Stripped Bolt-hole (intake manifold)

[Ponch ®]

I was in the process of re-installing the 2bl intake on my engine. I got all of the bolts tightened up to spec (45 pounds of torque, IIRC), but when I got to the last one (which in this case would be the one at the very front of the intake,  on the driver's side), I felt something break and the bolt kept turning and turning. I pulled it out and it turns out somehow the thread in the head's bolthole got stripped.

So, since its one bolt out of 10, can I do without it, or am I screwed (again)? Or do I need to go through some long complicated process to fix it?

[dodge freak]

You are screwed ! Well hold on is it a small or big block motor ? If its a small block thats where the coolant water flows and it will leak in to the motor and outside as well. On the big blocks I think there is no water ports so you could try and see if the intake is sealing. Vacuum leak ok you can change that a water leak no way it ruin your motor.

A hel-coil is not that hard to do but yeah the manifold is coming out. I bet if you used a little longer bolt it would have been ok but too late now. Unless its just the bolt threads that are strip. Pull the bolt out and look, you just might get luckily but its a long shot.

[Ponch ®]

You are screwed ! Well hold on is it a small or big block motor ? If its a small block thats where the coolant water flows and it will leak in to the motor and outside as well. On the big blocks I think there is no water ports so you could try and see if the intake is sealing. Vacuum leak ok you can change that a water leak no way it ruin your motor.

A hel-coil is not that hard to do but yeah the manifold is coming out. I bet if you used a little longer bolt it would have been ok but too late now. Unless its just the bolt threads that are strip. Pull the bolt out and look, you just might get luckily but its a long shot.

yeah..its a small block, and it is near where the water ports are. I was hoping that maybe since all the other bolts went in, it would hold up. The bolt was intact, other than the pieces of metal from the head on it. Man, I aint never gonna get this thing running. 

someone at moparts also suggested Heli-coil...how does that work and is it pricey?

[dodge freak]

You know if you were using the stock bolts you just might be able to get a harden bolt to work. Those stock bolts are not threaded all the way and if you could find a bolt that is a 1/8 longer with the threads all the way down to the end it just might get tight. You have nothing to lose, try to clean the hole out, stick a smaller bolt in with grease to get the crap out and try a new 1/8" longer bolt. Good Luck.

[dodge freak]

Oh no its cheap- you take the manifold off and the hie-coil should come with a tap -oversize- you tap the strip hole -you know how -put the tap in a holder and with some taping oil or trans oil turn it in to cut new threads. You should back it out now and then to release the metal shavings. After the tap bottoms out clean the hole out very good. Then you screw the coil in till it stops. I think you might put some sealer on the coil first but maybe not it should say if it needs it. Thats it , its just time and a new gasket you need.

[dodge freak]

The last trick you could do but its not for the stock looking guys is to get a stud and thread it in till it stops , use thread locker so it stays put and just use a nut to thighen it. I have done this but you can only do one side or the manifold will not come off. This way the manifold could stay put. Its the fastest way but not cool for some folks.

[defiance]

Heli-coils are supa-cheap - You can get kits (like 4 or 5 coils, the matching tap, etc) for 10-15 bucks at auto zone.  And, they're easy - I had one of my water pump bolts break off, and the process of getting the bolt out (nightmare) messed up the threads pretty bad... Helicoiling it took about 10 minutes and worked brilliantly.  

In fact, they work so well that I know some shops that will put helicoils in ALL high-torque bolts in aluminum heads and blocks, right off the bat, just to make sure they don't ever strip.


Now, the only thing you still need to worry about is the water jacket.  I don't have a clue on small blocks, and I don't know how helicoils work as far as sealing, either.  

I'm guessing you could probably coat the coil in red loctite as you're installing it (loctite is water tight when it dries), then use some silicone or other sealant on the bolt - that might just do the job OK.

[Ponch ®]

- you tap the strip hole - you know how - 

well actually.....

[Ponch ®]

The last trick you could do but its not for the stock looking guys is to get a stud and thread it in till it stops , use thread locker so it stays put and just use a nut to thighen it. I have done this but you can only do one side or the manifold will not come off. This way the manifold could stay put. Its the fastest way but not cool for some folks.

I'm gonna try that first, since I don't exactly care about the 'stock look'. 
I take it I need a rather long stud, correct?

Oh, and just to be sure...its a 9/16 bolt, right?

[defiance]

Basically a tap is like a mixture between a drill bit and a screw.  It threads into the plain hole (the hole has to be the EXACT correct size; most kits come with the appropriate drill bit), cutting the threads as it goes.

