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  1. #1

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    Lean Condition I Cant Track Down...

    Ok... engine is a trx 3.3. It goes from running slobbering rich on a full tank of fuel, to way lean and overheating at about half a tank and below. When it gets lean it gets lean at both high and low rpm, but it's very noticeable at low rpm... the engine seems to idle up real fast, then drop suddenly, then idle up, then drop... etc etc... as if there are air bubbles in the fuel line, except there are not bubbles!

    I've sealed the exhaust header, the back plate, and where the carb fits in the block. I took the tank out and checked it extensively with air pressure and vaccum... no leaks. I can blow air into the exaust pipe when the intake port on the crank is not open to the carb and I get no air leaking anywhere.

    The leaning out is really noticeable once the fuel tank gets about 1/2 empty... but I swear there are no leaks in the tank or the lines. I thought maybe the dip tube inside the tank had a hole in it half way up or something, but wouldn't I see air in the line if that were the case?

    Could there be something wrong with this carb? Is there something I shoud check on the carb? WHAT AM I MISSING??

    I am totally lost. Been beating my head against the wall with this 3.3 for about 2 months now... get one problem taken care of and almost immediately another one pops up. Grrrrrr.....

    -cheers

  2. #2
    meef rustler's Avatar
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    RE: Lean Condition I Cant Track Down...

    Throw it in the trash. Trx engines are garbage. Buy an os .18 or a dynamite .19T or something. Those engines are near the size of the Trx 3.3, but way easier to tune and they are not overpriced pieces of trash.
    Ofna Jammin X1 Cr Pro with a Top .21
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  3. #3

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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: meef rustler

    Throw it in the trash. Trx engines are garbage. Buy an os .18 or a dynamite .19T or something. Those engines are near the size of the Trx 3.3, but way easier to tune and they are not overpriced pieces of trash.
    LOL... ya, this is a common sentiment that I am sometimes inclined to maybe agree with in part...

    The flip side is that its very conceivable that I can make mistakes... mechanically all of the available glow engines are pretty simple. If you have a good piston to sleeve fit, good bearings, good glow plug, and good fuel delivery, they will run well. At this point, I think I have everything but good fuel delivery, which could totally be my fault. I'm not ready to give up yet. I would like to get my overpriced money's worth out of these 3.3's. lol.

    I took the carb out last night... all seems well with it. No cracks, not plugged up... and no apparent leaks. I did notice that I had my idle gap quite a bit smaller than the stock settings... the wierd thing is that when I open that up, the engine rpm doesn't settle quickly after a wot run. This would make me think the LSN is or HSNis too lean... LSN is not to lean cause it definitely loads up after a while on idle. HSN doesn't seem too lean either. We'll see. Iwill play with it some more and see what Icome up with. Like most of my other posts, maybe this one will reveal my inexperience at the hobby... lol. Any thoughts would be appreciated.

    -cheers


  4. #4
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    RE: Lean Condition I Cant Track Down...

    It sounds like the HSN is a bit lean. Richen it up a quarter turn, and lean out the LSN a little. A high idle after WOT usually means a lean HSN.
    Her name was Lola. She was a show girl.

  5. #5
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    RE: Lean Condition I Cant Track Down...

    Before you play around with tuning much more, I think you ought to address the problem of half-tank lean. This has been a very big problem in HPI Savage trucks, but i havn't heard of it as prononounced as your issue with Traxxas vehicles.

    The key is that the change of pressure due to gravity and the level of the fuel drops in the tank is made less significant by pressurizing the tank.

    First thing I'd check is that the fuel system is tight. Make sure there are no air leaks in the exhaust system, the pressure line, and the fuel tank, and in particular, the fuel lid o-ring.

    Next I'd shorten the pressure line as short as you can make it without having it stretched or rubbing on some part of the vehicle.

    If the half-tank-leaning doesn't improve, come back and we can go over the modification options you may want to consider.

