I have an original 6 engine in my 6 conversion car. I have an oil leak at the stud circled in the pic below. I have tried to torque the nut on this stud without success. I then double nutted the stud to see if maybe the stud and become loose. I was able to turn the stud in a bit so I thought I was making progress. When I removed the double nuts and placed a washer and nut back on to torque to value it won't snug up. Instead, as I torque the nut...the stud begins to turn out. I have a bad feeling about this....Please chime in with your wisdom.

By the sounds of things the stud is pulling from the magnesium.
In order to fix it you will need to split the case and install an insert.
Sorry for the bad news but there's no other way to fix it.

Well that was what I was afraid of...I will just have to watch the leak CLOSELY and deal with the mess is makes...Really sickening...I guess these old Mag cases are pieces of shit now due to their age. I had inserts done on all of the head studs when the engine was rebuilt...the rebuild only has about 5-10K miles on it. Didn't consider having all the case studs inserted as well.

by the way...I just spent $14K on a rebuld of our 3.2 911 engine and their are absolutely no funds to pay for this kind of deal on the 914 now...

Anyone else have and more wisdom?

Clean it up real good to bare metal, degrease it and smear it with 5 minute epoxy.
Yes, it's not the correct repair, but it will stop the leak.

I had the same thing happen to me many years ago. That stud mounts just below the intermediate shaft bearing, and is not totally necessary if you're reasonable with the engine. My car had that stud removed, the case tapped for a bolt where the stud was, and a bolt with a washer installed. It held up until another stud pulled, then I had Supertec rebuild the engine with Casesavers throughout and their Supertec head studs installed.

I hear you 911 engines are not cheap to rebuild. I had Ollie's do some work on my 2.7 case years ago. I had them install case savers, shuffle pins and inserts on all of the studs within the case. You may try the epoxy route but I don't think it will last too long.

George how long was it...or miles was it before another case stud pulled?

Working pretty good on my tractor, it was leaking a couple quarts a day, not a drop now

Brian sorry to hear I don't visit here often since I sold my 914. You might get lucky with temp fixes but long term the case has to come apart. These mag cases were shit when new. I was recently turned on to Loctite 510 it's $$$ but seems to seal very well. Have you had a pro look at it like Donnie ? It can't hurt. Good luck.

Sorry to say I have had that same problem and nothing works other than split the case....it is one of the dumbest bolts arrangements...long bolt that looks almost like a thru case bolt but oh no taps right into the mag case next to the oil pump lay shaft and will strip in a minute if ruffly handled....I tried everything to stop the leak....the leak just gets worse and then becomes a major oil leak...

I fixed one without taking the engine apart. Bored the hole for clearance for a helicoil, made a long tap, inserted a helicoil, made a flanged sleeve for the opening, and installed the stud. Took a while, but it resolved the issue and the engine ran like that for years. I may still have the tooling.

The Cap'n

Cap'n,

I was looking foward to you chiming in...much respect for your wisdom/experience. Boring the hole and not leaving shavings must have been tough and then working blind with the helicoil must have took much patience. I am interested to know if you find the tooling. Have a look for it when you can and let me know. I will send you a PM.

Thanks Brian

brake clean the hole see if you can grab a few threads deeper if so . epoxy and a few threads and light torque saves you...ya not 100% correct but saves you time and $$$ all of the mag cases need a timesert in that location.. I have seen many of that stud glued in to solve the leak.. or have you're engine rebuilt and spend $$$ this stud is not that crucial.
But every case I do gets a insert on this stud...they all pull this one...

Gonna try to fix this today on my day off. I appreciate all the comments. Why do they all seem to pull this one? Really hope I can have some success. Would be shame to have to split case. If it comes to that I most likely would have to do this myself. Approx. how many hours would it take a pro to handle the correct repair with a timesert? You would want to repair all the studs with certs wouldn't ya?

Did you send the picture to Mike?

Tell Leslie she can't drive anything Air-Cooled for a Month!

It depends if you are taking the engine apart and reassembling it yourself or
do you plan on taking it to a shop for it all?

You could easily have the engine apart in 2 to 3 hrs. As for the time certs you could also do that if you know what you are doing. I would insert all of the inside studs.
The mag cases will all pull these studs at some point in time and doing it while apart is cheap insurance. Did you have the head studs done ? If not plan on doing those too. I used Ollie's for my 2.7 build and was happy with the service there. I put my engine together taking my time over a two week period. I'm sure it could be done within 2 days if you have the time.

Ok I removed the stud just a little while ago and the pics tell the story...As they say...that's racin...I am sad that my -6 is gonna be down for an extended period of time now... If anyone has anything encouraging to say please chime in.

That doesn't look good.. It's time to split the case and fix it properly.
You could call Ollie's and see how much it would cost you to have them do all of the inserts. Otherwise try to locate some locally and do it yourself. I think either way the case needs to be split at this point.

