Should I re-use this Precup?

[IDIoit]

i dont know man...
a cylinder needs to be air tight for compression.
in my unprofessional opinion, the metal ring on the gasket called the fire ring
is ment to contain the "fire"
if your cups dont seal, it is effectively creating a head gasket leak.

 

[MTKirk]

A close examination of the head gasket shows that the compression sealing area extends entirely across the precup to the main body of the cylinder head, where the real compression seal takes place. I don't believe the cup to head fit around the perimeter of the precup is a seal on all but the newest, tightest fitting cups. Therefore the combustion gasses get to the back of the cup any way.

I do (of course) allow for the possibility that I am completely wrong!

 

[SD94]

What if the hole in the precup is enlarged for a better more direct spray to the piston

 

[icanfixall]

What if the hole in the precup is enlarged for a better more direct spray to the piston

This can be done.. But you will need a comparator to make sure the areas are all the same. Do not change the inside of the cup. There is a design bump in there to cause better flame front so we get a better burn. I opened up my first set of new offshore heads in the precups. I removed the bumps and had a comparator to make sure everything was correct. It was lots of work for no gain. If anything it slowed down my burn and lost hp. The hard part is getting all 8 cup throats the same. One can be done easily. then you have 7 more to get done the same...

 

[riotwarrior]

What if the hole in the precup is enlarged for a better more direct spray to the piston

WHAT spray are you referring to? No fuel comes out of there.

Only combustion gasses come out of that hole. They work fine upwards nearing 400 HP so needing to open them isnt at tjis point a requirement.

 

[SD94]

Just a thought. Figured it might help power an fuel economy guess not