    If it does improve, then try tuning your engine when the tank is half full and use it in an acceptable, but not perfect, condition.

  6. #6
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    RE: Lean Condition I Cant Track Down...

    Agree, a right at the limit HS will begin to run lean as the tank emties. Same with helos and planes. If the tank lines inside are more than one season old or you have this truck used, then by all means change all the "in tank" lines. A small pin hole inside the tank will begin to suck exhaust gasses if the hole is exposed when the tank begins to empty and lean the mix. Even with a pin hole in the tank, the tank will hold vacuum and pressure as the hole is "in the tank" Those small bubbles may not be seen in the opaque fuel line. If your real lean, then the fuel coming in will begin to vaporize and actually produce pulses of back pressure in the fuel system. As it vaporizes at the hot carb throat, that pressure can push fuel back through the carb further leaning your run or it wil vaporize in the cyclinder too early and mess with the timing of the burn and cause erratic running. I would replace the lines first and see where that gets you. Before the next run go 45 degrees richer on the HS and then tune her back in. Hopefully you get her back to her scalded dog self and shred some turf(or asphalt).

  7. #7

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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: chris6414

    Agree, a right at the limit HS will begin to run lean as the tank emties. Same with helos and planes. If the tank lines inside are more than one season old or you have this truck used, then by all means change all the "in tank" lines. A small pin hole inside the tank will begin to suck exhaust gasses if the hole is exposed when the tank begins to empty and lean the mix. Even with a pin hole in the tank, the tank will hold vacuum and pressure as the hole is "in the tank" Those small bubbles may not be seen in the opaque fuel line. If your real lean, then the fuel coming in will begin to vaporize and actually produce pulses of back pressure in the fuel system. As it vaporizes at the hot carb throat, that pressure can push fuel back through the carb further leaning your run or it wil vaporize in the cyclinder too early and mess with the timing of the burn and cause erratic running. I would replace the lines first and see where that gets you. Before the next run go 45 degrees richer on the HS and then tune her back in. Hopefully you get her back to her scalded dog self and shred some turf(or asphalt).
    Well, the only thing that makes sense to me is having a pin hole inside the tank on the dip tube causing bubbles that are too small to see through the fuel line. Everything else on the entire fuel systemseems absolutely tight - the exhaust header, the exhaust coupler, all the lines, the carb body, the needles, etc etc... Ican put air to all of it through the exhaust pipe, while plugging everything off, and the only time Ihear air moving is when the crank window is open to the carb, and a little air comes out the front bearing through the hole that is meant to feed oil to the bearing. Iam going to swap my brother in law's fuel tank out of his revo in for a bit tonight and see if it makes a difference and report back.

    As far as the trx 3.3 goes... i don't want to sound too harsh on it. Aside from a failed rear bearing and a cracked plastic carb body, it's been a good performer. Part of my struggle is troubleshooting, which Iassume you just get better at with experience. Isaid this before... for the money (street price on ebay), it's probably an ok deal, and a great motor to learn on. That said... I will someday have an OS .21.

    Itook the kubota with it'sfront end loader a rototiller down to the corner of our 4 acre lot and put in a pretty nice dirt track the other night. Not too huge, but measures around 325' in total length. Plenty of high banked turns and jumps. I see the need for spare a-arm and suspension components in my future...

    Thanks for all the input.

    Cheers

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    RE: Lean Condition I Cant Track Down...

    Well, tonight I went out and started from scratch on the tuning. Inever had a chance to swap fuel tanks. I had to go way off of the normal needle settings I generally start with... but i got it to run fairly well. It's almost like a different carb or something. Ihad to richen both the high and low speed needles almost a full turn each from where I normally run it. Maybe something's partially plugged in the carb? I dunno. Still wants to go lean at idle, but only intermittently. It's wierd.

