How To ID Piston/Bore

[hjsmith00843]

I was told that the motor was a 440 big bore but I am unsure. Can I pull the top off of the motor and visually check it to see what it is and what the compression ratio is. I was planning to do this later in the week.

I can post pictures when I pull it apart. Just curious because I want to know exactly what I have.

[trx310R#24]

Originally posted by hjsmith00843
I was told that the motor was a 440 big bore but I am unsure. Can I pull the top off of the motor and visually check it to see what it is and what the compression ratio is. I was planning to do this later in the week.

I can post pictures when I pull it apart. Just curious because I want to know exactly what I have.

yes you can it should have numbers on the top of the piston and you can look it up but you kinda got to know what kind of piston is in it. =p

[JOHNDOE83]

Im not 100% sure, but they are measured in millimeters, Im guessing that if you could get your piston out and measure it, that would be one way to find out.

I dont know for sure....

[togup]

i have only seen numbers on the top of weisco pistons but you take off the head and if it is a 89 mm the inside of the jug should measure 3.505- 3.598 somewhere close to that but you need to throw away the head gasket if you pop the head off.
the numbers on my weisco are
4851H
4667MO8900
my guess is the last 4 digits is the bore but all my CP pistons do not have numbers

[gtt416ex]

yea you're right the last four digits show what bore it is (wiseco only). But seeing how most people use wiseco, you'll probably have one in your motor.

here's mine but as you can see its an 87mm, just thought a picture would help
http://i276.photobucket.com/albums/kk34/crg10493/100_1228-1.jpg

[JOHNDOE83]

I wonder what it would be if you were able to measure it?

[gtt416ex]

Originally posted by JOHNDOE83
I wonder what it would be if you were able to measure it?

the piston or the bore?

[JOHNDOE83]

Both? that way if anyone questions thier piston size, we could get a close measurement on what it would roughly be around for checking?

I dont know, Ive always wanted to measure mine and never have...lol.

[gtt416ex]

umm...someone correct me if i'm wrong, but i think the cylinder is on average .004-.010 larger in diameter than the piston. for example; if i was to measure my cylinder, it'd be ~3.435"(87.249mm)