Leak down test results on Rowans engine - help interpreting

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Rob Furniss
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Leak down test results on Rowans engine - help interpreting

Post by Rob Furniss »

We suspected Rowans head had gone / on it's way out and now suspecting rings (it was puffing smoke out of the breather) so just done a leak down test on all cylinders:

This is with the cams and cam carrier out.
Leakage
Cyl1 - 20% Cyl2 - 40% Cyl3 - 40%


Cyl4 - 35% Cyl5 - 30% Cyl6 - 30%

All seem a bit high, I believe around 20% is normal.
We could hear and feel air coming out of the holes near the valve springs, presume they are for the crank case breather / pcv system.
Couldn't hear air near the valves.
So does this mean some ring wear and what are our options, pistons out and new rings?

On two of them the gauge fluttered for about 3 seconds and the engine actually rocked a little on the stand, spooky. What does this mean? (EDIT:Now thinking it was compressed air pushing the pistons down)
He's seriously again considering forged, if we didn't have to re-ring and remove the pistons then we would just do the heads.

I'm going to re-do the leak down test a couple more times and take an average, not sure if the tester is that good really.


EDIT: He has now decided (again) to go forged, ordered conrods and pistons with new rings.
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