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Carbon Chunks in First Oil Change

L

lr172

Well Known Member
My freshly rebuilt now has 15 hours in service and I changed the oil and filter. The good news is that the amount of small aluminum flakes is dramatically reduced from the filter pulled at two hours. It seems that the problem is not persisting and was related to the initial break in.

The concern was the chunks of carbon that I found in the drain oil. There were several moderate size chunks of carbon that were found at the bottom of the drain pan. The bigger ones were maybe a 1/16" in diameter. I assume this is from blowby gasses generating heat and coking the oil, presumably in the oil ring cavities. I hadn't been paying much attention to oil temp (no alarms went off and the times that I looked it was 190-200). Today, at 75% cruise, the gauge went yellow and the temps were 218 (90* ambient, but typical of most of my flights).

Is this normal for a new or overhauled engine while breaking in? I have heard that it can take over 20 hours for rings to fully seat and the oil temps will run high untill that happens. Is that typical? My CHT's have been consistently below 400.

The oil is dark and bordering on black.

Larry
 
I am going to ring the bell and say something is not right. There are just too few hours on this engine for this condition. You did confirm your timing, right? You are the guy who thinks advancing timing makes things inside cooler.

You need the engine guys at Poplar Grove to look at this.
 
I do believe that decreased timing will increase cylinder temps, but my engine is run as stock. Timing was confirmed at 25* prior to first flight.
I am not sure that I have a heat problem 190-200 with 90* seems to be in range and I am not sure if yesterday's 218 was a trend or an anamolie (I had just had the cowl off to change the oil and Ign harness)

My concerns were the carbon chunks. I think that my rings haven't seated yet, as my seperator's catch can is still filling at a decent rate. I just don't know if this is normal and if not and what is causing it. I don't suspect it can be coming from the combustion chamber, so would have to be from the lower piston area or cylinder walls below the ring travel or the oil ring area. I suspect blowby heats the oil here and it cokes. Would like to know if this is somewhat common on new break ins. I am not sure most would catch this on an oil change, as you have to be careful draining oil out of the catch pan to examine the debris.

Larry
 
Hi Larry,
Glad to hear the shavings are reduced.May I ask what has been your oil use in those 15 hours? I assume you fill to 6qts and no more as it will be blown overboard to that level? Any unusual noise or vibration that you can tell? Have you been blasting around full rich,full throttle for most of the time?
RHill
 
rhill said:
Hi Larry,
Glad to hear the shavings are reduced.May I ask what has been your oil use in those 15 hours? I assume you fill to 6qts and no more as it will be blown overboard to that level? Any unusual noise or vibration that you can tell? Have you been blasting around full rich,full throttle for most of the time?
RHill
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Oil use has been a bit tough to gauge with pulling filters and all, but I would say that I am in going through a quart in about 5 hours or so. I run down to 5 then add a quart back to 6. Engine runs really well. I had a guy come by my tie down yesterday and commented that he saw me taking off and landing yesterday and that my engine sounded really good (unsolicited). I have noticed no odd noises, vibrations or odd behavior.

I have been trying to keep the plane at 2400-2500 in the 3000-4000 MSL range. I hope that is near 75% power. I have not been blasting around at full throttle. Do you suggest that? Maybe I should be. My carb is overly rich, so have to lean some but probably leaning more than I should. I am not doing LOP or anything. My take off power is noticeably better when I pull the mixture knob back about a 1/4" or so (12.5GPH on roll). At altitude, I have not pushed the red knob all the way in.

Larry
 
rhill said:
Hi Larry,
Glad to hear the shavings are reduced.May I ask what has been your oil use in those 15 hours? I assume you fill to 6qts and no more as it will be blown overboard to that level? Any unusual noise or vibration that you can tell? Have you been blasting around full rich,full throttle for most of the time?
RHill
Click to expand...

I will add a follow up on the piston pin issue. I had someone weigh an ECI pin as well as a Lyc pin with 2 plugs. The weight difference was 17 grams. Lyc's tolerance is 15 grams and I suspect that is a little conservative. I think that I will be ok, but may replace it some day. Not touching anything until I confirm that my cylinders break in correctly.

Larry
 
It may be a possibility that the small carbon junk is also remnants from before the engine was overhauled.
 
Zero4Zulu said:
It may be a possibility that the small carbon junk is also remnants from before the engine was overhauled.
Click to expand...

I considered that, but there were too many for that to seem feasible. Maybe 3-4 1/16" pieces and several small pieces. Even a couple of very small pieces in the filter. I am sure there is more in the pan itself. The crank case was pretty clean when I assembled it and would have noticed them. They were too big to have passed through anything fed by the oil galleries and they are the only things that I couldn't fully inspect.

