Z1000J Camcap bolts

[LeeJackson]

Gents

Manual is saying 12ft/lb for these but I can feel one starting to strip before the click.. Ahh.. I backed off to ten and its clicking but now in dilemma if I should back off and helicoil or leave it at ten? Yikes always a problem

Cheers
Lee

[Al]

Lee the manual is wrong in this regard! It should be 8.6 ft lbs or 104 inch lbs. However in practice; 6 to a maximum of 7 ft lbs is more than adequate if the cams are positively located and there is no upward pressure on them from the springs. (you would need a method of compressing the springs in order to do this). Ray / Steve have a modified 'G' cramp that holds the cams down, i use a bolt on frame for this made from scraps of strap metal banding.
I no longer torque mine down but 'nip' them to what i consider a suitable degree using the wrist ratchet method preferred on here.
If its started to pull the thread; have a damn good look at the thread on the bolt and see if it is either 'waisted' or elongated the threaded part!
Replace bolts that have the thread slewed along or those that have a particularly rough feel to the metal as they just rip at the alloy in the fixing point.

If you have a re-coil kit i would definitely do it now and not leave it because it will never be easier and the chances of it letting go dont bear thinking about.
Use the cam cap 'where possible' to centralise the drill and the tap with a sleeve round the shank even if that means wrapping them with a few turns of insulating tape! Needless to say it really is best done on a drill press to be dead vertical.

[Al]

For completeness and before this spirals out of control; you will need to measure the depth to the base of the blind hole with the depth gauge on the vernier. If you drill too deep or at an angle or the drill drifts off line, when you insert the helicoil it will push the side of the 'well' that the bucket sits / runs in; inward and pinch the bucket on its travel. The same is true if you elected to tap the next size up (8mm) which is equally well avoided but not uncommon to see!

AL

[LeeJackson]

Thanks Al, this is very useful info, of course now wishing I'd asked before I started. Lol. So I definatly want to try and avoid taking the head off again, but sounds like it needs to be pretty spot on to avoid any other issues! What do you reckon on going to an M7 fastener, or is that too close to be able to get a good thread?

Actually there are now two bolts with the same symptoms, I pulled them and both threads are damaged so seems I definatly have to do something.. No helicoils in the garage either so more delays I guess..

I like the jig idea, will have to make myself something for future to avoid more screw ups!

[LeeJackson]

Well not sure if this is good or bad news but one of the offending holes has already been helicoiled ( infact I think both have) but on of the coils pulled right out

[Al]

You may be OK to insert another helicoil in there. Thats a judgement call based on what you can see in front of you, i cant comment.
I have used 7mm to replace 6mm in non critical situations and the thought for me is that its a no no. You might get away if you can find a really good supplier of 7mm HT bolts but they are a 'non preferred' size and and such a bit marginal i suspect.
The outside diameter of the 6mm re-coil tap is 7.3mm approx and drill size is 6.3mm approx. However since you already have a 6mm coil in there youre choices are limited.
Re-coil kit in the UK was about £30 five or so years back. Extra coils of different lengths were a few quid a bag of 5. Worth their weight in gold but only if used with caution.
Are those stainless steel cam cap bolts you are using???
Are they also socket caps?

AL

[LeeJackson]

Al

Yes seem to be stainless steel ones, just what came out of it from Debben's so I'm assuming ok. I will order a helicoil kit and see if I can get another one inserted into the hole where the one came out as a first try. The other on the coil seems to be much more solid in there so need to think about what to do there more.

Cheers
Lee

[LeeJackson]

Also yes socket cap

[Al]

Put the bolt back in the one thats still in place and test at 6 or 7 ft lbs.
May still be OK at the lower torque!
As far as stainless socket caps are concerned, i thought that they weren't HT but stand to be corrected. All the stainless bolts i have inserted into fine threads in alloy have ripped the thread because the stainless threads are always rough (granular looking)! The other thing is that depending on the thickness of the cam cover gasket, i also believed that there was not enough room to bolt the cover down when using socket caps, that combined with the fact that they are so narrow, they collapse (cave in) the top of the hole in the cam caps themselves. Standard bolts have the 'spread head' on them for that reason.

Made a modification to the cam holder because it looked a bit frail holding onto just two head bolts. Now with bridge to beef it up a bit.

AL

[Al]

Another question; looking at the picture with the bolt with the helicoil on it, is that all the helicoil out or is there still a part of it left inside.
It only has 7 turns so would only have been 7mm long on a 6mm thread?
AL

[LeeJackson]

Al, makes sense on the HT bolts, I will have to change them all I reckon. It looks like there is still a bit of a helicoil in there which is going to complicate things further..

[LeeJackson]

Looking again bolts are marked 12.9 so I belive HT?

[LeeJackson]

Al,

I managed to run a tap down the one with the helicoil still installed and seems ok, so might get away with it. Will order some coils and try and get the rest of the other one out this week. Need to make the tool as well as obviously I'm getting a bit rough with it this way, so will have to work on that. Really appreciate the input!

[Al]

I'm afraid you are now in an area where an engineer needs to make a call regarding HT grades etc and i am not one, i do a bit of welding here and there.
I have been told that the effective length of a thread is one and a half times its diameter which is what prompted the comment about there being only 7mm of coil visible on that bolt. I take that to mean 9mm for a 6mm bolt but here we are talking about a 7mm thread effectively and not just that, its in alloy. Thankfully when i bought the kit i also got a load of different length coils and in situations like yours i have tapped the hole and then measured the free length of the hole and selected the coil length by the number of turns to be just that bit shorter than the cut thread if that makes sense.
Any how, i dont know how you plan to remove the remainder but what i have used looks like a chisel edged arrow. You turn it backward into the hole and it centres itself on the uppermost coil. It is narrowly angled and bites into the coils and anticlock-wise turning pulls it out. I borrowed it dont know if re-coil sell them.
Good luck and a steady hand should sort it all out.
AL

[Coose]

All good advice from Al as ever.
When I first bought my J it knocked when hot (as it still does), and on lifting the cam cover I found the front-right cap to be "displaced". Two of the bolts had pulled the threads out of the head. I've got away with fitting two slightly longer bolts for now and using the "eeeek, that's tight enough" method of torquing them. Though, I do have the intention of repairing them correctly.
I've since lifted the cam cover again to try to stop it leaking, where after two years of spirited riding nothing has moved.

I have every intention of rebuilding the motor (which was planned for this winter but didn't happen), where the threads will be repaired properly. I was initially looking at Timeserts, which due to their nature are significantly stronger than helicoils, but may cause an interference problem with the buckets in the same manner as Al has suggested if tapped to M8 as they're a larger diameter. I would seriously consider M7 bolts as you suggested Lee, though it would be dependent on finding 10.8 or 12.9 grade fasteners with a flanged head, though you could look at titanium?