I stripped one of my cam caps out when reinstalling my valve cover on reassembly of my engine. The other 3 went in fine, but the 4th stripped out. It seemed snug, so I left it in there. After a few hundred miles it worked loose, and oil was geysering from the bolt hole in the valve cover, down the head, onto the pipes. As you can imagine this was a big mess, and the smell of burning oil is just awful.
Enter the little savior known as the Heli-Coil. The guys in the Ace Cafe Delphi forum talked me through the process, but I thought I'd pass it along to the RAT forum since the cam caps are so easy to strip, and so precious.
In case anyone isn't aware, they cannot be replaced without buying the entire head assembly for about $1500.00 US. I'm sure something could be done to repair them besides the heli-coil if it isn't an option, maybe welding and retapping or some kind of JBweld patch job, etc. But the heli-coil works well and is cheap and easy to do.
I decided to heli-coil all 4 cam caps, which is an easy job but a hell of a committment. Mess them up, and you're screwed.
Here is a cam cap:
The top thread is the one that was stripped and heli-coiled:
The process involves drilling out the cam cap (yikes!), preferrably with a drill press, and a 1/4'' drill bit. Then, you tap the newly drilled hole with the tap supplied in the heli-coil kit:
Next, you screw in the heli-coil with this tool supplied in the kit:
Here is my new best friend, the heli-coil:
Once you screw in the coil you break the little tang off it, and you are done. The coil looks like a spring, the outside of it matches the threads you just tapped, and the inside threads match the bolts that hold the valve cover on. It provides a steel to steel thread-bolt connection and is much, much stronger than the aluminum to steel connection provided by Triumph.
They are so reliable in fact, they are used by Nasa and aircraft all over the world. The kit cost about $25 and included the tap and the mandrel tool. The size needed for the job is M6.
Be careful with your cam cover bolts, but if you strip them there is a fix that isn't too difficult or costly, just don't screw it up!!!
[ This message was edited by: sweatmachine on 2007-06-19 22:19 ]
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