|
2 possible causes.
1) The threads in the head, or bolt give up with the torque and vibation (rare when plastic pieces are involved)
2) Vibrations create torque peaks and plastic gives up little by little.
For #2 you can use bigger fender washers to increase the area of contact and lower the pressure per square inch in the plastic piece.
You can also try studs instead of bolts. Tha might require installing the manifold and then the studs, if the angle doesn't allow it to slide it in.
This happens a lot when you mate plastic and metal.
Another option is to use a strong loctite and give it less torque than specified. Sometimes less is more
|