Plenum problems (threaded balance tube bolts)

First up this is on my brothers zed not mine. He's asking for advice from me over the phone.
Well basically what he has done , earlier today he was changing the spark plugs , when screwing in bolts for the balance tube on the drivers side , has threaded the plenum inner thread.
So the 8mm stock bolts just spin , not catching any thread .
I suggested getting a tap set & bolts which he has done, but the next size up is 10mm .
So he's re-tapping the thread on the plenum so a 10mm bolt will thread in .
Problem is , he can't catch all the aluminum shavings from the tap , some are going inside the plenum , which means they will be sucked into the combustion chamber .
Obviously this isn't ideal , but what are the chances of doing internal damage with a few aluminum shavings in the plenum ?
I was thinking they would be pushed out the exhaust before they do any damage .
Thoughts and advice muchly appreciated
Cheers

 

Get a vacuum cleaner you're not particularly fond of, and suck them out? Just tape a straw / funnel to it so it fits into the balance tube hole.

-Kirill

 

Check THIS out.

 

thanks Kirill , I'll pass that advise on

 

Also a good idea is to put some grease on the tap as it will catch the swarf.

 

Thanks for the tip Jono , but I think it might be to late for putting studs in this case .
I mean the stock plenum thread has already gone .
funny you should mention that though , as my plenum seems to have studs on the drivers side also , previous owner must have threaded them on mine to

 

Should have heli-coiled it

Threads would then be the same size, normal and better way of repairing it
Also should have taped off any holes near where he was tapping.
short of removing the plenum and flushing it out Use the vacumm cleaner method.

 

Not sure what heli-coiled it means ? sorry
Well from what he's told me the bolt hole he's re-tapping goes from the top of the plenum straight to the inner plenum , which is why he can't stop the shavings getting in .

 

Just use the vacuum. If you are careful you will almost all of it.

I would have recoiled the holes rather than make em bigger

 

Ah ok , well this is not something I'm familiar with
what does recoiled and heli-coiled mean ?
I thought that once the original tread was rooted you had no choice but to re-tap it to the next size up ?

 

A heli-coil, recoil or keensert are thread repairs. They are basically a new thread, you tap the hole with the supplied(from a kit) tap, apply loctite and screw in the new thread. This returns te hole to the original size.

With a 10mm bolt, he may have issues getting a spanner on it.

 

Heli-coil

Is a stainless steel thread that replaces the original.
You can buy a kit that has any size you want.
see here.
http://www.google.com.au/search?sou...&ie=UTF-8&rlz=1T4GGIC_enAU207AU211&q=helicoil

Anybody who is taking plenums on and off regulary is going to need one sooner or later.

 

Or do as I have done

 

LOL

 

3 studs already exist.....

On the drivers side there are already two studs with acorn nuts, and the passenger side has a single stud/acorn nut on the front hole of the balance tube.

The two holes on either side of the small balance pipe at the rear (on the passenger side) are where the bolts go. I think the only reason for their existence is because of the AAC valve pipe bracket, which is a PITA to fit if you use studs.

 

Yep I understand now , I watched this clip on how it works
http://www.youtube.com/watch?v=RFYa6sjhh_E
Well it's probably to late for that now.
So where would one go about purchasing one of these heli-coils ?
I've not heard of them before today , would most auto shops have them or is it an item only engineering places would have ?

 

Any bearing or bolt shop should have them. It may not be too late, an 8mm helicoil uses close to a 10mm tap.

 

Nice
but in my mind if he's already tapped out the thread in the plenum to 10mm , is there any benefit to installing a heli-coil thread insert ,over using the 10mm bolts he bought ?
I'm still waiting for him to call me back , let me know what he's doing btw

 

A heli coil is alot stronger than the alloy thread and will wear alot better. Other than that it just looks odd when there are different bolts everywhere.

 

I see .
Well thanks all for the advise so far , I've learned a thing or two , appreciate it .
I'll let you know how things progress from here , depending on when he gets back to me .
Regards
Drew