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Damaged BB Head Bolt Repair
Posted By: challenger70
Damaged BB Head Bolt Repair - 07/09/13 03:03 PM
I noticed I have a damaged headbolt thread (7/16-14) on my block between #2 & #4 cylinder. I chased the threads with a tap and cleaned em up the best I can. I believe they will hold the 65ft/lb's they need to. They are just not as "sharp" as the other threads and I have a new bolt with perfect threads. This bolt had come loose before damaging the head gasket (it is why I have the head off). Should I just 1)go ahead don't worry about it, 2)use some thread locker on that thread, or 3)??. Anyway to fix this myself(I do not have a welder), without taking it somewhere, as I do not want to tow the entire car somwhere or pull the engine. Any such thing as a mobile thread repair service?
Posted By: RapidRobert
Re: Damaged BB Head Bolt Repair - 07/09/13 03:39 PM
I lube head bolt threads/under bolt head with 30wt eng oil then blow it off with shop air leaving a thin coating. I'd do that & torque it to 65 with the head off & if it all feels good then go ahead & go together & I think you'll be OK
Posted By: pittsburghracer
Re: Damaged BB Head Bolt Repair - 07/09/13 03:46 PM
Did you try using a bottom tap? If not give that a try and then as a band-aid maybe you can use a stud on that hole till you get a chance to fix it right on the next rebuild. DON"T use a cheap imported tap or a borrowed one that has been used way to many times.
Posted By: therocks
Re: Damaged BB Head Bolt Repair - 07/09/13 04:56 PM
Actually you want to use a thread chaser.Taps cut the TC just cleans up the thread.Then install head and torque to what you need.If it holds remove install head gasket and go.Must be aluminum heads for 65 Ft pounds.Thats what mine are with ARP lube.Rocky
Posted By: challenger70
Re: Damaged BB Head Bolt Repair - 07/09/13 06:16 PM
Quote:
Actually you want to use a thread chaser.Taps cut the TC just cleans up the thread.Then install head and torque to what you need.If it holds remove install head gasket and go.Must be aluminum heads for 65 Ft pounds.Thats what mine are with ARP lube.Rocky
My FSM says tighten them all to 50ft/lb first, then 65ft/lb 
Posted By: Cab_Burge
Re: Damaged BB Head Bolt Repair - 07/09/13 07:56 PM
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Actually you want to use a thread chaser.Taps cut the TC just cleans up the thread.Then install head and torque to what you need.If it holds remove install head gasket and go.Must be aluminum heads for 65 Ft pounds.Thats what mine are with ARP lube.Rocky
My FSM says tighten them all to 50ft/lb first, then 65ft/lb
I do 25 or 30 lbs, then 50 lbs and finally 70 Ft. lbs with a very thin coating of 5W20 WT oil on the bolts and a tiny bit in the head holes 
OP, if you decide to try and torque the bad hole make sure and make a spacer that will fit over the bolt and be very near the same length as the real bolt will be with the head on the motor Stick a bolt in the head and measure the amount of threads sticking out the bottom of the head and the make your spacer 
I bought several torque plates years ago and all of them came with spacers, it wouldn't suprise me that they started off as 1/2 inch I.D. black pipe 
Posted By: dogdays
Re: Damaged BB Head Bolt Repair - 07/09/13 08:01 PM
You could put a HeliCoil in it if it doesn't torque down. They will absolutely hold. That's the safest route. They're not cheap. Probably cost about the same amount to buy a kit as it would to have a machinist do it.
R.
Posted By: challenger70
Re: Damaged BB Head Bolt Repair - 07/09/13 10:05 PM
Quote:
You could put a HeliCoil in it if it doesn't torque down. They will absolutely hold. That's the safest route. They're not cheap. Probably cost about the same amount to buy a kit as it would to have a machinist do it.
R.
Is a HeliCoil something I can do myself? I am more concerned with that bolt losing torque over time due to the less than stellar thread condition (why I am considering using some kind of threadlocker) than the threads failing there is still a descent amount of thread for the bolt to grab, there just beat up a little.
Thanks for all the replies
Posted By: dogdays
Re: Damaged BB Head Bolt Repair - 07/09/13 10:12 PM
If that's the case, clean the threads as suggested elsewhere and torque the doggone thing up. If properly torqued it won't come loose.
No thread locker needed.
R.
Posted By: Cab_Burge
Re: Damaged BB Head Bolt Repair - 07/10/13 02:49 AM
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If that's the case, clean the threads as suggested elsewhere and torque the doggone thing up. If properly torqued it won't come loose.
