Heli-Coil Advice
Thread Starter
Racer
Joined: Jan 2007
Posts: 299
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From: Virginia Beach VA
Heli-Coil Advice
Sigh, well I ended up having to switch the heads from one side to the other...don't want to get into how that happened. Anyway the medium bolt on the drivers head right hand side that I had a problem with finally couldn't take the 70ftlbs of tq and seems to have stripped out. My question is would a chase fix the problem? I got to 65 ftlbs again, but upon trying to go to 70 it stripped out. I am going to get a chase to do all the other holes just in case. The only reason I am a tad worried is the location of the bolt and making sure I could stay straight in doing a heli coil install. Any tips and advice would be appreciated... Would this be a Home Depot item or Northern Tool/Harbor Freight ya think? I need at least a Thread Chase and possible a 7/16 14 Heli Coil Kit right?
*P.S. just to make sure when installing the bolts I cleaned my old ARP bolts and got them looking new, the only thing I put on the threads was motor oil, is that all you need? I read somewhere people putting silicone on the ends to keep coolant from coming up or something. It was my impression oil was all ya needed...Thanks.*
*P.S. just to make sure when installing the bolts I cleaned my old ARP bolts and got them looking new, the only thing I put on the threads was motor oil, is that all you need? I read somewhere people putting silicone on the ends to keep coolant from coming up or something. It was my impression oil was all ya needed...Thanks.*
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
I've used silicon and it works, prefer to use permatex#2. DO NOT use motor oil on head bolts (this.will also change torque readings). I believe ARP makes mention of these things in their bolt kits. I don't put used headbolts in a motor, due to strectch. I believe in chasing all holes prior to assembly and flush. Heli coils kits can be purchased at many places, places like summit offer thread chaser kits as well.
Last edited by mseven; Jun 15, 2007 at 08:51 AM.
Melting Slicks
Joined: Apr 2002
Posts: 2,118
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From: St. Charles, MO Route 66 Corvette Club
I had the same problem when I replaced the intake gaskets on my 89. All intake screws would torque to spec.......except one 
Stripped thread in the head.....and the bolt was cleaned and had threads chased with a die before installation???
Go to NAPA and get a Heli-Coil kit.....do not get an off brand! Go to Home Depot and get a small can of black cast iron thread lubricant. Mix 50% of this lubricant with kerosene and use this to lubricate the tapping for the Heli-Coil in the engine head. (Kerosene in an excellent machining lubricant for aluminum.) Place an oil soaked rag under the defective hole to catch any chips. Have someone help you to align the drill and tapping with the center line of the defective hole for the new coil. This is an easy job and the results will amaze you
Stripped thread in the head.....and the bolt was cleaned and had threads chased with a die before installation???Go to NAPA and get a Heli-Coil kit.....do not get an off brand! Go to Home Depot and get a small can of black cast iron thread lubricant. Mix 50% of this lubricant with kerosene and use this to lubricate the tapping for the Heli-Coil in the engine head. (Kerosene in an excellent machining lubricant for aluminum.) Place an oil soaked rag under the defective hole to catch any chips. Have someone help you to align the drill and tapping with the center line of the defective hole for the new coil. This is an easy job and the results will amaze you
Last edited by Sam Lam; Jun 15, 2007 at 09:04 AM.
Thread Starter
Racer
Joined: Jan 2007
Posts: 299
Likes: 0
From: Virginia Beach VA
Can anyone else confirm not to use oil on the bolt threads. About 3 people told me to use oil, including a shop around here who specializing in installing and repairing heads...Lastly are you supposed to use Permatex on the bolts or is it okay to install dry...most people also told me they never put anything like that on the threads...
Melting Slicks
Joined: Apr 2002
Posts: 2,118
Likes: 0
From: St. Charles, MO Route 66 Corvette Club
My experience is that head bolts must be lubricated before the torque process. I use Permatex Anti-Seize compound on all steel bolts that enter aluminum. This prevents the galvanic action that exists when you join two different metals. The Permatex compound is also a lubricant.
Ask for opinions......and you will probably get some different comments
Ask for opinions......and you will probably get some different comments
Thread Starter
Racer
Joined: Jan 2007
Posts: 299
Likes: 0
From: Virginia Beach VA
Cool, I'm not going to feel bad about using oil on the threads then...it being a lube lol...however, did you need some type of silicone preventing coolant coming up the thread, or other than a lube is it okay to have put the threads in without anything on it.
