There will be an acceptable range of cylinder compression and it will be specified in the workshop manual (its in the Haynes manuals).
I can't find on google what your compression is supposed to be on that model but I did find out that the ratio is around 10.5:1 which, if you assume atmospheric pressure is 14.6psi, then the actual compression spec could be in the region of 10.5 x 14.6 = 153 psi (more likely much higher in reality).
It would be better if you quoted what your test result was for each of the cylinders rather than an average plus the one highest.
On your car the 170psi one sounds fine but if you are stating an average overall compression of 110 psi or less then you must have one or two cylinders that are extremely low indeed (or the garage man faked the test to bill you for work that doesn't need doing
).
Make sure the test is being carried out consistently on all cylinders and to the manfacturers spec (usually throttle
wide open, all spark plugs out, starter motor spinning at best speed on a fully charged battery, and engine at normal operating temp).
A simple test to determine whether there is a problem on the bottom half of the engine or the top is to repeat the test with a teaspoon of oil in the cylinders that are under spec. Generally speaking, if you then measure a brief marked improvement immediately after adding this oil then you have worn/broken piston/rings or worn cylinder bore (and that could be confirmed, but not always, by blue smoke from the exhaust and/or oilled up spark plug during general use). If there is little difference with the oil test then that indicates a top end problem and you have leaky/burnt/cracked valves/valve-seats, weak valve spring(s) on the bad cylinders or a blowing head gasket/warped head (this could be confirmed, but not always, by slight misfiring under load).
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Originally Posted by markymoan
£500 i'd find an engine at a breakers its less work
+ get a second opinion but dont tell them what you have been told 
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or you can get a recon head fitted for £230 here..
http://www.cherrypicked.co.uk/engine...lacement.shtml
There's probably similar companies more conveniently local.