oil migration

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Darrell
Posts: 309
Joined: Mon Jul 29, 2013 7:09 am
Location: Vancouver Island, BC

Re: oil migration

Post by Darrell »

ddvorak wrote:Victor,
Well... the remedy was actually burning out a plugged exhaust pipe. And believe me, there was no visible signs of it being plugged. I was chasing an extremely rich condition and I inspected the pipe early on and was satisfied that it was fine. I spent much time working on the carburetor, ignition, checking compression, etc... and eventually burnt the pipe just because and sure enough, it was the total culprit. For 1500 ft elevation, I am currently running a 35 pilot, 180 main, O2 Nozzle and 5EJ13 on the 3rd notch. Standard Combat Wombat components would be 25 pilot, 190 main O4 Nozzle and the 5EJ13 on the 3rd notch, however, my 28mm carb is not OEM...
Dale
Same here. I thought my inner pipe (94) looked like it had hardly any buildup but I torch cleaned off what was there anyway. The before and after difference in power was astounding.

Later I flushed the whole exhaust pipe out with engine cleaner and a pressure washer
Darrell
---
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Location: Prescott

Re: oil migration

Post by --- »

Just so everyone understands the modified silencer question, the restrictive gizmo in the photo is a spark arrestor. Modifying for more flow may also tend to defeat the ability to arrest sparks. The intention is to require a multi-path route for exhaust through the silencer rather than straight through. This circuitous route bounces particulates around so that if and when they find their way out the pipe, they are no longer glowing hot. If you drill extra passage through the baffles, you may be providing some degree of straight through passage which defeats the purpose of the spark suppressor.

If that isn't a concern here, fine. I think a spark arrestor is largely overkill anyway unless you live in a high fire risk area. If a straight through silencer would serve, rather than modifying an arrestor, just install a simple silencer. You should be able to do this without damaging either the pipe or the spark arrestor.
GMc
viclioce
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Re: oil migration

Post by viclioce »

Well, spark arrestors are required for riding anywhere in US or State Forest land. I know you know this. If the bike is just going to be used on an open track, the silencer is not necessary. But riding anywhere in the first two locations it needs to be both in place and functional. ; D Victor

1978 175SL
1976 03 Wombat
1975 99 Road Toad (2)
1973 96 Dirt Squirt (2)
1973 “Wombat Combat”
1973 Combat Wombat
1972 94 Wombat (2)
1972 Super Squirt
1971 92B+ Ace
1970 92B Ace 100B (2)
1968 92 Ace 100
1966 Ace 90
; D Victor
---
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Re: oil migration

Post by --- »

That's a federal regulation. The same fed that is mandating higher and higher ethanol content in gasoline even though most high school girls know that ethanol reduces the efficiency of gasoline and is hygroscopic to boot. I worked for the fed too long to trust their conclusions on anything. But you are right, they are required. Their exact build configuration, however, is not regulated. If one is stamped as approved, I would assume that modifying it from its original design would void the approval. But Forest Service Enforcement doesn't know what they are supposed to look like anyway, so just don't start any fires.
GMc
DGardner
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Location: Northern Utah

Re: oil migration

Post by DGardner »

I'm having a new pipe made for my wombat at TTR performance dyno. So I ask Tim how big a stinger did his program call for and I think he said 19mm. I don't think there is 19mm in that silencer that Danny showed photos of . So could it be to restrictive? Could it be hurting performance? could there be to much back pressure for a sustained high RPM run? It will be interesting to see what Danny comes up with.
DGardner
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Location: Northern Utah

Re: oil migration

Post by DGardner »

One other thing, when Tim did the calculation on the circle F pipe that I was using had a peak torque of about 8500 RPM and the new pipe will have a peak torque of about 7000 -7200 RPM. I think the old pipe in the center was about 75mm and the new one is about 105mm.
Kels
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Joined: Mon May 11, 2015 9:07 am

Re: oil migration

Post by Kels »

When you increase the internal cylinder pressure of ANY engine (no matter the decade made) you must account for this in the exhaust system or you could have issues.
DGARDNER's engine is currently at near double stock HP output.

There NEEDS to be alterations to accommodate this added HP otherwise it may not survive at extended WOT running..

Any engine has the ability to withstand SHORT WOT pulls before having issues. It is about the TIME that these loaded pulls sustain!

