z style

i have a velocity .15 engine. its about 2 years old and im not running it anymore but perhaps i should. i took the backplate off to take out the piston and cilinder and they were kinda dirty and i took some finishing steel wool and i rubbed it on it and it actually took off the dirty and polished it. i did this to the whole inside of the engine and it seemed to be a lil smoother. i have ran it yet but maybe i should.

could rubbing steel wool ruin the engine by doing what i did or will it be fine if i make sure all steel wool is out?

wakbrdr

you should try to run it, but since you messed with the piston, it probable wont get a good seal and will lose compression

IhrtTamiya

since you used finishing steel wool you should be alright. you may want to check the piston seal and ring to see if your getting good compression or not. people port their engines all the time and i guess this is sort of the same thing. i say run it and see how she goes.

proptop

My Feedback: (8)

A small amount of varnish on the piston is normal, and will not hurt anything. Sometimes removing it will effect compression, only if the varnish was helping to seal things. You should be o.k. if you didn't get carried away and actually remove metal from the piston. That's hard to do, because the piston is a hard aluminum, and you'd have to work at it a bit.
Make sure there are no little bits of steel wool inside, and you should be fine. You might notice a little less compression, but after you run it awhile, it should come back a little. Unless you run it lean, or otherwise mess up the piston/ sleeve fit. The main problem with taking a runable engine apart is you are disturbing the microscopic wear patterns between the piston and sleeve bore.

IhrtTamiya

but since he polished both of them then he should be ok. if polishing the piston removed the grooves than so would polishing the sleeve. and besides, its finishing steel wool. it can be used on fine silver and wont leave behind a trace.

i8tweety

My Feedback: (11)

The problem is it removes material. If you "cleaned" the sides of the piston or the inside of the sleeve, you have damaged the engine. Any material lost between the piston and sleeve will at the very least reduce engine life. Our glow engines are designed to have the piston to seal the combustion chamber against the inner lining of the sleeve.

Billyman

My Feedback: (1)

Tweety, not exactly. Steel wool is usually graded on a numerated scale. (3) being coarsest (like 300 grit sandpaper). (2) like 400 to 500 grit, (1) like 600 grit. Then we get into the “fine� grits. (0) like 800 to 1000 grit and used for polishing aluminum and cleaning cookware, (00) like 1500 grit for cleaning or polishing soft metals such as copper and brass, (000) like 2000 grit for extra fine polishing, on anything, (0000) like 2500 to 3000 grit, ultra super fine similar to trying to polish something with newspaper.

The 0, 00, 000, 0000 are your “finishing wools�. Depending on which grit was used and how much elbow grease was applied, the material loss was bare minimal if any at all. The “if any at all� is what I’m seeing. At those fine grits it would take quite sometime to remove any material and a whole lot of scrubbing.

And no, our engines are NOT designed to have the piston to seal the combustion chamber against the lining of the sleeve.

Any metal to metal contact will result in galling and engine devastation. The piston rides along a coating of lubricant (castor or synthetic oil) sandwiched between it and the sleeve itself. They are not to make contact with one another. The varnish in which z style has removed is the coating left behind to prevent “dry starts�. Upon reassembling the engine, all he will need to do is make sure it cleaned out very well and there are no debris left behind, pre-lube the piston, sleeve, and other moving components then run it a little rich for a tank or two.

BOOCAKE4U

correct...there is no metal to metal contact between any of the moving parts when the engine is running (that goes for ANY engine)

might still be a good idea to treat the engine as new though, and run a few break-in tanks before getting too crazy...and clean it out really really well as mentioned previous (meaning not just wiping it out with a paper towel)

in the future you can just use any decent solvent to remove the gunk, also less work that way as you can just wipe it off

IhrtTamiya

i dont know boocake. polishing it is probably better every now and then than just cleaning the engine. also, nitromethane fuels have lube in them. this is used to keep the engine running smoothly. just using this as a lube should be fine and it may help on the first start up as long as the engine hasnt been sitting for some time.

BOOCAKE4U

i think you may have misunderstood my post...

the most important point being that neither polishing or cleaning the internals is ever even necessary (unless you get dirt in the motor)...the residue left behind is from the castor oil, there is no real reason to remove it at all (as billyman already stated)

and yes, i realize the oil is in the fuel..the point billy (and myself) were trying to make is that the residue left behind prevents any metal to metal contact while the engine is turning over without fuel being present (like when it is being started)...after the engine is running and the fuel is flowing, the oils in the fuel are coating all of the internals and all the moving parts are riding on that very thin layer of oil and are not actually touching each other...

i8tweety

My Feedback: (11)

Yes, they are in the same fashion piston rings are designed to form the seal in your automobile's engine. My statement was not intended to imply there is direct metal to metal contact. Common sense dictates as two metal surfaces rub together, there will be relatively rapid wear until there is a micro-gap (engine break-in period). My point is if the micro gap is enlarged by "polishing", "cleaning", or the like, the microns of material being removed (polishing does remove material) is a relatively high percentage of the gap at operating temperatures. When the gap becomes too large, the engine is worn out (time for a rebuild).