    One thing that I have noticed is that the fuel I am using requires needle settings that are not any where near what stock settings are for the traxxas fuel. The fuel I am running is Sigs, who normally makes airplane fuel, but has a couple different RC car blends too. This stuff is 50% castor - 50% Klotz synthetic with 10% nitro. I would have thought that the needle settings would be a little leaner for a lower nitro content, but for the past 4 gallons I have been running the HSN at 5 turns out (not 3 like stock) to keep it from running too lean. Tonight I was working on the 5th gallon, and I had to run 6 turns!! I am thinking maybe the castor makes the fuel thicker and therefore requires greater clearance between the needle and the seat?? Maybe the new gallon is a little different than the other 4? I just dunno. Still need to swap tanks and see if that makes any difference... but I really doubt there is a leak in the dip tube inside the tank... seems like a long shot. I did put a big long piece of fuel line on the tank and ran it way up in the air above the engine to see if I could get a bubble to coalesce from perhaps a bunch of tiny unseen bubbles, but no luck. I just don't think it's the tank.

    So, the bottom line is that there is either a problem with fuel delivery that I was able to compensate for by tuning... or I just stink at tuning. At this point I am open to either option, but I don't usually struggle this much unless there is an underlying issue of some sort that I am unaware of. Who knows...

    I do know that we had a blast breaking in the new dirt track. Wow... these revo's will take a beating!! I ran about 3 tanks through without breaking anything except the bearings in the clutch bell. Awesome. Can't wait for another bash session this weekend.

    -cheers

  9. #9
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    RE: Lean Condition I Cant Track Down...

    I didn't see if you took the engine apart to inspect the con rod. Your symptoms seem very much like my Jato had before the con rod spit and took out my motor. After it warmed up(about 1/2 a tank) would seem lean intermittantly in WOT runs and would then seem to richen back up by itself. It also would idle weird once warm. I have a used T-Maxx coming and the first thing I am going to do is take apart the motor and check the rod and piston before I even try and run it. It looks fairly new but you never know with trucks and cars. If the rod is worn, it is getting an RB or Davis con rod with some new Boca bearings. I would inspect that rod(top end) as it has no bushing. From what I can gather, the rod and bearing upgrade makes these motors darn near bullet proof for the avergage user like myself.

  10. #10
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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: Oacker

    The fuel I am running is Sigs, who normally makes airplane fuel, but has a couple different RC car blends too. This stuff is 50% castor - 50% Klotz synthetic with 10% nitro.
    Sounds like you are trying to run Champion "10".A good airplane fuel, butinappropriate for car engines. 20% total lubrication is way too high. And why cheap out with the 10% nitro level?

  11. #11

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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: nitroexpress


    ORIGINAL: Oacker

    The fuel I am running is Sigs, who normally makes airplane fuel, but has a couple different RC car blends too. This stuff is 50% castor - 50% Klotz synthetic with 10% nitro.
    Sounds like you are trying to run Champion "10".A good airplane fuel, butinappropriate for car engines. 20% total lubrication is way too high. And why cheap out with the 10% nitro level?
    I've seen people go round and round about the oil content, and I just don't care to do it. Granted, I am CHEAP, thus Ibuy inexpensive fuel... but there are too many red herrings in this hobby if you ask me. The bottom line is airplane fuel is not all that different than car fuel aside from marketing and a couple percentmore or less oil. To theprofessionalracer there is probably adifference... to the backyard basher, I doubt it. I have had terrific luck with this inexpensive fuel (not necessarily low quality fuel thought) thus far... no issues with wear inside the engine - crankrod and sleeve are all good.Idid have to replace therear bearing which is common in the 3.3, but have had no issues since replacing it. After almost 5 gallons I did a re pinch on the sleeve to bring the compression andperformanceback up to like new. Also, no issues with tuning until now.

    For what it's worth, my brother in law's revo is running traxxas top fuel 20%... he swears my revo is faster with the 10% nitro, though Ican't tell the difference myself. This is not to say there are no other mitigating factors that would cause this scenario to play out, ie tuning, piston/sleeve fit, etc etc.

