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Alloytec compression figures

gazzweld

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can anyone tell me what the cylinder compression figures should be for a 3.6L ecotec motor?
motor is using a bit of oil and l intend to do a compression check but don't know what acceptable pressures are. thanks.
 

VR38

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A compression test may not indicate oil usage, how much oil does it use between oil changes and does the engine blow smoke?
What colour?
What do your spark plugs look like?
 

gazzweld

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i have had the ute for nearly 4 years and it has always used approx 1.5 Litre per 5000k, and more if towing, which happens often. it doesnt visibly blow smoke and the plugs look fairly normal. after a period of weeks of short town use the oil filler plug gets a white sludge buildup under it, but doesnt do so on long trips, which is normal i guess as the engine gets hotter for longer. l was getting the engine light coming on fairly often with the fault being "multiple missfires detected", so i replaced the plugs and coils in january and it seemed to fix the problem. the check engine light had come on several times on a recent trip of 2500k, but the light cleared when the engine was switched off and re started. however, 10 ks from home the light came on and would not clear after a restart. the engine had a miss, and the code reader said miss fire on #5. took the plug out and the electrode had been pushed against the core, thus shorting out. how could that happen? i poked my inspection camera down the plug hole and could see where a piece of carbon buildup, about the size of a 20c piece, had come off the top of the piston and i assume that did the electrode damage.
i made up an extension piece for my compression gauge today to suit the hfv6, and did a compression check. cold dry figures are, in psi, 1-140, 2-160, 3-160, 4-70, 5-140, 6-170.
with oil added, 1-200, 2-210, 3-190, 4-170, 5-170, 6-210.
 

gazzweld

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Sorry, my bad....i will check it out. inside the inlet manifold and air inlet from air filter is very oily.
i will certainly look at a catch can install.
 

gazzweld

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thanks stick3, PCV competely blocked, plus the T connector behind the inlet manifold was very restricted. see how it goes now that its all cleaned out, although that wont fix the low compression figures for cylinder #4.
 

VR38

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10% across any pot is a problem, over 50% is a dead cylinder imo
time for an exchange engine.
 
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