Smoking after oil change

bg90coupe

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Smoking after oil change (long)

Ok this is goin to be kindof long so bare with me. I purchased a cobra clone from a member of this site with all the bells and whistles including a built cobra engine about a year ago. The motor has forged enternals 04 heads hv oil pump with billet gears etc. It has roughly 30000 miles. Shortly after the purchase I do the routine things I normally do just because that's the way I am. I install a thermostat new plugs (tr6 with same gap that's was in it) and changed the oil. I also deleted the pcv and installed a breather tank for each valve cover. The plugs I pulled out looked good. #2 was a little darker brown that the others but by no means in bad shape at all . The previous owner told me he used castrol gtx. I put in 7 quarts of 5w30 or 10w30. I can't remember because I've been thru a few weights and brands since then. Anyway when I first start the car after all this I get a big puff of blue smoke. Now it never did this the 3 weeks I had the car before the things I did to it. But I also read that these motors do that from time to time so I didn't think much of it. Pretty much everytime I start the car after that it does it. It will smoke when I rev it in neutral too. WOT there is also some smoke but it appears to be black. Normal driving it doesn't seem to be smoking except for leaving a stop light or if I let it idle for a long time but I haven't had anybody follow me. If I hold the throttle steady and "clear it out" it doesn't seem to smoke that much after that. I decided after a few weeks to pull the plugs. # 2 3 and 4 have some oil on the threads and tip. It's not a lot but plugs are pretty black. #2 is the worst as it appears wet on the tip. All the other plugs look fine. No I'm a little worried but I continue to drive the car and experiment with different oil brands and weights. Over the next several months I try rotella 5w40 and driven fr20. Smoking does not stop. I contact previous owner he says it was castrol gtx 5w20 that he used and that it didn't smoke or use oil with him. I recently put that oil in and I still get smoke. It also appears that it is burning some oil too but I can't tell how much because I've changed it so often over the course of 900 miles. Now over this time period I will pull plugs 2 3 and 4 to check them. They will sometimes look like they are clearing up. Other times they look black and a little wet. The car still pulls strong and runs fine. I have not done a compression or leak down test yet. Im trying to understand what is goin on with this thing. Sorry for the long post felt I needed to explain what I have experienced over the last year. Anybody have any ideas of what's wrong? I'm thinking valve seals but I don't understand why all of sudden after the routine maintenance.
 
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CobraBob

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Could be coincidental that you're seeing a bit of smoke after changing the oil. I don't see changing the oil causing the smoke out the exhaust. I would definitely do both a leak-down and compression test.
 

bg90coupe

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Forgot to mention it has a canton road race pan. Anyway I had a compression test done today. I don't think the shop did it right because the numbers are low across the board but are relatively close together so to speak

120 115
120 105
120 105
100 115

Cylinder 4 is lower but I don't think it's that bad. Idk they didn't squirt oil in it to see if it would come up either. Not sure if this was helpful or not to be honest.
 

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