Cylinder bolts won't tighten after 029 to 039 conversion

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Idk about the op, but in my case the holes stripped. The metal is clearly soft or they used too much torque when putting the bolts in for shipping (they ship "sealed" with spacers on the bolts) . I used the new bolt in the first hole at least and at some point started using the stihl ones. 2 of 4 stripped with a nut driver. The other two were stripping around 30 inch lbs. The new bolts and the stihl bolts are the same thread pitch in my case. And the bolts are threaded the same length. The threads on neither bolt ever got pulled or marred. Just the cylinder
OK, maybe I have the two examples mixed but at least we know in one case the cyl. threads are stripped. Thanks!
 
They look the same as OEM. In the attached pic, OEM are the darker bolts.
 

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Looks like the silver threads start a tad closer to the head too. Just an observation - don't know if it matters.
 
Funny thing is, the silver ones grabbed better than the OEM bolts. I was able to get them tight upon initial install. It wasn't until I went to start the saw that the bolts came loose.
 
I returned the short block to SawAgain last week and received a full refund. Unfortunately I'm stuck with the loss in time of 2 teardowns and rebuilds and fussing with things I shouldn't have had to deal with. In summary, the cylinder bolt holes were not threaded correctly, nor was the ground screw hole, and the muffler bolt slots would not allow proper fitment of the muffler bolts without grinding the bolt heads. I would recommend that anyone interested in purchasing the Hyway 49mm short block from SawAgain, be sure to call beforehand to ensure they have resolved these issues.
 
Sorry about the confusion but ripper2 is the same as Scottie68, the original OP. Not sure how the profile name got changed.
 
Well I just got my China kit for MS 310 and my cylinder bolt are totally different!! My original bolts are larger and course thread I think? Don't know what to do? Scott
 
That OEM design is totally garbage and worse than some of the stuff the chicoms come up with, self tapping bolts into a cylinder are just asking for trouble.

I was able to pick up one of these saws free that someone murdered the holes on the cylinder. Ended up throwing the garbage OEM self tapping bolts in the trash and running a fine thread bolt with a crush nut. Worse part about going that route is you have to cut the bottom fins off the cylinder, so more time involved but you'll never have a problem with the bolts again.

Also the ms290 muffler is one of the most restrictive iv'e seen so make sure you open it up if for nothing less but to cut down on the heat it's holding in.
 
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