To oil or not oil new cyl and piston

[romeo]

Romeo,

When Kawi went to the chrome, there were no Iron liners available for years.
There wasn't enough meat to bore out, and press in a custom liner.

When Kawi went to water cooled a few years later, only the KDX stayed AC for a couple years, and still with the chrome liners.

Spare top ends were the rule, but then the Chrome proved to be tougher than anyone figured. Most of the hot spot seize issues went away, and the number of busted rings chewing a groove became rare.

You ran "Heats"? Lemme guess you're in the iron shoe club?


Stay safe!
Dingeryote

Haven't really heard of the Iron Shoe Club. Just a long history with Motocross. I have three sons and one nephew racing this weekend, our race team also has a few more of my friends kids so lots of bikes to keep going. Me and my little brother are just too old and smart to ride those things anymore I guess,,,,, if you consider turning them into hotsaws smart. I never made it big in moto but a few of my riding friends did, lots of good riders come from the Southwest deserts, no lack of places to ride.

And 79 was before my time, I got on my first ride in 85 (a wore out Suzuki TM100).

 

[056kid]

Let's be clear...we're not talking about the difference between running well and running poorly, we're talking about ok vs. optimal.

"I've always done this and it worked out OK" is not an experiment, because nothing is manipulated. You have no way of evaluating whether the alternative is better or not.

There is plenty of theoretical and empirical information available on breaking in a 2-stroke P&C, and the data are in agreement with the theory. TZed's advice makes a whole lot of sense in light of both. Take it or leave it, but you can't dismiss it on any grounds other than your own opinion.

What is the difference between well and optimal, if a stock rebuilt saw is makin160 lbs of comp after 5 gallons, I am a happy camper..

 

[dingeryote]

What is the difference between well and optimal, if a stock rebuilt saw is makin160 lbs of comp after 5 gallons, I am a happy camper..

It might be capable of 165.....

At a certain point it is academic. Agreed.

Stay safe!
Dingeryote

 

[056kid]

agreed

 

[edisto]

Agreed!

 

[mowoodchopper]

Glazing is what stops break in of the rings, and glazing is oxidation of the oil film due to high temperatures. 2-stroke rings simply are not designed to deal with a layer of 2-stroke oil on the cylinder wall...4 stroke rings are.



Glazing my *** !!! On a two stroke!!! LMAO Were not talking about your breakfast at dunkin donuts !!

 

[056kid]

the bore of a 2 smoke isent sposed to have oil on it?


Damn I have been wasting alll that $ on all that oil

 

[dingeryote]

Glazing is what stops break in of the rings, and glazing is oxidation of the oil film due to high temperatures. 2-stroke rings simply are not designed to deal with a layer of 2-stroke oil on the cylinder wall...4 stroke rings are.



Glazing my *** !!! On a two stroke!!! LMAO Were not talking about your breakfast at dunkin donuts !!

mowood,

Glazing does occur on 2 strokes, and no the rings were not meant to deal with oil in a volume other than a vapor.

If ya coat the cylinder, the stuff has gotta go somewhere on start up.
What dosn't get burned completely will get scorched and glaze just like on the valved Horrors.
How much that affects things, and for how long is debatable, but it does affect ring seating, blowby and compression.

I'd like to think the new generation of synthetic oils and leaner mixes reduces the matter... Dunno.

Some folks are after every last 10rpms in the saw, it's crazy, but it's what makes 'em tick and they fuss over it.

Stay safe!
Dingeryote

 

[dragrcr]

You can't have it both ways Brad! The process of "breaking in" is wear, so you can't be worried about excessive wear if you aren't convinced it isn't going to happen.

Glazing is what stops break in of the rings, and glazing is oxidation of the oil film due to high temperatures. 2-stroke rings simply are not designed to deal with a layer of 2-stroke oil on the cylinder wall...4 stroke rings are.

Another factor to consider is that the rings are forced against the cylinder wall by pressure from the combustion chamber. This requires the chamber to get warm before the serious breaking in starts. If the oil is too thick on the cylinder wall, there will be blow-by, and you won't generate enough pressure against the rings for a proper break in.

Tzed...thanks for the excellent suggestion!



I haven't seen any real evidence that you have completed the growing up process.

oxidation of the oil? hummm, read up again.

I am an ASE certified master tech, i have 57 ford credentials, and have been riding dirt bikes my whol life, not to mention building several drag race engines, the one in my car had had about 500 passes down the strip, usually about 600 hp worth on the funny gas, and EVERY school, EVERY training program, and EVERY engine builder i know uses a light coat of oil on everything that touches metal to metal, 2 or 4 stroke its all the same.

Pretty simple, anything metal that rides on anything else that is metal needs lubrication, what happens if you pull that unlubed saw 100 times before it fires because something isnt right, or a fuel line is off ect...

in a race situation at a dirtbike track, where you need instant power and have no time to properly seat a set of rings, and you will be changing them after a race, i can see going light on the oil, but anything where longevity is concerned, ass long as you dont put soo much oil that the engine is burning it along the fuel, you are doing good.

 

[mowoodchopper]

mowood,

Glazing does occur on 2 strokes, and no the rings were not meant to deal with oil in a volume other than a vapor.

