I recently picked up a 12G295 real cheap on my local Craiglist alternative so I guess it's time to get to work!
I read up on previous threads that either never followed up or where simply missing the information I need.
I'm currently making my shopping list before I visit the machine shop, and I'm almost ready to add all this stuff to the basket.
- New studs (maybe ARP?)
- Small bore copper gasket
- Stainless steam thermo and hear gaskets
- Regular studs for exhaust and intake
- Lead free valve seat inserts
- Valve guides (not sure wich ones)
- Valve stem seals
- And just for the sake of doing the job right a new set of springs
I'm currently running the numbers to know how much I should tell the machine shop to skim the head by, other posts on this forum recommend a 10:1 ratio, and since I assume my stock 998 has dished pistons this CR is achieved by skiming 80thou (2mm) off the head.
Also 10:1 is good for 95 RON wich is widely available in my country.
Would my stock 998 engine's components, except for seals that might already be on their way out, wich are currently set to 8.3:1 ratio (quick google search) suffer any extended wear from this increse of CR? Should I chose a different CR just to stay on the safe side?
I'd love to come up with these numbers myself but I'm having trouble to find the required data.
As far as I understand the original head has 24.2cc's and the 295 has 28.4cc, so logic dictates I should skim the head enough to reduce the 28.4cc to a simillar volume as the 24.2cc but not too low as to affect valve/piston clearances.
I'm pretty excited to catalog my head restoration and can't wait to update this thread with the process!