couple of questions regarding case studs

[sb001]

How tight are these supposed to be in the case??
After removing the cylinder heads I was able to turn a couple of them inward by hand. I locked a couple of nuts on those and tiwsted them a couple more turns in but then I started getting nervoue about damaging them, plus they were then significantly shorter in the length they stuck out from the case compared to the other studs. (Just to be clear, the studs do not appear to be "pulled" they were just loose threadwise, and I need to know the mehod to determine their appropriate tightness in the case.)
Case is a genuine VW./Audi AS-21 replacement, the studs are 10mm no case savers as far as I can tell.

Thanks
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1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor

[sb001]

Here are a few pics if it helps-- I reset the couple of studs i threaded in further back out to match the length of the others.

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I'm the humblest guy on this board.

1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor

[sb001]

No one?? Seriously??
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I'm the humblest guy on this board.

1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor

[raydog]

I have never seen a torque listed on the studs alone. I have always just wound them in until they were a good snug. More than hand tight but don't bore them into the case. Best way to check is put the head back on and see how much thread you have left after the washer and nut are torqued on. If there isn't enough thread, at least it should protrude from the nut a little, then you should get some case savers put in. Maybe someone else has a measurement of the stud length coming out of the case.

Don

[Zundfolge1432]

Clean the stud threads then install using a small amount of sealant such as aviation permatex or even RTV. Do not crank them in tight just to where threads are flush with case. The sealant will hold them till everything is torqued.

Clean the other end of studs too, you want to spin the nuts down by hand no drag for accurate torque. The general rule with all studs is when nut is torqued you need to see at least one thread protruding for 100% coverage with a maximum of two and a half to three threads. These are aviation spec you can fudge a little with the car.

[sb001]

[sb001]

[JonRich55]

SB - do you have a Tap the size of the stud to clean the threads in the case? I too have not seen a torque spec for the studs, I try to make sure the threads are clean and get them all into the case the same amount using a thread locker to hold them.

On a spare case with 8mm studs (with case savers) I have a 16mm length for the short ones, 21.5 for the long ones.

[ashman40]

Here's my $0.02 on studs...
You want maximum thread engagement. What I mean is, if your stud threads are 1" long and your case threaded holes are 1.5" deep and threaded the entire distance... screwing them in more than 1" does not get you anything more (all else being equal). Threading them into case so the entire 1" threaded section of the stud is engaged (no threads showing) gives you the maximum retention strength. Going in deeper doesn't give you anything more. On the flip side, if you can only get 3/4" of the 1" inserted into the case you need to do more to clean out the hole and get the full 1" screwed in otherwise you are leaving out 25% of your retention strength "on the bench".

There is such a thing as a deep threaded #3 stud which threads deep into the case. But this doesn't give more retention. Being that deep serves a different purpose to prevent case cracking.

[sb001]

Thanks all-
I guess I do have case savers installed after all:

This stud I just pulled out did not seem too gunked up nor the threaded insert, but I can't twist it back in all the way by hand to where the threads are flush with the case- I have to lock nuts on it and use a ratchet. By comparison the one next to it I can twist in by hand until the threads are INSIDE the case.
If I set them all to where the threads are exactly even with the case as ashman suggests, but there are still a couple that are still hand-loose at that setting, and twist in further when i try to torque the head nut down, I suppose it means the case saver is wallowed out?

P.S. I will say that I noticed some tiny metal shavings when I pulled this stud out, and it became wobbly as I twisted it furher out as if the case saver is wallowed out; however as I stated earlier when i try to put it back in I have to lock nuts on it and thread it in with a ratchet to get the threads flush with the case so maybe it's OK?
_________________
I'm the humblest guy on this board.

1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor

[JonRich55]

Are the case savers all at the same depth? I have seen some where they very in depth. if you use a different stud on the ones that appear to be wallowed, do you get the same experience?

I have always made sure the studs do not move while the nuts are being torqued to the correct setting.

The good news is that if a case saver itself is damaged, they can be extracted and a new one inserted and locked down without machining the case.

[sb001]

[heimlich]

Just screw them in with sealant. You don't want them loose as they will wiggle around. As they wiggle and move they will come out and damage the threads.

Make sure to check the depth that they do not screw too far into the engine case. I had one that hit against the crank because it went in too far.
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[raydog]

Also keep in mind, the more you keep winding those studs in then taking them back out, you ard also wearing at the case threads. That magnesium is soft. I would also use a thread chaser rather than a tap to clean the threads. A tap will still remove some metal. They are made to cut threads.

[sb001]

Got the studs removed, cleaned up, applied some permatex thread sealant and reinstalled so the threads are flush with the case. Only a couple slight mishaps- one of the case savers began threading into the case when I was trying to tighten down the stud more, so I left that one alone- then the case saver on the opposite side began threading OUT of the case when I was trying to remove the stud- I was able to hold the case saver in place while removing the stud the rest of the way then when reinstalled that stud the case saver screwed back into the case tight and seems fine (thank goodness.) Both of these were the upper forward studs on opposite sides of the case if that makes any difference.
Cylinder heads back on, torqued down to 18 ft/lbs (I thought I had 10mm studs but after measuring they appear to be 8mm with the case savers.)

Case saver threaded slightly into the case:

_________________
I'm the humblest guy on this board.

1969 autostick sedan, family owned since new
1600 SP engine
Solex 30 PICT 3 carburetor
Bosch 113905205AE autostick distributor