If ya coat the cylinder, the stuff has gotta go somewhere on start up.
What dosn't get burned completely will get scorched and glaze just like on the valved Horrors.
How much that affects things, and for how long is debatable, but it does affect ring seating, blowby and compression.

I'd like to think the new generation of synthetic oils and leaner mixes reduces the matter... Dunno.

Some folks are after every last 10rpms in the saw, it's crazy, but it's what makes 'em tick and they fuss over it.

Stay safe!
Dingeryote

Never seen it Dont believe it!!!!!!!!!!!!!!

 

[mowoodchopper]

oxidation of the oil? hummm, read up again.

Thats what I thought!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[dingeryote]

Never seen it Dont believe it!!!!!!!!!!!!!!

Iv'e never seen an atom split, but darn sure believe it can make a mess!! LOL!!

Stay safe!
Dingeryote

 

[mattmc2003]

I've read most of this post, and someone may have brought this up already, so i apologize if im behind on this...so.... what does the factory do? Stihl and husky? I would just about bet they oil rings and all. I don't see that it does harm. What if your carb is not spot on, and you gotta pull on your rebuilt saw eight or ten times? And what if you just oil the skirt of the piston, the ring isn't seated on that first startup regardless of what you do, so some oil will get by and get on everything anyway. So i don't see that it matters. Thats just my two cents.

 

[Zero Gravity]

Use plenty of 2 stroke oil for assembly. The start it and race. No break in on a two stroke. If you baby it, that's what you will get. Don't ask me how I know. This definitely the correct method.
ZG

 

[thomas72]

I build an engine with a pre-oiled top end. A engine is not going to magically break in because of the absence of oil for the first few seconds. It takes at least 20 minutes to start breaking an engine in depending on how it is manufactured to run. The more "souped" up the faster the break in.

 

[Paul001]

I'll follow Stihl's recomended procedure, use oil.

If you have another preferred method, feel free to do so.

 

[Zero Gravity]

I've read most of this post, and someone may have brought this up already, so i apologize if im behind on this...so.... what does the factory do? Stihl and husky? I would just about bet they oil rings and all. I don't see that it does harm. What if your carb is not spot on, and you gotta pull on your rebuilt saw eight or ten times? And what if you just oil the skirt of the piston, the ring isn't seated on that first startup regardless of what you do, so some oil will get by and get on everything anyway. So i don't see that it matters. Thats just my two cents.

All of the engine plants that I have visited assemble the engines dry. They prelub with hydraulic pressure on the final line, then they fire them on natural gas hoods.
ZG

 

[tdi-rick]

Use plenty of 2 stroke oil for assembly. The start it and race. No break in on a two stroke. If you baby it, that's what you will get. Don't ask me how I know. This definitely the correct method.
ZG

Do that on an air cooled, iron sleeved, reed or rotary valved kart engine and you'll have a seized piston within 30 seconds, guaranteed.
It used to take a minimum of three 15 minute sessions, slowly building the heat and revs before unleashing them.

But then we are talking of only 100cc and over 25HP.

 

[edisto]

oxidation of the oil? hummm, read up again.

That's what everything I've read about glazing says. So what is the cause then?

Pretty simple, anything metal that rides on anything else that is metal needs lubrication, what happens if you pull that unlubed saw 100 times before it fires because something isnt right, or a fuel line is off ect...

The recommendation was to only oil the skirt. That keeps the oil layer thin, but not nonexistent. Pull the saw 100 times and it will be well-lubed.

I build an engine with a pre-oiled top end. A engine is not going to magically break in because of the absence of oil for the first few seconds. It takes at least 20 minutes to start breaking an engine in depending on how it is manufactured to run. The more "souped" up the faster the break in.

No-one said the break-in occurs because it is unlubed. The idea is that just oiling the skirt keeps the lubed layer thin enough that you don't get blowby (decreasing the cylinder pressure, which decreases the force exerted by the rings on the cylinder) and reduce the chances of glazing, which stops the seating process.

 

[dragrcr]

Oil oxidation is a result of moisture, metal particals and o2 in the oil, although heat can speed this process up, it is not a factor when talking about break-in.
what you are talking about is when you have an excessive amount of oil, above the rings, and the oil reaches its flash point, and burns leaving deposits, or when the oil on the cylinder is heated to the point of break down, when it looses its viscocity, and lubricating properties, then the oil will burn onto the cylinder, essentialy eliminating the contact between the rings and cyl. people dont understand how a ring works, the pressure caused by combustion actually gets between the ring and the wall of the ring land, pushing the ring against the cyl. wall. I do agree that if there is an excessive amount of oil used during assembly it can indeed lead to something similar to a glazed cyl, generally glazing is a broad term used to describe this as well as when metal particals "polish" the cyl. robbing compression, and it is also used do describe wash down, where fuel on the cyl. reduces the rings ability to seal combustion.


like everything, a little bit goes a long way, and a lot can lead you to more damage, but given the choice of the right amount of prelube, or none above the skirt, i think the vast majority of both performance and longevity engine builders will pick the using a light coat on the cyl.