Piston bores

[Hawwy]

Hi all

My friend has bought a glanza v and he is rebuilding then engine as it had sonething wrong with it when he got it , needs headgasket i think

Basically its his first toyota etc and he is saying the bores where the pistons go are very very smooth and they are not meant to be, it causes to burn up oil? Is he right in what he is saying? Or shal i tell him its okay?

Cheers

[madmax_926]

Did he buy it from Maidstone Kent ?

[Hawwy]

No mate he bought it from leeds.

So is he right in saying it is fukd or no?

[Starlet__SR]

Cross hatch honing is a good process because it holds small pockets of all keeping the bore well lubricated. Best thing to do is have an engineer measure the bores for wear.

Day

[Hawwy]

But he was told the block has been honed basically he is saying piston bores just too smooth and they dont usually be as smooth as they are

[Taggy]

The piston bores will be super smooth, its called "glazed" they are not supposed to be rough on an engine which is run in. You would only ever have a rough surface when the bore has been cross hatched and honed ready to accept new piston rings. If they were not smooth when running normally your engine wouldnt be able to make a good seal with the piston rings.

Edited June 19, 2012 by Taggy

[Hawwy]

So smooth is okay yeh

[Hawwy]

and rings have been done previously apparantly , he says he doesnt want to touch bottom end , just wants to do do waterpump hg timing stems etc

[Starlet__SR]

If its had a rebuild before and its been run in correctly, the bores will seem smooth due to the bedding in process. Did you do a compression test before separating the engine?

Day

[Hawwy]

Well he sayin it has to be cross hatched so oil can sit on the scratch lines to keep the pistons lubed??

And compression was 147-150 all cylinders