head stud leak - how to address

[b15605]

Hello all, I have a pesky oil leak I am chasing down and need some help. For the full history of this adventure, see the forum topic below:

https://www.thesamba.com/vw/forum/viewtopic.php?t=806507

For those that don't want to read the full topic above, here is a synopsis:

73 super with stock 1600 DP

Leak on left side of engine, it is not from the oil cooler, but after using a boroscope I discovered it is a steady flow from the #4 lower left (looking at the engine case) case stud that is leaking. Per suggestions from other Sambanians, I used blue loctite on the inner threads while I had the engine out...this did not change anything; therefore, my assumption is that the leak is around the outer threads and the block on the case save. It seems this hole is close to an oil gallery between #3 and #4 cylinder (?) and perhaps this case saver has cracked into the oil gallery. pic of area below - after it had been cleaned up:

So then, how is this best repaired - or can it be repaired properly. I have another used case in my possession, so would it be better to (a) attempt to repair this case - maybe a good vw machine shop could install new case saver (b) send the backup used case out for line bore, etc. and transplant the guts from my current engine in or (c) invest in a new case (aluminum or magnesium?)?

Really looking for advice here. This group is more focused on engines so swapping the topic here as I think I will get more input and traffic in this subject. I do appreciate the input so far from folks in the main Super channel

[Dougy Dee]

That looks like a Key-Lock insert. Can you get it out?

To confirm that is where your problem is block off the oil galley and use compressed air and soapy water to check for bubbles...

[Rob Combs]

I have an almost empty case sitting behind me; thought I'd take a look behind that stud location. Here are the oil galleys behind the red lines:

Not much behind that stud other than the center main bearing support web. On my case it looks like a blind hole too, not open to the back.

It is possible the case is cracked between the stud location and the oil galley, but are you certain the cylinder base was not leaking onto then around the stud, making it look like the stud is leaking past the threads?

[b15605]

Not 100% certain it is stud vs. the base of the cylinder. Boroscope is best I can do and with that engine tin deflector in there it is super hard to get a look in that area as you can imagine. I did put fresh RTV in at the base of the cylinders as well when I had it apart a few weeks ago, but admittedly, didn't clean the area perfectly of oily residue while doing it - so yes, it is possible. Maybe another go with the boroscope is in order...it really looked like it was coming from the stud though in live action with boroscope.

[jim martin]

Makes sure the inserts are fully seated. If the studs don’t come out don’t worry . Brake kleen and blow with compressed air a few times . Assemble the top end Then use wicking grade loctite around the inserts and studs problem solved. Won’t leak
_________________
B.C's fastest street legal vw , June 2006 Hot VW's feature car 9.81 sec at 145.26mph.
Sponsored by :
LUCAS OIL PRODUCTS http://www.lucasoil.com
KROC head porting services
Dialedinperformance.com
Airspeedparts.com topic http://airspeedparts.com/forums/index.php?topic=914.0

[b15605]

Jim,

I assume you mean loctite 290? It is a wicking grade and looks like it will withstand up to 150C/302F from my research?

Any risk of fouling up the oil galley? Or once it hardens and fills the crack no concerns?

And this is a good suggestion - so thanks for this.

[jim martin]

Yes that’s it .spin motor 90 deg in stand son dack is flat and we use an acid brush trimmed down or a tooth pick to pool it around the head stud and insert . Leave it like that for a day or 2 . Blot off extra with a paper towel and flip and do other side . It’s a ano
Anaerobic so will only cure in no air condition.
Don’t rush it . We let each side sit like 2-3 days a side .
But focus on cleanno
_________________
B.C's fastest street legal vw , June 2006 Hot VW's feature car 9.81 sec at 145.26mph.
Sponsored by :
LUCAS OIL PRODUCTS http://www.lucasoil.com
KROC head porting services
Dialedinperformance.com
Airspeedparts.com topic http://airspeedparts.com/forums/index.php?topic=914.0

[modok]

If you drill the #4 bottom inner stud hole too deep in the case, it intersects with the oil galley going to the center main bearing.

[Glenn]

[EVfun]

[b15605]

I will try to use the green loctite this weekend. Have to admit I am skeptical myself, but a $10 fix with some decent effort is better than the more involved option - new case.

