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-   -   New Engine Break-in: flakes in oil filter (https://vansairforce.net/community/showthread.php?t=128939)

lr172 08-27-2015 04:00 PM

Quote:

Originally Posted by rhill (Post 1009490)
Problem,....... Can't mix pins with out replacing the opposing cylinder pin. These should all be up-graded to Heavy wall and your choice of plug end or the superior type with plug ends built in. Did you weigh your pistons to see how close a match they are? Most case shops leave the oil galley plugs out for you to clean before assembly
RHill

My rods were balanced by the shop, but I did not weigh the pistons. My pins are all heavy wall pins. ECI told me that the new pins were matched weight to the old pins. After installing the engine I wished I had weighed them. How critical is it to replace the opposing pin?

Larry

rhill 08-27-2015 04:10 PM

Quote:

Originally Posted by lr172 (Post 1009494)
My rods were balanced by the shop, but I did not weigh the pistons. My pins are all heavy wall pins. ECI told me that the new pins were matched weight to the old pins. After installing the engine I wished I had weighed them. How critical is it to replace the opposing pin?

Larry

Unless you have a balance issue,I'd forget about it.This was from a yellow tag included in my piston box's. Same with the aluminum in the filter,change the filter out early and see what you have.If it ain't broke don't fix it! Down the road you can pull the plugs and scope the cylinders to see if there is any scoring,easy enough to do.
RHill

lr172 08-27-2015 04:40 PM

Quote:

Originally Posted by rhill (Post 1009498)
Unless you have a balance issue,I'd forget about it.This was from a yellow tag included in my piston box's. Same with the aluminum in the filter,change the filter out early and see what you have.If it ain't broke don't fix it! Down the road you can pull the plugs and scope the cylinders to see if there is any scoring,easy enough to do.
RHill

I should feel it if I have a balance issue, correct? I suspect the engine can't pull itself apart without feeling something, correct? I wouldn't say my engine is a smooth as a swiss watch, but I don't feel anything out of the ordinary. I will pay closer attention on the next run.

I did not document which cylinder got the new pin, so I would likely have to pull 3-4 cylinders to replace the opposing pin. That means most of the baffling has to come off :mad: I found the SI from Superior, they indicate the weight issue with interchanging, but they don't document the weight difference. If it is only a few grams, I figure it will fall under the tolerances for out of balance rods. Given that my rods were balanced, I should have some room for some weight offset margin. I will call superior tomorrow.

Larry

DanBaier 08-27-2015 04:55 PM

Perhaps another point of view - it isn't especially alarming that a freshly assembled engine will generate some aluminum, and it's very possible that it's the piston pin plugs. But it may not be. Sorry to say, but there are many other potential issues. So, I'd recommend that you just follow the guidance of the service letter (earlier post) and not assume the source.

If, with a little more time, the metal stops showing up in the filter, then I'd leave it alone. I definitely would not pull a jug to replace a piston pin plug. (If somewhere down the line it has to come off, that's another story.)

There are so many reasons that there could be balance issues that it might be easier to take it to a shop that does prop balancing once you get past the question of where the metal is coming from.

YMMV

Dan

lr172 08-27-2015 05:58 PM

rHill may have figured out my shavings issue. My block came back shiney clean from ECI with the gallery plugs out (it had clearly been "hot tanked" as all of the paint was gone). This was my first aircraft rebuild, but have done many auto engines. Auto machine shops (performance shops anyways) fully clean the blocks after machining and the rebuilder doesn't need to clean out the galleries. Though they don't install the gallery plugs for you. I foolishly followed that convention and didn't think to clean out the galleries. If aviation shops don't clean them, that would explain the alum. flakes.

Either way, I will cut another filter at 10 hours. As long as the quantity of metallic debris is on the decline, I'll just keeping pulling filters every 10 hours until comfortable that it has stopped.

Thanks for all of the guidance here.

Larry

lr172 08-27-2015 06:02 PM

Quote:

Originally Posted by DanBaier (Post 1009506)
I definitely would not pull a jug to replace a piston pin plug. (If somewhere down the line it has to come off, that's another story.)

Dan

I was only considering pulling the jugs to replace the pin / plugs due to the weight difference. My current thinking is that there is not enough difference in weight to cause serious issues. Tomorrow I will call superior to find out the actual weight difference and see if I can find out an acceptable tolerance. Because my rods were balanced, I should have a pretty good margin to work with. I don't know what to expect from the piston weights though. They did not list weights on them like performance auto pistons (sold in weight matched sets), but I suspect they run them relatively tight in tolerance.

Larry

BillL 08-27-2015 06:54 PM

Quote:

Originally Posted by lr172 (Post 1009522)
I was only considering pulling the jugs to replace the pin / plugs due to the weight difference. My current thinking is that there is not enough difference in weight to cause serious issues. Tomorrow I will call superior to find out the actual weight difference and see if I can find out an acceptable tolerance. Because my rods were balanced, I should have a pretty good margin to work with. I don't know what to expect from the piston weights though. They did not list weights on them like performance auto pistons (sold in weight matched sets), but I suspect they run them relatively tight in tolerance.

Larry

Good course of action. I wouldn't get all worked up over a little weight difference. If it is within factory weight class, then fly on. The engine certainly won't know it. You probably won't either.

rhill 08-27-2015 09:01 PM

Prop ballance
 
The new Dyna Vibe will pick up prop and crank unbalance.Sometimes you wont feel vibration that the tool will pick up. It's money well spent,have the prop balanced,it will put your mind at ease,any weight difference,will as you noted, be small,pulling the engine apart at this point will do more damage then good.One final note,along with the filter change,pull the finger screen at the back of the sump.
RHill

lr172 08-27-2015 10:53 PM

Quote:

Originally Posted by rhill (Post 1009575)
The new Dyna Vibe will pick up prop and crank unbalance.Sometimes you wont feel vibration that the tool will pick up. It's money well spent,have the prop balanced,it will put your mind at ease,any weight difference,will as you noted, be small,pulling the engine apart at this point will do more damage then good.One final note,along with the filter change,pull the finger screen at the back of the sump.
RHill

Good idea. I figured that I would change the oil and clean the screen at the 10 hour change to get any flakes out of the oil and pan as best I can.

Larry

BillL 08-28-2015 06:21 AM

Quote:

Originally Posted by rhill (Post 1009575)
The new Dyna Vibe will pick up prop and crank unbalance.Sometimes you wont feel vibration that the tool will pick up. It's money well spent,have the prop balanced,it will put your mind at ease,any weight difference,will as you noted, be small,pulling the engine apart at this point will do more damage then good.One final note,along with the filter change,pull the finger screen at the back of the sump.
RHill

Doesn't the accelerometer mount to measure the vertical acceleration? That would not get a piston/pin balance issue, those forces are lateral, and secondary forces.


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