IhrtTamiya

boocake-yes there is a reason for polishing the engine. have you ever heard of port and polish for 1:1 cars? as heat and rubbing take place the oil can become sticky and binding may occur. after polishing an engine, all residue is removed and the piston has a smoother surface to glide upon which increases performance and the engine is a little more reliable.

BOOCAKE4U

the purpose of porting and polishing to to increase flow by opening up and removing restrictions in the induction and exhaust, it has nothing to do with reducing friction between the piston and sleeve

i will state it again for the third and final time...when the engine is running, the piston is riding on oil, not directly on the surface of the sleeve...therefore, removing the thin film of dried oil that the fresh oil is riding on top of will have no effect...anyone who has problems with the castor residue inside their engine needs to either quit worrying about it or use a better fuel..end of story

IhrtTamiya

no not end of story. when oil gets hot and used then it needs to be removed and replaced. when you take off the old oil residue and add new oil you are giving a slicker "surface" for the piston to ride on. this helps in performance.

and porting and polshing is done in the block itself...not the head. this means pistons.

BOOCAKE4U

hehe...you're killin me

the oil is in the fuel, as you stated several posts ago...so how does it get "hot and used"? it is burned and shot out the pipe for the most part, and replaced with fresh oil with every revolution of the crank...

in a real 1:1 engine with a valvetrain, porting and polishing is done to the heads and manifolds to get more fuel and air mixture into the engine and to get more exhaust out (and to match-port the openings in the intake and exhaust manifolds with those in the heads for the same reasons)...in our little 2 strokes, there is no valvetrain so the porting and polishing is done to the intake, transfer and (sometimes) exhaust ports in the sleeve to achieve the same effect...not many modifiers will even touch the piston and if they do it is only to match its opening to the port in the sleeve they have just opened up...not that this has anything to do with the subject of this thread, which was about cleaning the goop out of the engine...

a quality fuel uses what is called "degummed" castor oil, and this will leave a very thin light film in the engine...there is no reason that this will ever need to be removed and doing so will probably shorten the engine's life....the only circumstances when cleaning the internals of the engine is a good idea are:

1.if you get dirt in the engine
2.if you overheat the engine badly enough to have black carbon buildup on top of the piston and on the underside of the head
3.if there is some breakage inside the engine (blown plug, broken rod etc)

so the long and short of it is, buy a decent motor and use a decent fuel and don't worry about it...i have motors with over 10 gallons of fuel through them which still run great and i would never even consider using steel wool or anything rougher than a paper towel on the piston/sleeve...anybody else can do whatever they want to their own engines, but consider the following....if there was a legitimate reason or advantage to using steel wool on your piston and sleeve, they would have figured it out 40+ years ago and people would actually be doing it today...

IhrtTamiya

obviously youve only seen the rough steel wool. didnt billyman go over the differences in steel wool? and he shouldnt have compared them to sand paper(steel wool is a little finer and less abrasive)
also: didnt you say that there was castor oil in the engine that the piston floated on before start up? yea. this gets used and burnt up as the engine goes through heating and such. polishing the sleeve and piston will not shorten the life of the engine, it may even extend it.

BOOCAKE4U

yeah, good luck with that

LSP972

My Feedback: (13)

Interesting discussion.

Boocake, you stated there is never any need to remove castor residue. I know of one situation where there can be a need; the combustion chamber.

Castor build-up in the squish area of the combustion chamber will eventually cause the engine to over-compress and begin pounding itself (vibration).

Now, whether or not this matters in these little buggy engines is a good question. It matters big-time in helicopter application, since any vibration in a heli is A Bad Thing. This is one reason 99% of heli pilots use all-synthetic fuel. I don't even know if it IS a problem in these little car/truck engines. Plank flyers have been running high castor content fuel since the hobby began, and it just hasn't been an issue with them. So, perhaps the delicate world of helicopters is the only place it matters.

As for your contention that the residue, varnish, whatever you want to call it, provides a "cushion" against metal-to-metal contact, well; perhaps. But there is always fuel present to provide lubricity during starting, since fuel must be present for ignition to take place. And the only way for it to get there, aside from removing the plug and direct-priming, is to go up the sides of the cylinder.

Personally, I think castor residue, inside the engine AND out, is undesirable. On the outside, it retards cooling. Same on the inside, in addition to possibly decreasing tolerances and gumming things up after the engine has sat unused for a time; especially on a ringed engine.

I run all-synthetic fuel with an ounce of added castor per gallon (for bearing protection) in my r/c aircraft. In the trucks, I run a 50/50 castor/synthetic blend (Morgan Omega), primarily because castor has a higher flash point than the synthetics and provides a degree of protection against a lean run, and is still a better lubricant. These little engines run fast and hot, usually with less-than-ideal cooling. The half-castor gives me some peace of mind; and after three and two years, respectively, my buggy engines still have all of their original parts.

I recently bought a vintage OS 61 FSR that has seen a lot of high-castor fuel. It is brown, inside and out. The crock pot/antifreeze trick will remove all of that. I also recently restored a 48 Surpass four-stroke that has been sitting idle for over ten years, with castor residue everywhere. I ran it before and after the crock pot clean-up, and once cleaned I got nearly 200 more rpm and MUCH improved transitioning between high and low throttle.

