Stripped bolt hole on head... pls help

[packinkimber45]

So I was installing the upper rear timing belt covers on the head last night and stripped one of the holes. I'm talking about the plate that go behind the intake cam gear that the upper t belt cover screws onto. The first time I was torqueing the bottom bolt it felt like it stripped, but then it took the torque. I decided to put loctite on all the bolts just for insurance. Torque specs call for 7-9 ft/lbs. The first time I torqued it I did 7. After applying loctite on the bolts I decided to go 9 ft/lbs. All took the torque except for the last one. It kept spinning so I stopped. Its still on the head loctited. Should I just leave it alone since its loctited or take it back out? It wasn't loose or anything, there was resistance when it kept turning and the loctite hasn't cured at that point. What options do I have? Drill, tap and use larger bolt? Or helicoil? I don't want that bolt falling out causing t belt failure. I inspected the threads in the hole before I loctited the bolt and they looked darker than the rest. Was it helicoiled before? I don't want that plate on with just one bolt, I don't want any chances for it to contact my t belt. What should I do? Thanks

 

[akira235]

you could heli coil it. personally i'm ocd about stuff coming loose so I wouldn't leave it like it is for fear of the loctite wearing off

 

[packinkimber45]

Is heli coil better to use for that specific locationor time sert? It doesn't require a lot of torque but I don't want just a band aid fix either.

 

[turboglenn]

not sure which hole but if it's deep enuogh for a heli-coil, use one. And a rule of thumb i've come up with on 10mm bolts is to NEVER try and get them to torque spec, i just toss a drop of blue loctite on them and only get them good and snug with a 1/4 inch ratchet

 

[94_TSi]

not sure which hole but if it's deep enuogh for a heli-coil, use one. And a rule of thumb i've come up with on 10mm bolts is to NEVER try and get them to torque spec, i just toss a drop of blue loctite on them and only get them good and snug with a 1/4 inch ratchet

+1 on that

 

[LiquidX]

Heli coil it if you had to have it on. I'm currently without both of those plates due to the garage not installing them and the cam gears need to be off. However there was a bolt in one of the holes and it was working itself loose and I caught it before it fell into the belt.

Heli coil will make it stronger as you'll put in a steel thread

 

[BogusSVO]

since it just holds the back time cover, its a 6mm x 1.00, if you take your time you can tread in a 1/4 bolt of the same length.

no heli coil iss needed

take the 1/4 bolt, put a drop of oil on it and slowly work the bolt in like a tap, the alum is soft, and the steel bolt will cut its on threads.

the bolt you have stripped out, is there to keep the belt cover from rattling.

 

[Murdog]

I would not use the 1/4" bolt...that can cause other issues...use the helicoil...

 

[packinkimber45]

since it just holds the back time cover, its a 6mm x 1.00, if you take your time you can tread in a 1/4 bolt of the same length.

no heli coil iss needed

take the 1/4 bolt, put a drop of oil on it and slowly work the bolt in like a tap, the alum is soft, and the steel bolt will cut its on threads.

the bolt you have stripped out, is there to keep the belt cover from rattling.

Bogus, I was originally going to do heli coil but decided against it. Mainly due to cost. I'm also worried of the helic coil working itself out and causing issues later. No experience with heli coil but concerned me when I thought about it.

I would like to use a different size bolt, however I want to do it right by redrilling it and tapping.

1. Can you recommend me the next size I should go to as far as bolt size? I would like to use something that is of common size that is easily available. I was going to go with an m7x1.00 but it's not a common size, then I though about 1/4 20. But the size difference between m6x1.00 and the 1/4 20 enough for the threads to work right?

2. Would I need to get a grade specifc bolt, grade 5 or something? It only calls for 7-9 ft/lbs so I would imagine not.

3. Depending on the size you recommend what drill bit should I use with the consideration of coarse thread vs fine coarse thread vs medium coarse thread?

4. And off course, what tap should I use.

5. Is the method you described earlier about just threading a bolt in there a better method than redrilling? Since the head is aluminum I assume it is easier to screw it up due to its softness. Redrilling a hole that is already there makes me really nervous. Me doing it that way as you described it with the 1/4 bolt is there any ill effects of doing that?

6. When you said 1/4. Do you mean just 1/4, 1/4 20, 1/4 28... or am I getting the tap and bolt size mixed up? I'm not really making sense on this question, please clarify... Lol sorry.

Thanks.

I would not use the 1/4" bolt...that can cause other issues...use the helicoil...

Can you tell me why the 1/4" bolt is a bad idea? Thanks.


Just to clarify the bolt hole I am talking about ...

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[92AWDHX40]

too hard just find a tap, then thread a new bolt.

 

[packinkimber45]

Part of the threads are already gone but some in the back are still there. I want to do it right. Not just tap it.

 

[zfanatics]

Use a 1/4 bolt with self-tapping tread and be done it it. It will NOT coming loose. If you want extra security then add a drop of tread-locker.

 

[packinkimber45]

Use a 1/4 bolt with self-tapping tread and be done it it. It will NOT coming loose. If you want extra security then add a drop of tread-locker.

I'm not sure how much bigger a 1/4 bolt is compared to the original m6x1.00 but should I redrill the whole to a little bigger size to accomodate the new bolt? I'm not familiar with bolts, is a 1/4-20 okay? Thanks.

 

[Colt4G63 also]

You should really use a helicoil. They last forever, and are much stronger than the original threads. The kit might cost you $30, but you get like 6-8 of the coils in the kit, so you can go ahead and strip the other holes too.

 

[66ss]

tap it out and throw a bolt in it...also try some "indian head" by permitecs

 

[packinkimber45]

After debating on doing it, I went ahead and used Heli coil. Got it done. Wasnt hard at all, just a little scary since I was drilling into aluminum. Went smoothly, redrilled and tapped the hole straight. Used red loctite on helicoil and blue on bolt. I feel better now. Lol. Thanks everyone.