No thread locker needed.
R.
Posted By: challenger70
Re: Damaged BB Head Bolt Repair - 07/10/13 03:35 AM
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If that's the case, clean the threads as suggested elsewhere and torque the doggone thing up. If properly torqued it won't come loose.
No thread locker needed.
R.
The only thing that concerns me is that this very bolt came lose, and I have no idea why, could have been not properly torqued by the builder. Would locktite hurt anything other than making bolt removal more difficult in the future? The helicoil idea is tempting too. I don't want to do any unnecessary work but want it fixed right. Thanks for the input.
Posted By: pittsburghracer
Re: Damaged BB Head Bolt Repair - 07/10/13 03:48 AM
If this is going to keep you awake at night do yourself a favor and measure the head bolt. Now measure the head and the depth of the hole. See if there is anyway that you can use a longer bolt OR STUD to see if you can get down deep enough to hit the good threads at the bottom. Like I said earlier when you start a new build one of the first steps that you do is to chase the threads and thread the hole the whole way down to the bottom. That way you get proper torque on the bolt instead of trying to tap the hole with the bolt. Maybe your builder skipped that step, maybe he didn't. This is why I build my own engine so there is no second guessing. I know its done right. To many shoemakers out there. If you need a longer bolt check Summites site and buy a single LONGER bolt for that hole.
Posted By: a12superbee
Re: Damaged BB Head Bolt Repair - 07/10/13 09:57 AM
I too would look at a longer bolt or stud if possible.
Helicoils are great but if you haven't done a few, it's easy for the whole project to go from bad to worse.
I use them at work often enough but avoid them when there are other options.
Posted By: JohnRR
Re: Damaged BB Head Bolt Repair - 07/10/13 02:21 PM
I would put a stud in the hole and forget it, it sounds like putting in the helicoil is above your skill level and if you do it wrong you are only going to make things worse. the hole has to be drilled and tapped straight, thread locker on the threads may give you a false torque reading.
Either tow it to a shop that can handle it or get a stud and nut from ARP.
Posted By: challenger70
Re: Damaged BB Head Bolt Repair - 07/10/13 03:26 PM
Quote:
I would put a stud in the hole and forget it, it sounds like putting in the helicoil is above your skill level and if you do it wrong you are only going to make things worse. the hole has to be drilled and tapped straight, thread locker on the threads may give you a false torque reading.
Either tow it to a shop that can handle it or get a stud and nut from ARP.
I am liking the stud idea the most, any idea how much "virgin" thread I would pick-up? Thanks 
Posted By: JohnRR
Re: Damaged BB Head Bolt Repair - 07/10/13 03:34 PM
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I would put a stud in the hole and forget it, it sounds like putting in the helicoil is above your skill level and if you do it wrong you are only going to make things worse. the hole has to be drilled and tapped straight, thread locker on the threads may give you a false torque reading.
Either tow it to a shop that can handle it or get a stud and nut from ARP.
I am liking the stud idea the most, any idea how much "virgin" thread I would pick-up? Thanks
can you cut the block down thru the damaged hole and post a picture of it along with showing the amount of bolt engagement ??
Without knowing how much of the original thread got disturbed by running a tap in the hole that is going to be a little tough to even guess at .
I'll make your head spin a little more , putting in a stud that grabs more thread LOWER in the hole is going to distort the bore differently than whatever fastner was used when the bore was originally honed , assuming it was done wit ha torque plate , then add in any wear from the amount of time it was run wit hthat head bolt flopping around in the valvetrain.
Now that I think of it 
Posted By: pittsburghracer
Re: Damaged BB Head Bolt Repair - 07/10/13 04:22 PM
We are not talking about a Pro-stock engine here guys. Fix the dog-gone thing and run it. Cheese and rice.
Posted By: JohnRR
Re: Damaged BB Head Bolt Repair - 07/10/13 05:33 PM
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We are not talking about a Pro-stock engine here guys. Fix the dog-gone thing and run it. Cheese and rice.
all i did was answer the question he asked ...
Posted By: pittsburghracer
Re: Damaged BB Head Bolt Repair - 07/10/13 05:41 PM
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We are not talking about a Pro-stock engine here guys. Fix the dog-gone thing and run it. Cheese and rice.
all i did was answer the question he asked ...
Sorry John that wasn't really pointed toward you. It just that some guys get so book crazy on every little issue their cars never hit the road. I personally would NEVER use a helicoil on anything after working with keenserts in the mill. Helicoils would fail everytime we used them and this is why we started using keenserts. For what he is doing going deeper and using a stud would last forever. Destort a cylinder. To the guy that is worried about this come-on now. 
