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Discussion Starter · #1 ·
Hi Team,

When I installed the chrome valve cover earlier in the spring I found that the threads for the two rear bolts were stripped. Yes the ones inside the aluminium head.

At the time, I put on the new cover and tightened the front bolts to the correct torque. The rear two were maybe finger tight but would spin if I went any further. Since then, I've done maybe 1,500 miles and I have no leaks if I keep it under about 150 miles/day. Over 150 miles/day and I get a little seepage.

Then over the weekend I did almost 300 miles - lots of it at interstate speed - after which I saw some pretty good threads of oil streaking across the plastic engine cover. That was a sure sign its time to do something.

So what's the right approach here guys? I see two options:

1. Get slightly larger bolts, possible tapered, and gently screw the new bolts into the stripped aluminum. The question of course is: what size bolts and where to find?

2. Repair the stripped threads. This option I'm less clear on as I've never done this job before? What tools/materials are needed and what's the process?

Thanks in advance for any help here.

P
 

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Repair the stripped thread - it is not difficult. It needs care obviously, but straightforward enough. I will locate a thread for you now...........

Here it is:

http://www.triumphrat.net/twins-tec...ing-stripped-valve-cover-cam-cap-threads.html

Do NOT do your option 1. That is a very nasty approach to the problem.

Properly repaired with Helicoils (or similar) the threads are much stronger than original, and you should never have the problem again. Do one cam cap at a time, you should be fine.
 

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thanks for linking my post Prop.

Pete: Just be sure to know/remember that the cam caps (the thing you'll be heli-coiling) must go back to their original location and orientation, they cannot be used in different locations in the engine

A haynes or triumph manual would come in handy here. You'll also need anti-backlash pins for the cams. A lot of forum members have made their own. Don't drop anything down into the engine!
 

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Discussion Starter · #4 ·
thanks for linking my post Prop.

Pete: Just be sure to know/remember that the cam caps (the thing you'll be heli-coiling) must go back to their original location and orientation, they cannot be used in different locations in the engine

A haynes or triumph manual would come in handy here. You'll also need anti-backlash pins for the cams. A lot of forum members have made their own. Don't drop anything down into the engine!
Hey Sweat - The good news is that the cap cap threads are fine, its the threads for the cam cover bolts that came up. BTW could you confirm or deny that this is the helicoil gizmo I'll need: http://cgi.ebay.com/ws/eBayISAPI.dl...Track=true&ssPageName=VIP:Watchlink:middle:us

Thanks,

P
 

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Hey Sweat - The good news is that the cap cap threads are fine, its the threads for the cam cover bolts that came up. BTW could you confirm or deny that this is the helicoil gizmo I'll need: http://cgi.ebay.com/ws/eBayISAPI.dl...Track=true&ssPageName=VIP:Watchlink:middle:us

Thanks,

P
that's the kit, and I'm talking about the threads for the cam cover. They are the only threads in the cam caps. You can get that kit at any decent auto-parts store though, no need to order.
 

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Discussion Starter · #6 ·
that's the kit, and I'm talking about the threads for the cam cover. They are the only threads in the cam caps. You can get that kit at any decent auto-parts store though, no need to order.
Thanks Sweat - I getcha now with the cam caps and I won't filp them around. I'm tempted to go ahead and drill the helicoils but the cost of getting this wrong is pretty hefty so what I may do is source all the materials and then take the gear and the cam caps down to a mechanic I trust and have him do the helicoil work with drill press on his bench. Might cost me an extra $100 for shop time but that's a far cheaper route than a new head if I screw it up.

... caution being the better part of valor.


Thanks guys, this has been very helpful.

P
 

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when you start down this road, take some pictures. im getting ready to do this myself.

Side Note: anti-backlash pins?
 

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The anti backlash pins are for the gears on the camshafts. If you pull all the cam caps at once then you need these pins.

However, if you are able to take off only one cap at a time, repair it, reinstall it, then move to another one, I think you would be OK just leaving the camshaft in place.

You can see what the antibacklash pins are for here:

http://www.triumphrat.net/twins-technical-talk/96205-12000-mile-service-overview.html
 

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Dumb question ...

Can it be done in-place? Or is there not enough clearance to get the drill in there?
 

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Easily enough room, just would be worried about swarf getting everywhere in the motor - even though you don't make that much. I suppose you could have a friend there with a shop vac while you are doing it....but I would prefer to take it out. Then you can use a drill press to hold the tap and get the threads started square for the helicoil.

You don't power the drill press, just use it to hold everything - then turn the chuck by hand.

Also, you kind of need access to the bottom of the cap to break off the little tang on the end of the helicoil. You can also make sure you haven't screwed it too far through.
 
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