Stripped 944S valve cover bolt

JD159 · 08-15-2014, 04:46 PM

Hi all,

I've got a stripped cam cover bolt. Not the 5mm head, but the actual thread in the cylinder head. The bolt seems to measure with a 1.15mm thread pitch and 13.5mm in length. Because this is not a standard 5mm hex bolt measurement, I don't think I can get a timesert or helicoil that will work. Since the foot pound torque for the bolt is only 7, can I use an epoxy based thread repair kit for this application? I was thinking jb weld with a bit of grease on the threads so that it can be removed.

Thoughts? Options?

flash968 · 08-15-2014, 07:22 PM

i'd weld it up and redrill and retap it, but that means pulling the head.

v2rocket_aka944 · 08-15-2014, 08:26 PM

since its just the valve cover (not a structural piece) i'd just put some epoxy on the threads and put it back in...

or tap it to the next bigger size (even if that meant there'd be one SAE bolt

)

JD159 · 08-15-2014, 08:47 PM

Flash not a chance on pulling the head. I think the epoxy might do the trick. I don't think I could use another size bolt. It doesn't even leak its just one of those things you like having right lol

JD159 · 08-15-2014, 08:54 PM

Might call some machine shops see if anyone can make an insert. I've seen a few solid inserts which are interesting. Used to relocate misdrilled holes. Could work...

Any ideas that don't involve removing the head or engine would be what in looking for

Sometimes the "right" way is just too impractical for something that isn't even causing a real issue.

911tracker85 · 08-17-2014, 06:26 AM

Quote:

Sometimes the "right" way is just too impractical for something that isn't even causing a real issue.

ain't that the truth.

flash968 · 08-17-2014, 07:15 AM

i agree that it is impractical.

a helicoil or keensert might do the trick. i would not use epoxy. it will eventually fail, and deposit crumbled bits in your valve train.

JD159 · 08-17-2014, 07:27 AM

Good call on the epoxy possible getting into the valve train. Monday I should have an answer after I get a hold of some machine shops.

Speaking of keensert...

If I can find one of these, and maybe get a custom tap made at the pitch of the valve cover bolt, this would be perfect and practical.

flash968 · 08-17-2014, 07:58 AM

are you sure you have the size right? if i'm looking at the right one, it seems to be the same as on the 968, which is an M6 x 1.25

JD159 · 08:43 AM

Flash will double check. My thread pitch gauge only measures in increments of a tenth. The 1.1 didn't quite fit, neither did the 1.2. Seemed to be in between. Used a dial calliper and it appeared to be 1.15. But I know the socket I used was a 5mm hex bit

JD159 · 08-17-2014, 08:44 AM

Sure your looking at the right bolt?

flash968 · 08-17-2014, 09:58 AM

sorry - i just checked - it's M6 x 1 not 1.25

the socket may be 5mm, but the bolt is 6mm

you should have no problem finding what you need.

JD159 · 08-17-2014, 10:35 AM

Ahh good call! I went by the socket size didn't think to measure the actual threaded part of it. Can you double check the thread pitch? Every time I put my 1mm gauge on it didn't sit nice. I'm gonna check that again.

flash968 · 08-17-2014, 11:21 AM

i did - i actually laid a tap across a new bolt (i keep a few around). i also ran a nut down the threads. i also ran the tap in the nut to make sure the nut was right. i also used my thread pitch gauge.

i'm sure - 6mm x 1

JD159 · 08-17-2014, 02:36 PM

Hi Flash,

Just to update, your absolutely right! I pulled out one of the good bolts and used the thread pitch gauge and it fit perfect at 1mm. My mistake was I used the gauge on the bolt that tore out the threads so it didn't seat overtop the threads it ripped out. I'll be able to timesert this properly and get it good as new!

DannoXYZ · 08-17-2014, 10:59 PM

I wouldn't use Timeserts to repair that. The expanded threads at the bottom exerts an outward-force on the joint and can cause the outer metal to crack over time. A lot of 911 people have had cracked heads and blocks from Timeserts.

For a low-load application like that, use EZ-lok inserts. They don't expand and add stress. The Loctite-type glue on them holds very well.

JD159 · 08-18-2014, 12:56 PM

Looked into the EZ lok. Gotta take off the valve cover to see how much material I have to work with. Here are the specs for the EZ lok

Application FOR USE IN METAL
Style HEAVY WALL
Material CARBON STEEL
Thread Type METRIC COARSE
E-Z LOK Part No. 450-6
Internal Thread M6-1.0
External Thread M10-1.5
Length (mm) 10.49
Metric Tap Drill Size (mm) 8.6
Tap Size M10-1.5
Minimum Full Thread Depth (mm) 11.99
Drive Tool Catalog No. 500-3

I need to use an 8.6mm drill bit and an m10 tap in order to thread the EZ lok into place. Think I have enough material around the original without compromising the strength of the bolt or risking cracking the head?

DannoXYZ · 08-19-2014, 07:23 AM

Perhaps, can you post a picture of the area in question? There are other inserts that aren't quite so thick.

JD159 · 08-19-2014, 08:24 AM

Will do. I'll see what i can find.