Guest Anonymous Posted May 9, 2001 Share Posted May 9, 2001 To cut a long story short, I stripped a thread on my (alloy) head, where the rocker saddle stud taps in, with the head still on the car. Damn, I thought, now what; don't tell me I've gotta rip the head off.... Spoke to a mechanic friend, who said yep a thread repair kit (such as a "Helicoil" or "Recoil" kit) will be strong enough to fix that. But no, he wasn't available to come help fix it. Spoke to a friend who's a fitter, who said yep you'll find it a doddle to do. So, went down to my local bolt bar and bought a kit, taking the stud as reference. I've got a spare stuffed head, so I practiced on that first. Hmmm no probs. OK let's do the real one. Out with the tap supplied in the kit, cut carefully, making sure no swarf falls down oil holes, make sure the tapping is straight. OK, now let's put in the coil, using the tool in the kit. Again, no probs, in it turns. And then finally the errant stud. A little crooked but basically OK! Done, reassemble rocker gear, motor starts fine! Bottom line is, these things are pretty easy to do. I was a little nervous before I started but basically just going slowly it's pretty straight forward. Definitely a DIY. Just wanted to post this to reassure anyone ever contemplating one, who doesn't do it every day. Quote Link to comment Share on other sites More sharing options...
DavyZ Posted May 9, 2001 Share Posted May 9, 2001 Good to hear; there's hope for me yet! David Quote Link to comment Share on other sites More sharing options...
Drax240z Posted May 9, 2001 Share Posted May 9, 2001 Lone, I broke off an easy out in a grade 12 bolt once. Does that count? Of course, I had to really try to get it to do it. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 10, 2001 Share Posted May 10, 2001 Haha, thats close enough. Lone Quote Link to comment Share on other sites More sharing options...
DavyZ Posted May 10, 2001 Share Posted May 10, 2001 I have also broken easyouts before--no fun, no fun. I have been blessed by not having a hard time removing the easyout! Quote Link to comment Share on other sites More sharing options...
blueovalz Posted May 10, 2001 Share Posted May 10, 2001 Question: I this the stud that holds the rocker arm down? If so, I am concerned about the strength of the coils only with respect to the length of the threads that HeliCoils have. Helicoils to me are as versatile as duct tape, BUT, I know that with only 1/2" of threads that the coil provides (close guess) that I would be concerned that this may pull out if you have any descent spring strength. Have you thought about stacking two together for the full 1" or so of threads. (am I missing the boat here or does anybody else see this). I realize that the coils are actually stronger than the original threads, but I still would not want to depend on 1/2" of threads holding the stud in, even with iron heads. Terry Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 10, 2001 Share Posted May 10, 2001 Terry, You're quite right, it's the rocker arm stud and there's only about a 1/2 inch or so of thread (perhaps less) on the Helicoil. However, the actual amount of thread originally there was only about this amount to start with. And the way I stripped it was thru over-tightening, not over-revving (d'oh!!). The valves/springs on my head are standard (dammit...) and the motors don't have a reputation for pulling studs so I think I'll be OK. Also, the fitter who I originally spoke to actually cautioned me about putting two Helicoils in one hole; he said he's never got it to work properly, and that they tend to bind up badly. However, thanks for the word of warning. The way the rockers are set up is a saddle arrangement (a saddle across each pair of pressed metal rockers), so even if one stud gives way hopefully the other stud will hold it in place for long enough to shut the motor down (while making horrible rattling noises, I guess). I'll keep an eye on 'em. Mark. [ May 09, 2001: Message edited by: zedskid ] Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 10, 2001 Share Posted May 10, 2001 Glad to hear it worked so well. My luck would have had the tap break off in the hole. You ever try to easy-out a tap? Good job, cheers Lone Quote Link to comment Share on other sites More sharing options...
383 240z Posted May 13, 2001 Share Posted May 13, 2001 I've been using heli-coils for quite some time with great results you can stack them for a greater depth of thread engagement Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 17, 2001 Share Posted May 17, 2001 I'm just gonna chime in here w/ a "basic" engineering rule -> more than 1&1/2 of the bolt's dia. to length of engagement ratio is not necessary in most applications. My experience as a tool/mold maker haven't proven this "rule" wrong yet. Just FYI Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted May 18, 2001 Share Posted May 18, 2001 Well I'm easily meeting that ratio - thanks, that's reassuring! Quote Link to comment Share on other sites More sharing options...
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