RajDatta

I ran into a major problem while tightened the head on my car. Turns out that one of the head tightening bolts would just keep tightening and the stud would just keep coming up higher.
After taking it all apart and pulling the stud out, I saw that the stud had metal wrapped around the top 5 threads. I looked into the block and noticed that there were still some threads left and counted 3 complete threads left on the bottom.
A few questions:
1)How many threads are there all together in the block
2)How are the studs held, from the top, ie the last thread, or is it that it bottoms out into the block. Also, how much "meat" is there on the bottom end. I would hate to tighten and go thru the block.
3)Anyone had a similar experience and knows what I can do about this?

I have excellent access to the hole if needed, it is the hole that is supposed to be torqued 4th in the sequence. I went by factory specs and could not even get past the first 90 turn.
All help would be greatly appreciated. I was really excited about taking my 968 turbo S replica to Hershey in 3 weeks but it seems like its in jeapardy now.
Thanks
Raj

TonyG

Have the car towed to a machine shop, and have them fix the threads properly. They should be able to do the job with the head off, and the block in the car.

Don't even think what you're thinking!

If you can't get to the first torque sequence, you're done. 3 threads left isn't enough.

m42racer

I remember someone writing something here about the Heads Studs and their design. Seems it talked about all the torque going into the threads and not the stud. Maybe you should look for that post and talk to who ever wrote that. I got the feeling he knew what he was talking about.

Just my 2c worth. My thoughts are you fix that 1 and who's to say the others are ready to pull.

Simon

RajDatta

What a bummer!! I think I might be towing it to a machine shop as suggested by Tony. I spoke to Tim from SFR and he suggested a Helicoil. Does anyone have experience with those?
Raj

Mark G

They work. My trans mount on my early 911 racecar is helicoiled and has been trouble free. No personal experience in a block, but they're supposed to work very well. I wouldn't hesitate, but there are others with more knowledge than I that might know of limitations in the 951 block.

Dal Heger

Do a TimeSert instead of a helicoil. It's better for the high torque bolts.

Dal.

fast951

As TonyG suggested, take it to a machine shop. If you attempt to do it yourself and fail, you'll be in that much more trouble. A good machinist, might be able to fix it while the engine in the car. However, finding one that agrees to do it in the car, is a different story.
Do it correctly the first time, or pay much more to redo it again...

Good Luck.

RajDatta

Guys, just an update. I sent the car to our local independant (autotechnik). The service manager (Tom) seemed very knowledgeable and willing to help me with the situation. He at no point mentioned that he cannot accomplish the task without taking the engine out and did not try to milk me in any form.
He is also suggesting a time-sert and has successfully done so before in other applications.
I am praying for the best, lets see what happens.

PerformanceDevelopments

Do not use either Helicoils or Timeserts. Although both are very good and have the same OD thread and pitch, neither are capable of doing the repair without some possible problem. Tell your repair shop to use a "Keensert". These have additional stakes, (3) on the outside dia, which are driving into the block after the insert is threaded in. With the required torque on the stud and the stretch on the thread as a result of poor stud design, your chances of a successful repair are greatly improved. In any repair we do, these are what we use and recommend.

Peckster

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by PerformanceDevelopments:
<strong>Do not use either Helicoils or Timeserts. Although both are very good and have the same OD thread and pitch, neither are capable of doing the repair without some possible problem. Tell your repair shop to use a "Keensert". These have additional stakes, (3) on the outside dia, which are driving into the block after the insert is threaded in. With the required torque on the stud and the stretch on the thread as a result of poor stud design, your chances of a successful repair are greatly improved. In any repair we do, these are what we use and recommend.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">What's the difference in cost? Any problem doing it with the block in situ?

cheetah chrome

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by 968TurboS:
<strong>I sent the car to our local independant (autotechnik). The service manager (Tom) seemed very knowledgeable and willing to help me with the situation.</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">i bought my car off of tom a year ago, he wont bull**** you....when i bought my car he gave me a 45 min "heads up" speech on what the common problems are w/ 944s...you'll never hear a person trying to make a fast buck say that. i had to pickup my car a couple days early because my stealth blew a head gasket and when i called tom he mentioned that the cars ready to go but the shops detailer isn't in that day. when i got there he was washing my car...ever see anyone in management do that. best of luck