In my two month timing belt replacement job (2002 Honda Accord), i misread the torque requirements for the valve cover bolts and sheared two of them off. While trying to drill out the bolts, i gouged the holes past the 1/4" needed for the helicoil insert. Here is the question: Can i purchase helicoil the next larger, insert it properly and take the correct size helicoil and insert it in the larger helicoil? Kinda like a Helicoil within a Helicoil? any help is appreciated.

 

I doubt it would work.

1. The outer/inner diameters won't be PERFECT. In other words, I'm pretty sure the next larger size won't have an inner size that's a perfect match to the oddball hole that the small HeliCoil would require.

2. I bet the thread-pitch is also different on the next-larger size.

I'm gonna move this over to General Tech. where it belongs. Please don't post questions in the DIY section.

 

There are different types of inserts that can be installed in larger hole. Suggest getting professional help. If you're determined to DIY, go to youtube and view all the options. Timsert is one option, but there are quite a few systems for your problem. It could probably be weld-inlaid and retapped.

good luck

 

You may be past the point of no return on this.

You should call a machine shop and find out if they have some sort of a service that could fix this.

This may be an option:
You may have to get a rebuilt cylinder head and install a new head gasket. It will cost some money, but you will have the problem fixed.

 

Thanks to everyone for the advice....

 

Inserting a heli-coil into another heli-coil will not work effectively. The compression forces will deform the two heli-coils and they won't hold up to temperature changes and the stresses. You can purchase inserts called reducers that will accomplish what you want, but you're looking at professional machining to ensure correct positioning. At this point, you should be looking for a reputable shop to repair the head.