i read an article a day or so ago that dave gierki wrote, apparently he's a guy that has been engineering and working with two stroke engines for 30 plus years. he said that newer studies show that engines last longer and run better when they are broken in while running in short, hot, lean spurts and not longer, cool and rich. i was wondering if you guys have heard of that supposedly "newer" way of breaking in an engine. just read that article and it ended up beign a pretty heated discussion with some guys interested in the newer method which they say worked and other guys saying that they choose to go by what the engine manual told them which is running rich. sooooo just want your guys take on that and if you've heard of that debate.

I may have some info regarding my new dirt bike engine rebuild that might shed some light on this subject......While putting in a new piston/rings in my 4-stroke dirt bike,some guys on a motocross forum swore by the "dry method" of breaking in new engines. This is were the put in a new piston/rings without any oil except for on the wrist pin. They just put the piston with the rings on it into the cylinder with no lubrication at all. They also drain out the engine oil from the engine so that when the cranked the engine over at first,no oil would lubricate the cylinder. Once they put everything together with no oil,they would crank the engine over 40-50 times with no lubrication. Then they would add oil to the engine,start in up for a few minutes to get it good and hot(a "heat" cycle they called it),let it cool all the way....change the oil and WALLA,the engine was ready to go beat the crap out of. Some people claim this seats the rings to the cylinder better then the old fashion way,thus making in perform better.

Although this info pertains to 4-stroke dirt bike engines,I'd bet the guys you read this from are thinking the same rules apply to our 2-stroke model engines. This "DRY METHOD" I just told you about sounds just like what you discribed.


I dont know what to think about any of it,but its something to think about anyway.

Yep, it's a bit of a hot topic (no pun intended...but it works well ) and I've read that article by Dave Gierke but from some of the things mentioned it appeared to have been written a very long time ago, back when ABC was quite new and they were still figuring out just how tight to make the pinch. I did an experiment on a brand new ABC to see if I could destroy it by running it very rich and cool right from the first start. I ran it like that for 45 minutes then stripped it down for a close look at everything. The piston was totally undamaged, not a mark on it, so it not only didn't get destroyed it wasn't even starting to run in. I was also checking the pinch during every 5 minute run and it didn't change from what it was out of the box.

That experiment got me to change the way I run in an ABC, now I do the first run in a 4 stroke (maybe just breaking into a 2 stroke a little) then slowly lean each run to gradually build up heat over maybe 30-45 minutes. Others of course vehemently argue with me because they've read something somewhere...I'd prefer to go by what I've found out for myself .

i have overhauled a lot of gas diesel engines both 2 stroke and 4 stroke engines.i always ran them in with no water in the engines for the first 5 minutes to get the rings seated.i dont think i would advise running an engine with no oil.non ringed rc engines need to be ran in a little lean to get the piston properly seated.i agree with what springhillflyer said he read about short lean runs for breakin.but not with ringed engines.

when i broke in my engine i ran it four stroke for a full tank "super tiger 61 ringed" after that i ran i rich two stroke for a tank and then on the third tank i slowly leaned it to where its supposed to be. its running fine now and its not that old, its probably run a gallon and a half through it but the top of the piston and the head are black black black with some sort of residue. where would that come from or what causes it. i did try a bit of homemade fuel for about 5 minutes where i was just burning 80% methly hydrate and 20% oil. engine ran fine at high speed but the transition from low to high was really sluggish so i quit. it was for no longer than 5minutes so i'm curious if thats where that black crap came from.

downunder, i'm not a 100% certain but i think that article was written in 2002.

The standard method of breaking in wide open at full throttle and a little bit rich for lubrication and cooling works very well. Literally hundreds of thousands of ABC engines have been broken in this way and it's working just fine.

Why bother with all the black magic and voodo? Do what works for 99.9999% of other RC guys and break it in just like Dar Zeelon wrote about in his Tapered Bore break in thread. It's in the Glow engines forum and can be found with a simple search for "Tapered Bore"

I have my own slightly modified method of madness, but it's basically the same as whats in that thread. I am a very experienced gear head and I didn't need that article to tell me how to break in an engine. But it's an EXCELLENT reference for newbies or people with minimal experience in the hobby.