    I did run a half a tank of traxxas fuel through recently just to check if my fuel was the issue and i basically had the same results just at different needle settings.

    Well, I said I wasn't going to do it, but as far as oil content goes... one thing I will say is that it makes sense to run higher total oil content with lower nitro content. From what Iunderstand, nitro brings additional oxygen to the combustion cycle, thus allowing for more fuel to be entered into each combustion stroke which generates more power. With a lower nitro content, you have less fuel going through each combustion cycle... in order to keep the VOLUMEof oil the same through each stroke, you would need then a higher total oil percent. What exactly these ratios are I do not know. All Iknow is that Ihave run this fuel in two different 3.3's without issue. Tuning is definitely different... but once it's tuned your good to go. All that said... I do not think 20% oil content is necessary, though Ipersonally dont see a problem with it. Heck, isn't traxxas fuel like 17 or 18%?

    At this point I am just going to run the engine. I was able to keep it below 270 last night bashing about pretty hard, mostly in the 240 range, so I'm good. It may not be running perfectly, but again I'm not racing... just bashing about.

    cheers.


  12. #12
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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: Oacker


    ORIGINAL: nitroexpress


    ORIGINAL: Oacker

    The fuel I am running is Sigs, who normally makes airplane fuel, but has a couple different RC car blends too.* This stuff is 50% castor - 50% Klotz synthetic with 10% nitro.
    *
    Sounds like you are trying to run Champion ''10''.**A good airplane fuel, but*inappropriate for car engines.* 20% total lubrication is way too high.* And why cheap out with the 10% nitro level?*
    I've seen people go round and round about the oil content, and I just don't care to do it.* Granted, I am CHEAP, thus I*buy inexpensive fuel... but there are too many red herrings in this hobby if you ask me.* The bottom line is airplane fuel is not all that different than car fuel aside from marketing and a couple percent*more or less oil.* To the*professional*racer there is probably a*difference... to the back*yard basher, I doubt it. * I have had terrific luck with this inexpensive fuel (not necessarily low quality fuel thought) *thus far... no issues with wear inside the engine - crank*rod and sleeve are all good.**I*did have to replace the*rear bearing which is common in the 3.3, but have had no issues since replacing it.* After almost 5 gallons I did a re pinch on the sleeve to bring the compression and*performance*back up to like new.* Also, no issues with tuning until now.*

    For what it's worth, my brother in law's revo is running traxxas top fuel 20%... he swears my revo is faster with the 10% nitro, though I*can't tell the difference myself.* This is not to say there are no other mitigating factors that would cause this scenario to play out, ie tuning, piston/sleeve fit, etc etc.*

    I did run a half a tank of traxxas fuel through recently just to check if my fuel was the issue and i basically had the same results just at different needle settings.

    Well, I said I wasn't going to do it, but as far as oil content goes... one thing I will say is that it makes sense to run* higher total oil content with lower nitro content.* From what I*understand, nitro brings additional oxygen to the combustion cycle, thus allowing for more fuel to be entered into each combustion stroke which generates more power.* With a lower nitro content, you have less fuel going through each combustion cycle... in order to keep the VOLUME*of oil the same through each stroke, you would need then a higher total oil percent.* What exactly these ratios are I do not know.* All I*know is that I*have run this fuel in two different 3.3's without issue.* Tuning is definitely different... but once it's tuned your good to go.* All that said... I do not think 20% oil content is necessary, though I*personally dont see a problem with it.* Heck, isn't traxxas fuel like 17 or 18%?*

    At this point I am just going to run the engine.* I was able to keep it below 270 last night bashing about pretty hard, mostly in the 240 range, so I'm good.* It may not be running perfectly, but again I'm not racing... just bashing about.**

    cheers.

