ring break in question

I have heard from 3 different sources about a different ring break in method. Curious if anyone has experience with this. The idea is to have the fresh pistons and cylinders installed. Leave the head off. Connect an electric motor to the crankshaft and let it spin for perhaps an hour. The idea is that with no oil or heat on the cylinders the rings will have a much better chance of breaking in right away. I would imagine that the oil supply to the bottom end is connected and full and circulating.

Caint fix stupid.
br oil is your friend

So, you asked 3 people and got 3 answers.

That‘s a conundrum for sure. But not one the Internet will fix... you’ll now get dozens of different answers...!

Personally, if in doubt, I just ask myself what OEM engine builders do. They might not be building blue printed race motors, but they build engines that work.

I‘m not aware of any OEM engine builder who does what you suggest. They build the engines, put oil in, and run them.

Years ago when racing and going through a seizing up phase, I bedded new rings into the bores by hand, working the piston up and down with fine metal polish on the rings. Checking until I’d got the cross hatching and the rings ‘just so’. It was a real tedious process and in hindsight I’m convinced it was a total waste of time.

Bottom line for me these days, unless you‘re building something very special with space age tolerances etc: just build the motor, with oil, and break it in ‘sensibly‘ on the road.

My problem is that I live in the city and breaking in a motor is difficult to do on city streets. Usually I can look down the spark plug hole and see a small amount of oil on the pistons for a few hundred miles even though I do everything I can think of to get things right. I've said that the rings are not fully broken in until 1000 miles. I would like to hasten the procedure.

All I have done is put a light coat of oil around the rings for the ring compressors to slide off as the pistons are going in the bores and no oil on the bores, once the motor has fired up the oil will be pumped throughout the motor including the bores, rings don't take long to bed in, but the secret in running in a motor is not to labour the motor at anytime and the rings should be bedded in within the first 100 or so miles, my first rebuild on my Norton I put to much oil in the bores and the rings didn't bed in and glazed the bores so now all engine rebuilds I do are dry bore and let the pump do the lube when fired up and running.
But of course everyone has other ideas but this is the way I have done it on all the British bikes I have rebuilt including a few Norton motors and have had no problems with ring bedding in, so dry bore for me.

Ashley

seattle##gs said:

My problem is that I live in the city and breaking in a motor is difficult to do on city streets. Usually I can look down the spark plug hole and see a small amount of oil on the pistons for a few hundred miles even though I do everything I can think of to get things right. I've said that the rings are not fully broken in until 1000 miles. I would like to hasten the procedure.

Click to expand...

City riding is good for breaking an engine in. Lots of variety in the engine loading, including engine braking. Shorter runs and more expansion / contraction heat cycles. The last thing you want is steady 60mph on a highway for hours. Just avoid abusing the throttle.

“I live in a city,” he says.
The engine is not interested in excuses.

There are places in cities where you can give it bursts of throttle in second gear. There are even places outside cities that you can transport the bike to.

Your electric motor idea is silly. It does not replicate the high pressure conditions in the cylinder of a running engine.

If you ride in the city I’d argue you really don’t have to worry about deliberately riding slowly. On the contrary, try to ensure you open the the throttle, do some traffic light drag racing, etc. A good burst of throttle is good, especially if followed by closed throttle engine braking as that draws oil up the bores.

The main thing you gotta think about here is not over thinking it !!

Just ride it.
Get up real early & ride OUT of the city.

0-30mph quickly is as good as 30-60mph quickly.

kommando said:

0-30mph quickly is as good as 30-60mph quickly.

Click to expand...

But stuck in heavy traffic may be create an overheating event, the one thing everyone agrees on about break-in.

seattle##gs said:

I have heard from 3 different sources about a different ring break in method. Curious if anyone has experience with this. The idea is to have the fresh pistons and cylinders installed. Leave the head off. Connect an electric motor to the crankshaft and let it spin for perhaps an hour. The idea is that with no oil or heat on the cylinders the rings will have a much better chance of breaking in right away. I would imagine that the oil supply to the bottom end is connected and full and circulating.

