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Cross threaded cam cover bolts

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84
Hi,

When putting my cam cover back on I realised that I let the torque wrench handle slip (locking thingy at end wasn't tight) from 12nm to higher. Now i've got some bad thread on the struts so I cannot get any of the 6 to torque to 12nm. Great. To be fair, the nuts didn't have much resistance, i just realised my error when one got a lot easier. Wish I had bought a cheaper car to learn mechanics on! I don't know if the cover is leaking or not, but will soon find out.

Has this happened to anyone before, and could they offer some advice?

I think I need to change number 6 (and 1x #7) on the diagram :http://www.hondaoriginalparts.com/h...ck_01=17S5T501&block_02=E__1002&block_03=9814

As this goes into the cylinder head, does it require any special removal/installation instructions?

I might get Honda/a specialist to do it for me, even though I feel confident. Whats the worst that could happen?

On a side note - cam cover removal... the brake fluid reservior gets in the way of removing the cover. The bolts that holds it there are hard to get to (so I scratched some paint). Has anyone else come across this? I couldn't get access to remove the bolts then brake fluid.
 
If they're cross threaded you have basically 2 shots at repairing it... one being a bit of a bodge and the other being the propper method.

Option 1 - run a tap down the existing thread and hope it comes good - this will never be 100% as it will not be a complete thread, but might still give you enough purchase to acheive 12nm.

Option 2 - open up, re-tap & heli-coil back to size. This is a bit more involved and I would not recommend you attempt this unless you are competent and confident with a drill in your hand. This method will give you a thread stronger than it came out of the factory.

Find out the thread size for me and I can tell you the best size to go up to for heli-coiling and what size drill to use etc etc.
 
Option 2 can only be used if you've got enough metal to be able to open up the hole.

You do have another option, but it involves plugging the hole with some stud iron and drilling the original hole, but again like the helicoil method, requires you do have enough excess metal around the hole
 
^ he speaks the truth.

Option 3 - plug, re-drill and re-tap. Even more involved than option 2 and you can't do this yourself unless you have a lathe and the knowledge of interference fits or know someone who can help you with these things. You must choose the right plug material also, or you'll end up with a crack propogating from your repair. It needs to have the same (ideally) or a lower co-efficient of thermal expansion.
 
This sort of happened to me the other week. I was tightening the last nut, barely touched it and the bolt physically snapped!

I went to Honda to order a replacement bolt, as you've found out there is 5x one size and 1x another size. I ordered one from the 5x sized bolts and have it sitting to be fitted but haven't got round to it yet.

To be honest, I think it will just be a case of removing cover, removing knackered bolt from the head, putting new one in and then re-fit. I don't see why it would be any more complicated than this.

As for taking the res bracket off, I never had any problems taking that off, I've always got it on and off without scratching paint etc.
 
To be honest, I think it will just be a case of removing cover, removing knackered bolt from the head, putting new one in and then re-fit. I don't see why it would be any more complicated than this.

The difference is you only snapped the bolt, a snapped bolt isn't a major issue assuming it can removed. Stripping the thread means you have little to no threads left in the hole which is a slightly bigger issue than what you had, as you've not got enough metal to screw the bolt in.
 
The difference is you only snapped the bolt, a snapped bolt isn't a major issue assuming it can removed. Stripping the thread means you have little to no threads left in the hole which is a slightly bigger issue than what you had, as you've not got enough metal to screw the bolt in.
You don't need to strip the thread, just replace the bolt. The thread that has cross threaded will be at the top of the bolt, not the thread that holds the bolt in the cylinder head. Well at least I wouldn't think so, as there is no need to remove at the cylinder head end to change the rocker cover. Just buy new bolts and replace. Easy.
 
I would also add to not bother with the torque wrench as it's clearly useless. Tighten the nuts hand tight and do another quarter turn with a socket set. There's very little pressure up in the rocker cover, so it doesn't need to be that tight. Just tight enough for it to stop the vibrations from working the nut loose.
 
As above, Jermal is correct.

From the OP, the guy has threaded the end where his nut holds the cover onto the bolt.

Remove from head and replace with new bolt = sorted :)
 
Hi guys, thanks for all your comments. Much appreciated.

To clarify, I actually stripped the thread from the struts that poke through the cam cover. Most are knackered. Cylinder head is fine.

I don't think there is enough metal to fix them because the thread towards the bottom is completely missing. Just stripped off. Bloody wrench! I torqued the nuts that hold the clearances in place, no problem there.

I think my easiest, but most expensive option is to buy new struts. And nuts, they're pretty knackered too. Honda will charge half an hours labour to fix, which is an easy decision for me.

I kind of wanted to check there would be no side effects replacing this many struts. The service manual states the struts and bolts have to be removed in a certain order to prevent warpage. Obviously the head won't be dismantled but it will partially have struts removed.

Finally... Do you think the engine should be cold to fit them? They get torqued to 22nm and if the engine is still warm then the torque will be wrong?
 
They just bolt into the head, it won't cause any problems I don't think. Put it this way, if it was me I would happily replace all of them.

I would do it when cold to be honest. I done my cam cover before when hot and it never sealed properly, for obvious reasons. Just do it when cold to avoid problems like that, as you mention above, and also to make it easier for you as obviously it gets pretty damn roasting there.
 
They just bolt into the head, it won't cause any problems I don't think. Put it this way, if it was me I would happily replace all of them.

I would do it when cold to be honest. I done my cam cover before when hot and it never sealed properly, for obvious reasons. Just do it when cold to avoid problems like that, as you mention above, and also to make it easier for you as obviously it gets pretty damn roasting there.

and please don't get Honda to do it for you. As long as you can remember lefty loosey, righty tighty, anyone can do it. Honda will charge you at least £40 labour just to unscrew and screw in 6 new bolts.
 
and please don't get Honda to do it for you. As long as you can remember lefty loosey, righty tighty, anyone can do it. Honda will charge you at least £40 labour just to unscrew and screw in 6 new bolts.

Yes this.

And besides, it took 2 "mechanics" from my Honda dealer to decide which specific bolt it was..... I had to tell them in the end when all I wanted them to do was confirm I was correct.

All I established when querying Honda about this bolt was that "you have a nice engine mate".....
 
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