluate my options at that point.
At this point all attempts to get a tool on the studs have failed, there's just not enough sticking out to grab onto them well enough to make them turn. I tried welding a nut to one and a bolt to another one but both twisted off with little effort (I'm an ok welder, nothing to brag about). My next attack plan is to drill and left hand tap them then thread in a left handed bolt as an extractor. I might even go nuts and try welding the bolt once it's threaded in just to give it a bit more strength beyond the threads. Honestly not sure how well it will work, the studs may prove too hard to tap but if that's the case I will re-evaluate my options at that point.
11-01-2016, 09:47 AM
#7
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There was a guy on Pelican that managed to get out his short broken studs by cutting a slot in them with a Dremel, and then using a large screwdriver to back them out. I would probably heat them first to loosen any thread locker that may be in there.
If this doesn't work, then you can try the drill and tapping approach.
Mark
If this doesn't work, then you can try the drill and tapping approach.
Mark
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11-01-2016, 12:56 PM
#8
Instructor
Unless you're highly experienced at stud removal and have all and I mean ALL the clever little tools and jigs that a pro has, I'd take those cases to a machine shop that's done hundreds if not thousands of extractions and have them do it. There's an old saying "you can't beat a man at his own trade"
The same shop will be able to do a magnaflux test as well. That Zyglow stuff is pretty cool, though.
The same shop will be able to do a magnaflux test as well. That Zyglow stuff is pretty cool, though.
11-01-2016, 01:15 PM
#9
RL Technical Advisor
Unless you're highly experienced at stud removal and have all and I mean ALL the clever little tools and jigs that a pro has, I'd take those cases to a machine shop that's done hundreds if not thousands of extractions and have them do it. There's an old saying "you can't beat a man at his own trade"
The same shop will be able to do a magnaflux test as well. That Zyglow stuff is pretty cool, though.
The same shop will be able to do a magnaflux test as well. That Zyglow stuff is pretty cool, though.
FYI,...Magnaflux only works on ferrous parts,...Zyglow is what we use for cracks in aluminum, magnesium and other non-ferrous metals.
11-01-2016, 01:53 PM
#10
Instructor
Aah jeez, so my cast iron cases aren't "numbers matching"? Shoot, the guy I bought the car from said the 911's that came from the factory with Opel engines are really rare and valuable...
Duh, "magna" = magnetic... Thanks for the correct Steve - gotta keep an eye on me all the time...
Duh, "magna" = magnetic... Thanks for the correct Steve - gotta keep an eye on me all the time...
11-01-2016, 04:11 PM
#11
Team Owner
yeah id have a machine shop tackle that .. but if you do it yourself and it does all go south you can bead blast them and use them as cool wall art.
11-02-2016, 03:14 PM
#12
RL Technical Advisor