jfbrubaker1969
New member
Work continues...
So after I got the pistons installed, I temporarily installed the oil pan so that I could support the engine in order to removed the front engine mount and front engine cover so that I could access the timing chains. I knew there was a failure with one or more of the timing chain components, but I wasn't prepared for the amount of destruction! It looks like the plastic timing chain guide that is on the intake side of the engine exploded! There was plastic pieces and shrapnel all over the place (there was a lot in the oil pan when I removed it.). With the guide in pieces, it looks like the chain was able to spin the bottom bolt out, but because the bolt hit the front engine cover before it was able to work its way completely out, it just spun inside the bolt hole and gouged it out!
Fortunately I didn't have any explosives on hand, so I had time to calm down and look for a solution that didn't include me ending up in jail! After some research, I felt a threaded insert would be the way to go, so I contacted a buddy of mine that is a pretty good machinist and asked if he could make me a jig to aid in drilling out the hole and tapping it for the insert. I was able to get some measurements of the three raised bosses that were close together AND at the same height and was able to use CAD to work out the correct geometry and then design an appropriate jig.
In the below image, the bolt location circled in red is the one that got chewed up, the two other bolts circled in blue would be used to hold the jig in place. My friend had the suggestion of 3D printing the jig since it was for a one time use only. It would be much faster to make since the company he works for has some pretty high end 3D printers.
I designed the jig to have three machined aluminum inserts for the 'business' end of the jig. The first insert had a 6mm diameter hole so that I could use a bolt to get it centered properly (there were enough threads at the bottom of the hole to center the bolt). Once the jig was properly set up and held in place with the other two bolts, the second insert with an 8.5mm hole was used to guide the drill bit and the third insert had a 10.5mm hole to act as a guide for the M10x1.5 tap.
I wasn't sure if the 8.5mm drill bit would be large enough to completely drill out all of the chewed up aluminum, so I decided to fill the hole with JB Weld first. I figured at least 80% of the threaded insert would be encapsulated by aluminum, so I wasn't worried about the threaded insert failing and pulling out, but I though filling any 'voids' would help to support the threaded insert and hopefully eliminate any possible vibration of the bolt/insert.
To avoid any air bubbles when filling the hole with JB Weld, I used a syringe to fill the hole from the bottom up.
After drilling out the hole with the 8.5mm bit, you can see there is only a little bit of JB Weld filling in a couple of 'low' spots, it's mostly clean, solid aluminum.
And here it is with the EZ-Lok threaded insert. I threaded a 6mm bolt in and it feels really solid. I watched a number of YouTube videos where independent people tested different thread repair methods and every time, the bolt would fail before the EZ-Lok insert would so I'm feeling very confident with this repair method.
So after I got the pistons installed, I temporarily installed the oil pan so that I could support the engine in order to removed the front engine mount and front engine cover so that I could access the timing chains. I knew there was a failure with one or more of the timing chain components, but I wasn't prepared for the amount of destruction! It looks like the plastic timing chain guide that is on the intake side of the engine exploded! There was plastic pieces and shrapnel all over the place (there was a lot in the oil pan when I removed it.). With the guide in pieces, it looks like the chain was able to spin the bottom bolt out, but because the bolt hit the front engine cover before it was able to work its way completely out, it just spun inside the bolt hole and gouged it out!
Fortunately I didn't have any explosives on hand, so I had time to calm down and look for a solution that didn't include me ending up in jail! After some research, I felt a threaded insert would be the way to go, so I contacted a buddy of mine that is a pretty good machinist and asked if he could make me a jig to aid in drilling out the hole and tapping it for the insert. I was able to get some measurements of the three raised bosses that were close together AND at the same height and was able to use CAD to work out the correct geometry and then design an appropriate jig.
In the below image, the bolt location circled in red is the one that got chewed up, the two other bolts circled in blue would be used to hold the jig in place. My friend had the suggestion of 3D printing the jig since it was for a one time use only. It would be much faster to make since the company he works for has some pretty high end 3D printers.
I designed the jig to have three machined aluminum inserts for the 'business' end of the jig. The first insert had a 6mm diameter hole so that I could use a bolt to get it centered properly (there were enough threads at the bottom of the hole to center the bolt). Once the jig was properly set up and held in place with the other two bolts, the second insert with an 8.5mm hole was used to guide the drill bit and the third insert had a 10.5mm hole to act as a guide for the M10x1.5 tap.
I wasn't sure if the 8.5mm drill bit would be large enough to completely drill out all of the chewed up aluminum, so I decided to fill the hole with JB Weld first. I figured at least 80% of the threaded insert would be encapsulated by aluminum, so I wasn't worried about the threaded insert failing and pulling out, but I though filling any 'voids' would help to support the threaded insert and hopefully eliminate any possible vibration of the bolt/insert.
To avoid any air bubbles when filling the hole with JB Weld, I used a syringe to fill the hole from the bottom up.
After drilling out the hole with the 8.5mm bit, you can see there is only a little bit of JB Weld filling in a couple of 'low' spots, it's mostly clean, solid aluminum.
And here it is with the EZ-Lok threaded insert. I threaded a 6mm bolt in and it feels really solid. I watched a number of YouTube videos where independent people tested different thread repair methods and every time, the bolt would fail before the EZ-Lok insert would so I'm feeling very confident with this repair method.