    20% oil content is WAY too high, especially for car engines. Plane engines run a lot cooler due to a prop being right in front of them. The parts never heat up enough to expand, so the extra oil is needed. Same is true for boats. An oil content that high in a car leads to pre-ignition, overheating, and crappy idle, they are just not designed for it. 18% is the max you should ever run in a car, which is still too high IMO. Traxxas Fuel is 16%. O'Donnell Race is 7% synthetic, which is what I run.
    Her name was Lola. She was a show girl.

  13. #13

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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: proanti1


    ORIGINAL: Oacker


    ORIGINAL: nitroexpress


    ORIGINAL: Oacker

    The fuel I am running is Sigs, who normally makes airplane fuel, but has a couple different RC car blends too. This stuff is 50% castor - 50% Klotz synthetic with 10% nitro.
    Sounds like you are trying to run Champion ''10''.A good airplane fuel, butinappropriate for car engines. 20% total lubrication is way too high. And why cheap out with the 10% nitro level?
    I've seen people go round and round about the oil content, and I just don't care to do it. Granted, I am CHEAP, thus Ibuy inexpensive fuel... but there are too many red herrings in this hobby if you ask me. The bottom line is airplane fuel is not all that different than car fuel aside from marketing and a couple percentmore or less oil. To theprofessionalracer there is probably adifference... to the backyard basher, I doubt it. I have had terrific luck with this inexpensive fuel (not necessarily low quality fuel thought) thus far... no issues with wear inside the engine - crankrod and sleeve are all good.Idid have to replace therear bearing which is common in the 3.3, but have had no issues since replacing it. After almost 5 gallons I did a re pinch on the sleeve to bring the compression andperformanceback up to like new. Also, no issues with tuning until now.

    For what it's worth, my brother in law's revo is running traxxas top fuel 20%... he swears my revo is faster with the 10% nitro, though Ican't tell the difference myself. This is not to say there are no other mitigating factors that would cause this scenario to play out, ie tuning, piston/sleeve fit, etc etc.

    I did run a half a tank of traxxas fuel through recently just to check if my fuel was the issue and i basically had the same results just at different needle settings.

    Well, I said I wasn't going to do it, but as far as oil content goes... one thing I will say is that it makes sense to run higher total oil content with lower nitro content. From what Iunderstand, nitro brings additional oxygen to the combustion cycle, thus allowing for more fuel to be entered into each combustion stroke which generates more power. With a lower nitro content, you have less fuel going through each combustion cycle... in order to keep the VOLUMEof oil the same through each stroke, you would need then a higher total oil percent. What exactly these ratios are I do not know. All Iknow is that Ihave run this fuel in two different 3.3's without issue. Tuning is definitely different... but once it's tuned your good to go. All that said... I do not think 20% oil content is necessary, though Ipersonally dont see a problem with it. Heck, isn't traxxas fuel like 17 or 18%?

    At this point I am just going to run the engine. I was able to keep it below 270 last night bashing about pretty hard, mostly in the 240 range, so I'm good. It may not be running perfectly, but again I'm not racing... just bashing about.

    cheers.

    20% oil content is WAY too high, especially for car engines. Plane engines run a lot cooler due to a prop being right in front of them. The parts never heat up enough to expand, so the extra oil is needed. Same is true for boats. An oil content that high in a car leads to pre-ignition, overheating, and crappy idle, they are just not designed for it. 18% is the max you should ever run in a car, which is still too high IMO. Traxxas Fuel is 16%. O'Donnell Race is 7% synthetic, which is what I run.
    I totally understand this point of view... but the first 4 gallons of fuel with 20% oil I have run through this engine without issue tells me (and perhaps only me - lol) that it's not as big a deal as some say. Really, tuning on this 3.3. hasn't been a problem until just the last week or so. Idle has been good, plugs don't foul, and the power has been great. That having been said... to each his own. I experimented making my own fuel at one time... proanti I think you helped me out on that... Iwas running zero nitro and 16% castor oil with raised compression. Ran unbelieveably well after I got the bugs worked out of the tuning. I stopped making the fuel cause the easy start didn't seem to like the extra compression. At the end of the day, I just think there is more than one way to skin the proverbial cat... but I digress. At some point I will probably try some fuel with less oil content... but the low cost of the sigs is hard to pass up. In my mind, $40 for a gallon of traxxas fuel at the lhs or $24 per gallon with freight for the sigs is a no brainer... that's like 40% more runtime per dollar and I like that. Is my engine performing at peak? Maybe not. Does it perform well enough for a schmuck who wants to bash around the yard a little bit and cant drive worth a hoot anyhow? Absolutely.

