Pronto
Believe nothing you hear and half of what you see.
- Joined
- Dec 9, 2002
It's been said many times but I will say it again since it happened to me. The pp and gaskets are about 5mm thick. The 3 stock bolts and 2 studs with captured nuts are not long enough to safely deal with that much loss of threads to seal the upper plenum. With the pp, the stock bolts have about 5mm of engagement and the studs have even less. Over the 15 or so years I've had mine, I've had to take the upper plenum off for various reasons. Finally the last time the 2 studs came out with a nice ring of aluminum in the threads. They didn't seal and there was a massive vacuum leak. Probably slowly happening over time. I thought about helicoils or timeserts but only about 4 mm of the top threads were ruined and the threaded holes are close to 20mm. I sealed off the opening and then ran a M8 1.25 tap down each hole and cleaned them out. I got 3 30mm M8 bolts and found some exhaust studs that worked (Help 03411). The studs need a washer and nut that are about 8mm thick for the throttle cable bracket and PCV line to sit on top of correctly. The stock nuts can be used on top of the studs. The studs have hex tits on them so you can easily thread them through the plenum and tighten them in lightly. I used a light coating of copper spray on the gaskets. Torqued the bolts and nuts to 180 inch/pounds. All is good, no vacuum leaks and was quick and simple. The studs could be used on all 5 holes as well. Hope that helps. For those chasing high blms you might want to look into this too.