Like mentioned earlier.. hold your hand over a candle for 3 secs vs 13 secs.. You'll get the idea..

It takes TIME, in a bad state, for an engine to fully fail.

Chalking everything up to a lean jetting condition is simply not justified. Much more in play here with modified engines.
---
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Re: oil migration

Post by --- »

Doug,

The calculation of a stingers ability to pass fluid within a given time is a function of diameter AND length. A stinger of 19mm internal dimension but only an inch long offers less restriction than would a 19mm stinger 5 feet long. This is simple fluid dynamics. I assume the program in question also identified a length for the stinger.

Point is that without flow testing the spark arrestor in question, we can't make other than broad assumptions about its performance. I would broadly assume that any spark arrestor is more restrictive than a straight through silencer of similar proportions, but that doesn't by itself answer any questions.

Kels,

The phenomenon you describe would be attributable to heat soak. Once production of heat increases to a point that the engine can no longer shed that heat, the engine temperatures rise rapidly. The amount of time it takes is a function of heat produced, and the design parameters of the engine and its ability to cool. Every engine can arguably become heat soaked if asked to do more than it is designed to do. So, yes, it might be wise here to take heat building problems out of the total design. Or, it might be that the owner needs to know the limits. If it is not required, for example, for this bike to have a spark arrestor while racing, take the darned thing out and mount a silencer instead. If a spark suppressor is required, either find one that doesn't restrict (good luck with that one) or back off the throttle and or gear down.

In the old Hodaka flame thrower pipes, the stinger is short and fat, and the inner diameter of the stinger, on my Ace anyway, was the same as the o.d. of a VW Bug tail pipe silencer. The little chrome tips that stuck out the back of Bug mufflers. It is nothing more than a small glass pack silencer, weighs very little, and isn't expensive even today. Might be worth a try.
GMc
Kels
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Joined: Mon May 11, 2015 9:07 am

Re: oil migration

Post by Kels »

Shorty... There is much more in play here than typical heat soak. The resultant failure can be related to the heat soaking but the actual dynamics of what occurs with a restricted pipe is much more complicated.

To touch, LIGHTLY, on it..
1) Pipe PRESSURE increases... This effects the ability of the pipe to function as a TUNED PIPE.. Many dynamic variables in play here.

2)Pipe temp increases... Again.. effects the way the pipe functions as a TUNED PIPE.

3) Heat is directed on the exhaust skirt, hence, the non typical type seizing pattern shown.

4) Added heat AND Pressures alter the dynamic compression ratio and the resonance of the pipe.. There are several orders of resonance in a good tuned exhaust system.. These orders are effected which, in turn, effects the entire function.

5) Intake charge density is altered due to the added heat.

6) Pressure differentials are altered which are critical to intake scavenging.

I'll stop here.. but , point being... not as simple as you make it out to be...

With the decades following the 70's and and advancement of 2 stroke complexity and understanding.. came many new dynamic variables and the true complexity of the 2 stroke engine.

These variables add a complexity to the diagnosing of engine failures and their associated remedies.

Ideal gas and fluid dynamic laws pertaining to things like an exhaust system simply fall short in the real world. Ideal laws are just that.. Ideal.. the 2 stroke engine does not fall under the ideal category.
---
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Re: oil migration

Post by --- »

Kels wrote:?....

With the decades following the 70's and and advancement of 2 stroke complexity and understanding.. came many new dynamic variables and the true complexity of the 2 stroke engine.

These variables add a complexity to the diagnosing of engine failures and their associated remedies.

Ideal gas and fluid dynamic laws pertaining to things like an exhaust system simply fall short in the real world. Ideal laws are just that.. Ideal.. the 2 stroke engine does not fall under the ideal category.
You have made this statement, and others like it, several times over past weeks, but offer nothing other than the statement itself as proof of the idea. It is not enough to say things have changed. If you care to share, identify what it is in internal combustion theory that has, in fact, changed in the past 100 years or so, but please don't just offer links to your self-published opinion pieces on your website. They are not tech articles, and contain no science and no test data. Take any one of your assertions and put it into a context that has application here, and offer, if you can, repeatable test results that support your conclusions. Or, if you rely on the science of others, cite them and their work so we can go and read for ourselves.

