small problem....

[KongGMC]

Okay so I got my head bolted on today.(sorry it's been taking me forever to get all of the necessary crap together) Anyway, I get the cams tightened down and lubed up and I'm eager to see how it will look with my freshly painted valve covers on it and when I get to the last valve cover bolt on the passanger side rear of the head, it's stripped out. At first I thought maybe the bolt was just getting hung up on the gasket so I tried gung hoeing through it. I didn't want to hurt it so I backed it off and tried a different bolt in the hole. Same thing. So I took the valve cover off and look and the hole and it's like all kinda screwed up in there. So I'm thinking of trying a thread tap first. If that doesn't work what should I do? Never done a heli-coil before and I'm not sure if a different type bolt will work. I hate to just cram a self tapping sheet metal screw in there cause that's just ghetto.

Let me know guys. I'm gonna try that tap tomorrow but any and all advise is very much welcomed!

 

[benchwarmer]

Heli-coil is the best solution for stripped threads and it's pretty easy. Just fix it right the first time so you don't have to worry about it later.

 

[suprarx7nut]

If you helicoil let me know how you did it.

My heli-coiling experience was an utter disaster.

 

[castrol supra]

Can you not increase the hole diameter to the next size..., then tap it and up size 1 thread size???

I have 1 bolt on the extreme top of my water pump that I loctite the heck out of.

 

[IJ.]

There's a knack to fitting HeliCoils

Done a couple of 100 of em over the years and at first I'd stuff just about every 2nd one I'd try.

You need to keep some downward pressure on the tool so the Coil doesn't skip a groove and go all mongy.

Once in you use the little tool to snap the drive lug off and CAREFULLY remove the lug using a piece of wire with some grease on it.

 

[trydrew]

I also recomend the helicoil. Infact, not too long ago I did it to the same exact bolt you are talking about. Just make sure you dont get any metal shavings in the head. If you have never done helicoiling, i recommend practice. I'm not saying it's hard, but just find a M6x1 (iirc) hole to test on. It's really pretty easy once you get a feel for it.

Or you can try drilling the hole in your valve cover bigger and tapping the head up one size. Your choice really.

 

[Figit090]

I had to helicoil a few exhaust studs with the head bolted down. that was a bit of a pain but its doable. The annoying part was believing the engine shop when they said it's rare to strip out an exhaust stud. its utter bullshit, especially for an aluminum 7m head.

I first practiced on a blown B&S lawnmower block before going at my 7m though, it helps to see how the metal reacts to being drilled, how it feels to clog the bit, get too much bite, and so on...having not much drilling experience.
I used the bolt holes in the head of the block, and since Briggs and Stratton just drill one long hole for the head bolts from the top of the head down the side of the block...i was able to keep threading the helicoil until it exited the side of the engine. It was nice because I got lots of practice with one coil.

Just take it slow and keep the drill straight, follow the directions and use a good amount of lube when tapping the new threads for the coil.

Its not as bad as you might think. :icon_razz

OH and as for re-drilling the valve cover hole larger, i'd be careful. It's cast aluminum and I'd be worried about it compromising the integrity of the area around the hole. I don't know a lot about it, but the concern came to mind.