I just tore the cracked rear iron off of my engine (s5 NA) to replace it and noticed the last builder didn't use corner seal plugs. Why not and what if any consequences will I encounter? I've heard maybe cold start compression is compromised.

s5 NA, 2500 miles on a rebuild. Stock port for daily driving.

 

Perhaps they are solid corner seals?

 

some people dont put them . me personally ive done it before,no issues

 

low rpm sealing will be slightly worse.

 

Zero in my experience of building tens or hundreds of engines that way. When I reuse original corner seals I never leave the (hard as a rock and deformed) plugs.

When I replace corner seals they come with new plugs, so I leave them there.

 

some builders prefer to leave them out because they might fall out anyway. This is how my engine is and no issues at all.

 

The engine ran good before I pulled it due to a cracked rear iron oil leak (awful surprise of buying a second hand engine). So the only thing I was really worried about was maybe flooding or the tiny triangular bit of the apex seal falling out.

 

It does have new springs at least. Looks like FD springs.

 

Was wondering the same thing but then again they only cost $30