Lets Talk Oil consumption

AKBill said:
I agree with you 2400/2450 is my normal cruse rpm.

I traded a oil screen for a set of rings today. The IA I'm working with has a hone. Should be able to hone the cylinder and replace the rings by Monday.
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I consider 2400 rpm my normal low altitude cruise, and 2500 my 7000msl+ cruise. I just double checked my poh and it agrees.
 
AKBill said:
So I was talking to a friend about oil consumption. He said in the old days they would sprinkle a tablespoon of Bonami into the intake when running. Run 3/4 throttle, then change oil. Said it deglazed the cylinders and seated the rings.

Anyone heard of this old trick??
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My original auto shop teacher from high school told our class about a GM service bulletin that helped reseat the rings when they went to chrome-moly rings and customers couldn't get them to seat. It called out Bonami by name in the bulletin. This was in the late 80's and he had taught for many years. I imagine this fix was from the 60's or 70's.
 
I wouldn't do that to an engine unless it was a last ditch effort to save an automobile. I would never fly in an aircraft after doing that.
 
GlennAB1 said:
I wouldn't do that to an engine unless it was a last ditch effort to save an automobile. I would never fly in an aircraft after doing that.
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I agree 100 % but it is something I would do to a cat or truck...:)
 
AKBill said:
So I was talking to a friend about oil consumption. He said in the old days they would sprinkle a tablespoon of Bonami into the intake when running. Run 3/4 throttle, then change oil. Said it deglazed the cylinders and seated the rings.

Anyone heard of this old trick??
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That was the Chevrolet cure, when they first went to chrome rings, and their brand new cars would burn oil in mass quantities.
 
Well I really screwed the pooch on this one.

I installed a cylinder 75hrs ago, it had high oil consumption. Did a compression test last week and is was 56/80. I may add I did not use a straight mineral oil for break in. I used my normal oil Aero Shell 15/50. So I thought I would pull the cylinder, hone it and install a new set of rings and use the correct break in oil.

Pulled the cylinder yesterday and the rings and cylinder walls and piston are scored, beyond the point of any repairs.

I certainly did not think this would happen....:(
 
Break in using semi-synthetic oil- very bad idea. Thanks for following up. Happy (happier) New Year!
 
AKBill said:
Well I really screwed the pooch on this one.

I installed a cylinder 75hrs ago, it had high oil consumption. Did a compression test last week and is was 56/80. I may add I did not use a straight mineral oil for break in. I used my normal oil Aero Shell 15/50. So I thought I would pull the cylinder, hone it and install a new set of rings and use the correct break in oil.

Pulled the cylinder yesterday and the rings and cylinder walls and piston are scored, beyond the point of any repairs.

I certainly did not think this would happen....:(
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Even Shell doesn't recommend that...
 
(Pulled the cylinder yesterday and the rings and cylinder walls and piston are scored, beyond the point of any repairs.)

Was this cyl on the right side & was the scoring worst on the top surfaces? If so, it may be cold start damage after a long shutdown. Oil spray from the rotating crank etc will get to the upper surfaces of the right cylinders last. Just a theory of mine.
 
nrpetersen said:
(Pulled the cylinder yesterday and the rings and cylinder walls and piston are scored, beyond the point of any repairs.)

Was this cyl on the right side & was the scoring worst on the top surfaces? If so, it may be cold start damage after a long shutdown. Oil spray from the rotating crank etc will get to the upper surfaces of the right cylinders last. Just a theory of mine.
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It was the number #1 cylinder Lycoming O320. I will need to look to see if scoring was worse top or bottom..
 
Stewartb said:
Break in using semi-synthetic oil- very bad idea. Thanks for following up. Happy (happier) New Year!
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I had a good friend and IA look at it this morning. He said he has never seen scoring in a new cylinder like this. His comment was you may have run it to long on the ground.. Yes I used the wrong oil for break in but I still don't see that causing this much damage. I will to post pictures later of the damage..
 
Aeroshell 15W50 should not cause scoring like mentioned above.
The additive package has anti-wear agents that will slow down the break-in period but that should be the "all" of it.

I'm thinking there is some thing else here not apparent to the untrained eye.

Sounds to me like chrome rings in a chrome cylinder.
 
did any one check ring end gap prior to installing the piston?
what lubrication was used as assembly lube?
 
Tom-D said:
did any one check ring end gap prior to installing the piston?
what lubrication was used as assembly lube?
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I did not check end gap, my bad. Purchased an overhauled cylinder assembly and installed it.
I used Aero Shell 15/50 as an assembly lube...:(
 
AKBill said:
I did not check end gap, my bad. Purchased an overhauled cylinder assembly and installed it.
I used Aero Shell 15/50 as an assembly lube...:(
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I'd box it up, send it back to the overhauler and demand a new cylinder kit.
 
Tom-D said:
I'd box it up, send it back to the overhauler and demand a new cylinder kit.
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I'm going to take pictures later this morning and send them to the folks I bought the cylinder assembly from and say for their input. I will give the them full story, wrong break in oil and all .... My plan is to sent the cylinder back..
 
Checkout_my_Six said:
well....improper end gap could cause a ring to snap. :eek:
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Agreed but when you buy an overhauled cylinder assembly you would thing that is done as part of the overhaul. That is why I did not check it. Never again is all I can say..
 
AKBill said:
Agreed but when you buy an overhaul cylinder assembly you would thing that is done as part of the overhaul. That is why I did not check it. Never again is all I can say..
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I've had to make adjustments to brand new assemblies from Lycoming.....so, it's no guarantee, but worth a shot in letting them know.
 
Checkout_my_Six said:
well....improper end gap could cause a ring to snap. :eek:
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When well supported in a new piston ring groove it may not.. but it will skuff like hell
should been very difficult to install the piston in the cylinder. but it will go with a bigger hammer.
 
Tom-D said:
When well supported in a new piston ring groove it may not.. but it will skuff like hell
should been very difficult to install the piston in the cylinder. but it will go with a bigger hammer.
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hammer is not needed.....the choke area will do the end gap in....specially when affected by extreme temps.
 
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are you certain this overhauled cylinder had end gap clearance? They'll go together fine without a hammer and the wrong clearance.
 
Checkout_my_Six said:
are you certain this overhauled cylinder had end gap clearance? They'll go together fine without a hammer and the wrong clearance.
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That's the big thing,, we know squat about this cylinder. You are assuming it was done correctly, so did the owner.
 
I just overhauled a Lycoming IO-540 and used new cylinders from Lycoming on it. Every single cylinder was good on ring end gap at the bottom, but had problems in the choke area. If the new cylinder has a choked bore do not assume anything, check the ring end gaps as prescribed in the Lycoming overhaul manual.

One of the cylinders was so tight in the choked area that it butted every ring. It would have done a number on the piston and bore, had I not checked.

I personally agree with Tom, I do not believe the choice of oil used for assembly and break in was the primary problem here. It isn't good for break in, but I don't think it did the damage observed.
 
nrpetersen said:
(Pulled the cylinder yesterday and the rings and cylinder walls and piston are scored, beyond the point of any repairs.)

Was this cyl on the right side & was the scoring worst on the top surfaces? If so, it may be cold start damage after a long shutdown. Oil spray from the rotating crank etc will get to the upper surfaces of the right cylinders last. Just a theory of mine.
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For what it's worth, most of the engines I've disassembled have had scuffing on the thrust side of the piston, regardless of which side of the engine the cylinder is installed on. One side of the engine will have pistons that are scuffed on the bottom, the other side will be scuffed on the top.
 
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