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Discussion Starter #1
I'm working on a 350 engine and I can't seem to get a bolt to fit into the crank to hold the pulley up. I think it may be stripped inside the crank. I've tried several bolts and nothing is going in smoothly. Any suggestions? Should I go buy a tap and die kit?
 

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You got a leaky spark tube...
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Try tapping the crank snout. It's a 7/16-20 thread (fine thread). If you still don't have any luck or the threads still look pretty trashed then go to a fastener supply store or some other place that sells high quality heli-coil sets and install a heli-coil. I had to do this on my 350. The first set I bought came from NAPA and the tap just chipped and trashed itself, even with ample lube. I bought another heli-coil set from Tacoma Screw and it worked well. It had a much higher quality tap and installation tool.
 

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Discussion Starter #3
awesome. i think the finest thread that i tried was 7/16-14 or 16, i'm not sure. So I definately had the wrong bolt. i didn't go any finer than that, they were all more coarse. so tomorrow i will be getting that bolt and i'll see where to go from there. i'll keep you posted, thanks.
 

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You got a leaky spark tube...
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7/16-14 is a standard coarse thread bolt, 7/16-20 is fine thread. I know my local NAPA always has a good selection of bolts and nuts, including fine thread fasteners. Have you tried a fastener supply store? They'll have what you need.
 

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Well I have a few bolts that I got off of cranks from the junk yard. Those thread in a couple of turns at most then they stop. I really think it's the threads in the crank. I haven't tried tapping it yet, i'm not too sure how to. Any suggestions as to how I do that? Thanks for your help
 

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You got a leaky spark tube...
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2,854 Posts
Go to the store and buy a GOOD 7/16-20 tap and a handle. Start the tap by hand as far as you can get it to go. Put the tap handle on and thread the tap in about 1/2 to 1 turn at a time. Then back the tap out a bit and run it in a little further. Just slowly work your way in until you've bottomed out in the hole. If the tap starts to get tight don't force it. It may need to be cleaned out or it may be bottomed out, too much force will break it and you will have a nasty time trying to chip the darned thing out. Taps are very hard and brittle. Using a chisel to chip out a broken tap is not fun and you wind up repeatedly sharpening the chisel. You may even want to stick a piece of wire in the hole to get an idea of how deep it is and then mark the tap just a little bit short of that distance to give you an idea of where the tap is at. Make sure you use some lubricant while you're tapping too, that'll make it a little easier.

Don't be too worried, tapping is very simple. You just don't want to break it.
 

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Discussion Starter #7
I tapped it this afternoon. I sprayed some WD-40 in the hole and it slid right in. I thought it was going to give me a hard time, luckily it didn't. Thanks a lot for your suggestion.
 

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You got a leaky spark tube...
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2,854 Posts
Many times it's just a small booger on a thread and you just have to get that cleared out. :thumbup:
 
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