Also, to say that just because an engine in function is not an ideal does not equate to the conclusion that laws of thermodynamics and fluid dynamics don't apply or have changed. These laws certainly have not changed, particularly as a result of changes in engine design. Overall efficiency of any internal combustion engine has not changed significantly in the last 50 years (somewhere around 25% efficient) and more to the point, design changes in modern two stroke engines have no bearing at all on an engine designed in 1970. The rules haven't changed, and neither has the Hodaka engine. Folks have found ways to make them more powerful than as originally designed, certainly, but not more efficient, and thus no closer to an ideal. You can't make more power without using more fuel, and you can burn more fuel and also raise efficiency. Engines turn fuel into heat. More fuel, more heat. But 75% or more of the heat generated is lost, through the exhaust, the cylinder and head, and through the engine cases. If this were not so, the engine would not get hot to the touch.

What you assert here is what my English teachers used to call "glittering generalities." They sound great but are meaningless. If you wish to share some of this new theory and new science with the crowd, feel free.

It wasn't my intention to suggest that heat soak was a causal function. It is, rather, a result. In this case we were discussing the spark suppressor only, and it's general effect on the bike. It didn't matter, and doesn't matter, that increased pipe pressures also have a ripple effect on other variables. True or not, it wasn't the point. Citing to these phenomenon without a reason only shows what you believe you know about engines generally, but doesn't help solve the question of what to do with or about a restrictive spark suppressor.

In short, you can't change one aspect of a power plant without affecting the balance of the equation. That's a given. But that wasn't the problem. If you have a suggestion for altering the flow of a Hodaka spark suppressor to the benefit of the engine as built, have at it. I don't have one other than removing it and replacing it with something else. Drilling holes in the baffles will marginally increase flow, but may not really have much of an affect either, other than making it no longer a spark suppressor.
GMc
Kels
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Re: oil migration

Post by Kels »

You're right Shorty..

The modified Hodaka engine requires the SAME components as the stock Hodaka engine.. :o

Even though the modified Hodaka engine is putting out much more power than the stock Hodaka engine, the efficiency remains the same! :o :shock: :lol:

The Hodaka engine of the 70's and the Honda engine of the same year(era) have the SAME efficiency and require the same components. Afterall.. they are just a silly internal combustion engine.. :mrgreen: :roll:

The combustion (the "C" in Internal Combustion) chamber of the 70's Hodaka engine is no more efficient than a Modern 2 stroke engine head from 2016.. They function exactly the same way.. All you can alter is cranking compression because cranking compression is a TRUE indicator of the real value of internal cylinder pressure ;) :o :shock:

Current engine oils offer no advantages over oils from the 70's.. Afterall, it is just oil!

Plug color tells you most of what you need to know to properly tune an engine. It is a true "sight" into the engine internals and state of tune. :o :shock:

There have been no real significant developments in expansion chamber design, head design, ignition design, cylinder porting design, and carburetor design since the 70's.. So if you install any recently designed component on an engine from the 70's .. you gain very little.. :( :o :shock:

Current IC engines are no better than those of the 70's.. There have been little to no advancements! :lol: 8-)

Thanks for setting me straight on all of this... I'm going to go immediately and convert all my 200HP engines to piston port-- 2 transfer design-- points ignition engines since all this talk has just been 100% speculation with absolutely NO DATA to support it!

Just Glittering Generalities!! Your teacher was a genius!!!
---
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Re: oil migration

Post by --- »

What a stunning rejoinder. I am humbled in your presence.

Ignorance is its own comfort. Thermal efficiency hasn't changed since my dad was an automotive engineer in the early 50's. But don't trust me, look it up. You do know the difference between thermal efficiency and fuel economy, right?

Making power is not a function of efficiency, but you know that too, right?

So, since your genius in this area far exceeds our collective minds, please feel free to enlighten. Just use supportable facts and repeatable data, since you have all this at your fingertips. All I ask is don't offer any more links to puff pieces on your website that offer no science whatever.
GMc
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Bullfrog
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Re: oil migration

Post by Bullfrog »

I really did think there would be a longer period of relative peace and civility after your return to the chat room. Reckon I was wrong about that.

I will have to admit that when you returned to posting, I thought of an interview with Richard Dreyfuss I heard many years ago. When Richard was asked, "What do you think you'd like to have engraved on your tombstone?" His answer was, "I knew this would happen!"

