x14xe
Member
Registered: 15th Dec 05
Location: Sutton-on-Hull, Kingston upon Hull
User status: Offline
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I did mine myself, got the head sent off for skimming, i reground the valve seats, etc... all the parts and machining inlcuding a new cambelt (thought i would change it while it's off) for £150. although it took me nearly a week
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Will_Sport
Member
Registered: 28th Jun 04
Location: Notts
User status: Offline
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does it start on 3 cylinders sometimes?
mine went about 70k miles.... although it was only a slight leak (where ainsley said)... not that noticeable until did a compression test (leak down or whatever) and they said after about 30mins one had dropped a lil.
cost me £350 for skimmed head, comp test, oil etc and a new cambelt roller cos 1 plastic one was cracking (thank fcuk they saw it!)
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SVM 286
Member
Registered: 13th Feb 05
Location: pain
User status: Offline
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quote:
Originally posted by Lazarus1
My Opel book says 10.5 i'm guessing thats 10.5 bars or 152 psi?
Cheers.
That is actually the compression ratio Lazarus and not a measurement of pressure.
It simply means that is the ratio of the swept volume that the piston compresses.
i.e. In layman's terms, if the stroke of the piston in the bore from BDC to TDC compressed a volume of 10 centimetres including the combustion chamber into a space that was 1 centimetre in volume, the compression ratio would be approximately 10:1.
This is a bit over simplified because the actual volume of the combustion chamber is taken into account when measuring the capacity at TDC and BDC, and it is non uniform in design.
I hope you get the idea though.
As a good example, I did a compression test, (twice over) on my Mother's 6 cylinder 3 litre Mercedes the other day.
The test results were nice and even. Approximately 158 - 165 psi per cylinder (not bad for a 150k miles car). However, the cooling system is over pressurising, the car is using coolant, and the coolant smells wrong.
I believe there is a tiny breach of the head gasket and that combustion gases are contaminating the water jacket. I need to obtain a sniffer kit to confirm my suspicions, but it looks more than likely that I will have to remove the head.
Not good fun. 
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SVM 286
Member
Registered: 13th Feb 05
Location: pain
User status: Offline
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quote:
Originally posted by Lazarus1
...one more thing i understand the sniffer test,but corsa808 confused me about the compression test,could you tell me how it's done?
Thanks.
If you are referring to the compression leak test Lazarus, it is quite straight forward.
With the piston at BDC, a threaded union is fitted to the spark plug hole and a compressed air line is connected to the union.
The pressurised air is fed into the engine.
If no air escapes then all is well.
If however, air comes from the exhaust pipe or inlet tract, this means a valve or valves is/are burnt out.
If air comes out of the oil filler cap, this means that a piston or piston ring has failed or possible a large breach of the gasket into an oil way has occurred.
If air bubbles out of the cooling system header tank, this means the head gasket has breached at a water way.
I hope this helps to clarify things a bit.
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Lazarus1
Member
Registered: 5th Apr 02
Location: Skopje,Macedonia
User status: Offline
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My car runs fine now but these are good things to know.
Cheers SVM 286.
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