Larry
 
ENGINE O/H AND OIL

WHO REBUILT THE ENGINE, WERE ALL PARTS DIMENSION CHECKED , PROPER FIT ECT. SOUNDS LIKE IT WAS NOT CLEANED WHEN APART, GETTING ALUM FLAKES IN OIL NOT GOOD, SEND THE OIL OUT FOR A SOAP SAMPLE, THEY WILL TELL YOU WERE METAL IS COMING FROM,
LYCOMING SERVICE LETTER , STRIGHT MINERAL OIL FIRST 50 HR'S NOTHING ELSE.
 
P.S SOUNDS LIKE CARB. NEED ANS O/H OR AT LEAST TO SHOP CK FLOAT LEVEL, ENGINE GETTING TO MUCH FUEL WILL TURN OIL BLACK ,MAY HAVE INTERNAL LEAK , HOW DO THE PLUGS LOOK, ARE THEY REAL BLACK , OR OIL FOULED
 
A1AVIATON47 said:
P.S SOUNDS LIKE CARB. NEED ANS O/H OR AT LEAST TO SHOP CK FLOAT LEVEL, ENGINE GETTING TO MUCH FUEL WILL TURN OIL BLACK ,MAY HAVE INTERNAL LEAK , HOW DO THE PLUGS LOOK, ARE THEY REAL BLACK , OR OIL FOULED
Click to expand...

I overhauled the carb and float is brand new and set exactly to spec. Plugs look good. Tops are dry and have a nice grey cast to them. I have a fuel flow gauge, so have a pretty good idea what is getting to the carb. I have the richer of the two carbs for this engine and I mistakenly drilled the jet based upon the experience others have had. I don't mind having to take off with the knob 1/2" back. I only get 2200 static and don't believe that I need more than the 12.5 GPH that this setting gives me.

Larry
 
Larry,

218 on the oil temp, 12.5 GPS on takeoff fuel flow, carbon chunks. I am assuming this is an 0360?, if so that is just too many problems. Oil temps should be below 200 or at least below 205. Take off fuel flow should be around 17gph, what are your CHT's on take off climb.

If this were my engine it would be on the ground until these issues were corrected.
 
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Pat Stewart said:
Larry,

218 on the oil temp, 12.5 GPS on takeoff fuel flow, carbon chunks. I am assuming this is an 0360?, if so that is just too many problems. Oil temps should be below 200 or at least below 205. Take off fuel flow should be around 17gph, what are your CHT's on take off climb.

If this were my engine it would be on the ground until these issues were corrected.
Click to expand...
If I recall correctly, the oil temp green band noted on almost all oil temp gauges I've seen is generally between 180-220+. Especially during break in, I wouldn't be too worried about 218.
 
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I am not worried about 218. It was the first time that hot and it was 95* outside. If it keeps creeping up, I will investigate, but temps have usually been around 200 with high ambients and this seems normal for break in. I know that the extra blow by increase oil temps, so expect this to go down a bit after rings seat.

Any ideas on the carbon? I have found a few articles that seemed to indicate that it was not problematic. I probably won't worry too much unless I see it after the rings seat. I will also run it a bit richer to help keep the temps down.

Larry
 
TS Flightlines said:
is this a field overhaul, or a refresh from a engine supplier?
tom
Click to expand...

This is a field overhaul. The cylinder were done by harisson and case tested/machined by ECI and it got new pistons.

I have done some more research and it seems that excessive heat can cause carbon deposits to form in the oil and this was consistent with my thoughts. I am wondering if this excessive heat is common with break in. I did some more research on CamGaurd and it seems that one of it's properties is to help reduce carbon deposits. Is there any harm in adding that during the break-in.

Larry
 
Who cleaned the oil sump? Intake tubes? Accessory case? Are the chunks hard? Cut one with a razor, is it old sealant or gasket?
 
lr172 said:
This is a field overhaul. The cylinder were done by harisson and case tested/machined by ECI and it got new pistons.

I have done some more research and it seems that excessive heat can cause carbon deposits to form in the oil and this was consistent with my thoughts. I am wondering if this excessive heat is common with break in. I did some more research on CamGaurd and it seems that one of it's properties is to help reduce carbon deposits. Is there any harm in adding that during the break-in.

Larry
Click to expand...

I agree but also think you may need to push the engine a little harder during break-in.