Ed
Keep the rubber side down!
---
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Re: oil migration

Post by --- »

Ed, your comments are completely gratuitous and out of line. If you want to make negative comments about me and what I say, send them privately. You don't like me, I don't like you. That has been established. But I would ask you the same thing I ask Kels- does your comment add assistance to the question about exhaust pipes? I think not.
GMc
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hodakamax
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Re: oil migration

Post by hodakamax »

Gentlemen, time to step back and look at the overall problem. Everyone needs a view or opinion. My weird sense of humor is sometimes taken wrong by others but those who know me expect and accept my silly attitude. When I get in trouble I apologize. I really like telling my opinion and listening to other opinions on the Forum. To me it's a social thing, not a battle of egos.

I will mention names. Kels arguements are only intimidating but usually irrelevant or vague. All negative. He was wasting my time and now Gregs. I refuse to communicate or be insulted by him. He adds nothing to our Forum except dissent. I think Greg feels this way also.

I completely agree with Greg's response which wasn't as harsh as mine. Speaking for myself and hopefully others on the Forum this is not how our Forum should operate. People will not cause me to not participate but I really can't waste my time on issues that are directed away from the real purpose of the Forum which is to help others and develop friendships rather than to bolster egos.

All Max's opinion of course as always. ;)

Max
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ossa95d
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Re: oil migration

Post by ossa95d »

Like Max my sense of humor is sometimes misinterpreted, but there is quite often humor to be found in most situations. Likewise there will often be bits of helpful information in most conversations.

I have to agree that as an old guy I struggle with many of Kels' assertions, but I enjoy reading the substantive parts of his theories. I'm sure for me there is something to be learned here, but will continue to wait to find the research data and real life applications to back it up. Kels, it is fascinating and worthy of consideration! Thank you.

I have also always enjoyed Greg's contributions and find him to be very knowledgeable with considerable experience to back it up. Welcome back Greg and keep contributing.

But unlike the others what I really enjoy is the drama. Life can get boring here on the farm, and you guys have really spiced up my day. I look forward to logging in to the forum and not only learning something interesting, but being entertained at the same time! Like most Soap Operas it can get a little predictable at times, but still very entertaining! Thanks! :D
Ivan AKA "Pop"
taber hodaka
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Re: oil migration

Post by taber hodaka »

A new dimension has been added, to the meaning of down hill. When we feel personally attacked, our response should be in private. Never write a letter to the editor when upset or mad, because it would look like someone got under your skin, reflecting that you were mad, beyond upset and out of control . Greg a very highly intellectual came back on line. At the same time Kels another highly intellectual was trying to explain how fluid dynamice actually propel's my 1965 hodaka. Tuned with modern methods my hodaka would go down the road with such power I did not know existed. Tuned simply the new modern way I am assuming without messy jetting as such. Greg your first frustrated response April 21 11:26 AM the first paragraph should probably have been sent in private. Kels your response should have just been wadded up and thrown. In the old days it would have been 17 paces and boom boom I hope we are all beyond that. To enjoy the forum we must show some restrant and respect. (Kels Greg) (Greg Kels ) you two intellectuals could probably sit down and have a very good deep discussion with each other and we would not have to play referee, I do not dislike any of you all though we can all be a pain in the as once in awhile. Mandatory reading { How to win friends and influence people} A few of you will be sent to bed with no supper, your food will be fed to the chickens but Max and I will eat the icecream. Lighten Up --------------Clarence Spelling who cares?
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hodakamax
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Re: oil migration

Post by hodakamax »

Clarence--I did read the book, it was a good example of how all humans should be but unfortunately aren't. I do try to live by it. What is the ice cream flavor tonight? 8-)

And Ivan--Life is supposed to be funny! :lol: (and entertaining.) :D

Max
DGardner
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Re: oil migration

Post by DGardner »

So like I was saying the gas and oil separate from each other.......Oh I see we have moved on. I think one of the problems here is there are some members that have to comment on every post. If you don't agree you don't have to reply to it! some are 160 to what ever the other person has to say. Take Ed he knows more than 99% of us but he doesn't comment on every post that is posted even if he doesn't believe it. Kelsey's world is 2 stroke engines most of us should think about what he is trying to tell us and if you don't like it....so what just move on. Oh and I talked to the pipe maker....the stinger will be longer than 1 inch and shorter than 5 feet!
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hodakamax
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Re: oil migration

Post by hodakamax »

Doug, I reply to posts that interest me. When I see questionable information that might be leading us off the path I comment. I don't skip over someones theory and then tell them that they don't know what they are talking about while quoting non-reviewed so called scientific papers that are irrelevant. The people on the Forum are not stupid and shouldn't be treated as such. Sorry, I require common etiquette when discussing subjects. Oh, add a few misquotes and you are in trouble with me. It seems I'm not the only person that takes it that way.