Do what works for everybody else and stop trying to reinvent the wheel.

well rcpilot i AM new at this and thats what this forum is for i assume.......i read the article, i didn't know what to think, so i asked. i'm not trying to push anything here.

Hi everyone, I am new to this forum, just signed up. I have been interested in this post and subject for a while now, since I first heard about Dave Giererke's "lean and hot" tuning method. I have read some of Gierke's material and have come to greatly respect his opinions on subjects pertaining to the RC world.
from what I have seen on this forum, there are a few individuals that have been around and seem to have plenty of experience and when they post anything you can right away see the wisdom in their thinking. What I have noticed is that those individuals have for some reason been avoiding this subject... I wonder if this is too contriversial a subject to discuss on this forum.

Any subject is controversial with some people, so don't let that stop you!
The rest of us enjoy hearing differing opinions.

My opinion is that these engines come with up to a three year warranty, and some of these companies have been making engines for quite a while, so break-in should be done according to the manual.

People may have their own beliefs, as with this article, and it may even hold true for people with experience tuning engines. My educated guess is that 2 stroke engines might just 'seat' better with short, hot break-in cycles, but that the chance of something going wrong is greater in this extreme environment. If there are imperfections, they will work themselves in slowly in a highly lubricated atmosphere, and the lube will work as a seal for small openings if it needs to. If it is a lean, hot mixture and there is something that is borderline within tolerance, there is a much higher chance for something to permanently go wrong. Many of these engines are now made in China, and due to their recent problems with manufacturing standards, I wouldn't trust that the tolerances on their engines are as exacting as we might expect them to be.

This is a beginner forum. My advice would be to follow the directions in your instruction manual for break-in. Many of the manuals will specify the difference between breaking-in a ringed engine, which for Super Tigres is 6 min. of running rich before the pinch-and-release test, and for an ABC engine is starting rich and 'leaning out' immediately to the pinch-and-release test (which is not actually running lean).

Running lean for break-in would void the warranty, and yes, they can tell.

Thanks. My $.02

thanks for the vote of confidence there knight74. its just that i can't throw out david kierki's opinion cause i agree with johnwhof here, the man obviously knows what he's talking about and look at his experience which is 30 plus years of not only operating he also engineers them. i'm not saying the members on here don't have that experience cause its obvious they do and i respect that. its obvious rc pilot isn't a fan of lean hot breakins and david kierki is. i don't know any of the two so i don't know who to believe. i've heard of guys trying that method and their engines perform better in the long run. and i heard of guys breakin them in rich with no problems. one way has to better than the other. i'm not knocking anybodies opinion..........its just nice to hear facts.

fatorangekat....do you have a supertiger engine? cause if you quoted the manuel for the breakin procedures our manuels are 80% diffrent. i was told to run rich for two tanks and then go to the pinch method in my manuel.

The pinch at the top of the stroke is how max power is made. It is also an interference fit that is very hard on the crankpin and rod. On a new engine the idea is to get the engine up to temp quickly, but still running at a slightly rich scream. Using an undersized prop helps ensure that the load on the engine doesn't contribute to a runaway excess heat condition. The high rpm break in gets the liner expanded sooner, and the piston speed limits the amount of time per stroke that the piston is in the pinch zone. There really is no controversy, any method will work 99% of the time. Most ABC engines I've handled [recently] that weren't sold for competition have very little pinch anymore. It became too much of a headache for the manufacturers' warranty service, because of the old school know it alls who thought they were breaking in a 1960 Fox .40 iron / steel engine, then had to turn in an engine with a failed rod or crank.

i quoted the manual thats linked on towers site, which is for the .40-.52 range, ABC and ringed. Ive switched to an OS 46AX engine, break-in is different for that engine, and they don't talk about break-in for ringed engines in my manual, which is why I quoted the Super Tigre, just to show the difference.

It's a moot point for most of your mass produced, name brand engines nowadays.....the break in is non critical because they are not sending run of the mill engines out with overly tight fits any more. It is still a good idea to pull the head and backplate to flush the engines out and look for burrs. You would be amazed at what you will find if you submaerge the engine in solvent in a closed jar, then tape the jar to an orbital sander and leave it running for awhile.

If you are ever lucky enough to run across a brand X engine with a lot of pinch, it's like finding a pearl. With an engine like that, I like to pull off the head and backplate, lube the engine with trans fluid and spin the engine for a few minutes with a drill motor until the fluid runs clear.

combatpigg,
By removing the backplate you VOID the warranty, But I agree with you as I have done this for many years.

