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I made a mistake and over torqued a bolt and felt is start to give. Now I need to figure out how to fix it. I have aluminum heads and was replacing my intake manifold gasket. I must have over torqued the rear bolt by cylinder 7, as I felt it start to give. I stopped and hoped for the best, but I have an oil leak on the "china wall", so I need to pull it back apart and try to correct this. Actually, I had a leak there before and was attempting to correct it when I did this. Ugh!
To be clear, I do have a torque wrench and thought I was torquing it in the right order and to spec. I believe my wrench is cheap and either is incorrect or I incorrectly used it. I now have a much nicer wrench to use. I expect that this was 100% user error, so before anyone tells me how much of an idiot I am, understand that I agree. Very frustrated that I have this issue to solve.
So, any suggestions on how to correct this? I haven't pulled anything apart yet. I don't know if this is a "through" bolt hole or not. I could tap the hole a size larger, but not sure about the shavings. I'm sure that is not an option if it's a through hole. I've never used a helicoil before. What should I do to do this right and not a Bubba fix? I really don't want to have to pull the head.
If you have to heli-coil it...just tape up the holes and lifter valley. Put grease on the tap to catch what you can. Shaving cream is a good catch-all also...just vacuum it out when done.
But as mentioned..a longer bolt might get to good threads. Double ck length of all of them to make sure.
Intakes don't torque to much even though they are 3/8" bolts. A good snug with a box end wrench is fine. Warm it up...let it cool down and snug them again.
First off, let’s be clear exactly which bolt you are talking about. The title of your post says “head” bolt but in the body of the text it sounds like you are dealing with a bolt that attaches the intake manifold to the head.
Assuming it is an intake manifold attachment bolt, you likely have started to fail the threads in the aluminum head. This is not the end of the world so start by taking a few deep breaths.
Go ahead and remove all the bolts attaching the manifold. Carefully watch the offending bolt to be sure it backs out while you unthread it.
Installing a helicoil is a straightforward process and is a very common repair for aluminum threads. Your biggest challenge here is how much access you have to be able to drill and tap the hole for the helicoil. There are many YouTube videos on how to do this so watch a few and get yourself familiar with the process.
You may want to call the manufacturer of the heads and get their input.
First off, let’s be clear exactly which bolt you are talking about. The title of your post says “head” bolt but in the body of the text it sounds like you are dealing with a bolt that attaches the intake manifold to the head.
Assuming it is an intake manifold attachment bolt, you likely have started to fail the threads in the aluminum head. This is not the end of the world so start by taking a few deep breaths.
Go ahead and remove all the bolts attaching the manifold. Carefully watch the offending bolt to be sure it backs out while you unthread it.
Installing a helicoil is a straightforward process and is a very common repair for aluminum threads. Your biggest challenge here is how much access you have to be able to drill and tap the hole for the helicoil. There are many YouTube videos on how to do this so watch a few and get yourself familiar with the process.
You may want to call the manufacturer of the heads and get their input.
I see where I may have incorrectly titled this thread. It is a bolt for the intake that threads into the head. So the head is what is starting to strip from the intake bolt. Thanks for helping straighten that out.
I can look into the helicoil, but am concerned that drilling and tapping is going to drop shavings into the engine inside that actual bolt hole. Again, I don't know if that hole goes all of the way through or not. If it does, what is my solution then?
JC - I don't foresee any issues getting the bolt out. My issue is with repairing the threads that are in the head.
If you have to heli-coil it...just tape up the holes and lifter valley. Put grease on the tap to catch what you can. Shaving cream is a good catch-all also...just vacuum it out when done.
But as mentioned..a longer bolt might get to good threads. Double ck length of all of them to make sure.
Intakes don't torque to much even though they are 3/8" bolts. A good snug with a box end wrench is fine. Warm it up...let it cool down and snug them again.
If you have to heli-coil it...just tape up the holes and lifter valley. Put grease on the tap to catch what you can. Shaving cream is a good catch-all also...just vacuum it out when done.
But as mentioned..a longer bolt might get to good threads. Double ck length of all of them to make sure.
Intakes don't torque to much even though they are 3/8" bolts. A good snug with a box end wrench is fine. Warm it up...let it cool down and snug them again.
JIM
Everything Jim said........100%
I will add that some cylinder head manufacturers install heli-coils from the factory.....I know Brodix does.....and it actually increses the strength of the threaded hole.....
Also.....make sure you run the pattern on the bolts per the manual.....
Thank you all for you help with this. I'll tackle this next week and feel like I'm prepared now. Last trick is to get the "china wall" to not leak. I used gasket sealant instead of the rubber gasket, but must have not used enough or didn't let it sit long enough to start setting before installing the intake. So I'll research that again to get prepared.