On the lighter side your questions and discussions on oil migration did make me think on the processes of lubrication and to rethink some of my statements. It's obvious to me now that due to intake conditions oil can be separated or at least enriched and build in the crankcase and yes, migrate through the engine. In my opinion though it is all irrelevant in that the engine is still lubricated by the oil in the mix ratio and when under race conditions is not depending on migration for lubrication. Enriched oil content appears to flushed through the engine at high RPMs with exactly the same ratio as it was mixed even though some of the fuel has turned to vapor. All fuel would not be vapor due to the saturation of the air.

Max

PS--and I really enjoyed the Maicos! :)
bobwhitman
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Re: oil migration

Post by bobwhitman »

I too enjoyed the improved site, until recently. How about Greg & Kels locate a private site where they can pontificate... and insult without limitation, and the rest of us can go back to - succinctly - posing and solving issues with Hodakas?
Bob
Larry S
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Re: oil migration

Post by Larry S »

I have no dog in this fight but, I'm on Arizona's side on this one. Bullfrog, your response was not cool. Az, your reaction was worse. Both of you, put on your dunce caps and go sit in the corner.

Kels has pissed off more than one member of this forum. He makes these grandiose statements with no facts to back them up - except for his own website.

Greg and Ed, go off line and kiss and make up. We need both of you.

Larry s.
Kels
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Re: oil migration

Post by Kels »

Larry S wrote: Kels has pissed off more than one member of this forum. He makes these grandiose statements with no facts to back them up - except for his own website.
Larry s.
1st of all.. You will NOT find anywhere where I resorted to any name calling or offensive postings.. That was left to the others.

Really??? No facts to back up 2 stroke theory??

How about the facts in Bell's, Blair's, Bossoglia, and Jenning's books?? Those are just a few..

Then... add in the COUNTLESS SAE papers written by the likes of Yamaha, Honda, Kawi etc. etc.

Feel free to purchase them , Like I did, and study them (like I have) .. then try and make sense of it all (like I have tried as well)

OK, let's add in the 20+ years of 2 stroke engine development I have done , along with a Patent.

Point being.. From the list above.. VALID conclusions can be drawn and advancements have been made based on FACTS and DATA from experts in the field. This is not conjecture by any means...

Taking it a bit further.. How about the FACT that the current 125cc 2 stroke engines make 2-3 times the power of the ones from the '70's?? How are these not FACTS and DATA to support advancements?

You know I was watching "Engine Power" today on TV..as well as many youtube videos (2 stroke and 4 stroke).. In all their engine builds a spark plug is never pulled... Crazy huh?

To have some discredit SAE papers about oil migration based on "their" personal ideas AND NO FACTS is just nuts!

To hear how 95% of all burn downs are due to lean jetting.. REALLY!! (where are the facts to support this statistic?)

At the end of the day, I am here to help.. I got no dog in this fight at all. But if we are going to talk about lack of facts and data well... :?: :?:
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hodakamax
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Re: oil migration

Post by hodakamax »

Wow, It appears Kels has lost touch with reality. It's probably because he doesn't realize that we're not talking about liquid cooled watercraft but air cooled vintage two strokes where jetting is the main cooling factor. To make an assumption that jetting is not a factor in cooling is absurd, just absurd. We didn't have the luxury of coolants circulating around all the hot spots so we provided cooling with the atomization of fuel. Not only does the main jet allow for cooling fuel but also allows more oil to enter. Denying this is beyond comprehension (or at least mine.) People that read books and papers need a little field time to address reality. Thinking like that would get you fired on our race team. Or did you race?

Thanks Larry for your opinion, I find it strange that more people don't have one.

Max :D

PS--again I seem to be wasting precious time---
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Bullfrog
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Re: oil migration

Post by Bullfrog »

"jetting is not a factor in cooling"

Um, I'm pretty sure Kels didn't say that.

Ed
Keep the rubber side down!
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