Posted By: challenger70
Re: Damaged BB Head Bolt Repair - 07/10/13 07:09 PM
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We are not talking about a Pro-stock engine here guys. Fix the dog-gone thing and run it. Cheese and rice.
all i did was answer the question he asked ...
Sorry John that wasn't really pointed toward you. It just that some guys get so book crazy on every little issue their cars never hit the road. I personally would NEVER use a helicoil on anything after working with keenserts in the mill. Helicoils would fail everytime we used them and this is why we started using keenserts. For what he is doing going deeper and using a stud would last forever. Destort a cylinder. To the guy that is worried about this come-on now.
I appreciate the opinions and your expertise
Posted By: JohnRR
Re: Damaged BB Head Bolt Repair - 07/10/13 07:12 PM
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Quote:
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We are not talking about a Pro-stock engine here guys. Fix the dog-gone thing and run it. Cheese and rice.
all i did was answer the question he asked ...
Sorry John that wasn't really pointed toward you. It just that some guys get so book crazy on every little issue their cars never hit the road. I personally would NEVER use a helicoil on anything after working with keenserts in the mill. Helicoils would fail everytime we used them and this is why we started using keenserts. For what he is doing going deeper and using a stud would last forever. Destort a cylinder. To the guy that is worried about this come-on now.
I didn't take anything by it .
Funny , opposite here on helicoils ... military/aerospace ... anything that is alum and gets threads gets helicoiled at minimum.
I'm with you , way over thinking here and I apoligize for going over edge. It should have already been back together with a new bolt ... 
`
Posted By: Cab_Burge
Re: Damaged BB Head Bolt Repair - 07/10/13 08:40 PM
Put the head on the motor and torque all the stock head bolts on it several times, 2 or 3 times, and if the bad one holds march on
If it doesn't hold, then fix that hole
Posted By: R/T Lee
Re: Damaged BB Head Bolt Repair - 07/11/13 03:25 AM
At one point in time I thought Locktite was a emergency/ 1 time use deal. I've been through a couple Locktite courses and it really changed my outlook on the use of locktite. It fills the thread space in the bolt hole, and only cures in absence of air. use high strength Red 277. It will hold, wont loosen on you, and will come out when you want it to.
Posted By: Cab_Burge
Re: Damaged BB Head Bolt Repair - 07/11/13 03:34 AM
Quote:
At one point in time I thought Locktite was a emergency/ 1 time use deal. I've been through a couple Locktite courses and it really changed my outlook on the use of locktite. It fills the thread space in the bolt hole, and only cures in absence of air. use high strength Red 277. It will hold, wont loosen on you, and will come out when you want it to.
I've broken off a 3/8 cam bolt by using red locktite 
Blue is better on some places like cam bolts, header bolts,oil pan bolts, threaded wheel studs and other similar fastener applictaions
Posted By: challenger70
Re: Damaged BB Head Bolt Repair - 07/11/13 08:53 PM
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At one point in time I thought Locktite was a emergency/ 1 time use deal. I've been through a couple Locktite courses and it really changed my outlook on the use of locktite. It fills the thread space in the bolt hole, and only cures in absence of air. use high strength Red 277. It will hold, wont loosen on you, and will come out when you want it to.
I've broken off a 3/8 cam bolt by using red locktite Blue is better on some places like cam bolts, header bolts,oil pan bolts, threaded wheel studs and other similar fastener applictaions
I wouldn't be as worried about breaking a 7/16" head bolt as a 3/8"
Thanks for the additional ideas/thoughts
Posted By: dogdays
Re: Damaged BB Head Bolt Repair - 07/11/13 10:43 PM
If you install red Loctite correctly you have to heat it to 482 degrees F to get it to release.
Chrysler head bolts are Grade 8, so it will be possible to disassemble even a properly-assembled joint using the Loctite 271 (red)
But, as it sets up in the absence of air, it may mess up your torque readings and as such I wouldn't use it.
R.
Posted By: Cab_Burge
Re: Damaged BB Head Bolt Repair - 07/11/13 10:44 PM
Posted By: Supercuda
Re: Damaged BB Head Bolt Repair - 07/11/13 11:06 PM
Quote:
The only thing that concerns me is that this very bolt came lose, and I have no idea why, could have been not properly torqued by the builder. Would locktite hurt anything other than making bolt removal more difficult in the future? The helicoil idea is tempting too. I don't want to do any unnecessary work but want it fixed right. Thanks for the input.
