SBT piston size?

[J_loughman]

I have an SBT motor in my 1996 XP with the 787 motor. I’m currently redoing the top end. The pistons that came out of the SBT motor are stamped “1.0” on the face of the piston. Does this mean I need to choose the 1.0 mm option on the SBT website when ordering my new top end?

 

[WhiskeyD]

1.0 means its 1mm over sized. You'll want 1.5mm over pistons for the rebuild depending how damaged the cylinder walls are.

 

[J_loughman]

The cylinders looked good. Did a quick honing on them. Still 1.5?

 

[mikidymac]

You are wasting your time here and clearly don't understand what is going on. I am not trying to be mean or belittle you, just don't want to see you waste money.

Your engine let go and there was significant damage.

You need to have the cylinders measured accuratly by a professional and see if they are still within spec.
If they are then you can order new 1.0 pistons and have them honed to final clearance by a professional shop.

If they are not in spec then they have to be bored oversized and larger pistons fitted and clearanced. As you are already at the standard maximum of 1.0 your only option would be 1.50 or new sleeves.

Finally you need to determine why it failed or you are going to spend all this time and money and it is going to fail again. They do not fail like yours for no reason.