am timing probs

[martyn&tara]

Whilst fixing a BHG on my 90t i discovered that the pistons had been replaced at some time with over size. Nice surprise until i came to set up TDC ready for the new gasket. I use a DTI gauge to find TDC and was surprised to find that TDC occured 7 degrees before the mark on the bottom pulley. The difference in hieght between the factory mark and the new TDC position is 0.5mm. I am assuming that the block has been decked but the old gasket was standard.
The question now is do i set up the cam timing to the new mark.With the piston being 0.5mm higher in effect will that cause contact. I have set up with the piston at Tdc on the gauge and the cams on there usual marks and turned the crank several revolutions by hand and all seems ok but i am unsure of the clearance especilly when the engine is at opperating temp and high rpm.
If i set up to the factory marks then surely the engine would be sluggish as the valve/crank timing will be 7 degrees out.
Your thoughts guys would be appreciated.
Martyn

 

[JustAnotherVictim]

That would probably mean your crank is toast due to the keyway on the crank being fubar'd.

I hope it isn't but that's my first thought.

 

[martyn&tara]

That would probably mean your crank is toast due to the keyway on the crank being fubar'd.

I hope it isn't but that's my first thought.

Hope its not that.
Engine was running fine until the gasket let go and even then i drove it home.

 

[cjsupra90]

just set it up as you would if nothing has been done, you should not have any problems unless the head has been drastically shaved also. My block was stock and my head was shaved .025" which is about .63mm and no problems except for maybe a small lose of power do to cam timing be off slightly, but it was not noticable and this was probably offset due to the small rise in compression ratio.