[imasillygoose]

am rebuilding a standard sj70 1.3 motor and I need to know if the block has been bored out was told there would be a stamp on the top of the piston, there is a stamp and it says B2 can any1 tell me what this means ? is it the standard bore and if not what bore does it refer too ? thx

[Santos]

tape measure handy? From memory std is 74mm
whilst not as acurate as caliper it should let you work out if its 74.5 or 75mm which are the most common aftermarket oversses i have seen. Never seen a 74.25 in the flesh although as OEM its supposed to exist.

FYi 75mm is just a STD 8v g16 1.6l piston.

[fordem]

I think you're getting some bum information there ...

For the sake of discussion, let's say that it is "standard" bore, what do you do now? Buy replacement standard pistons, just replace the rings??

What you need to know is really how worn are the bores - and that will be determined by measuring them with an internal micrometer - when you have that dimension, taken in two directions, you can then determine how oval (or out of round) the bores are, how worn they are, whether or not they need to be bored oversize and how much oversize they need to be bored.

To answer your question, and I'm quoting from a G16 engine manual not a G13 (because I don't have one handy), Suzuki says ...

Quote:

NOTE:
Two sizes of piston are available as standard size spare part
so as to ensure proper piston-to-cylinder clearance. When
installing a standard size piston, make sure to match piston
with cylinder as follows.
a) Each piston has stamped number 1 or 2 as shown. It represents
outer diameter of piston.
b) There are also stamped numbers of 1 and 2 on the cylinder block
as shown. The first number represents inner diameter of No.1
cylinder, the second number of No.2 cylinder, the third number
of No.3 cylinder and the fourth number of No.4 cylinder.
c) Stamped number on piston and that on cylinder block should
correspond. That is, install number 2 stamped piston to cylinder
which is identified with number 2 and a number 1 piston to cylinder
with number 1.

Also, a letter A, B or C is stamped on piston head but ordinarily
it is not necessary to discriminate each piston by this letter.

Also from the same manual - a piston with a #1 stamp will have a 74.98~74.99mm dia., one with a #2 stamp will have a 74.97~74.98mm dia - now please remember, these numbers are for the G16 engine, I'm including them so you can get an idea of the differences we're discussing - approx. 0.01mm - both are still standard bore.

What is the significance of this if you're doing a rebuild - absolutely nothing - if your engine has been "miked" and does not need a rebore, you're probably just going to buy a set of rings and reuse the existing pistons, if it does need a rebore, the machine shop will measure the replacement pistons and bore to suit them.