Getting proper piston liner height when liners are flush

[bunni]

Second go around on engine rebuild because I'm crazy and decided to take this on almost 10 years ago This time around though, I've cleaned up the liner seats like I should have the first time. See photos, left is clean, right still has burned crud.
IMG_1526.jpg


My current situation is that all liners, no matter how I swap them, are all within 0.001" of the block deck. With most being basically flush with the deck. Measured with straight edge+drop indicator (see photos) and follow up with a flashlight to really show that there is no (or next to no) light penetration between the straightedge+liner or straightedge+block..
IMG_1530.jpg IMG_1536.jpg IMG_1535.jpg

The liner was freely placed, not clamped down, but there was zero wobble. Final measurements will happen with the liner lightly held in place with clamps. But the problem is getting the correct protrusion/nip from the liners. If they are flush without shims, the yellow shims (0.13-0.16 mm) boarder on not being thick enough. The superseding metal shims from Volvo are 0.15 mm. And the shims from DPI are 0.0055" (~0.14 mm).

Whats the best way to move forward with this? Can I just use yellows (a "yes" answer to this makes me nervous unless there is some data behind it to back up that being on the low end/just under the measurement is still perfectly fine)? Are there known sets of thicker shims that are still compatible with the engine? Do I need to have 3-4 thou machined off the block? Did I completely botch the measurements somehow and need to redo it? Some other option I'm not considering?

[Ron]

Did I completely botch the measurements somehow and need to redo it?

Your gauge is not zeroed:
NotZeroed.jpg

[bunni]

Its not going to ever be 0 there unless its completely extended. That's the 10ths gauge as its a 1" travel plunger. The large gauge that's set at 0 is the thousands dial, and you'll notice in the two original photos, the 10ths dial is in the same position in both photos.

[Ron]

When you lay it on the block, it should be fully extended and read zero on both dials...

[bunni]

When you lay it on the block, it should be fully extended and read zero on both dials...

I cannot adjust any of the dial arms, as they are calibrated and mechanically linked together. All that can be done is to rotate the outer rim to rotate the thousandths scale. So, I can only zero the thousandths, and only by rotating the dial face, the arms cannot be adjusted. If it were a digital gauge I could zero out the whole thing. But, like I said previously, between the two photos both dial arms (tenths and thousandths) are in the exact same position when in the final measurement point.

In this setup, the plunger cannot be fully extended and flush with the straight edge. It would not be able to measure the piston liner protrusion from the block if the liner and straightedge are above the block since it would bottom out with the plunger being fully extended and therefore always read 0.

Lets take a step back and presume I am measuring it correctly, and the liner and block deck are flush. What are my options in moving forward with that?

[Ron]

That be the case, for that particular liner, you would need to go through several yellow shims to find one measuring at least 0.160mm (PITA), replace the liner (expensive), or shave the deck (~changes timing chain geometry).
I would go with a 0.160mm+ shim. (This would put it within spec. ...and if they are all "short" like this one, you will get plenty of squish.)