Cleaning underneath valve cover

[agisthos]

I think I will do the same as you then, drill and tap. I know my powder coater was aware, but even so.

Just be aware if you do this.... after I had my M20 engine rebuilt there was a weird popping and cracking sound coming from head after turning the engine off. We finally realized it was the sound of the plate moving with heat contraction. When its riveted its totally fixed, but with bolts it will move under expansion/contraction.

[JehTehsus]

Just be aware if you do this.... after I had my M20 engine rebuilt there was a weird popping and cracking sound coming from head after turning the engine off. We finally realized it was the sound of the plate moving with heat contraction. When its riveted its totally fixed, but with bolts it will move under expansion/contraction.

Thanks for the heads up. I may even be able to rivet it again, I know there is a rivet gun hiding somewhere around my uncles shop.

[jeffnhiscars]

Rivets would have to be exactly the right size to both grip and not bust out the cast aluminum holes..or worse just fracture the aluminum and have it fall apart while you're driving. I Would also think that anything that's so caked in there that chemicals or pressure washing won't remove it isn't going anywhere just from driving around. 🤷♂️

[JehTehsus]

Rivets would have to be exactly the right size to both grip and not bust out the cast aluminum holes..or worse just fracture the aluminum and have it fall apart while you're driving. I Would also think that anything that's so caked in there that chemicals or pressure washing won't remove it isn't going anywhere just from driving around. 🤷♂️

I think in terms of sand leftover from blasting coming out into the valve train, it is unlikely normally, especially since that portion of the valve cover is often under some degree of vacuum or another due to the valve cover vent.

All that being said, I am running my valve cover vent open to atmosphere (through a catch can) since I am boosting the motor. Probably still not an issue with the engine running, but if there is a momentary reversion where crank case pressure drops below atmospheric I would not want to pull crap into the valve train.

You make a good point about the rivets, however, some bolts with a drop of loctite is likely the safest approach.