Racing Pistons - Now what?
Posted: August 8th, 2006, 5:15 pm
Mr. Croft - Hi
Have just acquired a set of .30 over Ross racing pistons (cheap) for a 1608cc (actually a PBS race motor sans head.) Appears hardly used, Fiat factory rods appear worked and potentially hardened.
My desire is for these to be the beginnings of a true race motor versus the 8.9 to 1 motor you have provided so much guidance on.
Very high domes - seller thought 12-13:1 buckets. I am guessing a 8-10mm domes (not yet measured). My questions is...now what? What diagnostics must I run on the pistons, crank and block before embarking on this slow money gobbling project? If I am asking too much - please just state so. I am reading your book and gathering thoughts.
Piston diameters and block bores are very tight tolerance on initial measure. I will magnaflux the near virgin crank. The block will be acid dipped, decarbonized and checked for cracks. Main journals will be check for align bore and concentric diameters, etc. Crank, rods and possibly pistons will be cryogenically treated for hardness - or ??
* What is correct process to measure the domes? Just rise from piston top or do you need to measure anything from valves reliefs
* I plan larger valves in the head - what measures or precautions are needed to ensure no interference?
* What else don't I know (be kind) that I should be considering to ensure these parts are good to start a slow build up for a 2007 season motor?
As always, I really appreciate your help, support, the effort put forth with this site. Your are the best :D
PS - got the car to run about 75 deg C finally. not quite the 70 deg C you recommended but it was 105 deg F on race day on an 80 mile race.
PSS - your 3A cam helped me take 6 seconds off my fastest time at Road America a week ago. Same track where unfortunately just a few days later DeMatta hit a deer on the course; major head trauma
PSSS - give some thoughts to a cam recommendation for this project.
Thanks,
Have just acquired a set of .30 over Ross racing pistons (cheap) for a 1608cc (actually a PBS race motor sans head.) Appears hardly used, Fiat factory rods appear worked and potentially hardened.
My desire is for these to be the beginnings of a true race motor versus the 8.9 to 1 motor you have provided so much guidance on.
Very high domes - seller thought 12-13:1 buckets. I am guessing a 8-10mm domes (not yet measured). My questions is...now what? What diagnostics must I run on the pistons, crank and block before embarking on this slow money gobbling project? If I am asking too much - please just state so. I am reading your book and gathering thoughts.
Piston diameters and block bores are very tight tolerance on initial measure. I will magnaflux the near virgin crank. The block will be acid dipped, decarbonized and checked for cracks. Main journals will be check for align bore and concentric diameters, etc. Crank, rods and possibly pistons will be cryogenically treated for hardness - or ??
* What is correct process to measure the domes? Just rise from piston top or do you need to measure anything from valves reliefs
* I plan larger valves in the head - what measures or precautions are needed to ensure no interference?
* What else don't I know (be kind) that I should be considering to ensure these parts are good to start a slow build up for a 2007 season motor?
As always, I really appreciate your help, support, the effort put forth with this site. Your are the best :D
PS - got the car to run about 75 deg C finally. not quite the 70 deg C you recommended but it was 105 deg F on race day on an 80 mile race.
PSS - your 3A cam helped me take 6 seconds off my fastest time at Road America a week ago. Same track where unfortunately just a few days later DeMatta hit a deer on the course; major head trauma
PSSS - give some thoughts to a cam recommendation for this project.
Thanks,