Weber Tractor Serv. Posted October 18, 2017 Share Posted October 18, 2017 Okay, I've got a 1992 cabover Mack with a 1996 E7 engine in it. On starting and running up hill or on flat ground no smoke, even on cold morning. Going down hill light blue smoke on de-acceleration. When I get to the bottom and hit flat ground again put my foot in it and get a ton of blue smoke for a few seconds, then it clears out. Nobody seems to know what's causing it. The consensus is if it was the rings it would smoke all the time. Somebody else suggested maybe the valve guides. Anybody have any ideas? Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted October 18, 2017 Share Posted October 18, 2017 I have a ideal but you need to do some checking.Valve seals or guides.Bad rings can do same thing. 1 Quote glenn akers Link to comment Share on other sites More sharing options...
fjh Posted October 18, 2017 Share Posted October 18, 2017 (edited) 12 hours ago, theakerstwo said: I have a ideal but you need to do some checking.Valve seals or guides.Bad rings can do same thing. agree with Glenn also ( how old is your air cleaner?) Don't forget the engine is in vacum when coasting pulling oil thru the turbo seals due to clogged air filter is a good possibility! Edited October 18, 2017 by fjh 1 Quote Link to comment Share on other sites More sharing options...
Weber Tractor Serv. Posted October 19, 2017 Author Share Posted October 19, 2017 Filter is changed regularly and is good. I tried changing the turbo and no difference. No evidence of turbo leaking either. If it was the rings wouldn't it smoke all the time and especially at start up in the morning? Quote Link to comment Share on other sites More sharing options...
41chevy Posted October 19, 2017 Share Posted October 19, 2017 (edited) 11 minutes ago, Weber Tractor Serv. said: Filter is changed regularly and is good. I tried changing the turbo and no difference. No evidence of turbo leaking either. If it was the rings wouldn't it smoke all the time and especially at start up in the morning? Valve guides and rings will let oil past them on deceleration because of the vacuum (for want of a better term) BUT. I'd personally check the Valve Guide Seals first, they do get "dry" and worn from age and allow oil past the valve guides, more on Deceleration than acceleration. Edited October 19, 2017 by 41chevy Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
mrsmackpaul Posted October 19, 2017 Share Posted October 19, 2017 air intake hose collapsing in under vacuum down the big hill causing it to scavenge air from everywhere else and drawing in some oil with it Maybe pull the air intake hose of at the turbo and take it for a run down a big hill and see if its any better, sort of eliminates a whole heap of things Paul Quote Link to comment Share on other sites More sharing options...
fjh Posted October 19, 2017 Share Posted October 19, 2017 11 hours ago, Weber Tractor Serv. said: Filter is changed regularly and is good. I tried changing the turbo and no difference. No evidence of turbo leaking either. If it was the rings wouldn't it smoke all the time and especially at start up in the morning? One would think If it were rings you would have oil consumption issues and excessive blowby! I as the others suspect valve guide wear! Quote Link to comment Share on other sites More sharing options...
Weber Tractor Serv. Posted October 21, 2017 Author Share Posted October 21, 2017 Good Idea Paul, I like that Quote Link to comment Share on other sites More sharing options...
41chevy Posted October 22, 2017 Share Posted October 22, 2017 4 hours ago, Weber Tractor Serv. said: Good Idea Paul, I like that People tend to over look the simplest. Paul Quote "OPERTUNITY IS MISSED BY MOST PEOPLE BECAUSE IT IS DRESSED IN OVERALLS AND LOOKS LIKE WORK" Thomas Edison “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’” P.T.CHESHIRE Link to comment Share on other sites More sharing options...
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