Melting Slicks
Joined: Apr 2002
Posts: 2,118
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From: St. Charles, MO Route 66 Corvette Club
Rap87: You have to check your holes 
to answer the question on using a silicone sealant. If the thread goes into the coolant system, you should use a sealant (and this also acts a lubricant for the threads). If the threaded hole is a blind hole, use the anti-sieze compound. If you need help to check your holes, let me know 
My opinion!
to answer the question on using a silicone sealant. If the thread goes into the coolant system, you should use a sealant (and this also acts a lubricant for the threads). If the threaded hole is a blind hole, use the anti-sieze compound. If you need help to check your holes, let me know My opinion!
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From: Southampton NJ
Thread Starter
Racer
Joined: Jan 2007
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From: Virginia Beach VA
Alright to me I didn't see any of the bolts going into the coolant passages, however, if you could explain to me which ones might go into the passages I would appreciate it. Do only the medium bolts go into the coolant passages or? Also, by stud do you mean put some All-thread in the hole?
Race Director
Joined: Sep 2000
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From: The Top of Utah
All 17 of the SBC head bolts, on each head go into the water jacket of the block, in a production block. None of the head bolt holes are blind holes. Your FSM, if you took the time to look, says to coat the head bolt threads with a sealant. It even gives the GM part number you can use as a "for instance" for the sealant. I like to use Permatex #2. The head bolts are steel and the block is cast iron, both ferric metals. There is no need to be concerned about these two "dissimilar" metals as thread partners.
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Thread Starter
Racer
Joined: Jan 2007
Posts: 299
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From: Virginia Beach VA
It was my understanding from reading that in FSM, the permatex aided in the removal of the bolt. You're telling me their are 17 potential leaks on your cylinder head? Coolant should be entering from the top of the head at the big water coolant holes...Can anyone else confirm that all the threads go into the water jacket? I believe what I am going to try to do first is to put in a stud like was suggested and see if that'll work.
Le Mans Master
Joined: Feb 2005
Posts: 5,146
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From: The Motor City
Can anyone else confirm that all the threads go into the water jacket?
Thread Starter
Racer
Joined: Jan 2007
Posts: 299
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From: Virginia Beach VA
I concede you guys are 100% right, all bolts must be coated with Permatex #2 or something similiar, which I did on the passenger side head bolts. However, looking over at the driver side bolt hole that is damaged I have found this. It is the medium size screw hole on the right and you can still thread in a bolt, however, you can barely see any thread. My question is, any ideas on how to get a drill in this are...are their self tapping studs, or should I go try to buy the next tap up and see if the hole is big enough to tap now that the threads are gone? All other bolt holes look good. I do have the Heli Coil get for the hole, however, I am worried about fitting a drill and staying straight in this area...Thanks a ton.
Burning Brakes
Joined: Sep 2001
Posts: 1,013
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Absolutely! The only way to go. You can order kits directly from Timesert www.timesert.com Put sealant on the timesert before installing it.Don't think for a second that a regular heli-coil will have a chance of sealing and holding the torque dependably.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
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From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
head bolts
when head bolts are screwed into the engine, the bolts come in direct contct with the water. the unprotected theads wick up some of the water to the point that they won't pass any water.
But.........
the engine pressurizes the water jacket, and the water is pushed up through the heads until the rust forms heavily, and blocks off the water imgration. this means that the water that permeates the rust constantly has water in the rusted areas on the bolts, and slowly over time eats away aththe threads, in the block, and on the bolt.
I always use a silicone sealer on the threads of the head bolts for that reason. once the silicone sets up, 3 things happen.
1. the bolt doesn't rust in place.
2. the block threads are protected.
3. the water cannot migrate into the oil since the water is under pressure, and the oil is not
But.........
the engine pressurizes the water jacket, and the water is pushed up through the heads until the rust forms heavily, and blocks off the water imgration. this means that the water that permeates the rust constantly has water in the rusted areas on the bolts, and slowly over time eats away aththe threads, in the block, and on the bolt.
I always use a silicone sealer on the threads of the head bolts for that reason. once the silicone sets up, 3 things happen.
1. the bolt doesn't rust in place.
2. the block threads are protected.
3. the water cannot migrate into the oil since the water is under pressure, and the oil is not
Thread Starter
Racer
Joined: Jan 2007
Posts: 299
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From: Virginia Beach VA
Well, as for the heli-coil, I don't understand it. I drilled the hole completely straight and the tap provided won't tap any threads what so ever...I'm at a loss. This should be pretty simple, but its not. I guess I
ll look into the time-sert, but any idea why the damn tap won't try to even tap the cast-iron, this is pretty ridicolous.
ll look into the time-sert, but any idea why the damn tap won't try to even tap the cast-iron, this is pretty ridicolous.
Race Director
Joined: Sep 2000
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From: The Top of Utah
Originally Posted by rap87
Well, as for the heli-coil, I don't understand it. I drilled the hole completely straight and the tap provided won't tap any threads what so ever...I'm at a loss.
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