Kind of bummed out at the current moment. Finally got time to work on my '15 Touring that's been down for a few months. I had the head off to do a valve job, and while that side of things has gone well as I was torquing the head down, head bolt #7, the middle head bolt passengers side, decided it didn't want to torque down. It will tighten just won't torque down. All others are fine.
So long story short, what are my options for a fix?
Chris S. Hill
Have you checked to make sure it isn't bottoming out on some debre? Otherwise you may have to shorten it a bit.
Always, always, always run in a drill bit, blow out and tap the block holes. Years of crud and rust get packed into the holes. Doing that can save grief later. It will also keep you from creating an unwanted "Plug" out of your head bolts.
It won't look nice, but put a stud in the block and the stud stays there. Then you can put a nut on the stud and torque it all you want.
You can get a bunch of chromed acorn nut covers and cover all of them up and it will look O K because they will all look alike.
You could check and see if you have a high head bolt mis-matched for a low head instead of the shorter bolt for a low head.
55 Lbs is not much. Try above. May be a soft bolt and you are twisting it. Toss it, clean the holes and use different bolt.
A Heli-Coil will fix that. You can borrow my kit if you want. Here are some pics, sorry for the picture quality I was trying to get it back together so I could go for a ride before it snowed last week.
First you drill out the bad threads with a 29/64" bit and vacuum out the shavings. Notice I used duct tape to keep shavings out of the engine.
Then you tap the hole with a special Heli Coil tap. Again vacuum out the shavings.
You can now insert the 7/16 X 14 Heli Coil insert with the supplied tool. After it is just below flush with the headgasket surface you remove the tool and use a punch to break off the tab at the bottom. Then vacuum out the tab.
Finally clean off the head gasket surface, paint it and the head with KW Copper Coat, and install the head and head gasket.
Chris Hill,What do you mean when you say your head bolt won't torque down? Reading this thread I see many have offered solutions to a problem that is not completely defined in my mind.
1) Has the bolt stopped turning and it has left a noticeable gap between the bottom of the bolt head and the top of the boss on the cylinder head? (Bottoming?)
2) Has it gone completely into the hole and is still turning with some effort but not getting any tighter? (Bolt or Block thread is stripped?)
3) Is the bolt elongating as you tighten it so it will not maintain torque with your torque wrench? In this case, the bolt head is touching the head and the block threads are intact. (Bolt is yielding?)
In each case the fix is different.
55 ft-lbs. is about all that most T blocks will stand for and is the generally accepted torque.
When I tighten it down, I can feel it start to give as when I get to a point where I know it should have been at the torque I was tightening the others down to.
I would say your description #2 best describes my situation. I tried another head bolt and it seemed to get tighter but I could still tell it would not torque down.
It sounds like you'll need at least 1 and maybe 2 Heli Coils. I'd try to torque all bolts before I started the Heli-Coil installation and identify all holes in need of repair so I would only need to make the mess once.
The procedure Royce outlines worked for me. Good Luck!!
Sounds like you've got a hole in the block that's nearly stripped.
Royce's posting is a good one for installing Heli-Coils. The only thing I would do different would be to set the head back on the engine, line it up nicely with the bolts holes, and use it as a drill guide.
Chris, If it's case #2, then I agree with the others. If you don't use the head as a drill guide, there's other tools like the port-align they sold on TV a few years ago to keep the drill perpendicular in the hope the drill follows the axis of the stripped hole.
Royce's photos are nice but he's putting the insert into the wrong hole. I thought you said you need the middle of the passenger side.
Ummmm sorry guys. You can't use the head as a drill guide. The holes in the head are 7/16". The heli coil tap requires a 29/64" hole.
You actually don't need a drill guide because the drill is only removing the old thread material. Once the hole is stripped out there is not much there. The dril is basically cleaning up the hole. Most of the material is already gone.
