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hi guys,

I've been searching this forum and reading plenty posts on various topics - and decided to join. I hope you guys can help me! The wealth of knowledge here is mind boggling

I live in South Africa and I recently acquired an Alfa Romeo GTV (116). The car is 100% original and unmolested but has some a few niggles - first and foremost the engine.

The engine is running OK but knowing from experience the car doesn't quite run as it should. Decided to do a compression test today and the results were not good at all. I know a "healthy" engine should have 100+psi on each cylinder - my car's compressions all float around the 90's with cylinder number 4 on only 60psi - it stays at the indicated compressions though and doesn't go down, so I'm assuming there isn't a "leak". (These were all done cold, have not done a "hot" compression test yet)

Before I pull the engine and start dismantling I want to know if there are any other things I can check to possibly diagnose what is wrong? From what I gathered the car was standing for quite some time before I took her over so I'm suspecting some serious carbon build up and sticky valves.

There is no water in the oil or vice versa, so I'm suspecting the head gasket is OK. The car also doesn't overheat and temperature always stays constant once warmed up. I changed the plugs and plug wires which alleviated the problem slightly but it still has that annoying misfire sound. I drove the car from where I got it to my house (probably about +-30km) and didn't see any visible smoke coming from the exhaust. There is no discernable difference in the "misfire" sound when the engine is hot/cold. it always stays the same.

Any help and suggestions would be appreciated. Feel free to ask any other questions to help me diagnose the possible solution to this problem.

kind regards,
Derik
 

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...compressions all float around the 90's with cylinder number 4 on only 60psi - it stays at the indicated compressions though and doesn't go down, so I'm assuming there isn't a "leak".
I am not sure I understand what you mean. The compression gauges I've used all hold the reading at the gauge so that doesn't tell you if the cylinder isn't leaking. For that you need a leak down tester. That is usually two pressure gauges - one measures how much air is being put into the cylinder & the other measures how well the cylinder holds pressure. (the piston is typically positioned at TDC with the valves closed).

One useful thing about a leak down test is that you can pinpoint any weak areas. The rings will always leak a little bit but you shouldn't hear any leaks past the valves or via the head gasket.
 

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Discussion Starter #3
I assumed they showed both...so next test would be a leakdown test to find the source of my problem. Any possible ideas as to what could be causing the low compression?
 
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