    Thanks everyone for their thoughts. Different strokes for different folks - it's what makes the world go around.

    -cheers


  14. #14
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    RE: Lean Condition I Cant Track Down...

    If it hasn't been mentioned yet...
    Seal your carb O-rings with AE green slime or clear silicone automotive brake lube, slather them above and below the O-ring and reinstall.
    Of course while you have the needles out check for nicks on the O-rings, or if you can get a cheap set of new ones do that too.
    (HPI sells the K4.6 set with new slide boot and all O-rings for $4 and works on my K5.9 and the Axial .28 also... not sure about if Crapxxas sells those)

    I made it thru three 5 minute heats and a 20 minute A-main with a HSN O-ring that was sliced in half and rolled over just by using Sil-Glyde brake lube on the needles.

  15. #15

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    RE: Lean Condition I Cant Track Down...

    UPDATE:

    After days and days of fighting with this tuning issue... wasting fuel, scratching my head, and getting frustrated... I just slowed down for a minute and figured I must be missing something.  Something simple - and that I need to start from scratch.  I disassembled the engine completely and VOILA!! 

    Sure enough... it was something simple that I completely overlooked.  There was a chunk missing from the seal on engine's front bearing causing an air leak.  I swapped front bearings and all is now well with the world... engine tunes perfectly and runs just like I remember. 

    Cheers.

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    RE: Lean Condition I Cant Track Down...

    i just read your story and i've been through the same thing with the 3.3.the front seal only seals against grit,not air for long.the problem i found is the crank to block clearence.the crank is suppose to almost touch the block and the oil/fuel mixture in there creates a seal.if you take the crank back out and look in from the rear,the hole will appear to be egg shaped in the bottom,oils rear bearing better,but promotes air leaks around crank.the only way i ever fixxed any i work on is to replace the front bearing with an aftermarket double sealed on both sides and pre greased.when it knocks the edge of the new bearing,it will prob.start again.an easy test is to shoot nitro cleaner behind the flywheel with it idling,it will either idle way up for a second or cut off.hope this helps.by the way,i've run 15% omega airplane fuel in my cars and trucksfor years and never had any issues.

  17. #17

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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: Oacker

    UPDATE:

    After days and days of fighting with this tuning issue... wasting fuel, scratching my head, and getting frustrated... I just slowed down for a minute and figured I must be missing something.* Something simple - and that I need to start from scratch.* I disassembled the engine completely and VOILA!!*

    Sure enough... it was something simple that I completely overlooked.* There was a chunk missing from the seal on engine's front bearing causing an air leak.* I swapped front bearings and all is now well with the world... engine tunes perfectly and runs just like I remember.*

    Cheers.
    isnt the contrast between what people tell you could be wrong and what is actually wrong astonishing?

    20% fuel is a bity slobbery, but the higher rpm the motor is run the leaner it gets, and the only thing protecting it is the oil. i had probably the equivalent of 200,000 miles on an old ninja .27, but the crank bushing was still tight and the piston couldnt be pushed out the top when i went to rebuild it- so i always run high oil content.

