Electro12WH 50 #1 Posted May 16, 2011 I have a 4.6 hp Wisconsin ABN engine. The spark plug hole is stripped, so I took it to the Toro dealer who said he could repair it with a helicoil. I got a call back today and he said that the metal is too brittle. The threads just tear out. The insert will go in part way but won't hold. Any ideas? I have a couple. 1. Make an over size insert with a fine thread bolt cut off and drilled and taped for 14mm in my lathe. Drill and tap the head for the bolt. 2. Weld the head up and redrill and tap for 14mm. Are these practical? Share this post Link to post Share on other sites
bigd 0 #2 Posted May 16, 2011 i've put in hundreds of helicoils and never had a problem like you dealer is describing.i suppose its possible the metal is not able to take one if thats the case the whole head is probably brittle i would look for a new head Share this post Link to post Share on other sites
buckrancher 2,678 #3 Posted May 17, 2011 you need a keen insert I think you can get them from MSC or McMaster-carr Share this post Link to post Share on other sites
Electro12WH 50 #4 Posted May 17, 2011 i've put in hundreds of helicoils and never had a problem like you dealer is describing. I got the head back today. When it stripped out it took out about the first 5-6 threads. The rest of them are still there. Now, if it was me, I would expect to run a drill down there before rethreading, but the guy says no. So when he threaded it, he said it was tapered and got tighter as the tool went down. He put a helicoil in but only about 4 threads worth. I showed it to my friend Paul who runs a tool rental and is smart about this stuff. He said the insert is probably enough, otherwise take to a machine shop that is skilled at this. Share this post Link to post Share on other sites
Electro12WH 50 #5 Posted May 17, 2011 I installed the head and plug. It runs fine. Share this post Link to post Share on other sites
