?? Re: Retorque of head bolts

[XS650D]

I have a persistent leak in the front right corner under the exhaust valve and noticed when doing a retorque
at 30 lbs on the big nuts that the nut directly above the exhaust valve (were the leak is) when torqued the head stud
feels like its twisting, but not turning. Once I hit the torque of 30 and release the tension the stud feels like it
springs back a little. Like I have bottomed the nut on the stud.I have the thicker copper washers on the
outside. Im not getting that with the other 7 nuts . Maybe I need my Torque wrench re calibrated not sure.
Is that normal with those really long head studs.I did notice that the nuts are wearing depression into the copper washers.After so many retorques maybe the washers need replaced.

 

[bosco659]

Try a non acorn nut with an open end. That way can’t bottom out. P

 

[Jim]

Have you looked real close at the threads on the stud? Maybe a burr or cut that's causing the nut to bind at that point? Have you tried a different nut?

 

[XS650D]

Try a non acorn nut with an open end. That way can’t bottom out. P

Good call. See if I have a nut that size and thread but I doubt it.Will hit the hardware store.Any idea size?
Will I have to retorque the whole head if I remove that 1 nut to test? Are the acorn nuts designed to bottom or just for looks.
Could I just cut the top of the Acorn nut.I did check the threads and all good there.

 

[Jim]

Will I have to retorque the whole head if I remove that 1 nut to test?

No.

Are the acorn nuts designed to bottom or just for looks.
Could I just cut the top of the Acorn nut.

In this application, they act as a seal for the stud. There's oil pressure from the rocker box under 'em. That's why you need the brass (or copper) washer. With a plain nut, oil will wick it's way out the threads.
... and no, the acorns shouldn't come close to bottoming unless you have the short ones on there. Pic?

 

[Jan_P]

Perhaps an extra flat copper washer
Between the Acorn nut and the washer there now

 

[BowlingSS]

The size is 10mm. It is either 1.25 or 1.50 on the thread pitch. I would have to look it up.
Torque is 27 ft lbs according to my manual. Thread pitch is 1.25.

 

[GLJ]

Are you using any lube on the threads?

 

[XS650D]

There was a lil oil still on the threads so I did not reoil them. Nuts easily threaded by hand.
The nuts are approx 3/4" top of crown to bottom maybe a lil more, not sure if thats stock.Pic coming shortly. if I can figure out how to post it lol
Ive had my torque wrench for over 20 years, never dropped or abused but it could be off.
Goin to pick up another tomorrow unless I can get it calibrated somewhere.
Thx for the specs. Going to try swopping another nut tomorrow first.
Good info Jim on the wicking of oil working its way up, never would have thought of that.
Guess thats why the Acorn Nuts apparently

 

[Jan_P]

When I did not own a Torque wrench I sometimes used a Fishing scale
Getting the force on a wrench ..Force x Length of wrench = Torque
Those fishing scales was cheap ones with a spring in them
But surprisingly accurate
And was simple to check accuracy on fex lifting a bucket of water
with 10 liter water
That can give a fair indication if Your Torque Wrench " Is alive "
Saving some bucks

 

[Jim]

Goin to pick up another tomorrow unless I can get it calibrated somewhere.

Do a youtube search for "checking a torque wrench." There's tons of homemade ways to check it.
Jan's suggestion above is a good one.

 

[bosco659]

There was a lil oil still on the threads so I did not reoil them. Nuts easily threaded by hand.
The nuts are approx 3/4" top of crown to bottom maybe a lil more, not sure if thats stock.Pic coming shortly. if I can figure out how to post it lol
Ive had my torque wrench for over 20 years, never dropped or abused but it could be off.
Goin to pick up another tomorrow unless I can get it calibrated somewhere.
Thx for the specs. Going to try swopping another nut tomorrow first.
Good info Jim on the wicking of oil working its way up, never would have thought of that.
Guess thats why the Acorn Nuts apparently

Crappy Tire always has them on sale, in fact I think they’re on sale now.

 

[bosco659]

Lucky you . Gap in the torque range between the two. Maybe check the store. Doesn’t seem right. I would think the 3/8” should be good for 50ft lbs.

Lots on Kijiji too.

 

[XS650D]

Thx Guys got one out of my fishing box and will test that way.

 

[XS650D]

Wow!! My torque wrench is off by 7 lbs
Based on my fish scale. No wonder the head bolts r twisting. Over torqued . Lucky I didn’t sheer a bolt!!
My fish scale is old so I’m going to get a 10 lb weight and confirm that it’s accurate before resetting torque wrench. Found a great vid on how to do with exact same unit. Thx again all. Hopefully I haven’t damaged the gasket, surprised it haven’t leaked much worse

 

[Mikey]

Are you using any lube on the threads?

Was there a posting a long time ago saying that if you used lube or anti seize it would throw off your torque reading

 

[bosco659]

The inaccuracy on your torque wrench doesn’t explain why the fastener is “springing back”. That condition sounds more to me like the stud is bottoming out in the nut or there is thread damage inside the nut. To test the bottoming out theory, just remove the nut, add a couple of regular washers and see if you can torque it to the correct spec without the spring back. If you can, the stud length or nut depth is the problem. You’ll still need to disassemble and put the proper washer in place.

 

[bosco659]

Was there a posting a long time ago saying that if you used lube or anti seize it would throw off your torque reading

That’s correct and you need to adjust the torque values accordingly. Trouble is there are so many types of lubricants. I think 30W motor oil was commonly seen in these charts.

 

[XS650D]

K thx, so the head won’t have warped or damaged the gasket? My torque wrench has probably been wrong for a while. I will try a open bolt and check threads before the retorque after calabration

 

[bosco659]

You’ve used this torque wrench on all the fasteners so I don’t think you’ve damaged the head. The head gasket may have been over compressed though, or very worst case studs elongated. I’d address the possible bottoming out of the threads first then tighten up that problem nut and see if the leak persists.