Case Saver cylinder stud repair experience shared

[Frog]

I thought it might be useful to share my Case Saver installation experience.

Due to a pulled cylinder stud, I decided to install Case Savers (threaded inserts) in all 8 locations. My thought was that I did not want to find myself pulling another stud during another pre-ride tune up.

It turned out to be a lot more work than I had expected. That said, I am delighted with the results. Hopefully, this post can help the next guy and maybe dissuade those not willing to deal with some of the potential pit falls.

WHY CASE SAVERS

Case savers are the largest threaded insert for this application (that I know of) and in turn their external threads (M14x2) have the most purchase on the aluminum engine case.

THE CHALLENGES

The biggest challenge is actually inserting the case saver. I ordered three batches (24) of these inserts, from two different manufacturers and found that they were quite inconsistent in their quality. On my first thread repair, I made the mistake of driving a stubborn insert in, thinking that the wrench would overcome the friction and it would go in all the away. It got stuck halfway in. I ended up using plenty of heat and an “easy-out” to remove it. This situation should be avoided at all costs, as there is a good risk of damaging the engine case.

If you look at the insert carefully, you will see that it is meant to lock into place in two ways. The first is an “interference” fit thread cut. This means that the threads are larger than typical, such that they bind with the engine case threads. The other system is that the insert external threads do not go all the way to the top. This top shoulder is meant to serve as a stop for the insert….or bind with the base material if driver further. But, if you add up all this friction it is too much to be driven flush in our application. Unless there is an insertion tool out there that I am not aware of. So, one needs to find a way to reduce this friction. I tried different techniques and concluded that the easiest was to chase half of the insert threads with an appropriate die….and file down the shoulder some. I also used high strength loctite.

Due to the large size of these inserts and the amount of material that is drilled out, there is more potential to drill off center and/or at an angle. For this reason, one needs to devise a system to keep the drilling in the right location and perpendicular to the case. I machined a jig that can now be used again and again, knowing that I had 8 to do. But, one could probably do a fine job with a wood block version, assuming that the jig pilot hole was drilled on a press or the like.

I was a bit paranoid about getting shavings in the motor. But with a vacuum cleaner system, things were kept very clean.

PHOTOS

Here is a photo album that I put together with some commentary. Not all the steps are of the same hole.

http://picasaweb.google.com/10305098700 ... directlink

RECOMMENDATION

I would recommend Case Savers for this application, but be warned that the installation can be a challenge. I found very little information regarding this process.

If you want to keep the repair simple and are only doing one, it would probably be easier to use a heli-coil.

I hope that this is helpful.

Thank you all for your help in this process. My bike is back together and running strong.

[R90Steve]

Nice work. I would have been pretty nervous drilling the oil holes. Just out of curiosity, how did you lay out the holes for your jig?

[Frog]

Nice work. I would have been pretty nervous drilling the oil holes. Just out of curiosity, how did you lay out the holes for your jig?

I measured my two cylinders and laid it out from there. The layout on the cylinders is not exactly consistent, but close enough. There is quite a bit of room for those studs.

[Garnet]

Nice how to and photo set. I'm gonna save that in case I need to do it someday.

That seemed like a large hole into the gallery. I asume the that is the way it is done at the factory. I have never had to touch the studs on a 247. I seem to remeber them being much smaller on a /2 engine, but that is different.

[Airbear]

Frog, I followed the horror story as it happened. Thanks for posting this excellent concentrated 'how-to'. The pics and descriptions are superb and show the whole story very clearly. I fear I'll be facing this job in the future - (valve clearances on the left jug are bigger each time I check them). Thanks again.

ps: the example of the crap insert as supplied is truly appalling.

[Zombie Master]

Great post Frog. They really should have more information available for the installer. Well now that it's done your good forever!

[dougie]

Wonderful "how to" Frog.
Thanks very much for taking the time.

[vanzen]

Zoot allures, what an ordeal that was !

Glad it worked out for ya.

[Garnet]

I seem to remeber them being much smaller on a /2 engine, but that is different.

That's cuz the oil comes down the push rod tubes on a /2, duh.

I was thinking of the cross drilling in the head of a classic era single. The oil comes up a pipe in the cylinder and splits off into two oil galleries in the head that lead to the headbolts.

[Chuey]

That's a pretty sad looking part, the case saver from Empi. Empi used to be a name as respected as they come. Their parts were top quality and they were premium parts that were considered as good as factory originals.

I've been spending some time at "the Samba", the VW website to learn more about my bug and the work I'm doing on it. I was shocked to learn that Empi no longer enjoys a good reputation. Man, that's sad. There are plenty of people who will buy crap if it's cheap enough. Making top quality parts that cost what they should will always have a place in the market. It may be a smaller market share, but it will always be needed and someone will find that they can make a living by doing good work and having a smaller market share. Maybe that's the crux, "making a living". When a company is sold, the buyer has an image in mind of what they can "do" with the company. Often, it takes a turn from what it's roots were before it sold.

Chuey