quick info needed.., from expirienced 7a engin builders.....plz Options

[mandrek]

hello all, i just have a quick question.. I'm in the process of gathering parts for a boosted 7a.. i have located a set of OEM, from the factory, Toyota 4agze pistons, and for a great price since the guy is just looking to get rid of them (change of plans..#.. thing is that they are .050" oversized..

now my question is.. is this a option that was made available to give Toyota service techs a slug that would provide tighter clearance on an old motor? #as i am suspecting# or is this an OEM replacement for use in a motor that has had to have the cylinder walls worked on #say to remove scoring) and thus the reason for the increased bore diameter..

the motor I'm looking to put these in is a 96 7a, and had 218K on it.. the walls of the cylinders are smooth as glass, and there are next to no markings showing wear. ill post a pic if need be.. but i don't think that it would be needed to answer my question..

i guess that what i am really getting at, is this... if i get these pistons will i need to have the block bored to accept these, or is this kind of o/s a tolerance check measure?

thank you..

This post has been edited by mandrek: Oct 22, 2011 - 11:24 AM

[Smaay]

everything in your post is correct. the bolt is the weakest link in the rod. the only problem is i dont know any companies that make a high performance rod for the 7A. it was never a performance engine.

1mm over is the same as .040 over and yes you can do it but you are pushing the limits of the cylinder, thats why i recommend only .020

as for pistons, i have used Diamond pistons in the past. i sent them a stock piston and for about 550 bucks they sent me a new set of machined pistons with wrist pins, rings, and clips. sometime next year i need to rebuild a friends 7A-FE and ill have to do the same thing.