I believe you should keep it higher than 75% as long as cylinder and oil temps remain in the green zone. They should come down once the rings seat. At that point, oil consumption, CHT and oil temps should stabilize in the lower normal range.
 
No Cam Guard for now

Lycoming wants you to run straight weight no additives for the first 50hr.Then a multi weight after the rings & brake-in are complete.Ring alignment,Glazing issues are what I suspect.If the issues we have already covered caused damage,it's already done.My vote is to fly another 5-10 hours and see what you have.I'd be inclined to pull all four jugs match weight for the pistons and the wrist pins,replace all 8 end caps with New 60828 caps,as well as the one non matching wrist pin or get three more of the superior one piece pin/caps SL13444-1.So all four match in part and weight and are new pieces.It's too late to play with rod bushings as removing the rods would require replacing the $$$bolts&nuts.Please check the pin/bushing tolerance for spec. Replace the rings with new Lycoming or Superior and hone the cylinder bores.It's not what you want to hear and lot of work but its what needs to be done IMHO.
RHill
 
rhill said:
Lycoming wants you to run straight weight no additives for the first 50hr.Then a multi weight after the rings & brake-in are complete.Ring alignment,Glazing issues are what I suspect.If the issues we have already covered caused damage,it's already done.My vote is to fly another 5-10 hours and see what you have.I'd be inclined to pull all four jugs match weight for the pistons and the wrist pins,replace all 8 end caps with New 60828 caps,as well as the one non matching wrist pin or get three more of the superior one piece pin/caps SL13444-1.So all four match in part and weight and are new pieces.It's too late to play with rod bushings as removing the rods would require replacing the $$$bolts&nuts.Please check the pin/bushing tolerance for spec. Replace the rings with new Lycoming or Superior and hone the cylinder bores.It's not what you want to hear and lot of work but its what needs to be done IMHO.
RHill
Click to expand...

Thanks for your input here. I have been a bit afraid that glazing could be an issue here. I agree with putting more time on the engine to see what happens. How do I determine if I have a glazing issue? Is it just a matter of oil consumption not stabilizing? Does a compression test show glazing? Can I see it with a borescope?

The rod bushings were replaced during the overhaul and the rods were balanced as well.

Larry
 
Raymo said:
I agree but also think you may need to push the engine a little harder during break-in.

I believe you should keep it higher than 75% as long as cylinder and oil temps remain in the green zone. They should come down once the rings seat. At that point, oil consumption, CHT and oil temps should stabilize in the lower normal range.
Click to expand...

Thanks. I intend to do this going forward and wished that I had for the last 10 hours.

Larry
 
aerhed said:
Who cleaned the oil sump? Intake tubes? Accessory case? Are the chunks hard? Cut one with a razor, is it old sealant or gasket?
Click to expand...

I cleaned everything pretty well (including accy case and sump), but now that you mention it, I am not sure how thoroughly I cleaned the drain back tubes from the heads. It is possible the chunks were hiding there. I expect the oil has some detergent in it and may have loosened it. Anything visible was spotless.

The chunks are definitely carbon and not gasket material or sealant. They crack and crunch as expected.

Larry
 
lr172 said:
Thanks for your input here. I have been a bit afraid that glazing could be an issue here. I agree with putting more time on the engine to see what happens. How do I determine if I have a glazing issue? Is it just a matter of oil consumption not stabilizing? Does a compression test show glazing? Can I see it with a borescope?

The rod bushings were replaced during the overhaul and the rods were balanced as well.

Larry
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Oil consumption is a biggie and of course Temperature,a cylinder leak down test,bore scope.I forgot to ask,How is your oil pressure cold&Hot? The rings like to move around and from time to time line up. The old numbered pistons weight could be all over the place and had to be matched by group.The new 14D numbers are made at Lycoming on a new machine that starts with a forging and comes out the other end a fully finished piston,even reaches out and wipes the drool off your face,its that slick. I have three sets,one of the old,I went through two cases to get 4 pistons that match within two grams.The other two sets were as sent and both are spot on. You don't know what you have till you weigh them. As before I'd run this some more but accept that their is enough going on that pulling all 4 jugs and the sump off for inspection is the right thing to do. IMHO
RHill
 
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rhill said:
Oil consumption is a biggie and of course Temperature,a cylinder leak down test,bore scope.I forgot to ask,How is your oil pressure cold&Hot? The rings like to move around and from time to time line up. The old numbered pistons weight could be all over the place and had to be matched by group.The new 14D numbers are made at Lycoming on a new machine that starts with a forging and comes out the other end a fully finished piston,even reaches out and wipes the drool off your face,its that slick. I have three sets,one of the old,I went through two cases to get 4 pistons that match within two grams.The other two sets were as sent and both are spot on. You don't know what you have till you weigh them. As before I'd run this some more but accept that their is enough going on that pulling all 4 jugs and the sump off for inspection is the right thing to do. IMHO
RHill
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I went out and ran it hard yesterday for an hour and a half. 2600-2700 at 3000'. Oil Pressure was 70 PSI (typical) and temp never got over 195. CHT's were all 360, except #1, which is much richer and ran at 330. Oil pressure cold is 65. I won't know how much oil I am burning for another couple of hours.

