Divide PTW BY 2?

[88mk|||]

Not sure but been reading mixed things. Measure piston skirt, measure cyl bore, subtract the two, than divide by 2?

 

[hvyman]

What are you trying to figure out?

Piston skirt length varies between all the piston manufactures and for a measurement is useless.

 

[88mk|||]

Sorry, PTW in title (piston to wall)

 

[Piratetip]

Why not just follow the TSRM?
Everything is outlined for the stock pistons.
7M-GTE:
Standard Oil Clearance - .0028 - .0035"
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=78

Unless you are using aftermarket like JE.
Then each company has their own spec sheet to use.
For JE made pistons using 2618 T6 Al.
http://www.jepistons.com/PDFs/TechCorner/SCPDrawings/piston_instrc2618.pdf

 

[88mk|||]

Ok, so subtract piston and bore. Easy enough, if I use a bore gauge which measurement should I use. The top, middle, bottom of the bore?

 

[Piratetip]

That is already outlined in the middle of the TSRM page posted above.
(b)

 

[Piratetip]

You need to measure all points on the bore, top, middle and bottom.
Determine if there is any taper.
Recommend reading this section in its entirety.
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=EM&P=74

I believe the online manual does not outline the cylinder taper specification:

1987 Hard Copy TSRM page EM84
Procedure and Spec out of round and taper 0.02MM / 0.0008 Inch

If it is beyond this, have it machined.

 

[88mk|||]

ok thx