YMMV...

.

BOOCAKE4U

but the question is, would you ever use steel wool on the piston and sleeve of any of your engines? my guess is no...hehe

i can see removing the reside chemically, which is why i mentioned using simple green at the beginning of this thread, not familiar with the "crockpot technique" but i am sure it is equally effective...

to address the points you bring up, i too have seen engines so gummed up with brown goop that they were very noticably sticky....but that was a looong time ago and they were airplane engines....it does not seem to happen with the modern quality car fuels, probably because of the "degummed castor" that most of them use (probably klotz benol in most cases)...i am not sure why this would happen more frequently in a copter engine, unless it is just load or fuel-related (or a combination of both)

and i can think of one instance where the engine is turning over without lubrication...when it is being primed and started...the engine might turn over 15-20 times on a starter box or with a bumpstarter before the fuel makes it though the line and up to the carb...definitely arguable how much this wear will factor into the life of the engine, but it sure can't be helping...i do recall one company who sold a "turbo pre-luber" device which pressurized the oil system on 1:1 turbo cars before the engine ever turned over....they claimed that starting an engine without oil pressure (like those first milliseconds every morning) was what caused almost all the wear in an engine and turbo...they may have been a bit biased but i know that many 1:1 engine builders will do the same thing before firing up a new engine (by cranking the oil pump with a drill and adapter made from bar stock, when the drill jumps out of your hands you know the system is pressurized...heh)

the above does not take after-run oil into account, so the point is pretty much moot if it is used regularly (as most hobbyists do i hope)...my main goal in this whole exchange was just to hopefully prevent someone from taking their engine apart to "clean" it and wind up putting it back together with steel wool fibers or even worse, polishing compound inside it...like i said before, i have some older engines with more than ten gallons through which still make good power and haven't needed any "intervention" inside because i have always treated them well and run quality fuels...they have a nice light coat of "honey" inside and thats it, no goop, carbon buildup or discoloration...

anyway, probably no harm in removing castor residue as long as it is done with NO ABRASIVES...a good soak in some sort of solvent and a wipe with paper towels is all that is needed, otherwise there is no point in even breaking the engine in

scottm

Boocake is exactly right that the oil film prevents metal to metal contact. And porting and polishing is done to the heads not the block of a four stroke. Ihrttamya might be thinking of blueprinting, which is done to the block and heads, but again has nothing to do with polishing a piston.

Castor oil was used for glow engines and 1:1 race engines for years because it was the most effective lubricant at high temperatures. The pro and con of castor is the gum. It will actually help a nitro engine survive running too lean, by forming residue on the piston that works as a lube to some extent. Pro racers today use it for that reason - it will help them finish a race if they tune too lean. But then the residue needs to be removed on a healthy engine. An old engine may loose compression if the film is taking up clearance. Castor is less useful on a ringed nitro engine because it causes ring sticking, which is probably why heli fuel doesn't have it.

LSP972

My Feedback: (13)

<<...my guess is no..>>

And you would be correct...

IhrtTamiya

fine steel wool doesnt leave behind any more stuff than a paper towel would. and im sure he didnt use polishing solvent, just a good rub down.

have any of you seen a primer on the fuel tank? i have. is this standard? its the same thing as when you start up your lawn mower or weed eater. you have to push the button to get fuel in the carb. my friend has a primer on his tank and it takes fuel up to the carb before start up and doesnt require pulling the starter to prime the engine.

also: finsihing steel wool is really abrasive. it takes a lot of pressure and work to get scratches with that stuff. i say it is good to polish the sleeve and such every now and then.

oh well, why are we arguing about this? run the engine dude(which im sure you already have). you should have done it, but even if no one answered this post, if your engines screwed thens it screwed. if not, then you did something good. start er up and tell us the results.

Rcbros

My Feedback: (1)

AAAHHH MY head is twisting stop!!!!

i8tweety

My Feedback: (11)

Let's remember we are not talking about ringed engines. In a ringed engine, the piston ring is compressed when installed and opens up (as it's under tension) as the ring and sleeve wear. If you polish the sleeve in a ringed engine (which I don't approve of either as you should step up your ring size every few times you hone it).

What do you think polishing is? It doesn't fill in scratches, it REMOVES MATERIAL until the surface metal is worn down to the same level as the base of the scratch. Polishing a metal object and making it shiny removes the surface layer of the metal! The difference between a new engine (freshly broken in) and a worn out engine is only a few microns!!!!!!!!!!!!!!

You can port and polish the case as well as the intake ports on the sleeve if you wish. You can even clean the top of the piston if you feel you must (I don't encourage that either), but do not, I repeat DO NOT polish the side of the piston or the bore of the sleeve. It reduces engine life.

IhrtTamiya

by polishing im pretty certain he did not mean actually polshing the thing to remove scratches. he probably just removed the varnish and since when does polishing mean removing scratches? all it does is fill them in when using a compound. but as i said before...run the engine and have a good time.