3.0 P&C's, replace or run?

[simsalabim]

My Alusil set all came back within specs for taper, roundness and ring landing dimensions. Before they were removed, my leakdowns were all at or less than 2%.

Then, the number 6 revealed it had a bit of a snack sometime or another (see photo). The fingernail test is marginal, and I am considering hand dressing and running it as opposed to spending the big bucks for a whole new set.

I am quite aware of the debate surrounding Nikasil vs. Alusil , but at this point, I am just trying to figure out if I am crazy for thinking I can run what I have with this damage.... suggestions? opinions? all are welcome!

[Eagledriver]

I wouldn't worry about the scratches on the piston skirt. If you have scratches like that in the cylinder, you have a problem. One thing about these pistons is that they have a coating on them to keep them from gaulling on the cylinders. If you dress the scratches you'll remove the coating.

-Andy

[simsalabim]

Thanks for the input Eagle D.

I will post a photo of the corresponding cylinder soon. In the meantime, even though everything measures out in spec, should I be concerned that the P&C's are a high mileage set? Any metallurgical etc. issues here?

[roblav]

Check the ring groove thickness.

[Eagledriver]

I have rebuilt several 3.0 and 3.2 engines for my street and race cars. The only things I've ever found out of limits is the top ring groove. I would reuse this set with the original rings if the ring end gaps are in limits, the cylinders have minimal ware (never seen them wear out) and the scratches aren't too bad. I've had good luck with Alusil, using the old rings. Really the only alternative is a 3500 dollar set of brand new Mahle's. Any used set's are probably no better than what you have.

-Andy

[simsalabim]

Thanks much for the input Andy.

Would it change your mind if I told you these have almost 200k miles on them?

Again, ring grooves are good, and the corresponding cylinder scoring is not that bad (awaiting photo to post).

$3,500 hurts to think about... but, so does another rebuild. Still, 2% leakdown ain't so bad even if it was at TDC.... decisions.

If I can find a good used set of Nikasils with half as many miles for a decent price, wouldn't that be best?

Thanks again for lending your experience!