You know that on a bog block with steel shim head gaskets you have to retorque after first warm up. If not you will probably blow the head gasket between two cylinders. Maybe this is the issue.
Posted By: challenger70
Re: Damaged BB Head Bolt Repair - 07/12/13 04:45 PM
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The only thing that concerns me is that this very bolt came lose, and I have no idea why, could have been not properly torqued by the builder. Would locktite hurt anything other than making bolt removal more difficult in the future? The helicoil idea is tempting too. I don't want to do any unnecessary work but want it fixed right. Thanks for the input.
You know that on a bog block with steel shim head gaskets you have to retorque after first warm up. If not you will probably blow the head gasket between two cylinders. Maybe this is the issue.
I suspect as much too...It was put together bu Jasper in IN and I would not recomend them at all, I was very new to the hobby and the shop handling the work on my car when I first got it 12 years ago went with them. It runs strong but has had other issues too... live and learn.
Posted By: dogdays
Re: Damaged BB Head Bolt Repair - 07/12/13 05:16 PM
Every bigblock Mopar and every smallblock from at least 1957 through the late '70s (or later)used a steel shim head gasket.
NONE of them required retorquing.
And you can't convince me that the Mopar engine assembly line ran the engines until warm, then shut off and allowed to cool, then remove valve covers and retorque. If it's my company, at that point I say, "Get me a gasket that doesn't need retorquing!"
R.
Posted By: Cab_Burge
Re: Damaged BB Head Bolt Repair - 07/12/13 11:07 PM
Posted By: challenger70
Re: Damaged BB Head Bolt Repair - 07/16/13 03:07 PM
So I got around to doing a "dry run" and the bolt held to 70 ft-lbs. The only werid thing was after the round of 40, then 70 ft-lbs I redid a round of 70ft-lbs and that bolt turned a bit more than the others to get back to 70ft-lbs again but held fine, but this has me wondering if I should use a stud or the factory bolt.
Posted By: Cab_Burge
Re: Damaged BB Head Bolt Repair - 07/16/13 04:09 PM
Quote:
So I got around to doing a "dry run" and the bolt held to 70 ft-lbs. The only werid thing was after the round of 40, then 70 ft-lbs I redid a round of 70ft-lbs and that bolt turned a bit more than the others to get back to 70ft-lbs again but held fine, but this has me wondering if I should use a stud or the factory bolt.
Which ever one makes you feel the best
Posted By: pittsburghracer
Re: Damaged BB Head Bolt Repair - 07/16/13 04:29 PM
Just one reminder. Unless you FIX the thread every-time you tighten and loosen the bolt you are doing more damage to the UN-repaired thread. Make up your mind, do it, and move on.
Posted By: dodgeboy11
Re: Damaged BB Head Bolt Repair - 07/17/13 05:32 AM
Don't use loctite, if the threads are getting ready to pull, the loctite won't help. Based on that bolt turning more than the others on the retorque, I would not trust the hole as is. Here's what I would do if it were me. I'd buy the helicoil kit for that size and a new drill bit for the recommended size. Bolt the head onto the block with the old head gasket. Bolt torque isn't that important, you just want to make sure the head doesn't move. Use the head bolt hole as a guide to drill the hole out to the size needed for the repair. Be careful not to go off center, you don't want to oblong the head bolt hole, it is simply there as a visual to help keep the drill bit straight. If you have an old head that isn't being used, use it. If the heli coil tap will fit through the head bolt hole, you can use the head to visually make sure the tap starts straight. Once it is a few threads in and straight, remove the tap, remove the head and finish threading the hole. At that point, clean the hole out, install the heli coil, on this, you may end up stacking two or getting longer coils and break the tab out of the end. Make sure you don't thread the coil down to the bottom where the threads aren't as deep because when you thread the bolt in, if it goes deep enough it'll catch on the shrunken part of the coil and won't torque properly. You'll want to keep 3-4 threads under the coil to prevent this from happening. It's really quite a simple process and I may have overcomplicated it in my explanation, but this is what I would do if it were mine.
Posted By: challenger70
Re: Damaged BB Head Bolt Repair - 08/13/13 05:45 PM
I just wanted to update everyone that contributed, I got the car back together and it's running great so far, made a new Camaro ZL-1 owner very sad
I used a stock headbolt and it seems to be holding fine. Thanks for your help/input everyone.
Posted By: a12superbee
Re: Damaged BB Head Bolt Repair - 08/14/13 08:08 AM
Luckily it came out fairly easy with a punch driving it out off of the small step left on the twisted off part in the crank 
