Stripped Head studs

[Dean Westerburg]

Looking for advice from those with more experience with VW's.


One of the 8mm studs that goes through the head on my HAPI 1835 has some stripped threads. THe last guy just put 2 nuts over it. I found it when checking the torque on the head. Can I replace just 1 of these or do I need to replace them all to be safe? Does anyone know if the HAPI 1835 had the "Case saver" inserts or do these thread right into the casting?

I also found a pushrod that looks like it has been gouged by the side of a pushrod tube, I assume due to mis-assembly and attempt to run at some point. Should the pushrods and pushrod tubes all be replaced at the same time, or is just 1 ok?

Do I need to replace the pushrod tubes if I remove the heads?

Thanks for your recomendataions.

 

[soneraifred]

You can replace just one stud, but you’ll probably have to buy a whole set. You should be able to see the case savers in the case.
Also, you can replace just one push rod, but you’ll probably have to buy a whole set. Make sure you get the correct length. It is not necessary to replace the push rod tubes if they are in good shape. I always stretch them out a little bit before I reinstall them to make sure they seal well.

 

[Dean Westerburg]

I kinda figured those parts were were ok to change one at a time since they are not rotational and balanced, but I have no experience with this repair. Thanks for your help.

 

[kennyw]

I just happen to have a pic of what the Case Savers look like.

 

[aztrooper]

If it were me, I would replace all the pushrod tubes on the side you are replacing the pushrod. Especially if it is the same side as the head bolt you are replacing. My reasoning, you have to stretch them out to get them to seat correctly and then they are compressed when you bolt the head on. You might get into some metal fatigue if you stretch them back out and then compress them again. They were made for one time use. You should be putting new pushrod tube seals on anyway. The tubes and seals are cheap enough and good insurance against having to do it again because of cracks in the expansion portion of the tubes from expanding and contracting them to many times. Just my feelings.

 

[Bil4381]

Fastenal (Numerous locations) sell threaded inserts. They come in sets. A special DRILL, SPECIAL tap, insertion tool, inserts, to get you back to the original size. I think its important to use the best LOCTITE (green) while installing the threaded insert and to have the threads immaculate and oil free. Also Travers tool and die stock them. Warehouses in several countries. (READ AND FOLLOW THE DIRECTIONS) . Worked for me.

Looking for advice from those with more experience with VW's.


One of the 8mm studs that goes through the head on my HAPI 1835 has some stripped threads. THe last guy just put 2 nuts over it. I found it when checking the torque on the head. Can I replace just 1 of these or do I need to replace them all to be safe? Does anyone know if the HAPI 1835 had the "Case saver" inserts or do these thread right into the casting?

I also found a pushrod that looks like it has been gouged by the side of a pushrod tube, I assume due to mis-assembly and attempt to run at some point. Should the pushrods and pushrod tubes all be replaced at the same time, or is just 1 ok?

Do I need to replace the pushrod tubes if I remove the heads?

Thanks for your recomendataions.

 

[DeadRinger]

I would only use Time Sert inserts. Do all of them. Both sides. If one is coming out then the others probably are close. http://vwparts.aircooled.net/Time-Sert-Tool-Rental-8-x-1-25mm-1812-p/time-sert-rental-1812.htm

 

[Aviacs]

I'm curious what the "field" procedure would be for adding thread inserts?

Decades ago ("now it can be told" ) I made (& still have) a fixture with interchangeable drill & tap bushings, that bolts onto a 0-300/0200 series Continental for installing helicoils at any position of the base circle. The fixture is a fit in the case bore, and is located by the bots/studs that are not being drilled. IOW, it positively locates the position well within the tolerances of the base circle and cylinder base tolerances, and maintains 90 deg vertical to the case/flange face.

A good way to lose a stud (cylinder) is to have studs (bolts) in at an angle, or not quite on position.

Is there a good alignment tool for the VW cases?
Do them on a mill (with horizontal attachment)?
"Just wing it" - point and shoot?

smt

 

[John B]

The case savers on a VW in many instances need to be installed when the case is disassembled. This is especially true on the longer stroke cranks as the clearancing done to accommodate a longer than 69mm stoke crank can require the case saver to be clearanced as well. However, some 69 mm counterwieghted cranks also need this done.

The OP said his engine was a 1835, which would be a 69mm stroke and 92 mm bore, so if it doesn't have a counterweighted crank you should be able to just replace the case saver. Getting the old one out may be a problem though as they are put in with threadlocker and could need to be heated to remove. Sometimes they also just spin out when removing the stud. If the case saver isn't buggered up I would just replace the stud, but make sure the case saver doesn't come out.

Time serts are indeed nice but I would personally skip them unless doing a complete teardown. Also, while I have used them for thread repair, I have never used them in a hole that already exists. The standard case savers are I think 12mm OD standard metric thread and I believe time serts use proprietary taps of mysterious size for their inserts. I know that the time sert tap I have for 14mm spark plug threads says 14mm x 1.25 on it and that is the plug thread size. The tap is obviously larger than 14mm in that instance. The 8mm time sert may or may not be the right size for the existing case saver thread. Unless someone has actually done it and can attest to time serts actually fitting the existing case saver thread, I'd personally just stick to the case savers that have been put in VW cases for about an eon. They work just fine.

 

[kennyw]

... Does anyone know if the HAPI 1835 had the "Case saver" inserts or do these thread right into the casting?
...

So, @Dean Westerburg , does your 1835 have the Case Savers? I was kinda betting that it does....

 

[John B]

I'd think it does have case savers but that is a good point. Doesn't hurt to take a peek to be sure.

Case savers have been pretty standard to put on VW cases at least since I built my Baja Bug back in high school. That was 1981 when I built that car. Can you even find a new case that doesn't have case savers these days.

 

[Dean Westerburg]

So, @Dean Westerburg , does your 1835 have the Case Savers? I was kinda betting that it does....

Yep! It does! Glad to see that. Sounds like the origional setup before case savers would have been a pain to deal with.

 

[DeadRinger]

In that case if the internal threads are fine just replace the stud. Wouldn’t hurt to take out all the others and check the thread closely but then again if you do that just replace them all. Probably have all been over torqued.