  18. #18

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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: savagecommander


    ORIGINAL: Oacker

    UPDATE:

    After days and days of fighting with this tuning issue... wasting fuel, scratching my head, and getting frustrated... I just slowed down for a minute and figured I must be missing something.* Something simple - and that I need to start from scratch.* I disassembled the engine completely and VOILA!!*

    Sure enough... it was something simple that I completely overlooked.* There was a chunk missing from the seal on engine's front bearing causing an air leak.* I swapped front bearings and all is now well with the world... engine tunes perfectly and runs just like I remember.*

    Cheers.
    isnt the contrast between what people tell you could be wrong and what is actually wrong astonishing?

    20% fuel is a bity slobbery, but the higher rpm the motor is run the leaner it gets, and the only thing protecting it is the oil. i had probably the equivalent of 200,000 miles on an old ninja .27, but the crank bushing was still tight and the piston couldnt be pushed out the top when i went to rebuild it- so i always run high oil content.

    I call total BS that you had a Ninja .27 !
    Neal Smith..owner Clockwork Racing Engines

  19. #19

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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: supertib


    ORIGINAL: savagecommander


    ORIGINAL: Oacker

    UPDATE:

    After days and days of fighting with this tuning issue... wasting fuel, scratching my head, and getting frustrated... I just slowed down for a minute and figured I must be missing something.* Something simple - and that I need to start from scratch.* I disassembled the engine completely and VOILA!!*

    Sure enough... it was something simple that I completely overlooked.* There was a chunk missing from the seal on engine's front bearing causing an air leak.* I swapped front bearings and all is now well with the world... engine tunes perfectly and runs just like I remember.*

    Cheers.
    isnt the contrast between what people tell you could be wrong and what is actually wrong astonishing?

    20% fuel is a bity slobbery, but the higher rpm the motor is run the leaner it gets, and the only thing protecting it is the oil. i had probably the equivalent of 200,000 miles on an old ninja .27, but the crank bushing was still tight and the piston couldnt be pushed out the top when i went to rebuild it- so i always run high oil content.

    I call total BS that you had a Ninja .27 !
    I'll go ahead and take this oppurtunity to do something you've never done to one of my questions- answer it directly.

    now that i think about it, the motor may have been a .21- blue heat sink with a silver body, but i think i can remember the ".27" etched onto the top of the sink. either way it was a scalding hot mill, but it was some time ago. i have since sold that motor,along with many others. i stuck it in a buggy chassis and i could not find a spur small enough to labor the motor any so i turned it into a muggy or truggy or whatever.... * it had big tires* ...ran that motor hard on some 16% stuff everybody told me not to, with a mcoy #8, but it ran all the way up to when i sold it- probably about eight gallons.

    any other questions you'd like me to answer kneel?


  20. #20

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    RE: Lean Condition I Cant Track Down...


    ORIGINAL: savagecommander


    ORIGINAL: supertib


    ORIGINAL: savagecommander


    ORIGINAL: Oacker

    UPDATE:

    After days and days of fighting with this tuning issue... wasting fuel, scratching my head, and getting frustrated... I just slowed down for a minute and figured I must be missing something.* Something simple - and that I need to start from scratch.* I disassembled the engine completely and VOILA!!*

    Sure enough... it was something simple that I completely overlooked.* There was a chunk missing from the seal on engine's front bearing causing an air leak.* I swapped front bearings and all is now well with the world... engine tunes perfectly and runs just like I remember.*

    Cheers.
    isnt the contrast between what people tell you could be wrong and what is actually wrong astonishing?

    20% fuel is a bity slobbery, but the higher rpm the motor is run the leaner it gets, and the only thing protecting it is the oil. i had probably the equivalent of 200,000 miles on an old ninja .27, but the crank bushing was still tight and the piston couldnt be pushed out the top when i went to rebuild it- so i always run high oil content.

