skimming - compression ratio

[chimp007_uk]

i got my blydenstein head today, was showing signs from where it had been stored for a few years, so took it in to a machine shop to get it stripped and cleaned and valves recut and skimmed.

does anyone know the comparison for how much you skim off = how much the compression ratio increases?

i know the gte's are 10:1

also, would it be wise fitting an uprated cam to get better use of the head?

cheers

guys

[Adam]

Uprated cam would add power, due to better flowing head etc as well.

Just take enough off to get it flat.

[chimp007_uk]

it had a small scratch in the face so enough to take that out...

i wasn't skimming the head to get more power, i was just curious as i didnt want to get it skimmed too much that the cr is stupidly high.

[shazzi novavan]

http://www.pipercams.co.uk/NewPiperWeb/redesign/PiperCamFrames.html

try this hope it helps

[chimp007_uk]

thanks sharon. i will be looking for a cam soon, but just trying to find out if anyone knows what the combustion chamber volume is? so i can calculate what the cr will go up by when skimming the block, or if anyone knows a rough idea of what it will go up by, when skimmed by 0.5mm and 1mm.

[novamadman]

thanks sharon. i will be looking for a cam soon, but just trying to find out if anyone knows what the combustion chamber volume is? so i can calculate what the cr will go up by when skimming the block, or if anyone knows a rough idea of what it will go up by, when skimmed by 0.5mm and 1mm.

thats not a "known amount" as no head has been skimmed identically the same - you need to calculate that yourself from what you know about what you have

shane

[chimp007_uk]

i know how to do it, but does anyone know the combustion chamber volume for a 1.6 8v?

[novamadman]

no sorry, worth asking craig green as he turbod a 16 8v im sue he had to wrk with his comressionratio

shane

[Adam]

You have to measure the combustion chamber etc to work out the compression.

[Stuart]

last 1.6 head that didnt appear to have been skimmed that i measured averaged 36cc per pot.

ive youve had a rebore then your CR will be higher too ;)

[chimp007_uk]

not rebore, standard block. heads getting skimmed as it had a scratch and some slight corrosion where it's been sitting.

cheers stu

[shazzi novavan]

http://not2fast.wryday.com/turbo/compression/compression.shtml

[chimp007_uk]

thanks again sharon...

[Stuart]

also a CR calc description in the 1.4 guide in my sig ;)