93 this 350 running very rich

[Scooterwrench]

I reckon that's one way to seat rings. The preferred method is heat cycling. Start a new engine and run it at 2000 rpms for about 1/2 hour. Shut it down and let it thoroughly cool then repeat two more times at about 1500 rpms. If the rings aren't seated by then they ain't gonna. Your WOT pulls more than likely cleared the exhaust and O2 sensor of built up carbon.

 

[Schurkey]

Piston rings need cylinder pressure to seat.

Best solution that doesn't involve a dyno is to warm the engine by driving 10 or 20 miles out-of-town on a semi-deserted highway, turn around, disable the auto trans kickdown if applicable.

Accelerate normally until the trans is in HIGH (1:1, not overdrive) gear. You want large throttle opening, but NOT high RPM, so open the throttle as much as possible without "ping", and without the trans downshifting to a lower gear. Hold or increase that throttle opening until you're at the speed limit for the road you're on. Then pull your foot off the gas pedal, coast down to your starting speed, and repeat until it stops being fun. 10 pulls ought to be enough, with the biggest difference in power happening on the first and second pulls. But what the hell--you're already there, enjoy yourself, do a few more.

Heavy throttle gives high cylinder pressure, coasting brings high vacuum to get oil up to the rings to wash-away wear particles. Sub-2000 rpm to 3500--4000 rpm is probably ideal but can vary depending on tire size and gearing; and the speed limit of the road you're using. Anything over 4000 rpm on an automotive/light truck engine is wasted. High cylinder pressure, NOT high RPM.

Do this BEFORE you wear the texture off of the freshly-honed cylinder walls. The flat-tappet "camshaft break-in" is actually somewhat counter-productive to seating the rings...it's a necessary evil that we do because flat-tappet cams 'n' lifters are even more sensitive to break-in than rings.

Lake Speed Jr. is a representative of Total Seal piston rings, formerly with Driven Oil. He makes me a little crazy, and overall I don't think this is the greatest presentation...but it mostly mirrors what I've said above. High cylinder pressure, then high vacuum, alternating; high RPM not needed for ring seating.

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[jshfchtr]

I just walked over and started the truck again and 10 minutes of idle and zero smoke, I’d say the issue is fixed. Had the truck been street ready and licensed I’d probably never had noticed anything wrong, it’s weird to think me playing things legal and safe bit me in the butt.

It’s interesting to see the different methods of seating rings, I work in a shop that specializes in transmissions and formerly was a complete engine machine shop, one of my coworkers was the lead machinist and transitioned to transmissions when the shop decided to stop machining. I leaned pretty heavily on his expertise, he even broke out the old machines and bored and honed my block for me. His recommendation for setting rings was get the motor up to temp, find the biggest hill you could and engine brake in low gear down the hill to set the rings. In essence that’s what I did, just without the hill and probably more violent than needed.