StromTrooper banner

1 - 12 of 12 Posts

·
Registered
Joined
·
106 Posts
Discussion Starter #1
Hi all.

Earlier this week I managed to check and adjust the valves on my 2008 DL650A. Everything went fine thanks to all of the great posts here. The one thing that I did screw up was the valve cover bolts. I managed to strip the threads on the cam cylinder cover on one of the holes that the valve cover bolts through. This is very irritating, as I purchased and tested a new torque wrench that could accurately torque 7 ft lbs.

I don't think there is enough material left where I could re-chase the threads with a tap, but I'll try anyway. My question is this: If i can't successfully restore the threads with a tap, I'll need to use a HeliCoil insert. The only ones I am able to find in town are roughly 3mm in length. IIRC the bolt is 17.5 mm long. Do I need to get a longer insert? The staff at NAPA seem to think that the 3 mm insert should be just fine, as the valve covers aren't a high torque part. I'm a little nervous about this, but the logic seems somewhat solid. I would imagine that the 3 mm of stainless steel threads should be sufficient to handle 7 ft lbs of torque. HeliCoil has insert lengths of 10.5 mm and 14.5 mm that I could also special order. Am I making a huge mistake here with the 3mm insert? Should I order the 10.5 or the 14.5 mm insert instead?
 

·
Registered
Joined
·
710 Posts
I think 3 mm will work, as it isn't a high torque bolt. But if you want peace of mind, you can thread 2 inserts into the hole. The tool I have has a depth collar to control the depth you can install the insert. I have set it for twice the length of the insert, installed the insert, then ran another insert behind it. Red locktite both inserts, allow to dry, then confirm your install by running a tap through the threads.
 

·
Registered
Joined
·
106 Posts
Discussion Starter #3
Correction

The inserts that I have are 10mm as opposed to 3 mm. I don't know what I was thinking earlier. I'm fairly sure that the 10mm inserts will work OK now.
 

·
Registered
Joined
·
1,850 Posts
Correction

The inserts that I have are 10mm as opposed to 3 mm. I don't know what I was thinking earlier. I'm fairly sure that the 10mm inserts will work OK now.
I thought the 3mm number was a little goofy. I've had to do the same thing to a KLR head, and the 10mm is fine. It is holding up extremely well, by the way. It's not a difficult job to do, just take it easy, make sure you have a rag around the hole to catch any metal, and clean it up real well when finished.

Good luck.
 

·
Registered
Joined
·
7,442 Posts
make sure you have a rag around the hole to catch any metal
Yes, and a good layer of grease is also a help. The grease will catch chips the rag misses, and if you don't clean the grease off 100%, you're OK (but try to get all the grease out of there.
 

·
Registered
Joined
·
353 Posts
thread chaser

Years ago I had some pulled threads in a aluminum case and used a metric thread chaser rather than a tap and it works well. Prior to your helicoil drilling you might try a "chaser". I had to hunt online for one. It was flat end to bottom out more but more importantly it removes less material than a cutting tap. I was told it sort of can reform the treads from the vendor so decided to try it.

In my case it visibly did not remove a lot of metal compared to what I had seen with taps and then the bolt held to the torque spec. In my case I sort of stopped cranking not to far after the original threads went mushy so I think I had anough material to work with.

You might try that first prior to the drill-tap and helicoil method.
 

·
Registered
Joined
·
2,278 Posts
I managed to strip the threads on the cam cylinder cover on one of the holes that the valve cover bolts through. This is very irritating, as I purchased and tested a new torque wrench that could accurately torque 7 ft lbs.
Thanks for posting your story. I'm sorry your day sucked. :(

When you post something like this, it's very helpful for others if you can be specific about how you blew it, so we can learn from your experience.

Did you:

  • fail to use the torque wrench on that bolt;
  • use the torque wrench incorrectly; or
  • discover that the torque wrench was faulty in some way?
 

·
Registered
Joined
·
106 Posts
Discussion Starter #8
To be honest, I'm not exactly sure what went wrong. I have a craftsman brand torque wrench that will do 5-60 ft lbs, that has always served me well for years, but I don't trust it at the extreme ends of the range. I've been wanting a good quality light torque wrench for a while now, so I used this opportunity to pick up a very nice snap-on 1/4 drive 40-200 in lbs wrench.

I have always been nervous about steel bolts in aluminum threads, so I was as careful as possible when reinstalling the valve covers. I even put an old bolt in a vice, and made sure that the new wrench actually clicked at an indicated 84 in lbs. I didn't verify that it was an ACTUAL 84 in lbs, I just wanted to make sure that the wrench seemed functional.

Sure enough the first two bolts went in finger tight and torqued without a hitch, the third bolt was fine until I went to torque the bolt. The wrench didn't click at all, and by the feel of it I knew something wasn't right. I backed the bolt out and sure enough, the first 4 or 5 threads were stripped. I even went back and re-torqued the old bolts to make sure the wrench was functioning, and it was fine.

I don't consider myself a knowledgeable mechanic, so it is entirely possible that I simply did something wrong, but it does seem like the cylinder covers are made out of extremely soft aluminum. I'm really thinking that once I get this hole fixed, that I'll just tighten the rest at 5 ft lbs, rather than 7. Any thoughts?
 

·
Registered
Joined
·
2,278 Posts
The wrench didn't click at all, and by the feel of it I knew something wasn't right. I backed the bolt out and sure enough, the first 4 or 5 threads were stripped. ... Any thoughts?
I don't know what you experienced, but I have encountered situations where it felt "correct" to me long before the wrench said it was fully torqued. I stop at that point, go back and check my numbers, and do more reading. Sometimes, the reason is that the torque is spec'd dry and the fastener is contaminated with lube of some sort, in which case fully torquing it to spec will frequently give dramatic and disappointing results.

At 5-7ft/lb, it's really easy for things to go south, so I'm a lot less willing to ignore the feedback I'm feeling than I might be on a >80ft/lb fastener.

I'm glad you got it fixed. Thanks again for the cautionary tale.
 

·
Premium Member
Joined
·
432 Posts
I try to torque at a lower value and then go back and torque at the full value to give me a better idea that my wrench is doing what it should be doing. I would start at 5 lbs then go to 6 and then 7 lbs. Sometimes my wrench does not click when it should. May have something to do with how I am holding it. I don't really know.
 

·
Registered
Joined
·
281 Posts
It would not have been wise to settle for only 3mm length of thread for that fastener. As said by someone else doubling up on the insert would be neccesary.
Anyhow, you simply want to duplicate the depth of the OEM threaded hole. Stick something down in the hole to guage the depth then find an insert thats at least that long and if longer just snip it shorter with miniature dykes. ( Don't distort the insert while clipping).
As for stripped threads .... well, they're stripped. They cannot be fixed with a "chaser". If any spirals of thread metal come out of a hole the threads are not repairable with a "chaser". At times it's possible to deepen the threaded hole but this IS NOT fixing threads... it's adding more new good ones below the old ruined ones. A blind hole is frequently not threaded to it's bottom by the maker so by using a 2nd cut and then a bottoming tap you may be able to add some new threads down deep to the base of the hole. Caution; a bottoming tap relys on good threads to support it as it drives deeper into the hole and it exerts more force on those existing good threads than a taper, aka "starter" tap does.
Right best fix is the innsert.
dave
 

·
Evolving Curmudgeon
Joined
·
1,119 Posts
This exact thing happened to me last year and I repaired it with a 'Time-Sert' Kit. Works better and installs easier than heli-coil IMO. I have spares that will fit your needs if you PM me.
 
1 - 12 of 12 Posts
Top