One thing to keep in mind is to be careful because they are hardened, and a bit brittle, so you have to go slowly to ensure they don't break (if it breaks in the hole, the result is ... well, let's just say you're pretty much DOA)

[Ponch ®]

Basically a tap is like a mixture between a drill bit and a screw.  It threads into the plain hole (the hole has to be the EXACT correct size; most kits come with the appropriate drill bit), cutting the threads as it goes.

One thing to keep in mind is to be careful because they are hardened, and a bit brittle, so you have to go slowly to ensure they don't break (if it breaks in the hole, the result is ... well, let's just say you're pretty much DOA)

ah, that doesn't sound too bad (except for the breaking it in the hole part). Is it done with a manual tool or with a drill? I know that since you said its a combination drill bit / screw the answer might be obvious, but you also said it needs to be done slowly...

[defiance]

Manual tool, basically a t-shaped handle to turn it with.  Don't get near it with a drill!!

Sorry, my fault, I was using the drill bit analogy to describe its function - not method

[dodge freak]

ok now go to the store and find a long enough stud , it be the right size threads on one end and fine threads on the nut end. Make sure its long enough-1/2-3/4 longer then the bolt. Make sure you get a fine threaded nut for the stud if it does come like what I am thinking,in fact get two nuts so you can give it 10-15 lbs to get it good and tight. Use thread locker too, this way it should never come out. Maybe that nut you could try 35 lbs instead of 45 lbs.

[dodge freak]

Make that 1" -1 1/2" longer than the bolt cause its going to thread in deeper than the bolt.

[Ponch ®]

thanks guys...I was already fearing the worst, but these seem like rather simple solutions.

Good thing the OSU-Texas game isnt till later in the afternoon, cuz i'm certainly gonna be busy tomorrow morning. 

BTW - How come the bolt needs to be of a finer thread on the nut side?

[dodge freak]

Cause thats how the studs come here up in Michigan, not sure if thats everywhere but maybe-why who the heck knows. They might even come both ways just thought I let you know so you don't have to go to the store 2 times.

[Ponch ®]

what about tapping to the next size? Is that doable?

I really wouldn't mind that it wouldnt be 'stock', but I prefer functionality over correctness. I guess if I ever sold the motor the next guy wouldnt need to be a genius to figure it out.

[dodge freak]

I would not go the next size up on the end hole cause there is not that much metal around the end hole-it could crack as its getting tight.

Go with the hie-coil -its not that hard you just have to pull the manifold off.

You are right somebody might not like that stud if you go sell it. 318's are cheap motors but people are strange sometimes

[1973_WP29P]

Studs can come in coarse/coarse or coarse/fine.  Use the coarse/fine if possible.  I beleave the thread size you need is 3/8 - 13.  The size of the thread is not the size of the wrench you use.  If not sure of the size you need, take the old bolt with you to the store.  Someone there should be able to help you.  The coarse end of the stud is usually really short so this might not work.

If you go to the next size up you will have to drill a larger hole in the intake.  

The best thing to do would be bite the bullet and pull the intake off and Heli-Coil the hole.  


                                                                                                  Rod

[dodge freak]

  Think it is 3/8 bolt also.

[Ponch ®]

I think I'd already posted this earlier, but I must have forgotton to click on 'post' or something. Anyway...


Gotta love the idiosyncracies of our hobby. Before I went crazy and started doing all that stuff, I wanted to try the simplest solution. I went and got a longer bolt (about 1/4" longer, I think). I tried it on, and it went right in, and I was able to torque it down to 35 lbs. Go figure. I think it was just part of the thread in the hole that was stripped.

[SeattleCharger]

 

[dodge freak]

You know if you were using the stock bolts you just might be able to get a harden bolt to work. Those stock bolts are not threaded all the way and if you could find a bolt that is a 1/8 longer with the threads all the way down to the end it just might get tight. You have nothing to lose, try to clean the hole out, stick a smaller bolt in with grease to get the crap out and try a new 1/8" longer bolt. Good Luck.

Yea-that work great-why those Mopar factory bolts are not threaded all the way down I have no idea--this is one of the reasons I do not like using Mopar parts. It just seems like the aftermaket parts work better. I am sure thats not alway so.  What happen I think is the bolt is now on unsed threads , just a few but enough. Cast iron has its good points.Well you are done I guess.

PS if you even pop the intake off again take a tap of the same bolt size -clean all the threads and throw away all those old bolts and get ARP's or even harden bolts at the hardware store.