CCT Mounting bolt torque

Monkey! · Post by **Monkey!** » Fri Dec 22, 2006 7:50 pm

Just finished a load of work on my 'storm. I decided that I'd change the CCT's while I was servicing it. No signs of impending doom, but better safe than sorry I figured.

What a b&5t&rd of a job it ended up being! Seems like a lot of work to put the pistons at TDC on compression stroke but I did it anyway, even if the front did make me swear a lot.

It was all going well until I was torquing up the bolts on the front CCT. Haynes says 23Nm, so I set my wrench to just that. Ratchet ratchet ratchet. Snap......... That awful sudden loose feeling you only get when something has gone well tits up....

Feck..........

Has anyone else had this problem? Is the 23Nm figure correct?

It took an hour of fun with the drill, stud extractors and eventually a punch and hammer to get the thing out again (rags and stuff jammed down the hole to stop swarf filling the engine).

The rest of the job was easy but I dumped the torque wrench and just nipped them up instead with a ratchet as I didn't fancy dropping the engine to drill out a rear bolt too......

No long term damage, and nothing seems to be leaking oil so I guess the new gaskets are sealed.

Runs nicely now as well.

Ah well. It's winter and the roads are salty. What else would I do on the first day of my holidays than fettle in the garage??????

Max · Post by **Max** » Fri Dec 22, 2006 8:18 pm

When I changed mine a while ago, I looked through the Honda book and the 23 NM was for the cam chain tensioner blade inside, which at times it calls the cam chain tensioner. The screw for the tensioner is M6 and for general M6 screws the manual calls for 9NM. I can't remember but I think I torqued them to 10NM. that was 18 mths ago now and they don't leak and haven't moved . I now stand back and am prepared to be corrected

Monkey! · Post by **Monkey!** » Fri Dec 22, 2006 8:42 pm

Cheers Max.

I reckon you're right. Haynes is wrong. Gotta be.

Page 2-7

Cam chain tensioner mounting bolts- 23Nm

And then a little further down-

Cam chain tensioner blade and guide blade pivot bolts- 23Nm

So they are different items but Haynes have given the same figure for both

I should have thought about it before doing it. 23Nm does seem a touch much for an M6. The valve cover bolts are M6 and they're 10Nm.

Luckily the little bugger came out and I had a spare one in my box.

Worth remembering though if you plan doing any work and have the Haynes book.

It's wrong!!!!!!

Monkey! · Post by **Monkey!** » Fri Dec 22, 2006 8:58 pm

Same here as well.

http://www.kamware.com/vtr1000f/torque.htm

Is it all a big conspiracy?

I reckon I was lucky to get away with it in under an hour....

Kitch · Post by **Kitch** » Sat Dec 23, 2006 7:15 am

This has cropped up before and it was established that Haynes is wrong.

my Haynes book says standard gearing is 16-44 (when its 16-41) and I believe somebody else had one that gave a 56nm rating for cam bolts.

LotusSevenMan · Post by **LotusSevenMan** » Sat Dec 23, 2006 9:53 am

You nearly got it right. The torque figure for all bolts is:-

Up to shear; then back half a turn! You forgot the back half a turn didn't you?

Seriously though, what a B45T4RD to have got to that final point and that 'ping' sound. Maybe it was a bit more mushy/cheese like though as I've had heads etc come off Japanese motor bolts like that through corrosion as in outboard motors. They don't snap but just twist off.

Congrats on getting it all back together though Monkey! and in under an hour? What a star. Mind you, I would have thought that 'feeling' those bolts into place with a little thread lock perhaps would be the best solution here as 23nm which is nearly 17 foot lbs for us old 'uns is really excessive!!!!!
This can be usefu here:-
http://www.pitt.edu/~rsup/touqueconv.html

Monkey! · Post by **Monkey!** » Sat Dec 23, 2006 11:26 am

I was sweating a bit (cold sweat) when it snapped. Bit of deja vu of the disaster that unfolded 10 years ago when I sheared a brake bleed nipple on the wife's car and then snapped a stud extractor deep in the hole too.

It's not too bad drilling out stainless steel or brass. But you try getting rid of stud extractor! Rather helpfully, good old Mr Haynes recommends:

"Warning: Stud extractors are very hard and may break off in the fastener if care is not taken- ask an engineer about spark erosion if this happens"

I ended up binning the caliper and getting one from the scrapper!

I was also amused to read the piece in the latest RIDE about workshop tools- particularly liked the snakes and ladders game - plenty of laughs and all too familiar scenarios there...

delmeekc · Post by **delmeekc** » Sat Dec 30, 2006 4:31 pm

do all my m6 bolts to 10 to 12Nm including cct ones. The other thing to remember is you must have a really low scale torque wrench, have 4. If I use the 4Nm to 20Nm one and set it at 12Nm and then test it against a 10Nm to 54Nm one the large one actually puts 14 to 15Nm on the bolts which would damage the thread, especially in alloy. Never try it with something you don't trust. Never used thread lock on them either. Only normally put a tiny bit of thread lock (not stud lock) on all the unsprung stuff.