Ok so i have an old d15b block in the garage and i noticed that under the plug wires some metal is broken on the valve cover.

The broken part is at top of the spark plug holes where the wires would seal
and about half of the "ring" is broken.

my question is how would an imperfect seal affect the spark plugs/wires

 

Pics please.

 

Cant on phone. Its the part where the spark plug wire meets the valve cover.

 

nothing?

 

as long as oil is not leaking in there you should be fine.

the only issue you would have is that spark plug popping out of its place which will make the car run like crap. try some jb weld to patch it up

 

im wondering if it would let moisture into the spark plugs and possibly cause some rust

 

if your worried about it just take some rtv red high temp or simillar and use that to seal the plug wire to the valve cover. i dont think that high temp is trully nessecary but its probably more derable