Yes, the one I need to do would be to the Left(facing the front of the engine) of the one that Royce did on his model T.
LOL Tom I will go to the garage and take it apart and do the correct hole so you can see that one
You could try this before you get into all that helicoil work: clean out the hole, use a bottom tap to attempt to renew the threads, use a new bolt of the proper lenth. It might do the trick, If it doesn't you're not out much and are back where you started. John
I don't have a head here at work to measure. But, the head bolts are 7/16", I'm certain that the holes in the head are drilled larger than that, for clearance. The next drill size up from 7/16 is 29/64. I may be wrong, but, I bet if you tried it, a 29/64 drill would fit in the head.
I think I agree with Jerry,
29/64th is 1/64" larger than 7/16. The head is probably that large or larger.
I'm surprised you only need a 29/64th" drill.
Think of helicoils as an improvement. They are used extensively in aviation.
Thanks for everyones advice and feedback. I picked up a helicoil kit today and am going to tackle this tonight. Guess the T wouldn't be any fun if it didn't break from time to time, huh?
You are lucky that it was the hole it was. Mine stripped in the hole in center back and I had to remove the radiator, and loosen all the engine mounts, the exhaust nut, the fuel line and slide the engine forward about 5 inches to clear the firewall for drilling. The helicoil works just fine.
Chris, clean all the bolt holes out while you're at it.
Ken, one step ahead of you. I picked up a 7/16-14 tap today to clean all the bolt holes up. They were kinda nasty, guess I should of done that before.
Didn't get to far today. Drilled out the old threads and as Royce pointed out earlier, a 29/64's drill bit won't fit through the head to use it as a guide. As is it drilled out fairly easy.
I got hung up because turns our I don't have a T-Handle big enough to use with the 7/16-14 helicoil tap. By the time I realized it, it was to late to pick one up.
Use the head as a jig to align the drill bit, it just fits. The tap is too large to fit through the hole, so you have to eyeball it. Go slow and try your darndest to keep the tap perpendicular to the head. Fashion a jig if you can to keep it straight. If the tap wanders you get an enlarged thread which the helicoil insert conforms to resulting in a loose fit on the headblolt. Its the biggest drawback of helicoils. A solid insert doesn't have that problem since the inside threads are fixed, but you have to drill a larger hole. Helicoils are the first line of defense but they are not perfect.
If the block is out of the car, you can place it on a vertical mill and hold the tap perpendicular in a collet or chuck while you turn it. I did that on my car last year and it worked very well. I replaced all but two threads and the fit is excellent.
after i went through the broken head bolt episode, i will use only new head bolts. got the nice domed shiny ones for $12, bottom tapped all the bolt holes, and torqued the bolts to 55 lbs. if one wants to risk using old head bolts i would reduce the torque to 47-50 lbs.
Chris just read your post. If the drill bit doesn't fit the hole in the head, its because there is rust in there. Next time, just drill through it first. It goes easy.
You are right, what I ment was, that one should be able to reach 55 with out much trouble and that if you can not, there must be other problems as suggested.
Although Chris already has the block drilled out, and doesn't need this info.
The top of the head bolt holes may be mushed down a bit, check from the bottom to see if the 29/64" bit will go in.
Any I've worked on, the hole in the head was 29/64".
Almost all taps commonly available today are tapered at the end. Better for cleaning out the threads is a bottoming tap. A tapered tap can be converted to a bottoming tap by grind the end of the tap to eliminate the taper. If it's a common steel tap be careful not to overheat the tap while grinding or it will anneal and soften - frequently cooling may be needed. If it's a high speed steel tap then overheating shouldn't be much of a problem.
Well, finished things up tonight. Was able to snag a big enough T Handle at Sears.
All in all, the Helicoil worked like a charm. Probably the toughest part was getting it to start in the block.
So she's back together now, still running a bit rough (so I've got some more kinks to iron out) but at least this problem is taken care of.
Thanks all for your help.