Head nuts

[rado360]

I've seen 2 different specs for head nut torque on oilheads,Clymers says 15 ft. lb then 90 deg. more---another source says 17 ft. lb and 180 deg. more, any thoughts on whats correct?
Thanks, Tim:

 

[BMWRich58]

8nm, according to 1150RT CD repair manual.
16 ft lb's and that's it.
No leaks and it works for me!
NO additional TURN'S/DEGREES

 

[rado360]

NO additional TURN'S/DEGREES

Rich, could you double check thoses figures for me,because thats the first I've heard of no additional degrees, and 8 nm equal less than 6 ft. lbs. (nm x .73756 = ft. lbs.) unless I'm reading the conversion chart wrong,and that sure is possible.


Thanks Tim

 

[darrylri]

Sounds like he has confused the valve cover bolts with the head nuts.

 

[BMWRich58]

Yep,Darryl is correct. I miss read your post. Sorry...
Mine is for Valve covers ONLY...

By the way,why are you "redoing your head bolt torque?"

 

[fish]

We like to refer to ourselves as "moderators", not "head nuts".

As you were

 

[bmwmick]

Tim,
Here it is right out of the factory manual. 20nm is 14.75 FtLbs.

Mick

 

[rado360]

Thanks Mick,and Rich I,m redoing because I used to own an air head and when I got the oilhead I did the valves the way I did them on my air head,retorque then set valves--but I used clymer to get the torque and found that 90 deg might not be right,anyway I torqued them to the correct angle and now will leave them alone.
Thanks Tim

 

[BMWRich58]

Hey Tim,I do the same on my airhead before each valve adjustment except...I do not loosen the bolts,then retighten them . Reason is,the previous "owners/tech", torque wrench might be a little off compared to mine. So,if I loosen and retorque to specified number "with my wrench" and his/their torque wrench was a little tighter but showed the same torque value,I just reset the heads to a lighter value and can now expect head gasket leaks to form. So,I just check torque,and don't loosen at all. If it's loose,it will tightenup,if tight,the torque wrench will click. On oilheads,I've never practiced the retorque of the heads before valve adjustments,only after the 600 mile breakin.

 

[globalrider]

...I did the valves the way I did them on my air head, retorque then set valves--

Tim, even on the airhead, you didn't have to re-torque the head nuts every time you wanted to adjust the valves. That is putting a lot of wear and tear (and the chance for a mistake) on the threaded assemblies, especially those in the block which are already so close to the cylinder bore opening.

But you do have to at least check, and possibly adjust the valve clearances after re-torquing the head nuts.

 

[globalrider]

So, I just check torque,and don't loosen at all. If it's loose, it will tightenup, if tight, the torque wrench will click.

You do realize that you can torque a fastener to say 50 lbf.ft. in a continuous motion, then reset your torque wrench to 55 lbf.ft. and chances are very good (probably 100%) that the fastener won't turn any further, yet your torque wrench will click just the same at 55 lbf.ft. without any further torquing taking place.

You loosen fasteners so that you can correctly re-torque them. Once a fastener is set, you have to overcome static friction to get it rotating further.

Next question. When was your torque wrench last calibrated?

 

[rado360]

Next question. When was your torque wrench last calibrated? [/QUOTE]

Where can I get the wrench calibrated?

Tim

 

[globalrider]

Where can I get the wrench calibrated?

Tim

What make and model? Are they quality wrenches worth calibrating?

The most important aspect is that it is repeatable over time. For that, we are talking a quality torque wrench.

I have three click type Snap-On torque wrenches, two of which I calibrated myself at work. I think Snap-On provides calibration service. They should provide you with a print-out. Chances are they won't do five runs as I've done to check the repeatability of the wrench. If it is a Snap-On, the two that I calibrated had excellent repeatability (tight standard deviation) and accuracy was within specifications even below the top 80% of the working range. One wrench was calibrated 17 years after I bought it.

You really don't care if it is off, as long as you know how much it is off and you can compensate using the print-out.

In the end, fastener finish, oil on the threads, etc have more of an effect than the slight amount your wrench "may" be off. After all, we're not assembling jet engines.

 

[JRMSR]

For an oilhead, after removing the cylinder head and reassembling (shouldn't be doing that except for major overhaul), you tighten all 4 nuts slowly to 15 ft/lbs X-cross fashion.
Then you tighten each nut 90?? X-cross fashion, all 4. Then you tighten each nut 90?? X-cross fashion again all 4, to complete.

After doing this once on cylinder head reinstall, you must re-torque after 600 miles of use. On retorque, you loosen one nut at a time, torque it to 15 ft/lbs, then tighten 180??. Then do the next nut in X-cross fashion, till all 4 are done. Also loosen and retorque the M10 nut in cyclinder head.

Again, the difference is whether it is the first time since re-install of cylinder head (90?? all four, then 90?? again) or whether it is the 600 mile retorque after initial assembly (180?? each nut individually).

For valve adjustments only, you should never be loosening, tightening the head nuts.

Jim Morrow