    I call total BS that you had a Ninja .27 !
    I'll go ahead and take this oppurtunity to do something you've never done to one of my questions- answer it directly.

    now that i think about it, the motor may have been a .21- blue heat sink with a silver body, but i think i can remember the ''.27'' etched onto the top of the sink. either way it was a scalding hot mill, but it was some time ago. i have since sold that motor,along with many others. i stuck it in a buggy chassis and i could not find a spur small enough to labor the motor any so i turned it into a muggy or truggy or whatever.... * it had big tires* ...ran that motor hard on some 16% stuff everybody told me not to, with a mcoy #8, but it ran all the way up to when i sold it- probably about eight gallons.

    any other questions you'd like me to answer kneel?

    Well there never was a Ninja .27.. .21 and 28 ..And even if it was a Ninja .21 it was a turbo head engine and would not run on a McCoy #8.....Every Ninja was a turbo head engine.......... However there were Toki built Samarai .27's...Blue case and silver head, and they were standard head engines...
    Neal Smith..owner Clockwork Racing Engines

  21. #21

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    RE: Lean Condition I Cant Track Down...

    samuri, ninja... like i said, some time ago. it very well could have been a team infinity .27 with an aftermarket head- all i know is it was a raped ape and wouldnt die- on 16% oil.

  22. #22

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    RE: Lean Condition I Cant Track Down...

    Surprised to see this thread active again.  Since I started it, I've done two things...

    1) I put an OS carb on the 3.3 which improved tunability beyond the wildest of my imagination.  The 3.3 carb is ok I guess, but it's not even close to the OS as far as being totally sweet to tune.  Most noticeable is the absolutely perfect idle.

    2) I picked up an OS 21TM (used and needed some work) that I have been running in the revo from time to time.  If the 3.3 is a good running engine... the 21 is an absolute monster.  Love it. 

    In both engines I have been running Sig's car fuel with 10% nitro and 20% total oil (half castor, half Klotz) - both with the head shim removed to gain back some of the power lost by using low nitro.  I'm not keeping track anymore of how much fuel I run through the engines, but I know the 3.3 has at least 8 gallons through the piston, sleeve, rod, and crank.  I've replaced the bearings once (stock rear bearing lost it's retainer) and I've repinched the sleeve once to bring the power back after I had some tuning issues that overheated the motor a couple times.  It's my opinion that the oil content thing is kind of a red-herring... the average basher like myself can have great luck with high oil content.  I would go one step further and say the large amount of castor in this particular fuel can really save your rear end if you pull a stupid tune.  With 7% oil, your tune would have to be absolutely perfect - 100% of the time - which seems unrealistic.  Don't get me wrong... I'm not saying there's not a place for low content oils... they might be ideal for someone who is serious about racing, but not necessarily ideal for the average joe.  For me, the high oil content doesn't seem to cause any issues whatsoever with tuning, idle, or top end performance, and both engines run in an acceptable temperature range - the 3.3 around 250 or 260, the 21 around 220 or 230. 

     I will also quote this from the OS website:

    Finally, O.S. states in their engine instructions that you should use a fuel that has an oil content of no less than 18% by volume. Many so-called "R/C Car" fuels contain oil in the 12%-14% range. While these may work quite well when the engine's set correctly, low-oil fuels do not leave much margin of error if the engine gets a lean run. Nitro content can be as high as 20% by volume without worry about special engine tuning or setup.

    I've gotten to the point where I am very cautious about anything anyone on a forum says... I have actually seen people say that some bearings should be run dry... one way bearings, clutch bell bearings... etc etc... this is so ludicrous that I can't believe anyone would even believe such a thing.  When you put steel on steel at 30,000 rpm bad stuff happens, yet you will see this type of advice time after time on the forums... Not sure why that is... perhaps many of the people on the forums are young kids, teens or preteens, that just don't have a clue and like to hear themselves talk.  Who knows.  The bottom line is, there really is a lot of bs in the realm of RC forums... also some really good info as well...  readers simply need to beware while they sort through it.

    cheers



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