Who is brave enough to tell me? :-)

Right after I got my Type I engine for my =9173 Beetle built with nearly all new parts, I drove it around a residential neighborhood with plenty of stops and starts for about 30 to 45 minutes. That way it had some load on the engine verses letting it idle for 30 minutes with occasional revving it up.

Check the John Muir =91=85Keep it Alive=92 book for some more tips.

I got this from Rob and Dave=92s vw-resource.com.

"Run-In" After having your engine rebuilt you should take it easy for a few hundred miles. If it's not a complete rebuild a full run-in won't be necessary, but gently on the new bearings is a good idea. That run-in can be on the road -- just light on the throttle and don't load the engine hard -- use more rpm and less heavy throttle rather than the other way round. A full run-in is needed to harden new cam lobes - at first start go straight up to 2500 rpm and hold it there for 15 minutes, then change the oil. Then gentle driving for 500 miles and change the oil again, then it's finished. The high speed first run is supposed to be fine for rings and pistons since the engine is unloaded, but it's essential for the cam or it won't last. If you're only replacing the engine case, that means the cam shaft, pistons, cylinders, heads, valves etc. are all the same, so running them in is not necessary. But the crankshaft bearings will be new, and a little gentle running till they settle in is wise. Only one oil change should be necessary at 100-200 miles, just to flush out any particles which may be in there from the internal work that has been done. Then you can revert to the normal 3000-mile changes. The mechanic who replaced Dave's engine case and crankshaft said that run-in wouldn't be necessary. He put all of the parts together with oil, he said, so a preliminary spin wouldn't be necessary. And he said it wouldn't be necessary to change the oil for 3000 miles. Rob said, It's only precautionary, a few hundred miles is enough to dislodge any tiny fragments of metal which are always likely after a rebuild of any sort, no matter how careful you are/he is. I'd rather flush away a sump full of good oil than risk anything staying in there for 3000 miles. And a quick check of the valve clearance when you first change the oil to make sure nothing has tightened up and they should be fine. ~~~

To break in the piston rings & cylinders:

Drive at slow-ish cruising speed, and floor the throttle. Do not downshift, stay in relatively high gear. Let the engine build speed slowly, intentionally staying in "too high" gear for acceleration. You want to put load in the engine, make it sweat a little as if you were going uphill. When it has picked up speed and rpms, take your foot off the gas and let the engine slow the car down to where you started from. Then floor the throttle again and repeat the procedure. You can do this very effectively on an empty stretch of road somewhere, where other traffic won't get disturbed by your fluctuating speed. This is more efficient at pretty low speeds, maybe 2nd gear and 1500 rpms to 3000, then back again. Try to do this for 15 minutes or so, taking breaks every few minutes. It's not THAT critical.

You can pretty soon move on to normal traffic, just adopt a driving style where you accelerate full throttle from low rpms in a tall gear, rather than downshifting for better acceleration and using part throttle (as you would in a normal situation). When approaching intersections or red lights, use downshifting and engine braking instead of the brakes, to slow down. In other words, load the engine at low rpms when accelerating, and let it be your brakes when slowing down. If there's someone behind you I would put slight pressure on the brake pedal too just to turn on your brake lights, so they won't rear end you!

You can do this for a day or two, then go back to your normal driving habits, whatever they may be :D After the first hours of driving like this, most of the break-in will have happened.

Change the oil when you are done.

make sure your wastegate isn't sticking open, then just run it through the gears at full boost two times... enjoy...

Run one 4 minute race on a dirt track with no air filters and an open engine bay. Purdy much takes care of it too. :)

I had a set of pistons and rings from a turbo race engine kicking around the garage one time, and I took the rings off of one of the pistons. I spread the first compression ring open a little to get it out, and it wouldn't go back. I could bend it to almost any shape I wanted and it would stay. No springiness or tension left in it.

don't need it the pressure will push it out against the cylinder....LOL

I realize the idea is to get the rings to heat up (specifically the leading edges), then cool to conform to the cylinder. Honing the cylinders makes that more efficient.

But how do you think that works with plated cylinder walls?

can't help ya there John.... I can only assume(yeah, I know) that the rings are of a different composition for plated cylinders... purely speculation on my part...

