Missing Valve cover stud

[jp9094]

When I did the valve adjustment on my '83 r65 LS a while ago, I noticed that the stud that the valve cover screws on to would not tighten properly. I put this down to the mechanic who did some service on the bike a few months ago (he also stripped the final drive drain plug).

The stud and its corresponding cap nut have now parted ways with the bike. I have ordered replacement stud, cap screw and wave washer for the princely sum of US $ 5.67. My question is: is there a way of permanently fixing the stud to the motor WITHOUT using a helicoil or similar device?? Getting that done by a third party would cost much more than the price of the parts. Would JB weld or some kinf of loctite work? Will appreciate any advice.

TIA

[mrclubike]

Yes you can fix it without a Helicoil
You can make a longer stud that can go all the way thru the head into the cavity below the spark plug
Install a nut in the cavity and thread the stud into it
I ended up drilling and tapping 1/2 inch key stock to make my own nut
I suggest using a bolt with the head cut off and about 8mm of thread cut on the one end that can bottom out in the repair nut
The threaded rod you find at the hardware store is soft and it may twist off in  the repair nut if it gets stuck

[BPT]

If you're talking about that middle one, it was recommended to me to double nut it on the back side. More recently I saw somewhere online where there is a square nut that will fit snug in that area and won't turn. I found them at Fastenal but they wouldn't sell them to me, haven't checked Ace or Atwoods yet.

It's a common thing and I have the same problem so I was going to try one of the above cheap fixes along with some lock tight.

FYI - one other thing I heard of that's more permanent but avoids a helicoil is getting a stud with two different sizes (drawing a blank on what they're called...?).  Seems like it's something like M8/M10? You tap the stripped one bigger then you can keep the original cap nut on the front. But since you already have a fancy new stud, you probably wouldn't want to bother with that.
Good luck.

[mrclubike]

Here is a step stud for a VW that would work perfect
https://www.brickwerks.co.uk/repair-stud-m10-m8-73mm.html
But you still end up with the fragile threads in the aluminum
The nut inside the head is a lot sturdier

[Barry]

Besides ham fisted mechanics who service your bike,  the reason that central stud strips is because it's too short and usually doesn't engage all of the threads in the head.  I pre-emptively screwed mine in until it did, leaving fewer threads for the nut but that being steel in steel it can cope better than steel in alloy. A longer stud would be better.  And it doesn't need to be much more than finger tight if the gaskets are good. I don't have a torque wrench that goes low enough but if I had to guess it's tightened to no more than 5 ft/lbs and never leaks or comes loose.

[mrclubike]

Another reason they are  stripped out is because the head is warped and they wont seal unless you over tighten them
If that is the case
The head needs to be dissembled and the valve cover mating surface needs to be flattened
That can be done on a flat surface with some sand paper stuck on it like a drill press table or piece of glass
After mine were done they seal up just fine even when reusing the valve cover gaskets   

[BPT]

Barry's post made me realize I'd forgotten to mention the stud length. If you get them through BMW there are two different lengths and someone told me to make sure and get the longer one. I can't remember if the R65's originally came with the shorter version?
I haven't put mine on yet but I made sure to get the longer one and I'm going to try that with a nut on the back and see how that works. Like Barry said, with the other two studs holding the cover on, I think it should be fine as long as the stud is long enough to get the nut on it.

[Barry]

After mine were done they seal up just fine even when reusing the valve cover gaskets   

It's possible that my gaskets could be the original 42 year old ones as the bike had only done only 6000 miles when I bought it and it hadn't been used for years. They are without doubt 14 years old because I have never changed them.  I can't understand why people do change them if they don't leak.

[jp9094]

Strangely enough I never have had to overtighten the cap nut. It has only ever been torqued to spec my me. The bike has around 50000 miles and the gasket is the same as the one on the bike when I bought it 6 years ago. I bought replacement gaskets when I first got the bike and they sit in my parts drawer to this day!

It also has never leaked (touch wood)! Waiting for the parts to arrive and a try in before I decide on how to proceed. I remember reading in another thread about a product to use on the stripped drain plug, that would never come out once set. Will have to look it up after writing this.

Many thanks for the suggestions.

Thanks to all.

[jp9094]

From the previous thread on a stripped final drive drain plug:  "Whatever you do, don't use J-B Weld. My Saab 9-3 came with a glued sump plug. The stuff is permanent, even on oily alloy."

AM willing to give the JB weld a go. The parts have been shipped and should arrive this week.

Thanks to all for the advice,

[jp9094]

The parts arrived last night, so today I removed the valve cover and tried the new stud in to see how badly the hole was stripped. You can imagine my surprise when the stud screwed in without any problem!

Apparently it was not stripped at all! I guess after 37 years and 50000+ miles the poor stud was allowed to back out of its housing. So all is back in place, and I now know to check how tight it is before attempting to replace the valve cover. Lesson learned.

Thanks again to all who commented.

[Tony Smith]

Your first mistake was "torqued to spec". That only encourages stripped threads.

It is best to think of the central stud as purely decorative, the 6mm fasteners do the real work, just tighten the central nut just right enough so you don't lose it which is far short of spec.