Keith Browning Posted July 18, 2006 Share Posted July 18, 2006 How many of you are finding cylinder number 3 burnt? I just opened up our third one. Engineering is indicating that this is is being caused by an over boost condition. I do advise checking those turbos any time an engine comes apart! Any one have more information? Anyone see any burnt up #3's? Quote Link to comment Share on other sites More sharing options...
Kyle E. Grathwol Posted July 19, 2006 Share Posted July 19, 2006 Any ideas as to how an overboost can consistently damage the same cylinder? Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted July 19, 2006 Share Posted July 19, 2006 Here's a convoluted, non-engineer view.... my only claim to fame is an almost ongoing battle with "fuel stand-off" on carburetted cars with long duration cams.... The air in the intake manifold is not in constant motion and is subject to pulses caused when intake valves open and close. There is a particular resonance for each "column" of air (from inlet to valve) and all the other inlet valves can influence this column of air. Like a pipe organ, there is bound to be that one column that is the "sweet spot". Until engineering tells me I'm full of it, that's my story and I'm sticking to it... Quote Link to comment Share on other sites More sharing options...
gasgasman Posted July 19, 2006 Share Posted July 19, 2006 Jim. I like that theory. They can "fix" that by putting a crossover tube on the rear of the intake plenum. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 19, 2006 Author Share Posted July 19, 2006 Like a pipe organ, there is bound to be that one column that is the "sweet spot". Until engineering tells me I'm full of it, that's my story and I'm sticking to it... Jim I have asked the HotLine engineers about this and their answers were for the most part the same as your response. On the 6.0 it is cyl#3 and on the 7.3 it is #5 & #7. Those cylinders are also more likely do show signs of dusting first as well. My curiosity lies in what causes cylinder temps to rise more and burn the piston. If all cylinders are fueled the same does this mean that #3 is running leaner? Better? and thus hotter? Quote Link to comment Share on other sites More sharing options...
Diesel Jay Posted July 19, 2006 Share Posted July 19, 2006 Statistically, Nav isn't aware of any cylinders that are having more problems than the others. Nevertheless, I do know that there was zero time spent on "tuning" the intake manifold, and that standing pressure waves can occur. However, the standing waves have been shown to alter individual cylinder flow by only the smallest of percentages, so this is not a major priority. Honestly, I doubt that's the issue at play here. Quote Link to comment Share on other sites More sharing options...
snw blue by you Posted July 19, 2006 Share Posted July 19, 2006 Jim. I like that theory. They can "fix" that by putting a crossover tube on the rear of the intake plenum. Noooooooooooooooo! I like it just the way it is now. Makes doin' the HPOP much more tolerable. Oh and can't forget about the y-pipe. My stance is that if the engine is maintained properly we won't have any dusted cylinders but that is just my Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted July 20, 2006 Share Posted July 20, 2006 gasgas, you are off the Xmas card list for that... Jay, we need to remember that while the Navi 6.0 and the Ford 6.0 are the same engine, they aren't. They're about 100 ponies different and there is every chance that there is something there affected by it. I've fought long and hard with fuel metering issues on B and RB Dodges.... change a cam here and a carb jet there and it's like going back to school again. Let's remember that one key phrase is "overboost condition"... Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted July 20, 2006 Author Share Posted July 20, 2006 Here's a thought. If you stand in front of the truck and look at how the air enters the engine you might say it's pointed right at #3. The inlet neck comes from the drivers side and makes a sharp 90 degree turn down into the manifold. Maybe it's because its a shorter path with the EGR Throttle plate missing or the air just tends to continue swirling in that direction... food for thought Quote Link to comment Share on other sites More sharing options...
Diesel Jay Posted July 20, 2006 Share Posted July 20, 2006 Nav keeps separate warranty data for the VT365 and the 6.0L PSD, so they'll know if there's a specific problem in either application. Actually, the most likely source of the problem is one that's common to both -- EGR mixing. Mixing EGR with normal fresh air is phenomonally/incredibly complex. The only folks who think it might be easy are those who've never had to mess with the variables and equations. Very, very few folks understand it fully, and the 6.0L suffers from some "unoptimized" issues. Given a sticking turbo, it's possible for one cylinder, or another, to see substantially different volumes of EGR vs. fresh air, which can wreak all kinds of havoc. - Jay Quote Link to comment Share on other sites More sharing options...
joebutt Posted December 7, 2007 Share Posted December 7, 2007 just posted a #3 cyl piston failure- cleaned cylinder,replaced piston and head gonna fire it up tomorrow- thought injector was the root cause? Quote Link to comment Share on other sites More sharing options...
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