Cheers

The lean hot short runs followed by rich for a while then lean hot again is exactly what the instructions in my last brand new OS engine said to do and I did. That said I am a firm believer of following the manufacturers recommendations for break in regardless of what any yahoo on the internet claiming to be an expert says, myself included (for the record I am not an expert and make no claims to be one)

when i break in an engine, i start rich, run lean then rich then lean for four tanks of fuel. after each tank, i let the engine cool down completely. only after this will i consider flying the plane. (i fly os engines only, so i can't speak for other makes)

thanks for all your inputs guys....if i disassemble an engine to clean it, like remove the sleave, piston, head, bearings, and whatever else is there any special way i should run it when i set it back together?

The last i check ..all of my abc 2 stroke nitro engine dosn't have rings in them..so how in the heck are they going
sit rings that dosn't exist ...is beyond me.

Another thing that needs to wear is the bottom of rod and the engine's casing. The last I checked there was plenty of clearance
in a yammamahaaa...unlike my magnum or OS.lol.

If you had ever taken a 2 stoke nitor engine apart...you'll see notice stuff like this. A nice groove on the inside of casing from
the rod wacking or rubbing at it.
i don't think they need to be sitted...just clearance.lol

yes..i get threary of stressing part or cooking them to make them strong at first.
If it'd going to break...it'll break or fail in the oven. So the theory gose.
if it dosn't..then it probably last forever if you treat it right.
And yes..I've put parts in ovens before shipping it out.

but..i'll stick with the running it rich so there's lub for my rod.
I'll lean it out plenty later.lol

My OS manual says to fluctuate between "2 cycle" and "4 cycle" operation for 10 seconds at a time, which I understood as normal, not 'lean and hot', to rich.

I agree with Missleman, I don't understand why you wouldn't just follow the directions in the manual. Again, we're not talking about some one-off, high-end plane engine, these are mostly lower-tolerance production line models. Follow the directions and keep the warranty.

i will probably do that, follow the manual. like i said before i simply wanted to see what the guys on here thought. but if anyone could tell me if i should run my engine different for a while after its been totally disassembled for a cleaning it would be nice.

Don't dismantle the engine just to clean it out of any swarf that might be left behind. Just take off the backplate, glow plug and muffler and sacrifice half a tank of fuel by blasting it in through the exhaust port while aiming at the transfer ports. This should wash an loose stuff out of the transfer ports down into the crankcase. Hold the engine so the bearings are facing up so you don't wash anything into the rear bearing. Then blast more fuel up through the backplate opening to clean out the last bits of rubbish (if any).

The OS instructions are quite complete but assume that a beginner knows what "4 stroking" means. This 4 stroking on a first run isn't just for run-of-the-mill engines either. Both Jett and Profi say to run their pylon engines in a rich 4 stroke for a short time. Harking back to that ultra rich experiment I did, the top half of the rod bush was polishing very nicely while the bottom half still had the original machining marks which basically proved that the piston does [/b]not[/b] jam into the pinch and have to be pulled loose by the rod.

Using a small prop for running in is good advice, I used a 9x6 to run in a 51 size engine, but it's wise to use a fuel with a fair bit of castor, mainly to lubricate the rod ends, which ideally need around 30 minutes of light load running (that's where the small prop comes in) before they've polished completely.

One other tip for running in...use an old plug, especially for the first run, because if any tiny bit of swarf happens to get on the coil then that plug will be dead.

Springhillflyer -

After I have an engine torn down either for a very deep cleaning or replacing the bearings I run the engine on a test stand for one tank like a break in would be. I reduce the propeller load to about 70% of what a flying prop would be, I use extra lube ( I like castor ) and I run it rich ( two cycle operation at the verge of being 4 cycle with one more click of the HS needle richer ) at full throttle, I monitor the oil output from the exhaust. Looking for very clear clean oil and lots of it.

When a engine is torn down for a cleaning, you end up with a certian amount of dust, dirt or other particals that can not be seen with plane eyes. Even though it may look clean it is really not. Running it at a fast pace with lots of throughput gets the particals that you can not see out of the engine prior to any heavy loads being placed on the engine.

Richard