Perhaps someone reading this knows... did VW themselves do anything specific to break in new engines? There's no way they had time to drive each new vehicle to seat the rings.

Max

AFAIK each engine was test run (broken in to some extent at least) outside of the car, as they got assembled.

Jan, one of the video links you posted some time back showed each car hitting a chasis roller at the end of the production line to test the running gear...

The engines where also run at stands before they where hooked up to the chassis.

J.

Any details on this procedure? Was it long enough to test for leaks? Or just to make sure it would run?

Max

You can find the video on uTube, no details though. Try Google and Wikipedia.

J.

I don't doubt that there is a video.

The point of my question is to find out what, if anything, VW did to seat the rings on brand new engines. It seems like a lot of people are advocating a variety of techniques to do this ... and it might be sufficient to just drive the car normally.

Max

Max, and all,

I am getting the impression that the notion of seating the rings is urban legend, based on how many people I have asked whose opinions I think I can trust. How do all these new engines get broken in (ring- wise?) Not on an engine stand, as there is no load.

Thirty five years ago, when building V8 engines for drag racing, I never once broke in an engine before I took it down the track at top speeds. Build it up in the pits, fire it up, and run it, (SS, MP, and the like, no nitro and they sure seemed to run okay, week after week, till I pitched a rod through the block, or rolled the damn thing lol! No one I knew at the track ever "seated" the rings prior to making the first run on the new engine.

When I would rebuild a street car, not for racing, I did make it a point to 'stress' the motor thinking I was seating the rings, but I have zero proof if that did anything of value. Never had anyone come back and complain about compression, or blow-by, or performance issues I have never bought a new car, but I am quite certain that the owner is not told to go run it up and down a medium grade for half an hour to break it in. They are told to just go easy with it for a time, and to change the oil at some point mentioned in the owner's manual.

On AirCooled.net is a nice writeup by John about the air cooled breakin, but he also says that unless the thermostat and flaps are working, the engine won't ever get hot enough and the rings may never seat, which makes no sense to me, as the flaps fail open, so the engine will heat up and break in, regardless of the t-stat. Just pointing it out to show how I don't think many people really know for sure if its required, and more important than that, if its necessary, I am still looking for documentation on how long it is necessary to "abuse" the engine to seat the rings.

Jan is the very first person (out of several dozen) who has even mentioned an amount of time for the ring breakin. Everyone else just says to do it, but never says for how long, and I cringe at some who say for 500 miles, as that is just insane.

I think I will take it out, and give it half an hour of accel/decel in high gears on some of the grades around here, and then just drive it nicely for the first 500-1000 miles, staying away from constant 60mph runs on the highway. If it doesn't work, who knows if I will ever be able to prove it? :-)

Thanks a lot for the ideas, and the exchange of stories and info.

Al

just because the thermostat is designed to fail in the open position does not mean then engine heats up.... an overcooled engine is an overcooled engine.... I'm not sure why folks can't wrap their heads around why a thermostat is a good thing... the air is the medium, the thermostat is the control, just like water cooled cars with thermostats... either one with a failed(open) or missing thermostat can and will run cool...

that said, you can cook an engine lugging it even without a thermostat... load and heat seat rings, it's nothing new, always been that way... and it takes very little time in my experience...

And I just pulled that out of my a$$ :)

When I build my 1776 years ago, I used a leak-down tester to track when the rings were seated. On the bench, all four cylinders came up around 50%, new rings leaking like crazy. Then I just drove it. After a couple hundred miles (one tank of gas), I repeated the leakdown test. All four cylinders were under 5%.

Done.

Max

Because its an air cooled, not a water cooled, and once the t-stat is fully open on a -hot day-, it NEVER closes. Its only function is to speed the warm up process, in an air cooled. The t-stat in a water engine controls the temperature of the engine on a hot day by monitoring the coolant temps and using the rcooler water in the radiator to control it. The air cooled t-stat has no cooling source to turn to when things get too hot. Its not a thermostat in the same sense as a water cooled version. that is why no one can wrap their head around it. Its a false notion from the beginning

Toss in the fact that that there are no t-stats for a Type IV, if we accept that position, it means no one can rebuild and breaking any more air cooled Type IV engines.

No, I am not gonna afro-american rig a beetle t-stat.

John