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| JG33Replica |
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I have a problem with pcv valve sucking a lot of oil. Engine is worked alloy head 250 crossflow in a cortina. It has pcv valve routed through a catch can and It fills catch can with about 800mls of oil in just 300kms of driving. its a Fresh engine , pcv valve is connected to a fitting into the intake plenum just below four barrel holley carb. engine fitted with aussie speed rocker cover that has cone type baffles cast into it under pcv and breather holes. I also modified the oil pan to hold extra oil. Has anyone had the same problem or have any idea how to fix it.
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| 66 coupe |
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how much does the engine breathe with the pcv plugged and the oil cap off?
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| JG33Replica |
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More than I would like. Its only done about 500k. I have just disconected pcv. I restricted the line to less than half and still sucked a gut full of oil. I think that the desighn of the aussie speed cover or maybe to much vaccume from plennum are to blame. would like to cut the cone style baffle off and see if there was a change. I think it creates suction.
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| 66 coupe |
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it wont be a vacuum issue, it will be the engine is breathing excessively.
even with non baffled covers you wont pull 800ml in 300kms on a good engine... I think you have a more serious issue going on |
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| JG33Replica |
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yeah ok. I have done a compression test and one cylinder is 20 psi lower than rest. we had a noisy roller rocker on that cylinder and have pulled the cover to discover a retainer has failed and was just about to pull a valve through. very lucky we caught it before it all went bang. Going to replace the whole lot and try to solve the original problem. You may be right we might have had a ring crack or something. its just a big call to strip it down just to check.
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| 66 coupe |
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do a leakdown test, with the rocker cover off, this will show how much air is bypassing
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| JG33Replica |
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ok mate. I will see if I can borrow a leakdown tester or buy a cheap one. whats the idea with that. do I just check the results against the best and worst cylinders. is there an acceptable range.
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| 66 coupe |
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if its blowby then its either one cylinder or all cylinders equally depending on ring gaps, broken ring etc. the leakdown tester will give you an indication of whats going on.
a quick and dirty method is weld an air fitting to an old sparkplug base and just connect the air compressor to it,on each cylinder and see 1) how much air is bypassing the rings, and 2) if one cyl is worse than others.. or you can fire it up with the oil cap off and put up a video showing how much vapour its blowing out |
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| JG33Replica |
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OK I have the spark plug thing made up in toolbox already. I use it to change valve springs and stuff. I will do it and I will also get a video done. How many psi would be reccomended for blowby test.
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| 66 coupe |
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use 120psi from the compressor
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