0.50 bored over?

[Atlas]

Doing a rebuild on my 7MGE. Noticed the crown of the piston was stamped "050," usually when I see this I think of 0.50 bored over. However I'm not sure this is the case, as these appear to be the factory pistons. I'm looking to replace the oil rings and just wanted to make sure these are the standard bore Toyota pistons and not anything otherwise. Pics below. I'd appreciate any and all help!

Thanks! :icon_bigg

 

[Backlash2032]

Probably toyota pistons .5mm over, which is 2 thousanths over.

 

[Dan_Gyoba]

Mic the cylinder bore, but unless the engine's had a major rebuild, 0.50mm overbore isn't likely.

 

[ryansmith]

off topic but very nice picture quality, what is your camera setup

 

[Atlas]

This engine was, somewhere along the lines, rebuilt by the previous owner, at least the bottom end was. There are new rod and crank bearings, or that is to say, they're not the original. I'm just curious as to what that "050" mark means? This would make more sense if I saw this on an aftermarket piston, but seeing as how these are marked Toyota with a corresponding part number, I'm not sure Toyota ever produced an oversized kit. I'm just hoping they're stock just so I don't have to go through the trouble of finding the right sized oil rings. I'm sure there are a lot of guys who tore their engines apart as well, anyone ever catch these markings? Let me know, If they're just some factory nomenclature or what, because I'm hoping it's just that :icon_razz

If anything else, I could take a caliper to the cylinder bore as suggested and compare specs.


And my Camera setup is a Canon 50D w/Tamron 17-50mm f/2.8 :thumbup:

 

[IJ.]

1mm = 40 thou

.5mm = 20 thou over

 

[Atlas]

Ok just took a caliper to the cylinder bore and it measured 83.33mm so it looks to be the standard bore for the 7M. Can anyone confirm?

 

[IJ.]

83.00 is standard, measure an inch or so down the hole.