I had the same thing. I cleaned out the stripped threads with brake clean and a wicked long Q-Tip. (not a real Q-Tip, but one of those medical ones with material that doesn't fray...)

I bought a 150mm long tap and was able to tap about 10mm further with more threads. I found a longer stud, reinstalled it with locktite and it hasn't leaked a drop.

-bob

This is encouraging! Where did you find the 150mm long tap and longer stud? How long has it been since the repair or how many miles?

That stud was also leaking on the T motor that is in my car. I currently have the motor out and the cases are split. I will look at what is "behind" that stud. It might give you a better idea of what you can get away with as far as "in the car" repairs.

I will try to check tonight.

Also please check your PM's.

I forget where I found the tap. (maybe McMasterCarr?) I had a longer stud in my stash, but I'm sure you can find them at the usual places. (McMasters, Bel-Metric, etc.)
I fixed it earlier this year and the 914 is only used on the track, so maybe 10 hours? since I was able to tap it almost as long as the original thread-length, I don't expect it to fail.
-bob

Thanks for checking on that. I replied to your PM.

So you just turned in the tap...no need to bore a hole deeper first?

yeah. I measured the original stud and the hole. the hole was significantly deeper than the stud, etc.. I dont think the factory tapped it to the end, so I lucked out. (3R case if that matters...)
I used a bottoming-tap and the stud I used was threaded 'longer' on one end, so I inserted that end.

-bob

sorry I did not post sooner. Just got to the shop yesterday Pics of the stud in question I think. I have not pulled it yet so not sure how deep the hole is. I am sure there is plenty of meat left to lengthen the threads.

Do not see how you could do this "in car" or without splitting cases - if this is the stud you are talking about.

That is the one. Keep me posted if you pull the stud. It does look like there is plenty of meet behind there...maybe the Germans threaded that sucker much deeper and I'll get lucky...I plan to run a coat hanger down the hole tomorrow to see how deep it is as well.

Never thought that the threads might go deeper. It's a possibility. I might have a chance to pull the stud tomorrow. For now, Halloween partee!!

Not sure the threads are deeper but I do think the factory overdrilled it. Also you can get different timecert lengths if you are looking for more grip. Belmetrics has many sizes.

Other than headstuds, that one is the one that strips and pulls. I also did the transmission mount studs behind flywheel.

John

When ordering a replacement stud what spec does it need to be? I found this on McMasterCarr...

Also known as setup and driver studs, these studs are typically used in clamping applications. Inch sizes have a Class 2A thread fit; metric have a Class 6g thread fit.

Black-oxide steel studs are made of C1541 steel. The black-oxide finish provides lubricity and mild rust resistance. Studs have a min. Rockwell hardness of C27 and min. tensile strength of 125,000 psi. Those marked with a star have flat areas on the shank that facilitate installation with a wrench. For matching hex nuts in inch sizes see 95479A; for metric sizes see metric hex nuts.

http://www.mcmaster.com/#99067A248

you cut to cut to length..

double nut to install, then trim to length

darn double post

I measured the depth yesterday and it appears to be the same length as the stud (125mm). My case is a 3R as well. Was hoping that the threads were a little deeper than the stud and I could just clean up what has pulled and run a longer stud down in there and grab the extra threads (a well respected 911 engine builder - Mike Bruns was in agreement with this approach). Running a bit down in there to bore out enough material to allow for the tap to do it's thing may be a show stopper.

that sux... sorry to hear that the depth is different then mine. (for whatever it's worth, I have 2 more engine cases, an OEM -6 case and a 7R case.. both of them measured the same as the 3R case in my car... the 'hole' is about 10mm deeper than the factory threads)

at this point, unless you want to risk drilling the case.. ugh! full tear down.

-bob

Get a pro to time sert. See what Joe O'brien can do for you.

Maybe I need to do more recon and see if there is something obstructing my measurement...maybe some case material that has pulled..Will check on that.

I had a chance to pull this stud yesterday. The depth of the hole is about .835" and the threaded portion on the stud is nearly .6"

Interestingly, my cases are 4R/5R that show no signs of abuse. All of the studs (including this one) felt very tight. Removing the head studs was extremely difficult - they are very tight. But this stud came out very easily and brought the mag threads out with it. It appears that this stud see a lot of tension/stress even compared to the head studs.

Looks like no quick fix to me. Mine is off for some professional attention.

Where are you sending the case to have the time certs installed? Let me know if you are having all the case stud threads taken care of in this way and what the bill is if you dont mind.

Thanks,

Try Ollie's Machine ... Check the price list on the main page.

http://www.olliesmachine.com

I have a couple of Ideas depending on what all I decide to have done. I should know tomorrow or the next day. I will keep you posted

Bcheney, check your PM's. And I see from previous posts that you had all of the head studs serted not long ago. For this one stud I think I would DIY time sert this one stud. Kits are available with all of the tools (bits/taps serts) for about $125.00.