Head stud pulling out

[Robs66vw]

I have at least one head stud that has pulled out of the case. My question is: Is it save to continue to drive it? Also, what effect, if any, will this have on the engine?

[herbie1200]

I have the same issue. One of the central studs is 2-3mm out.

It is "central" so has an other stud at minimal distance.

Engine runs very well (stock 1192).

I know there is a solution: self-screwing (not sure about its correct name) stud that can be inserted without dismantling the engine, only by removing the rocker assembly.

I'll wait for further hints.

[Zundfolge1432]

More than one company made these repair studs and I’ll show you one I had close at hand. The other common type is pointed or more tapered on the side that screws into case. Both have a cutout to catch and keep metal shavings from going back into the engine during installation.

This type of repair was meant to be temporary although I have seen many that became permanent because nobody followed up with a proper repair. Proper being drilling oversize and using an insert like you’d find on 73 and up cases. What causes them to pull in the first place? Overheating, over torquing, brittleness of a case that’s seen many thousands of cycles.

Repair stud on left is noticeably larger and has coarse threads to provide a strong bite into the stripped hole.

Looking at the stud you’d notice it tapers along its entire length and is made to be installed without engine disassembly, however if it’s a top stud engine will have to come out and cylinder tin removed to install. Here’s food for thought, if one stud pulled others may be close to pulling in near future especially if another overheat event occurs.

[mukluk]

[herbie1200]

Thank you!

Any source for those "repair studs"? Which is their correct name, to start a google search in Europe?

My stud is there, but when I re-turned the nut at the correct force, the stud started to rise out. Now is 2-3 millimeter over the other studs.

I remember the stud, when engine was dismantled, was (by me, while the mechanic was at phone!) inserted too much in the carter, then un-screwed... surely in this phase damaging happened.

[Zundfolge1432]

CIP1 has them

[Erik G]

[herbie1200]

Thank you, but I have still something to ask, my mind is not clear.

My engine is a '63 1200 so it has 8mm studs; the self tapping case stud posted above is 10mm... is it only for 1500-1600cc?

Or is it an "enlarged" stud that I should use to compensate the enlarged hole in my case?

Does it fill in the original stud passage?

And: is the lenght 240mm correct for my engine?

The stud to replace is one of the two lower central studs visible under the rocker arm.

Thanks again.

[thomas.]

If you wanted a more permanent solution you might consider a time sert. (Link to one at end of post) You would have to pull the engine and cylinder though. On the plus side you would use the original hardware.

https://www.ebay.com/itm/Time-Sert-1812-M8-x-1-25-...:rk:2:pf:0

[calvinater]

Wouldnt a 63 1200 have come with 10 mm studs and no case savers?
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"Albatross"!

[herbie1200]

[mukluk]

[herbie1200]

Thank you mukluk.

Incidentally, you pointed exactly to the stud that I have to replace

I was thinking about 8mm on smaller engine and 10mm on larger... instead it seems that 8mm are on LARGER engines, to have more room for head enforcement.

Just ordered a couple (1 for spare) of "self tapping case studs" in the USA, I will report my work.

[FeelthySanchez]

Self-tappers are merely a Band-Aid, & Zundy has nailed it: a field expedient/emergency application only, designed & intended to get a vehicle down the road quickly.
These 2 engines are talking, & asking their owners for help. Installing a self-tapping stud now will almost guarantee that more shall soon pull.
Focusing, the reason behind those 2 studs pulling will still be there ....... the owner is simply buying some time before a complete rebuild.

[estilholliday]

The self tapping studs have the hole in them to catch shavings.... assuming people are using these with the engine still assembled, what would be the reasoning for this??

Do the studs extend all the way into the case? Meaning, if it is taken out will it leave a hole all the way to the interior of the case??

[glutamodo]

Some people diss those "fixit" studs as bandaids, but I drove a LOT of miles on them in years past and I never once had one fail on me.
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Andy T.


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[splitjunkie]

[splitjunkie]

[estilholliday]

I went to Lowe's and got a length of next size up all-thread with matching washers/nuts. I got it installed into the case, tightened down the heads and its working great. Granted, it doesnt necessarily look the best, but they can only be seen with the engine removed and the tins off.

Im not getting rid of the car, and it doesnt bother me one bit, Also, it adds to the coolness of being able to use unconventional means to make these things work.

[Pruneman99]

I doubt cheap all purpose all-thread is the right material for this application. I bet it looses tention very quickly with a few heat/cool cycles.

If you had it apart, why didn't you just insert the case or even use a repair stud?