My pistons came from Superior and had no numbers. Do you know if the the superiors more consistent in weight?

When I get to 40 hours, I will do a leak down test and borescope. If I have glazing problems, will I see it in the plugs? I am guessing that I would see oil on the plug or signs of oil fouling if the cylinder is glazed. Is that true? With the borescope, am I looking for excessive carbon desposits or coloring in the cross-hatch?
Larry
 
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Sounds like a plan. By then all this will sort itself out or you'll know for sure you got a problem.Cylinder leak down/compression test,Oil consumption,debris check the filter,Check the plug color,etc.The ECI/Superior pistons from Brazil are good,The weight issue may be a non event as you have 3 that are heavy and match? One a few grams lighter,if it were the other way around it would be more of an issue.The 2 plane prop balance might give you more data,stuff we covered in the other thread. Safe Flying!
RHill
 
I had the cowl off today to install a new jet in my carb. I found that when I try to run rich that #3 :& #4 run lean and #1 & #2 filthy rich (will test performance with new jet tomorrow). While I was in there, I pulled the top plugs. #'s 1,3,4 look great. No oil and a nice grey cast to them with no fouling. #2 (the rich cylinder that I am struggling to lean) had wet oil on it and was pretty black (oil fouling). Obviously the rings haven't seated in this cylinder and explains the black oil. I looked in the hole with a flashlight and there is some glazing, but most of the cross-hatch is still clean (obviously I can only see a small portion - borescope arrives next week). If I can get this un-balanced mixture fixed and run it hard for 10 hours, what is the lkelihood that these rings will seat? Do I stand a chance? I guess the good news is that if I do have to hone and re-ring, it will only be one cylinder.

Larry
 
lr172 said:
I had the cowl off today to install a new jet in my carb. I found that when I try to run rich that #3 :& #4 run lean and #1 & #2 filthy rich (will test performance with new jet tomorrow). While I was in there, I pulled the top plugs. #'s 1,3,4 look great. No oil and a nice grey cast to them with no fouling. #2 (the rich cylinder that I am struggling to lean) had wet oil on it and was pretty black (oil fouling). Obviously the rings haven't seated in this cylinder and explains the black oil. I looked in the hole with a flashlight and there is some glazing, but most of the cross-hatch is still clean (obviously I can only see a small portion - borescope arrives next week). If I can get this un-balanced mixture fixed and run it hard for 10 hours, what is the lkelihood that these rings will seat? Do I stand a chance? I guess the good news is that if I do have to hone and re-ring, it will only be one cylinder.

Larry
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Typically, once glazed tear down is in order. In the old days a dash of BonAmi in the intake would provide just enough friction to seal the rings. Hard to do with load on an plane. Sorry, maybe RocketBob or Russ can provide a trick. It can't hurt to address the other issues first, then make a hard WOT run at 5-6000 for a couple of hours to finalize.
 
Chinks in oil

If all the chunks are the same size it's likely walnut chips typically used to clean engine cases on overhaul. Carbon doesn't coke till it gets to 400 degrees and you would have had high temps. 600 degrees for synthetics. Walnut hulls sometimes get stuck in oil passages and break free after a few runs. Remove your oil auction screen and clean that too. If the rest of your flakes are getting lessor so will your unknown chunks. I just got back from lycoming school yesterday and it was very informational.
 
BillL said:
Typically, once glazed tear down is in order. In the old days a dash of BonAmi in the intake would provide just enough friction to seal the rings. Hard to do with load on an plane. Sorry, maybe RocketBob or Russ can provide a trick. It can't hurt to address the other issues first, then make a hard WOT run at 5-6000 for a couple of hours to finalize.
Click to expand...

I ran it hard for a couple of hours and no change. I ordered a ring kit today and will pull the cylinder, hone it and install the new rings. Better to do this now and not have to deal with another break-in cycle later. Heck, maybe I'll get lucky and find the odd piston pin on that cylinder and be able to replace it.

Larry
 
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