You can contain the shavings from your drill bit and from your tap by packing them with a heavy grease. If the grease loads up with too many shavings, clean the grease off and repack and continue.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
As for the stripped bolt, clean your head valleys of oil and get them clean, fill the lifter valley with rags as well. But bearing grease in the offending hole and on your drill bit, use a low speed setting so it can grab all the aluminum filings, once its done vacuum up the rest that didnt get picked up with the grease, you dont want to vacuum up oil as it can start a fire in the vacuum. Then coat your tap and make sure you are going in straight. You can temporarily place the intake on and use it as a guide so you dont get your tap in crooked, dont forget to vacuum out that little piece that helps twist in the coil that gets broken off when you are done
On your china wall you want any version of black Silicone. Some folks like THE RIGHT STUFF, I like ULTIMATE BLACK but what ever that is oil resistant will work, it has to be clean of oil residue, then you have to make a 1/4 inch thick bead from the head across to the other head making sure you fill in the gaps where there will be a triangle of the block, head and intake. You have to drop the intake on it straight down, once it hits you can tighten it up and let it dry.
As for the stripped bolt, clean your head valleys of oil and get them clean, fill the lifter valley with rags as well. But bearing grease in the offending hole and on your drill bit, use a low speed setting so it can grab all the aluminum filings, once its done vacuum up the rest that didnt get picked up with the grease, you dont want to vacuum up oil as it can start a fire in the vacuum. Then coat your tap and make sure you are going in straight. You can temporarily place the intake on and use it as a guide so you dont get your tap in crooked, dont forget to vacuum out that little piece that helps twist in the coil that gets broken off when you are done
On your china wall you want any version of black Silicone. Some folks like THE RIGHT STUFF, I like ULTIMATE BLACK but what ever that is oil resistant will work, it has to be clean of oil residue, then you have to make a 1/4 inch thick bead from the head across to the other head making sure you fill in the gaps where there will be a triangle of the block, head and intake. You have to drop the intake on it straight down, once it hits you can tighten it up and let it dry.
Thanks. I read that I needed to let the silicone set up for a bit before installing the intake. I did this for about 5 min, but not sure if that is the right method or not. Any thoughts? Fighting oil leaks and starting from the top. Need this resolved to find the next one.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
no, I always clean both surfaces well and put it on immediately, if it skins over it might not stick.....then let it fully dry, you shouldnt have any pressure in there to push it out if you run it too early....at least not much in a healthy engine, but you could leave a oil fill cover off when you first start it to check how it sealed. The good silicone is super sticky and hard to get off your fingers, even when its still wet. Just take you time and you will be fine. ANd be sure to check all your valve covers...they are the most notorious and worst offenders in leaks...and it makes it look like its coming from somewhere else....Also your distributor will bring oil up and come out at the base if you dont use a gasket there....and it will look like an intake leak
From: At my Bar drinking and wrenching in Lafayette Colorado
Here are some photos of me doing a HeliCoil repair on the intake manifold threads in the heads on a rare ZL1 Camaro with the factory aluminum heads. The important key on the repair is to be able to keep the drilling and tapping completely in-line with the existing threaded hole - on a big block, the holes are not perpendicular to the gasket surface... I'm not sure about the small block. I made a rudimentary alignment tool using threaded studs into the non-stripped holes and laying a straight board across to show the angle needed to be maintained during drilling and tapping. If you just "free-hand" the STI tap-drilling operation with no guide reference you can seriously screw up the hole and its alignment. Tag me back if you have any questions on the process or technique. You can see the installed HeliCoils in the completed photos. It's also important to knock the HeliCoil tang off once the installation is complete, unless you have the tools to use and install tangless HeliCoils:
Lars
I agree with the technique above.
I just replaced the intake on my 48 year old LS6/L88 aluminum heads, and had to replace some helicoils, on the assembled motor. It had a water leak / loose bolt.
And all my intake bolts had been fully heli-coiled many years ago.
But three of the helicoils where the water crossover goes are exposed to water and the steel heli-coils rotted/crumbled away, and pulled out on intake manifold installation.
So we did exactly what was pictured above. And my engine was at a machine shop, and that was their preferred way to fix it.
They said it was no big deal really.
From: At my Bar drinking and wrenching in Lafayette Colorado
Leigh -
Sounds like someone installed some cheap alternative to actual HeliCoils in your heads. Real HeliCoils are stainless steel, and won't corrode or "rot & crumble" away. Glad you got it taken care of, and let's hope they installed the "real deal" this time!
Lars
Help with stripped head bolt
Very frustrated that I have this issue to solve.
