Ok well im trying to learn some engine math and was crunching some numbers. I came across an interesting problem and wanted to see if there is something wrong with my math or the FSM data.

Per FSM data -

VQ30 Deck Height (from deck top to crank center) = 214.95mm ~ 215.05mm
VQ35 Deck Height (from deck top to crank center) = 214.95mm ~ 215.05mm

VQ30 rod length = 147.6 mm ~ 147.7 mm
VQ30 piston height = 45.4 mm
VQ30 crank center distance = 36.61 mm ~ 36.69 mm

This gives us a total height of 229.61 mm ~ 229.79 mm

VQ35 rod length = 144.15 mm ~ 144.25 mm
VQ35 piston height = 41 mm
VQ35 crank center distance = 40.36 mm ~ 40.44 mm

This gives us a total height of 225.51 mm ~ 225.69 mm

Both blocks have a 0.010 mm ~ 0.030 mm piston to deck height clearance. Head gaskets are the same thickness as well 0.9 mm ~ 1.0 mm.

If the crank center line is the same and the block height is the same, where the hell does this extra 4.1 mm of material go ?

 

The material does not go anywhere.

AFAIK the distance from the centre of the piston pin to the top of the piston is not given in any FSM. It is not a quantity that the spec needs to checked on.

The numbers that you used are just the vertical distance from the top of the piston to where the skirt measurements are to be taken. They really have no bearing on pin location.

I know in the VQ35, the top of the piston is pretty much flush with the deck at TDC. You can back out your piston height number from that or measure one you may have lying around.

 

OK now I see the problem.

I can take measurements of VQ30 pistons I have sitting around, but Id like to know what a VQ35 looks like as well.

Edit:

After some drinking the solution came to me. When I got home it was verified by measuring a spare DE piston. My caliper measurements said 30.3 mm from the top of the piston to the center of the piston pin.

Calculations (VQ30) -

215.05 mm - 0.03 mm - 147.7 mm - 36.69 mm = 30.63 mm (Piston top to piston pin center)

Calculations (VQ35) -

215.05 mm - 0.03 mm - 144.25 mm - 40.44 mm = 30.33 mm (Piston top to piston pin center)

 

Deck Height = Distance from top of piston @ TDC to top of block deck.

Block Height = Distance from crankshaft centerline to the top of the block deck.

VQ30/VQ35 Deck height = 0mm

VQ30/VQ35 Block height = 215mm

Block height - stroke radius - rod length = piston pin height (only if the deck height is zero)

 

Ok well I was looking up the old threads of the VQ32 hybrid and this is what got me going on some calculations. If I did the math right the compression ratio of the VQ32 (VQ30 crank and rods) is 9.71.