cygnusx1 Posted April 25, 2011 Share Posted April 25, 2011 (edited) As long as I can remember working with BMW's, back to the late 80's, they have always had issues with carbon buildup on the valves. I remember a "standard" procedure, at the dealer where I worked, where customers were charged enormous cash to have their intake/exhaust manifolds removed so that the valves could be blasted with some sort of snorkel/scuba device that fired and sucked back walnut shells through the head ports. Check out these posts over at the E90 forums. I'll probably get flamed over there for my comment. http://www.e90post.c...ad.php?t=521296 What the heck? Is is solely because the direct injection does not spray the back of the valves? On second thought, this problem existed for BMW before DI. When I ask technical questions on the BMW forums, the threads, no matter what topic, always turn into a discussion about how much wheel gap my 3 series has. Edited April 25, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
TimZ Posted April 25, 2011 Share Posted April 25, 2011 As long as I can remember working with BMW's, back to the late 80's, they have always had issues with carbon buildup on the valves. I remember a "standard" procedure, at the dealer where I worked, where customers were charged enormous cash to have their intake/exhaust manifolds removed so that the valves could be blasted with some sort of snorkel/scuba device that fired and sucked back walnut shells through the head ports. Check out these posts over at the E90 forums. I'll probably get flamed over there for my comment. http://www.e90post.c...ad.php?t=521296 What the heck? Is is solely because the direct injection does not spray the back of the valves? On second thought, this problem existed for BMW before DI. When I ask technical questions on the BMW forums, the threads, no matter what topic, always turn into a discussion about how much wheel gap my 3 series has. I like how the first response was a snipe saying that you don't get it, then offers no help whatsoever. I don't follow that forum so maybe it was just friendly banter Anyway, I do remember this issue from the mid 80's, and as I recall that problem was actually being caused by the injection of fuel on the back of the valve, or so they claimed. BMW then started recommending that you only use certain fuels that were of "high enough quality" and had detergent additives in them. As you noted, with DI this shouldn't happen since (I'm assuming) the fuel now gets injected after the valve. Blow-by or valve stem seals, maybe? Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 25, 2011 Author Share Posted April 25, 2011 (edited) I like how the first response was a snipe saying that you don't get it, then offers no help whatsoever. I don't follow that forum so maybe it was just friendly banter Anyway, I do remember this issue from the mid 80's, and as I recall that problem was actually being caused by the injection of fuel on the back of the valve, or so they claimed. BMW then started recommending that you only use certain fuels that were of "high enough quality" and had detergent additives in them. As you noted, with DI this shouldn't happen since (I'm assuming) the fuel now gets injected after the valve. Blow-by or valve stem seals, maybe? Oh yeah, if you try to get technical or act mature in there, you are basically taunted. That is some nasty carbon build up. I hope the BMW powered guys in here take note. Ron? Edited April 25, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted April 25, 2011 Share Posted April 25, 2011 I had heard this was an issue with the E39 M5s as well. Gross, that is insane! Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 26, 2011 Author Share Posted April 26, 2011 The admin cleaned up the thread. Bravo! But those valves really look nasty. The flows in those ports must be way down from when they were new. Yikes! Quote Link to comment Share on other sites More sharing options...
rags Posted April 26, 2011 Share Posted April 26, 2011 DC, Why is there so much oil in there on all of the pictures? Do they burn that much oil? Joe Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted April 26, 2011 Author Share Posted April 26, 2011 (edited) I don't know. BMW's for years have battled "crispy-chicken" valve and intake port deposits. I have seen them get really bad in a short time. Edited April 26, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
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