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Torque plate for measuring PTW clearance

Engine Building Fundamentals

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Hi all,

Just want to confirm, is necessary to use a torque plate when using a dial bore gauge to find the PTW clearance?

I am planning to build my 4G63 and I mostly see people not using a torque plate.


If the engine has been bored and honed with a torque plate then yes, you'd want to also use the torque plate to measure P2W clearance.

Or check it at the bottom of the bore, where any distortion from using/not using a 'plate is not a factor.

I work with primarily Alusil blocks and see a fair amount of distortion on both the top of the cylinder and bottom with torque plate / head and bedplate torqued down, so for me, all measurements are taken with top and bottom stressing fasteners torqued to spec.

For me, it's also worth spending the time after final honing to torque the heads down and measure cylinder bore concentricity from the bottom of the cylinder up to verify my torque plate has applied the stresses appropriately.