How long does it take rings to seat?

[polizei]

Hey guys, I just finished a top end rebuild and turbo conversion on my Carrera. I swapped the 3.2 L cylinders out for 3.3 L Mahles with 8.0:1 compression pistons. I've got about 700 miles on it since the rebuild, and I'm seeing smoke on idle and on acceleration. Am I correct in thinking that the rings have not yet seated? How long do the rings normally take to seat?

Thanks for your help!

[cgarr]

That depends on how hard you drive it.

[polizei]

Originally Posted by cgarr

That depends on how hard you drive it.

Could you give me a range? Really hard driving = 1000 miles? Really light driving = 5000 miles?

[cstreit]

Hmm... If you drive like a girl, they might never seat.

My method for seating rings? Drive easy for 100 miles to make sure the engine is okay, then beat the piss out of it (keeping the revs down) for another 100 miles. Works every time. YMMV.

[notmytarga]

What do you mean, exactly, by "beat the piss out of it". With your turbo conversion - how have you driven it during those 700 miles?

Wayne's rebuild book gives fairly good detail on the rationale for loading the frontside and backside of the rings by firm acceleration and deceleration. Avoiding going over 5000 RPM etc.

In the first days after getting my now 250 mile 2.7 engine on the road I pulled through my local mechanic's lot to 'honk and rev'. He yelled out to 'not flog it' and 'take it up Buckhorn'. What he meant was to drive HWY 299 past Whiskeytown Lake and up to the top of 3600 ft Buckhorn Summit. It climbs from 1600 to 3200 over about 3-4 miles of narrow tight turns (about a 6-7% grade). Now this made a lot of sense, so of course I did it. I picked a 90ish degree Sunday with two of my kids (14 and 5 yo) who have been anxious for Daddy's "really fast car" to get back on the road.

The load on the rings from the climb and the engine-braking decent was just the ticket. The outside temp during the climb was in the eighties and my oil temps ran as high as 240 but mostly topped out at 230.

I finished that day at 100 miles. Drained the oil, adjusted valves, retorqued headstuds (I retorqued them before placing the valve covers during the rebuild and got a quarter turn then - a wise move I must say; easier and more precise), installed the previously absent thermostat/oil lines/ 28 tube cooler, replaced the master cylinder and bleed the brakes for good measure. The above took three weeks!

With the lines and cooler I have not gotten over 210 F but haven't run the Summit again. I waited to buy the external cooler setup until I knew this rebuild was solid. I think running the hottest during the first 100 miles was a good thing for breaking in - it will rarely see those temps again.

I have been driving around town enjoying fast accelerations and engine braking, keeping it under 5K rpm. When is the earliest I should get it back to Thunderhill for a DE day?

[930gt-40r]

I think (could be wrong) that a combination of high heat and cylinder pressure are the ticket to break-in. How much of it I am unsure of...

[BReyes]

Mine sat immediately. Could it be something else? BTW brings back good memories breaking in Porsche motor. I basically made a lot of noise around town for a day or two . That is what you did too right?

[Laneco]

NOTMYTARGA

That drive up Buckhorn is one of my all time favorites. Absolutely fabulous!
angela

[Henry Schmidt]

Get it hot on a drive alternating loads and RPM for an hour. Let it cool for at least two hours. Make the same 1 hour drive with alternating loads and she should be good. If proper ring sealing has not occurred it may never.

This should be true of new cylinders and used cylinders with new rings. The issue with used cylinders is ovality. Put a round ring in an oval hole and seating could be an uphill battle.

I know ovality is not a word, but if GW Bush can do it why can't I.