Something with my Mitsubishi happened...

[Eta5tenya 0]

Hi all,
I'm trying to diagnose a problem with my Mistsi L3E fitted to a Volvo mini excavator (271 I think)..
Anyway after some hard starting and I think loss of power (stalls whilst digging etc.) , I've pulled the engine out to investigate.
I've looked through a few really good threads on this site about this engine, and I think there are a good few experts around here that know thier stuff, so thought I'd try a couple of questions..
1) On checking the compression (whilst running the starter) I get around 210psi. This was pretty similar on all cylinders..
From the L3E Manual it shows the pressure should be 413-455psi, so according to this I'm way off.
Does this pressure reading from the manual sound right ? It sounds quite high to me (the compression ratio of the enigne should be 23-1, so maybe should be more like 338psi (14.7 * 23 = 338) ?
I'm not sure I'm checking the pressure reading I'm getting against the correct value..
2) It seems the pressure is down whichever value I check against,so I'm trying to find out why.
The cylinder widths look pretty correct at 76mm, or thereabouts (within limits).
I can't see any cracks etc.
The rings were the next obvious thing, 1 measured gaps of:
No 1 - 0.7mm
No 2 - 0.55mm
Oil - 0.55mm
I'm not sure if this is a problem ; the manual gives the 'Standard' gap as 0.15 to 0.30mm, and a service limit of 1.5mm
It only recommends replacing the rings if they are above the service limit.
What is the difference between the Max 'Standard' gap and the Service Limit ?
Mine at 0.7mm are above the Max Standard Gap, but below the Service limit. Would you think they need replacing ?
Probably more to the point is do you think that even though they are below the service limit, they could be accounting for the loss of pressure (@200psi according to the 413psi figure in the manual) ?
Would this 'extra' gap or wear account for this much pressure loss ?
I did clean up 1 set of valves and seats and re-tested, I got about another 20-30psi, so I reckon with a good valve cleanup each cylinder would probably give around 230psi.. Still pretty low, would the ring gap account for this ?
Thanks for any help!

[Gambit 324]

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