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Old 2 Jan 2022, 16:55 (Ref:4092215)   #2599
911thillclimber
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Join Date: Aug 2007
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911thillclimber should be qualifying in the top 5 on the grid911thillclimber should be qualifying in the top 5 on the grid
Had a pass-out for this afternoon, so decided to check the squish 'height', crown height, and the rest of the ring gaps.

To the first, mounted the piston to the rod with #1 barrel and an old copper base gasket, then added 3 pea sized pellets of BlueTac on the sides of the piston dome and the very top with a smnall piece of cling film over the top so when crushed the bluTac would not stick to the piston.
Advanced the crank well over TDC.
Added the #1 head and torqued the lot to final spec, 26 lbft.
Rotated the crank until you feel the blutac being squashed and then over tdc for about 30 degrees.

Remove the head and measure the crushed BluTac with verniers.
Repeat for the RH side.

Results were 1.72mm and 1.76mm (doubt you can call the last digit accurate) Squish. So, about 70 thou. and the top was about 3mm!
I'm happy with that.

Thirdly, placed the top ring in all the other barrels and all need opening up from a gap of 12 thou to 15 thou, none larger.
JE spec is 17 thou min, the second ring is 4 to 8 thou wider.

Awaiting Peter's gap grinder before I can get serious.

Next step is to build up both sides dry and set the cam timing. (what joy) and then advance the inlet 80 thou via the rocker screw and rotate so carefully the crank 720 degrees to feel for interference.

If clear, drop the inlet back and do the same with the exhausts but to 100 thou and keep my fingers crossed....





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