old piston rings???

[hypedz34]

i just tore my z34 engine down to the block and was wondering if i could reuse my piston rings.i cleaned them up a little to check for cracks or any warping and they look good still.any help is appreciated thanx

[pocket-rocket]

It would be best to get new ones, but I've seen old ones reused. Just be sure to at least hone the cylinders to give them something to bite back into and watch for oil consumption until they wear in again.

[neo71665]

I wouldn't risk it

[asylummotorsports]

How soon do you want to do it all again?

[hypedz34]

ok thanx a bunch just ordered some new ones.also where could i locate the thread on cam timing?i have a couple questions on cam timing.

[bszopi]

http://60degreev6.com/content/Cam_Timing_Picture_Walkthrough

[60dgrzbelow0]

I just tore my z34 engine down to the block and was wondering if I could reuse my piston rings. I cleaned them up a little to check for cracks or any warping and they still look good. Any help is appreciated. Thanx...

The reason not to consider using "used" rings has less to do with the conditions of their chrome-molybdenum coated edges and more to do with their ultimate loss of resilient "springiness" to be able to seal the cylinder walls very well after so many millions of flexing cycles. Like rubber bands and human blood vessels, metal loses its strength and ability to sort of bounce back from the kind of fatigue that sets in because the upper third of each cylinder tends to wallow out wider due to the changes in the directional forces of the connecting rods against the wrist pins... causing each piston to cant from side to side and sort of dig into the top of each cylinder in line with these forces. Metal fails at the atomic level when their fresh, larger crystalline molecules heat up and while bending, creating ever smaller and denser crystals ..."work hardening"...and will do so until the crystals part and the metal fails completely. You can demonstrate this yourself with just a Paper Clip and the patience to bend it back and forth until it heats up from these internal issues and breaks on its own. The same things can happen to piston rings, too.

To compensate for this ever widening area, the piston rings are designed to expand into this wider area and this constant flexing in and out to go from wider at the top of each cylinder to being squeezed tighter at the bottom eventually fatigues the best of them. But as the engine ages and wears...so too does the ability of the rings to "spring back" and make a proper seal. Soon the engine oil invades the cylinder and begins to mix and burn with fuel and performance gradually dies as the oil in the crank case is infected and diluted by gasoline making its way under compression past those tired rings, making matters worse by thinning out the life's blood of engine oil and its ability to stave off engine wear. This is yet another reason to invest the time and money to have the engine block boiled out, and have the cylinders bored slightly larger to make them essentially straight again for the brand new piston(s) and ring set(s). Putting New Pistons and Rings in a Worn Block... is like putting a Fifty Dollar Saddle ...on a Two Dollar Horse.

The only thing these old rings are good for (and this must be done with gloved hands to avoid sharps injuries) is to break the solid edged rings into 2-3" curved lengths and lightly dragging these segments around the grooves of any re-usable piston sets to remove baked on carbon deposits that remain after their final cleaning... pulling only in one direction... with the broken edge trailing flat inside the grooves so as to avoid either scoring the aluminum areas in these valleys or damaging the adjacent lands and cracking them during this process.

[blowns10]

x2

Very well put!!.

NEVER REUSE PISTON RINGS

[3400-95-Modified]

All of this does depend on the current mileage and age of the rings though... Just remember that.

I've reused rings with 60k miles on them in my other 3400, and I'm reusing my current rings in my engine since they do not have that many miles on them and the cylinders are far from worn.

But on a higher mileage engine, I will agree with 60dgrzbelow0

[hypedz34]

yea the rings have 166k miles on them so im deff going to replace them.i just figured i would ask in case i would be able to reuse them.cause you never no.also thanx everybody for your help and also for the cam link