How long before rebuilt engine rings seat? EDIT. Help a 1st time engine builder.

[brianao34]

So I have approximately 120mi on my freshly rebuilt S50, replaced everything except for non essential wear items (crank,cams,pistons).

I've been following this guy's method. http://mototuneusa.com/

And I've heard anywhere from "they should seat at idle" to 2000miles before they seat.

Can anybody answer from personal experience how long it took their rings to seat and rebuilt engine to stop smoking?

Thanks

[Dj Buttchug]

its not so much seating rings. I think the term you are looking for is lapping the cylinders in... ?

in most cases a new engines rings are fully lapped in at around 100 miles. its also a good idea NOT to use synthetic oil in a new engine.

[redsubdivisions]

On my KA rebuild in my 240, it was less than 100 miles. Just run a little thicker oil to let it seat and you should be alright.

[mrsleeve]

You should be lapped in by now

[Cabriolet]

if you put them in correctly. they will set guaranteed in 4 pulls. if they haven't set in less than 100 miles, you F'ed something up. I've personally done 4 m20 engine's rings and one other ford engine and one VW. all the rings set by the second heat cycle.

[brianao34]

Ahh, come on, someone give a random story of hope for me

[butters]

I'm with the mototune theory as well and rebuilt my S50 a year ago. I went straight to synthetic (the rotella 5w-40 good stuff, though now I'm wondering if that's necessary especially in cold temps).

It didn't smoke even when I first started it up so.... yea. If that's the indicator, I'd say mine were seated/lapped right away.

Then again, I was lucky enough to have Brian and the guys at M&B Cylinder in Portland do the machine work and assemble top & bottom ends, and if you've seen HPF's "secrets behind 1000whp M3" video walkthrough of the process, you know they take it seriously and have tons of experience with this family of motors.

[quickervicar]

Not personal experience, but Porsche guys tend to be very insistent on seating the rings both on the throttle and off. (seating both faces with higher cylinder pressure & vacuum of trail-throttle)

Diesel guys will say 10,000 miles before they see a bump in compression & economy. But we're not talking diesel tolerances in these engines. Also, a diesel mechanic friend says that they used a white powder (I'm assuming something cheaper than cocaine) to pour into a cylinder that isn't sealing right. It was a mild abrasive that broke down right away but allowed the rings a chance to seat again.

An independent Euro garage I know refuses to oil the cylinder walls on VW & M-B diesels when he rebuilds them. He starts them dry & they seat by the time oil gets pumped to the walls.

EDIT:

Found it! http://www.jegs.com/p/Total-Seal/Tot...50299/10002/-1

Might be worth pulling the plugs and dumping a bit in

[brianao34]

Not personal experience, but Porsche guys tend to be very insistent on seating the rings both on the throttle and off. (seating both faces with higher cylinder pressure & vacuum of trail-throttle)

Diesel guys will say 10,000 miles before they see a bump in compression & economy. But we're not talking diesel tolerances in these engines. Also, a diesel mechanic friend says that they used a white powder (I'm assuming something cheaper than cocaine) to pour into a cylinder that isn't sealing right. It was a mild abrasive that broke down right away but allowed the rings a chance to seat again.

An independent Euro garage I know refuses to oil the cylinder walls on VW & M-B diesels when he rebuilds them. He starts them dry & they seat by the time oil gets pumped to the walls.

EDIT:

Found it! http://www.jegs.com/p/Total-Seal/Tot...50299/10002/-1

Might be worth pulling the plugs and dumping a bit in

Yea, I did just as much if not more "engine-breaking" along the way.

I've read up on that powder stuff and I think I'd rather tear it all down then toss some of that in there. Thanks though.

I'm going to ride it out a little more and hope for the best. :(

[der affe]

The powder is comet. I have used it on stubborn rings and it works.

[jlevie]

If the cylinders were cross hatched honed and the ring gaps are correct, the rings will seat immediately. If that was not done it can take a lot of miles to get the rings to seat, if they ever do.

When I build an engine I use Brad Penn 20-w50 oil, prime the oiling system with an electric drill, bring the engine up to temperature while bleeding the cooling system, and break it in by a 30 minute run at a constant 2500rpm. The rings will seat and the smoke will stop after 5-10 minutes.

[TobyB]

...and I'm a big fan of the 'warm it up, and get on it' method.

Done 5 or 6 engines that way, and they always seal well. Better than the constant idle...
...and the cam doesn't mind, as long as it doesn't idle below Jim's 2500 or so.

If yours is still burning oil at 120 miles, warm it up and do a series of 6k pulls
at wide- open throttle, with a 'lift and coast' with closed throttle.

What I've found, on everything from M20's to G72's...

t

[Dj Buttchug]

a new engine built correctly shouldnt smoke at all... OP who did the work? You? Post your measurements maybe?

[brianao34]

a new engine built correctly shouldnt smoke at all... OP who did the work? You? Post your measurements maybe?

I did the build, it's my first build so I expected something to go wrong, hated that it had to be the rings though...
I don't have measurements anymore, but I followed the TIS religiously. Made sure I clocked the rings, triple checked the ring gap, made sure they weren't upside down, etc.
I used WD-40 during assembly to keep rust off the cylinder walls. And at some point I put a little Marvel Mystery Oil in the spark plugs holes when the engine was complete because it sat for 4-5 months before I could put it in. That may have done me in.

I'd like to hear more on this comet thing if that might actually work on a modern engine. Burned 5 quarts of oil today driving hard for around 75 miles.

I'll be doing a leak down test tomorrow.

Compression tested today and it was 200-210 across the board, but I don't know how accurate that is considering each piston looked like it might be a little wet from oil. Smh

[Dj Buttchug]

I think you are correct in that the mystery oil added in the cylinders is the reason. Most BMW engines require the rings to be installed dry into a dry cylinder wall.

FUUUUUUUUUUUUU

:(