Click to expand...

I was rolling a rebuilt engine over yesterday, head off, and had the same thought. And I've been playing or working at this for a long time!
I'm surprised that a couple of people felt the need to tell you your idea is silly or stupid.
I can guarantee they haven't tried it, so they don't know.
Breaking in a rebuilt motor in the city is difficult. It can be worse than the freeway. The problem is, unless you break the law, you have very little choice on speed, length of idle time etc.
Back in the late 60s, before I had my road licence, I had good small business going rebuilding the local Honda engines. People speak of those old Honda's in revered tones, but they were a throw away motorcycle. Nearly anyway. At 10-15 thousand miles these little bikes were worn out in the top end. The bottom end had life remaining.
I would hone the bore, install new rings, lap the valves and the bike would run clean again for another 7 or 8 thousand miles. Then it was throwaway time.
I did about 30 or so of these low cost rebuilds and the only one that failed was a Honda 250 Dream belonging to a customer from downtown Vancouver. He rode the bike daily in city traffic commuting to work. The rings did not seat.
He left the bike with me for a weekend, so I scrambled with it in the gravel pit next door. A 250 Dream is a lousy scrambler but the exhaust ran clean by Sunday night.

I will probably stick to my tried and true method of breaking in, but I found your question interesting.

Glen

Directed at the OP.

Much ado about nothing. Just don't lug the motor.

If you built the motor right, you should be able to ride it like you stole it from the get go without hurting anything.

Have somebody trailer you to Arlington. Get on 530 and ride it to Rockport. Park it, and let it rest for 45 minutes and then ride it home. That route will give you all kinds of opportunities to run the motor at various loads and RPM. Or not

Without combustion pressure to push the rings against the cylinder, the spintron would not "break in" the rings.

Probably, but I'm not sure on this.
After just a few rotations checking timing etc it's easy to see that the rings are changing the honed surface of the bore. Using a magnifying glass, I can see the contact points forming and quickly widening out.
It is bedding in and it definitely won't glaze ( no heat).

Glen

I see.

When I hear of people running rings dry or whatever to accellerate "break in" I think about how long rings last before they wear out or the bore wears out. I'm more concerned about longevity and the smoking that comes from wear. Why shorten the life span of your motor? Just take it easy on a new motor for the first few hours and then do what you want. If it was built with the right clearances and tolerances you have nothing to worry about.

Jim I have had long life out of my bores and still the same rings on the pistons, I did a tight finial bore to hone job less than the recomaned advice am running Hepolite pistons and the rings they came with back in the 80s and as I have said the ring were lubed just not the bores, it don't take long for the oil pump to lube everything.

Ashley

It an antiquated engine from the who knows what era that they continued making bigger and has a iron bore which could be any shape but round the first time you cook it on a long up hill run.
Who knows what the cylinder and head temperature is sitting at traffic lights for any length of time.

Don't thrash it, don't labour it, give it some mumbo, give it some closed throttle, the rings will like it.
Run it then stop and let cool but not to cold.
If you have running in oil dump it at the recommended mileage and run some mineral, 300 miles / 500 kms should be enough.

After that do what you like.

I oil the (iron) bore lightly and never use ring compressors.

Once you hit the road and start varying the throttle/load the engine will reveal the point where it is tight, this is much easier to feel/notice when the bore has been machined to except new piston assemblies. I like .0045 skirt clearance so the tight spot is easily discerned. I use WD-40 and fingers to get the piston assemblies installed. Most engine builders have a pet preference for the lube they use, but no more than a light coat.

If you have only replaced the rings, made certain the end gaps are at spec and that the bore isn't tapered then Time Warp's advice is right-on. The rings will expand as you increase the load, so varying the load, without lugging aids their break-in. You should be able to feel the increased torque as they settle in; my experience is that 200 to 300 miles should complete the process. During the break-in process you will need to do many carb adjustments/syncs as the cylinders, typically, don't share the same bed until a leak-down or a compression test tells you that they have the same test results.

Best.