5k compression, how to up it?

[3T-Rona]

first of all whats standard compression ratio, think i remember sum1 saying a while ago that it was 9:1 or something? was thinking of doing the head gasket and seals etc and wondered if i could give the head a skim to give a bit more compression, sound anygood? anyone know any exact's to crank up the compression to a healthy ratio?
cheers
Joseph

[fangsport]

first of all whats standard compression ratio, think i remember sum1 saying a while ago that it was 9:1 or something? was thinking of doing the head gasket and seals etc and wondered if i could give the head a skim to give a bit more compression, sound anygood? anyone know any exact's to crank up the compression to a healthy ratio?
cheers
Joseph

keep planing until the rods bend from pistons hitting the top of the combustion chamber

[3T-Rona]

lol seriously ladies

[fangsport]

seriously, it depends on the CC size as to how much planing will effect the C/R. there are calculations that need to be done.
i have removed 0.042" off my 3T head but am unsure exactly what the new C/R is, possibly around 10.5:1(ish).

[3T-Rona]

yep i understand this much its a 5k so im assuming around 1500cc's the question was more has anyone already done it with decent results and know exactly how much to plane off.

[fangsport]

when i was reffering to CC size, i was meaning combustion chamber.

[3T-Rona]

i get ya. yeh i did a work book (apprenticeship) on displacment calculations an such, its easy to work out when u have all the information, stroke, bore diametre etc but other wise its a bit of a pig

[ChaosAD]

Your gonna have to get out the burrette and measure it. Then plane the head then measure it again to get the new compression ratio

[2LTR Rona]

had a KE25 with a worked 3K in it that blew the head gasket ages ago, ended up swapping the 3K block for a 5K, swapped over the CAM, which turned out to be a Stage 3 raging CAM, but the head was where it was all at.

3K head, ported n polished, over sized valve springs running a set of Webber twin 45mm side drafts, from memory it was running around 13:1, below 1200rpm it ran like a tractor but above that and it had a wee bit of punch surprised a few people that little thing

[spencer]

I dont know about all 5k's but mine most of the combustion chamber is in the piston as with the 4k-u(twin squish head). So planing the head isnt always the best option as alot would have to be taken away. A shallower dished piston is the best bet, go check out club-k