Quote:
|
Originally Posted by Flubflow
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).
__________________
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. |
Sorry I worded my post poorly, I meant that 170PSI was the average result from a working car he had tested earlier last week, not one of my Dads was that high. Unfortunatley we didnt get a printout or anything to show us what the results for each cylinder where, the only thing he noted was that the center cylinder was particually lazy (this is a 3 cylinder engine), though we couldnt really complain as he didnt charge us for linking upto the computer or the compression test since he couldnt give us a more specific answer.
I just find it odd really, it does almost seem like the typical copout that you always hear in the horror stories of repairs that never needed doing in the first place, the only thing is the guy at the garrage doesnt really seem to want to do the repair mentioned so it does seem unlikeley that he would quote us for repairs that we dont need doing that he wouldnt benefit from.
Another funny thing is that even though he didnt do anything but test the car it now starts almost like it should, Just everytime you let it drop to idle the engine shakes a bit (apparently it still stalls when it gets warm but we havent managed that yet).
__________________
Quote:
|
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 
|
Allready on getting a second opinion, though we cant book it in until monday.
The problem with getting an engine at the breakers is that apparently this is a common fault and as such it makes this particular engine harder to accquire (would it be possible to fit a larger engine to this car? such as one from the corsa 1.2 16v of the same age? apparently these are much easier to get hold of).