oem pistons set a/b

Boosted_da · Post by **Boosted_da** » Sun Apr 01, 2012 5:04 pm

ok im a little lost here i need new pistons for my rsx since the a4 pistons wont clear the valves. so i went to looking at tsx pistons and was fixing to order untill i came to this. so what is if any difference with oem set a vs. set b?

Boosted_da · Post by **Boosted_da** » Sun Apr 01, 2012 5:08 pm

http://www.hondapartsunlimited.com/find ... -%20PISTON

Waffles · Post by **Waffles** » Sun Apr 01, 2012 5:59 pm

It's related to piston size, the top of the tsx block would be stamped aaaa or bbbb, not sure if they mixed sets like with bearings.

JustRob · Post by **JustRob** » Sun Apr 01, 2012 9:53 pm

Like Waffles said, the difference between the two pistons are the size. Both piston sets show that they're for all automatic and manual '06-'08 TSX models. Here's a little more information and the specifications on both pistons as well as the oversize piston.

Every engine has some combination of A- and B-sized pistons. You can determine the sizes and their locations in the block by inspecting the markings on the timing chain end of the engine block. “A” pistons are marked with an “A” or unmarked; “B” pistons are marked with a “B”. Pistons can be ordered prior to engine disassembly.

Measure the piston diameter at a point 11 mm (0.4 in.) from the bottom of the skirt. There are two standard-size pistons (No Letter and B). The letter is stamped on the top of the piston.

Piston Diameter

Standard (New):

No Letter:
86.980-86.990 mm (3.4244-3.4248 in.)

B:
86.970-86.980 mm (3.4240-3.4244 in.)

Service Limit:

No Letter:
86.930 mm (3.4224 in.)

B:
86.920 mm (3.4220 in.)

Oversize Piston Diameter

0.25:
87.230-87.240 mm (3.4342-3.4346 in.)

Boosted_da · Post by **Boosted_da** » Sun Apr 01, 2012 10:58 pm

you guys are awesome thanks a ton!