O.k., I know this is probably an easy answer, but what is the best way to repair a stripped head bolt socket? While putting the head back on my '14, three bolts wouldn't tighten up. They are all in the same area, a nice little Bermuda's triangle right in the FORD area. All the others were able to tighten to the 55 ft. lbs., but these three were not going anywhere. I tried another bolt, but still not tightening. I'm assuming I have to remove the head again and tap out the three holes? If so, what size tap should I use? I now realize this is something I should have checked BEFORE re-installing the head!!!
You might have to hellicoil it to make it work.
Older post using Helicoils
I got lucky with one head bolt using a tap soldered on a shaft to reach with the head still on. Used bottom tap and longer
head bolt checking depth carefully. On old Ford iron IMO for me 45lbs is plenty with new copper gasket and Coppercoat spray. Checking again after running warm, to set the bolts tight and no leaks.
Do yourself a favor and do it right, pull the head. Make sure the threads on all the head bolts do not have any burrs on them, this is important as the burrs can cause the threads to strip. Hillicoil the block and reinstall the head tightening the bolts to just 50lbs.
I know this from experience.
I had to helicoil a couple of head bolt holes in my engine. It's the only way to go in my opinion.
It's said in the thread Dan posted the link to, but to repeat an IMPORTANT part of this, be sure you have all the debris out of the holes. I even used something long and pointed to be sure I loosened all the crud on the bottom of the holes then blew them out with a can of computer keyboard air.
I use a vacuum hose adaptor from Amazon after a bottom cut bolt and a sharpened pin prick to loosen carbon and etc. Works so far.
Sometimes the stud holes are not clean and plugged up with old rust, bolt will bottom out, use a pick or thin metal. Welding rod" clean out excess then blow it out, re tap threads re check with your bolts check all the lengths of your bolts , space up the bolt if you want to be a bit lazy and see if it's the length of the bolt causing this
When I did mine I tried an experiment. I too used a vacuum to clean out the holes. Then I put the little tube on the can of air, inserted it to the bottom of the hole, and blew it out. I was amazed at how much stuff stayed behind after vacuuming.
After thinking about it, I reasoned that the vacuum requires a flow of air to be effective. Since no air is allowed into the bottom of the bolt hole, it's not a very effective means of cleaning them out.
Just my experience. Your mileage may vary....
I use a smaller hose with a large stand up Vac. I should have mentioned a pre-Vac blow.
Can't seem to remember after the move from Fresno to Lakehills, Tx.
Use a Ford head bolt wrench to tighten up the head bolts. It's the correct length to do the job. I stopped using a torque wrench on any of the T bolts and use the correct wrench for the job. If you do choose to use a torque wrench is has been suggested to only go to 45 on the head bolts esp on the early blocks that are prone to stripping out the threads.
When you get those holes helicoiled and go to put the head back on, do yourself a favor and torque in 5 lb increments.
I stopped after reaching 35 lbs in my 13 ' block and thought I would give it a try.
Its now two years later and compression is good with no water leaks at all.
Going right to 50 or 55 lbs is asking for it I think, especially in an older block like ours.
Clean out the holes well and use a bottoming tap or make one from a good bolt and Dremel tool some groves in it (much cheaper).
As mentioned above, measuring to be sure the bolts aren't too long is critical. A too long bolt is just a perfect machine to strip threads.
Im assuming that you are saying the head bolt threads are stripped in the block. Its a little unclear as to the problem. If you are meaning the bolts do not reach the head before tightening then there is trash in the bottom of the holes.. Either way you need to take the head off for any resemblance of a good repair. After you have the head off take a flash light and look very closely at the threads as to condition of the threads. Then you will need to take a 7/16 NC (national course) bottom tap and chase the threads. You will probably also need to use a "pick of some sort to clean the bottom of the holes as there is usually caked carbon in the bottom of the hole. Use compressed air to blow them out. (use eye protection). If the three holes are stripped out you will need a heli coil kit. It will have the inserts, the oversize tap, the insert installing tool, and sometimes the drill bit. Remember that you want the inserts for 7/16 NC threads. Read the instructions for the inserts. After you are sure of all the threads being good or repaired, fit the head with out a gasket. You should be able to run all the bolts all the way down with your fingers. Use new head bolts, as worn threads on a used bolt is asking for stripped threads. When installing the head and gasket use copper coat on the gasket and anti-seize on the bolts. I would torque to 45 to 50 pounds but there are many different opinions as to torque. You will need to make a decision as to torque values based on the condition of your remaining threads in the block. If the bolts feel a little "loose" in the block I would lean toward the 45 torque or maybe even try 40 if you want to. When inspecting the threads closely you may notice the top thread is sometimes "chipped" or "broken" at the very top of the hole. This is common and does not affect the threads unless a very big "chip" is broken out. Good luck....
Thanks to all you T guy's for the great advice on repairing my stripped threads in the block. I need to make a trip to the hardware store or auto parts dealer to pick up the helicoil kit and a 7/16" NC bottom tap. I will keep you posted on the progress!
In any hole that has a helicoil inserted, do not run a tap into that hole. It can mess up the helicoil and even cause the tap to break when you try to extract it. Place a bolt through your head and measure how much thread is exposed. The helicoil only needs to be that length, and if you are cleaning threads the tap only needs to go in a little further than that measurement. Don't try to go too deep as it is possible to punch into the water jacket.
Bill, when you drill for the helicoil, use the head for a guide, install it snug with 2 or 3 bolts to hold it in place and then when drilling it will hold the bit at the proper 90º angle.
Ken, thanks for the great tip on using the head as a guide for drilling!