Mcoyne34 Posted July 5, 2015 Report Share Posted July 5, 2015 I found a J model for sale. Engine has just under 800 SMOH just over 3000 TTAF. The ad says it burns oil at a rate of a quart a hour, sometimes more and sometimes less. I know all engines burn oil, but Is this an abnormally high burn rate for a J? I assume it is since they felt the need to disclose that. What kind of problems, if any, should I expect from this? I'm a newbie, so forgive me if this is a basic knowledge question. Quote Link to comment Share on other sites More sharing options...
BKlott Posted July 5, 2015 Report Share Posted July 5, 2015 Yes, that is a high rate of oil consumption. Depending upon the cause(s) you could be facing some major expenses. The old school rule of thumb for Lycomings was something like 1 quart every 7 hours was considered the norm. Quote Link to comment Share on other sites More sharing options...
mpg Posted July 5, 2015 Report Share Posted July 5, 2015 They are disclosing that because any more oil than 1qt per 7hrs is too much. They are warning that a top OH is right around the corner,, in fact the top should be OHed Now, before you get to a corner that may be a catastrophic engine failure! But it may only need a ring job and some valve work. Figure that into the price of the plane. Quote Link to comment Share on other sites More sharing options...
Mcoyne34 Posted July 5, 2015 Author Report Share Posted July 5, 2015 They are disclosing that because any more oil than 1qt per 7hrs is too much. They are warning that a top OH is right around the corner,, in fact the top should be OHed Now, before you get to a corner that may be a catastrophic engine failure! But it may only need a ring job and some valve work. Figure that into the price of the plane. How much would I figure for that? If it's high enough it may push me into an E model, which also appears very nice. Quote Link to comment Share on other sites More sharing options...
Mcoyne34 Posted July 5, 2015 Author Report Share Posted July 5, 2015 Obviously it can vary greatly, just a ballpark idea is what I'm looking for Quote Link to comment Share on other sites More sharing options...
mike20papa Posted July 5, 2015 Report Share Posted July 5, 2015 Lycoming Service Instruction gives the following formula for max. allowable oil consumption for all their recip. engines: .006 x BHP x 4 / 7.4 = qt./hr that comes to .65 qt/hr. for a 200hp J. Come on, anything more than qt/7hr.s too much...says WHO?! I would begin by checking the breather hose tube where it connects to the alumn. tube and make sure the vent hole is open & clear, then do a compression check and follow up with a bore scope of the weak cyl. to check for excessive scoring. Could be as simple as some stuck or broken rings. Certainly more expensive items on a Lycoming to repair than pulling jugs & replacing pistons & rings. Bore scoping the valves & doing the "wobble test" could be more conclusive. Also, how does the engine perform? run hot? start-ups? developing full power? What kind of cyl. finish, regularly flown, etc. 1 Quote Link to comment Share on other sites More sharing options...
mpg Posted July 5, 2015 Report Share Posted July 5, 2015 Well,,, .65 qt per hr would seem allowable on a 2000hr engine as the maximum allowed at the end of life. But we are talking about an engine that is only 800 SMOH! This consumption is announcing that it is nearing end of life. An engine using that much oil is ready for OH,,, it is "on condition".... Bad condition. Besides condition,,, this consumption means that this plane shouldnt even fly FOUR hours at a time,,,Maximum!!! 1 Quote Link to comment Share on other sites More sharing options...
N201MKTurbo Posted July 5, 2015 Report Share Posted July 5, 2015 I had a broken piston once that caused that kind oil consumption. It only cost about $250 in parts to fix it. The engine ran fine. If you over heat the engine the Pistons get soft and the rings don't seal any more. The Pistons are toast, but the cylinders are OK. I wouldn't jump to conclusions about the cost, but it does need to be fixed. Quote Link to comment Share on other sites More sharing options...
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