Good day gone bad... two head-studs pulling-out

Special Coupe Frank

Special Coupe Frank

Well-known member
Finally got some time this morning before going to work to drop the head on my '28 and torque things down.

Things were going great - got the head seated, nuts on, appropriate stack of washers to compensate for missing cable clamp on # 8 stud, went round the tightening sequence a couple times, going from 30# to 35#, then to 40#.

I wanted to fire the engine up and get it warm, but it wouldn't start, and I discovered I had no spark.

Now I'm out of time, and have to go to work...

Get home from work, and set about resolving the spark issue - turrned out to be a loose connection where the armored cable goes into the distributor. Cleaned and gapped the points, re-set the timing, and had loads of fat, blue spark. :)

Turned-on the fuel, and with some fiddling, got the engine fired-up. :D

Let it run for a minute or so, until the head started to feel warm, then shut it down, and went about installing the water-pump.

Went to take the head nuts up to 45 #, and when I got to #6 stud, the most torque it would pull was about 25 # ( had gotten it up to 40 # earlier). Same thing with #8 stud. Took the rest of the nuts to 45 #, and then came back to nos. 6 and 8... neither would pull more than 25 # of torque.:confused:

So, it would seem that studs # 6 & 8 are pulling-out of the block...:mad::(

I used chrome-moly studs from Snyder's... I chased the threads in the block with an old stud with some slots cut across the threads, and installed the new studs with blue Loc-tite.

I guess I have to pull the head and do thread-inserts on # 6 & # 8...

Any recommendations on thread-repair inserts ?

SC Frank
 
heli coils have a long history of satisfactory performance. Its important that you drill the hole straight. You will need a device to align the drill bit vertically and to index it to the remaining studs.. Tools to hold the stud alignment are available from several of the suppliers. see:
http://www.brattons.com/uploads/images_products_large/08235.jpg

Some guys use an old head, slipped over the remaining studs.

Lock N Stitch also makes an excellent insert to repair stripped stud holes . See: http://fulltorque.com/

With basic mechanical skills and some intelligent attention to details, you can do it yourself with the engine in the car.
 
Another Fordbarn member had a similar problem, thought his studs were pulling out, but it turned out to be stripped nuts.

If the threads are pulling out of the block, or the stud is stretching, the top of the stud will protude further from the nut as you continue to tighten it, if it doesn't change it is the nut that is stripped.
 
I had the same problem with a newly rebuilt engine. Went to re-torque the head after first running it and a stud (the one between the intake and exhaust of #1 cylinder) started to pull out of the block. It was easy to tell because I could see the length of stud above the nut was increasing - so no such luck of having a nut strip :(

I didn't want to take the head off because it would mean getting a new head gasket. So I removed that stud, used the head as a guide (to make sure that I drilled out the old threads perpendicular to the surface of the block) and was able to tap and insert a helicoil that way. I had to make an installer for the helicoil from an old stud but the repair worked fine and held 65 pound feet of torque. A little while later I had to take the head off the engine for another reason and saw that around that stud there was a small crack that must have caused caused the hole in the block to expand enough when I was torquing the head to let the stud pull out. The crack didn't go into the water jacket so I left it alone.

So, you may be OK with Helicoils. It worked well for me.

Good luck and hope the repair is easy and gets you back on the road soon!
 
Kurt in NJ said:
Another Fordbarn member had a similar problem, thought his studs were pulling out, but it turned out to be stripped nuts.

If the threads are pulling out of the block, or the stud is stretching, the top of the stud will protude further from the nut as you continue to tighten it, if it doesn't change it is the nut that is stripped.
Click to expand...

Yes, that happened with a friend of mine that bought a new set of nuts. The new nuts were soft and they stripped. I would get a set of grade 8's.
 
look into time serts they are far better than heli coils, they are solid inserts with a locking tab on top will not pull out, you have to buy the kit, It comes with 5 inserts and the tapping tools with it, if you want to go this way let me know will send you the kit just replace the inserts you use, and send it back AL
 
Thorne Brown Frank with an orange pinstripe, thanks, put it together myself. I also have a 29 Special coupe that's Mountain brown and Thorne brown reveals.
Regards, Barry
 
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