| Author | Message | ||
| Ben Millermon (Brainsboy)
Junior Member Username: Brainsboy Post Number: 177 Registered: 5-2001 |
Well perhaps Im wrong on the tig comment, I didnt realize the heads were heat treated. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 438 Registered: 11-2002 |
Ben, the only possible problem with this technique, depending on application, is by welding you lose the heat treat on the casting. The aluminum goes to full soft, and one may be more likely to pull the threads again. Helicoils in many aluminum castings are installed in first production to add strength to a frequently disassembled component. | ||
| Mark Foley (Sparky)
New member Username: Sparky Post Number: 43 Registered: 3-2002 |
IMHO, if you have the room, Keenserts are a better way to go. Keenserts are threaded bushings, instead of the wound helicoils, and they are widely available from places like McMaster Carr. Mark | ||
| Paul Hill (348paul)
Junior Member Username: 348paul Post Number: 174 Registered: 12-2002 |
Here is a very interesting article from the CASA on re- helicoiling spark plug holes on an aircraft engine! http://www.casa.gov.au/avreg/aircraft/AAC/PART-6/6-058.HTM | ||
| Paul Hill (348paul)
Junior Member Username: 348paul Post Number: 173 Registered: 12-2002 |
One tip for successful installation of helicoils is to keep the chamfer at the top of the hole to a minimum, as this will help the first winding of the helicoil to go into the first thread of the hole and not jump the first thread. One of the greatest engineering ideas IMO � but a real PIA for production runs!!! Paul | ||
| Ben Millermon (Brainsboy)
Junior Member Username: Brainsboy Post Number: 167 Registered: 5-2001 |
My comment of "helicoils are a patch not a fix" was in relation to using a helicoil to fix the spark plug hole. IMO I would tig it not patch it. I do know that they use them in the oil and other locations, I just feel its better to have all the cylinders match then to helicoil it. If you saw 2 heads on e-bay for sale one was perfect and one had a helicoil in it, which would you want. Although a helicoil is stronger, most people want ferrari iteams perfect. | ||
| William Henderson (Billh)
New member Username: Billh Post Number: 50 Registered: 5-2002 |
The TR has a bunch in the engine from the factory | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 426 Registered: 4-2002 |
Dave is correct: there are situations where one routinely bores out a thread, and taps it for a helicoil insert on brand new parts. The steel heli-soil threads are strongler than any alumnum threads, and when installed correctly can increase the strength of certain high stress fasteners, or increase the lifetime of often changes fasteners and plugs. There are a lot of threads in NASCAR engines that are helicoiled during the preperation phase of engine block building. | ||
| philip (Fanatic1)
Junior Member Username: Fanatic1 Post Number: 90 Registered: 2-2003 |
Thanks Steve............I added years and such to my profile, the Helicoil question was in relation to my 348....since some threads on here stated that stripping was a common problem. Hopefully, I won't need one, but at least now I know what the heck it is!!  | ||
| Dave Penhale (Dapper)
Member Username: Dapper Post Number: 588 Registered: 4-2002 |
"Helicoil is just a patch for a problem" Not always the case, can be installed OEM production | ||
| Steve Magnusson (91tr)
Intermediate Member Username: 91tr Post Number: 1564 Registered: 1-2001 |
Not that there's anything wrong with what's been said, but I think you guys have mis-translated philip's use of (drain) "plug" to mean "spark plug". I know that on the '78 308B/S F had already started putting heli-coils in the engine and gearbox pans from the factory so there's no need to "upgrade" to a heli-coil in the drain plug holes philip (unless you have an earlier 308 that didn't have heli-coils pre-installed -- please add year and version to your Profile). | ||
| DJParks (Djparks)
Junior Member Username: Djparks Post Number: 95 Registered: 2-2003 |
Ran into a Toyota on a cross country trip that had a plug completely stripped and bouncing in the hole. I loaded a drill bit with grease to catch as many shavings as possible while drilling the hole, then loaded the tap with grease to catch as many shavings as possible during the threading process. Thoroughly vacuumed around and inside plug hole in an attempt to pick up what the grease missed. Everything worked and the car is still running today. Not a Ferrari though.I would pull the head on the Ferrari for sure. DJ | ||
| Ben Millermon (Brainsboy)
Junior Member Username: Brainsboy Post Number: 163 Registered: 5-2001 |
Helicoils are cheap the kits are expensive. I had priced a kit for an 18mm for around 125.00$ which includes the drill,tap, and tool to install the helicoil. It may be better to tig it and tap it, then you dont need to use a helicoil. Helicoil is just a patch for a problem, you might as well just tig it and fix the problem if your going to go through all the work to pull the head off. | ||
| Sean F (Agracer)
Junior Member Username: Agracer Post Number: 51 Registered: 2-2003 |
To helicoil your spark plug socket you'd have to remove the heads. First, you have to drill out the stripped plug threads, then tap the hole with an oversized tap. The helicoil then screws into the oversized tapped hole, making it the correct thread size for the spark plug. All this drilling, tapping and installing of the helicoil would put metal shavings into your cyclinder head (bad Idea!) hence the need to remove the head. It's not a simple fix, but cheaper than a new head for sure. The heat transfer properties would really not be affected much at all. Helicoils can be purchased at any auto parts store. | ||
| philip (Fanatic1)
Junior Member Username: Fanatic1 Post Number: 89 Registered: 2-2003 |
AHHHHHHHH!!!!!!!!!!! Thanks, so this isn't something I should do to avoid stripping...I should wait to see if it eventually needs it, then I would Helicoil. Thanks for the info. PC | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 427 Registered: 11-2002 |
Helicoil is a brand name for a thread repair insert, kinda like Kleenex to facial tissues. Stainless steel helical insert. Very good deal. Perfect for stripped female threads. For spark plug threads, may alter the heat transfer properties, though. That doesn't matter for a Toyota, but may for a race engine. Mc Master Carr or auto supply store. | ||
| philip (Fanatic1)
Junior Member Username: Fanatic1 Post Number: 88 Registered: 2-2003 |
Hello everyone. I've read a few threads about plugs getting stripped and how a Helicoil is a cheap fix......what is a helicoil...where can I get one? Is it just another type of plug....anything special..I've never heard of it, but I'm thinking I should probably replace my plug with one, before my plug does get stripped. |