Piston ring cleaning

[grandpa Love]

Wanting to verify my thought process. Once a motor is unstuck and turning we like to pull the pistons out and make sure the rings are clean and not stuck. We assume that if we torque the Connecting rod bolts back to spec everything is fine......we are really careful to get everything exactly back how it comes off. Second question, if we pour a thin fluid on top of the pistons and it drains past 2 pistons in a couple hours, 1 after 12 hours and one is still holding fluid 2 days later,what does this say about the rings?

 

[Janicholson]

Thin fluid as in benzine, or diesel should flow past a piston in a day or so (maybe an ounce) the ring end gap and skirt clearance is enough to allow that. I also recommend cleaning ring grooves and making sure the ring to groove clearance is at or less than .0015". new rings can be well worth the effort if the cylinder is not worn beyond .004, and the ridge is removed from the cylinder top. Good questions, and thank you and yours for being the careful mechanics you are!!! Jim

 

[Gary Mitchell]

Thin fluid as in benzine, or diesel should flow past a piston in a day or so (maybe an ounce) the ring end gap and skirt clearance is enough to allow that. I also recommend cleaning ring grooves and making sure the ring to groove clearance is at or less than .0015". new rings can be well worth the effort if the cylinder is not worn beyond .004, and the ridge is removed from the cylinder top. Good questions, and thank you and yours for being the careful mechanics you are!!! Jim

One thing I'd like to add is, (and I've resurrected a number of old red corpses), when reusing inserts or main bearings I always swap them top for bottom unless wear is really minimal. You don't have to think about that long to get why. gm

 

[used red MN]

Did you have the pistons all at the same level? Cylinders wear in a taper, if the pistons were at different levels the cylinder diameter may have been larger for some and smaller for others. For one that would change the end gap that the fluid could leak through.

 

[wore out]

Wanting to verify my thought process. Once a motor is unstuck and turning we like to pull the pistons out and make sure the rings are clean and not stuck. We assume that if we torque the Connecting rod bolts back to spec everything is fine......we are really careful to get everything exactly back how it comes off. Second question, if we pour a thin fluid on top of the pistons and it drains past 2 pistons in a couple hours, 1 after 12 hours and one is still holding fluid 2 days later,what does this say about the rings?

It would be interesting to overhaul the engine with new pistons and sleeves, break it in for a couple of hundred hours, then repeat your test.

My GUESS is that fluid would leak past the new parts much faster than it did past the carbon, gunk, and goo on the used parts.

 

[grandpa Love]

Did you have the pistons all at the same level? Cylinders wear in a taper, if the pistons were at different levels the cylinder diameter may have been larger for some and smaller for others. For one that would change the end gap that the fluid could leak through.

They were all even