Speaking of cases - if this doesnt work out, I would really appreciate thoughts on new case vs old case as mentioned above. I am sure it is an opinion thing and everyone has one, but varying viewpoints and experiences are healthy!

[b15605]

I am STUCK! Literally. I confirmed today the leak is indeed from the case saver by taking engine tin off and running it where I could really see.

I then began to attack the locksert. After some research it seems the best approach is to drill out the locksert enough so the locking pins can be tapped inward and removed - this went smoothly I would say:

Now that this is accomplished I cannot get the rest of the insert out of the hole. I used the only screw extractor I have that will fit and it simply wont budge. I assume red locktite was used and perhaps this simply isnt coming out. Do I throw in the towel? Any ideas are welcome. If I must assume this case is garbage - then it is what it is.

[EVfun]

Did you manage to pull the 4 keys out? If so can you drill it a bit more and a bit deeper? If drilled enough those key inserts just about fall apart. I’d recommend a reverse drill so if it starts turning it will be unscrewing.

Once out there should be some type of solid insert option. While a key insert looks big the threads are shallow, only about 60%, so hopefully there is room to oversize a little more.
_________________

[jim martin]

Oh dear .
Insert was in tight I hate to rub salt in the wound but should of used
The loctite 290 . When you do get this fixed use it on the other studs and inserts.
Good luck
_________________
B.C's fastest street legal vw , June 2006 Hot VW's feature car 9.81 sec at 145.26mph.
Sponsored by :
LUCAS OIL PRODUCTS http://www.lucasoil.com
KROC head porting services
Dialedinperformance.com
Airspeedparts.com topic http://airspeedparts.com/forums/index.php?topic=914.0

[modok]

You could screw it up further yet before ruining it permanently.
I don't completely understand what sizes we are working with but there appears to be plenty of space left to use a larger insert yet.

[b15605]

Reason I did not go with green loctite is I couldnt convince myself I could get it clean enough for the loctite to adhere properly behind the locksert. Recall we do have oil gushing out inside there somewhere.

The pootential crack into the oil galley is why I am trying to get the locksert out without drilling too far. Would like to get it out and be able to clean up the existing threads then put in replacement case saver with red loctite (after thoroughly claening oil residues). Hoping this would cure properly and prevent the seepage. At least this is my plan anyway.

Sizewise - all I know is I have 10mm studs but no idea of OD on lockserts

[modok]

Green loctite, to me, is 640 sleeve retainer.
Which if applied in the first place, in the right procedure, would have prevented any leak.
FORE SURE. No debate, it's just true.

So I guess they didn't do that when they put in the inserts.
And that'w why you have a problem now.
but the "wicking loctite", about that, I'm just not sure.
to this day I don't know if..... wicking loctite is a fantasy or a real possibility.
Possibly both. It's a solution for an imaginary problem.

What we all do know is nature abhores a vaccum
so most empty spaces are already filled with something.

I just don't really get how it could be practical in the real world.

[b15605]

Old insert is out! Thanks for the encouragement to keep drilling. It finally got thin enough to come out in chunks.

On to the next question. It appears tapping to clean up the threads is a necessity. How do I determine what the origina threads were/are? These 10mm ID case savers seem to come in 1/2-13 or M14x?? OD. What is the best way to determine which tap I need to clean up the threads?

This may just work…or at least I see possibilities

[EVfun]

[b15605]

Project Update: turns out the existing threads are M14x2.0.

I intended on ordering a thread chaser and somehow messed up and ordered a tap I assume the correct move here is to order a chaser as I do not want to remove more metal than necessary. BTW, the M14 x 2.0 bolts actually threads in pretty nicely with no wiggle so I am confident chasing the threads will clean this up.

Question on installing the case saver - should I gob the red loctite on there (slather as we would say in the south) or is it a dont go overboard thing. Also, looking in the hardware store yesterday and saw ‘gel’ red loctite - should I use this preferentially to standard ‘non-gelatinous’ red loctite. Any other tips on installing the case savers as it looks like I will get one shot at this…screw it up and I am back to drilling out inserts which I would like to avoid.

Thanks for the advice and guidance so far.