Sentra E16i Rocker Shaft Bolts

[gordonb1]

Hello, I'm the pleased owner of an M5 '92 Sentra Classic (Mexico) with 141K on the clock. Last year at 132K miles, the motor started sounding like a diesel. All five bolts of the rocker shaft were loose, one was stripped and riding up almost an inch. This was bolt #4 counting from the front of the engine. This bolt and bolt #2 have a stainless or chromed finish, while the others have a carbon black appearance. All bolts have the raised marking '7' on the head, over which is a 'dot'. I cleaned out the #4 hole and was able to thread in a new bolt '10.9' of the same diameter (8mm). All bolts torqued carefully with blue Loctite. (12-15 ft./lbs.)

Now at 141K the engine dies on the highway. The '10.9' bolt lost its head which momentarily jammed under the cam and stripped the timing belt. (#5 bolt was slightly loose and the #4 must have sheared under the impact load?) The timing only seems off by two crank teeth and none of the valves show excessive clearance, so I'm hoping no serious damage is done. I'm about to install a new belt and then will run a cold compression check before full re-assembly. Four questions.

1.Is this compression test the best way to check for valve damage? I don't have previous compression numbers.2. Should I try to put a helicoil into #4 hole? Will Permatex 'Stripped Thread Repair' epoxy work instead? The local mechanic says cleaning out the hole with a same size tap and then Loctite, will usually work. (?)3. How could a stainless bolt be almost completely stripped in an aluminum head? I can't see any indication of a steel insert.4. Some valves had almost no clearance at the rocker arm, is this normal? My Haynes says .011 is spec.Any experience with rocker shaft bolt problems will be appreciated.

Thank you, Gordon
Modified by gordonb1 at 8:50 AM 11/1/2005