(F*ucking)Cam cap bolts

[Svsam]

Is it common for these little bastards to snap when torquing them up, or am I just unlucky?

this is the second time I’ve had it happen, luckily first time it wound out with the broken head. Tonight, no such luck. 
I know they are only 10nm setting, though I read somewhere that wet and dry torques are completely different, anyone heard this before?

 

Edited October 16, 2021 by Svsam
Spelling

[Swiss Toni]

No! You’re not alone! Little bit at a time is the way. If they’re old bolts, they really need renewing from time to time. They eventually become brittle with the heat cycles. OE aren’t cheap. High tensile Allen’s do the job. 

Edited October 16, 2021 by Swiss Toni

[jonny1bump]

 Totally agree use new bolts, costs certainly worth it, especially on unknown head. 

On heads i know, i have never snapped a bolt, but have undoing bolts on  head never seen before I have.

9 ftlbs is plenty torque.

Same as the 6mm crankcase bolts old ones can fail too and that proper miserable when you just glued the two halves together.

To drill bolts out ya cam caps, head off put in pedestal drill.

[Svsam]

Does it add value if you snap a snap on extractor piece in there 

Give up on this one for now. 

[Gixer1460]

46 minutes ago, Svsam said:

Does it add value if you snap a snap on extractor piece in there 

Spawn of Satan those bloody things ! ! !  With that snapped off in there there's two 'easy' options (well 3 but last isn't a good one) 1. Spark erosion 2. Weld a nut onto the stub or 3. Bin the head and buy another !

[no class]

a proper mill with a solid carbide bit will do the job . since you have that extra threaded hole , bolt the cap down and use a steel sleeve inside the bore of the opposite side…. this will be a guide to keep the drill from wobbling around . before drilling …measure the depth of the bore from the top of the cap to the bottom of the threaded hole and set the machine stop … this will keep you from drilling too far into the head….use high speed and constant pressure ( medium) …. the extractor will get red hot and the carbide bit will go through it quickly…..keep the pressure untill you have passed through both the extractor and bolt .  left hand carbide bits are available too and may aid in the process   but  not always . This worked for me and I had 4 of them in the same head  to do .

[clivegto]

Yes I have had them snap before but only on 1 particular motor. Luckily they just turned out by hand. 

[TonyGee]

i think the trick would be to make sure the threads are all clean and the bolt secews in all the way easily by hand, then if it does snap you have half a chance of getting it out without drilling and the gods are on your side  

[CafeDragsterEFE]

"I know they are only 10nm setting, though I read somewhere that wet and dry torques are completely different, anyone heard this before?"

hello, did I read it right, that the torque is only 10nm for these bastards? Or what ius the right torgue.

cheers

Jussi

[Upshotknothole]

37 minutes ago, CafeDragsterEFE said:

"I know they are only 10nm setting, though I read somewhere that wet and dry torques are completely different, anyone heard this before?"

hello, did I read it right, that the torque is only 10nm for these bastards? Or what ius the right torgue.

cheers

Jussi

8-12nm per the Suzuki service manual. No mention in the manual of them being wet or dry, but I would think a touch of oil would reduce the friction of them going in.

[Crass]

Any torque setting quoted in a manual is always with dry threads unless specifically stated to the contrary. As a rule of thhumb reduce the torque setting of a greased thread by one third but there is absolutely no reason to lubricate cam cap bolt threads. They are not going to be exposed to the elements so should never seize in. Plus any lubricant will be trapped in a blind hole so may crack the alloy when it boils off and expands as a trapped gas. Keep the bolts and the hole dry before torquing.

[Gixer1460]

11 hours ago, Crass said:

Any torque setting quoted in a manual is always with dry threads unless specifically stated to the contrary. As a rule of thumb reduce the torque setting of a greased thread by one third but there is absolutely no reason to lubricate cam cap bolt threads. They are not going to be exposed to the elements so should never seize in. Plus any lubricant will be trapped in a blind hole so may crack the alloy when it boils off and expands as a trapped gas. Keep the bolts and the hole dry before torqueing.

Sometimes I do, sometimes I don't - I have no preference, but there again I don't use a torque wrench for these fasteners either and i've never snapped one yet although i've snapped a few that were OEM factory whilst removing them - that's one for the X files ! Regarding trapped grease / oil 'boiling off' and vaporising . . . . . . its unlikely an engine would ever get to a point where either would vaporise AND cause damage. Just checked 'Permatex assembly lube' flash point is 550 deg F / 288 deg C ! And engine oil similarly is 420 deg F / 215 deg C.