Probe standard size questions before installation

[Leviathan]

Hello guys,


My 7M is being rebuild actually, and i gave to the shop my PROBE pistons to install them. the shop need infos before working on the bloc but i am unable to give them the answers they need, cause i really suck with these things.

I did a search but i'm not sure about the infos i saw.


My 7M stock pistons are "mark 2" witch make 3.2650-3.2653 inch

the shop measured the Probe and said they were 0.03mm smaller at skirt.

is it normal???


Also in the piston clearance chart, there is 3 pistons series: FPS, SRS&PRS (same values)

but on the piston box it don't say what series they are


i guess i have to see for BORE: 3.000-3.624

for FPS series it says : min .0010 /// max .0040

and for SRS/PRS : min .0020 /// max .0060



if you guys could help me so i can give them good values i'd be very thankfull.

 

[suprarich]

Hello guys,


My 7M is being rebuild actually, and i gave to the shop my PROBE pistons to install them. the shop need infos before working on the bloc but i am unable to give them the answers they need, cause i really suck with these things.

I did a search but i'm not sure about the infos i saw.


My 7M stock pistons are "mark 2" witch make 3.2650-3.2653 inch

the shop measured the Probe and said they were 0.03mm smaller at skirt.

is it normal???


Also in the piston clearance chart, there is 3 pistons series: FPS, SRS&PRS (same values)

but on the piston box it don't say what series they are


i guess i have to see for BORE: 3.000-3.624

for FPS series it says : min .0010 /// max .0040

and for SRS/PRS : min .0020 /// max .0060



if you guys could help me so i can give them good values i'd be very thankfull.

It sounds as if you purchased the pistons prior to the machinist telling you what size pistons you need to buy. Lets hope that your bores are in good enough shape that the machinist can fit std size probe pistons into the Std toyota bore. Tell the machinist that you will want a .0035 to .0038 inch clearance piston to wall. .0035 inch for a near stock type power level and .0038 to .0039/.0040 inch for a higher power level. These numbers assume that your shop will be using a torque plate.
Also tell him that they have a chrome top ring so that he will know to apply the proper hone to the cylinder wall.

IF!! the bores are too large to accept the std size probes with the proper clearance, then you will need to return the probe std size for the next over size and have the machinist bore and hone to match the oversize set.