Epoxy : HeliCoil : TimeSert : KeenSert

[twinrider1]

Briggs Intek OHV. What was to be a simple valve adjustment turned out to be a rocker stud that had backed out and stripped the threads.

Anyone with experience in this sort of thing?

Guts telling me to remove the head to do it. Experience tells me the more you remove, the greater the chance to muck it up.

 

[monkeydelmagico]

Greenman just did a timesert on a ford http://forums.anandtech.com/showthread.php?t=2380766

What size motor? If it's small timesert kit will cost almost as much as replacement motor. Helicoil is cheaper.

 

[phucheneh]

I'm guessing this is a fairly coarse bolt going into cast iron?

Helicoil with a few dabs of red loctite. Easy-peasy.

 

[JCH13]

Epoxy - Terrible idea. Butt-turrible to be technical about it. You'd be looking at a ~90% or so strength loss when the epoxy hit 250F. No.

Helicoil - Inexpensive (even comes with the right tap), readily available at may parts stores, easy to install, and easy to replace. Modest strength gain over aluminum threads. Good option for this problem, definitely the most cost-effective.

TIMESERT - Pricey, generally have to order, modest difficulty to install (but not 'hard'), difficult to replace. Large strength gain over aluminum threads. Likely overkill for this problem.

Keensert - Modest price, can easily order from McMaster, I've never used one but the installation looks fairly easy, built-in thread locking, and somewhat difficult to replace. Modest strength gain over aluminum threads. Very good option for this problem IF you already have the requisite tap.

No need to remove the head for this work. Be careful when drilling/tapping. Use grease when tapping to catch chips. Do everything you can to make sure that you are drilling/tapping square to the hole.

 

[twinrider1]

Thanks guys.
As much as I like overkill and acquiring more tools, I'll probably go with the helicoil.

The hole appears to be a through hole, which I thought was odd. That's what made me want to take the head off. Though people do spark plugs holes with the head in place, so maybe I'm worrying too much about a chip falling in.

 

[boomerang]

I'd pull the head. The potential bonus on that is that the hole may be perpendicular to the mating surface of the head to the block and you'll be able to drill the hole on a drill press. Drilling the hole at the proper angle is going to be difficult. If you decide to drill it with the head on, get a friend to act as a spotter to keep you drilling at the proper angle. You can sight one direction while drilling and a spotter can sight the other looking at a position 90 degrees from your view.

If you were local to me. I've got a 6mm kit and may even have some inserts I'd let you use. I adjusted the valves on a Vanguard just yesterday and the rocker stud looked to be 6mm.

 

[jlee]

If it's soft enough, I'd drill it by hand (as in no power tools). You're only taking threads out, so it requires minimal effort and it'll be easier to drill straight than trying to feel it through a drill. Now if it's nasty hard material (I did it on an aluminum head 😀), that may not be a viable option.

 

[MongGrel]

Keenserts are more solid and probably require more material removal to insert correctly and you have to worry about making sure you get the tangs inserted correctly if you've never used them before.

I'd say go the Helicoils, but have never tried doing that on an engine like that in place, although I've done thousands of them over the years in various installations and repairs.

Have even done hundreds with keen serts in high end things, but Helicoils sound more practical.

The nice part about those is if you botch it for some reason, and still have material left to work with, keen serts come in various configurations you could even replace a smaller diameter Helicoil with.

Personally if I was doing it I'd take it off and throw it on a Bridgeport, but I'm not doing it I guess.