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Engine Specific Info and Questions => IDI Engine => Topic started by: James8485 on March 11, 2008, 01:19:07 pm

Title: An point to having oversized pistons in a 1.9L TD AAZ motor?
Post by: James8485 on March 11, 2008, 01:19:07 pm

is there any point
advantages and disadvantages to having oversized pistons in a 1.9L TD AAZ

any sugestions.....motor rebuilt and should i dirve very gentle.....ect....

i drive 250 kilometers a day no prob after my rebult

Title: An point to having oversized pistons in a 1.9L TD AAZ motor?
Post by: jtanguay on March 11, 2008, 01:22:02 pm

after a rebuild you should probably drive the engine kinda hard to seat the rings.  let the engine get warm first though.  don't drive fast, just load the rings by constantly changing rpm's.

did you get oversized pistons installed or no? were the old pistons still within spec?

advantage of oversized pistons: tight engine, good compression, easy cold starts, better mileage, low blowby... long engine life

disadvantage of oversized pistons: lighter wallet

Title: An point to having oversized pistons in a 1.9L TD AAZ motor?
Post by: mufflerbearing on March 11, 2008, 01:33:49 pm

advantage of lighter wallet: better power to weight ratio.

Title: An point to having oversized pistons in a 1.9L TD AAZ motor?
Post by: James8485 on March 11, 2008, 02:21:51 pm

yes i ordered new oversized pistons as they where oversized when the motor was ripped apart couldnt find oversized rings so have to buy brand new oversized pistons and rings set.....220.00 a piston i think.... so you think i will get better milage being oversized.....i have no knowledge about this and is it a good thing?

i have heard poeple go bigger for more cubic inch but i dont know it was kinda a shock when they said i had oversized pistons in it!

as long as its a positive not a negative im happy! money well spent!

Title: An point to having oversized pistons in a 1.9L TD AAZ motor?
Post by: MaxHedrm on March 11, 2008, 06:10:50 pm

The percentage change isn't much for the oversized pistons, so you won't see much added power or anything just from the increase in displacement. The improvement in compression from the better seal will help though.

Title: An point to having oversized pistons in a 1.9L TD AAZ motor?
Post by: jimfoo on March 11, 2008, 06:29:09 pm

But that depends on how oversized they are. My displacement went from 1896 cc to 1944 cc, so I expect a little more power because of it, and torque as well. Maybe not a lot, but a measurable amount.

Title: An point to having oversized pistons in a 1.9L TD AAZ motor?
Post by: raf_construct on March 30, 2008, 06:25:51 am

Mine went to 2050cc so basically its a 2.1TD now.  :twisted:
Hope to get it running next week, its a brand new engine now.

Title: An point to having oversized pistons in a 1.9L TD AAZ motor?
Post by: DA-BRT on April 21, 2008, 02:25:08 am

Raf: I allready posted your engine on the forum here.

Title: Re: An point to having oversized pistons in a 1.9L TD AAZ mo
Post by: stewardc on April 21, 2008, 03:38:47 am

Quote from: "James8485"

is there any point
advantages and disadvantages to having oversized pistons in a 1.9L TD AAZ

I did it so I could put this on the tailgate :roll:  :wink:
Seriously, the only reason for oversize is that the block is worn and needs to be bored out. Mine wasn't, but I wanted everything to be spot-on, so I bored and fitted new pistons.

(http://img.photobucket.com/albums/v648/stewardc/Truck/100_5737.jpg)