4-stroke fuel--Does anyone really know?

4-stroke fuel--Does anyone really know?
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4-stroke fuel--Does anyone really know? - 1/4/2004 9:05:40 PM

3d-aholic

Posts: 1992
Joined: 10/7/2003
From: Austin, TX, USA
Status: offline

I've read an enormous amount of information about 4 stroke fuel now. I've read articles that show scientific proof why less oil is better and different articles why 4 strokes need more oil. On the Wildcat website, they explain that 4-strokes need more oil than 2 strokes...but their 4 stroke fuel only has 15-16%. There is a fuel FAQ running around somewhere on the Internet that explains that 4 strokes need less oil....because the same oil is in the engine longer. My conclusion is that no one really knows. So I'm giving up on that question.

Now, my question is what is better in a 4-stroke. Castor or Synth.?

The Wildcat website says 100% synth.
YS must think Synth because they recommend the 20/20 which seems to be 100% synth.
My engine says a mixture of both are best.

How can there be so much disagreement? Does noone know the answer to this question either?

Post #: 1

RE: 4-stroke fuel--Does anyone really know? - 1/5/2004 3:28:39 AM

RaceCity

Posts: 1842
Joined: 7/10/2002
From: NotUpNorth, USA
Status: offline

There is no "real" answer to your question unfortunately.

The castor/synth debate has raised the blood pressure of many people on this, and other
forums related to r/c.

Castor has unparalleled performance at high temperatures. When synthetics have burned
away....castor is still there..lubricating.

But....castor will leave a residue that in time,will carbonize and need to be removed.

Synthethics run clean. There is little, if any residue left over and the lack of residue is
IMO sometimes interpreted as "better".

The fact that it "vanishes" without a trace should bother you.

Fuel manufacturers have a vested interest in convincing you that their "special" oil is better.

Truth is...if it's so "special"...why doesn't the whole world use it?

Dirty or not. Castor stays while the others burn away.

My philosophy is simple. It's cheaper to remove residue than it is to replace metal. Your 4C engine
represents a sizeable investment. Better to take care of it.

I'd suggest a fuel that contains at least SOME castor if you intend to keep your engine for
any length of time. Fuels such as Powermaster, Omega, etc...have ample oil/castor content
to keep your motor running well for a long time.

Hope this helps.

'Race

< Message edited by RaceCity -- 1/5/2004 3:54:06 AM >

(in reply to 3d-aholic)

Post #: 2

RE: 4-stroke fuel--Does anyone really know? - 1/5/2004 3:46:09 AM

3d-aholic

Posts: 1992
Joined: 10/7/2003
From: Austin, TX, USA
Status: offline

Well the thing is I'm going to make my own fuel for my 4-stroke

But do I make a fuel like-

Wildcats: 18% oil, 100% synth
Wildcat recommends the lubrication package be totally synthetic. The use of synthetic oil is important in four stroke engines to prevent gumming and varnishing of the lifters and coking of the valves. Varnishing will occur on castor based fuels. This can lead to sticking valves, which will cause the valve set to get knocked out of time. Coking of the valves will cause improper seating of the valves causing a reduction in compression and incomplete combustion. Four stroke engines also have high exhaust gas temperatures and the use of synthetics greatly reduces carboning at the exhaust ports.

or like...
Omega: 17% oil, 50% synth, 50% castor

or like...
Powermasters YS 20/20: 20% Oil All-Synthetic

or more like....
Powermasters other 4-stroke fuel: 15% Oil Synthetic Castor Blend (most likely 70:30)
+++++

As you can see, you can get a 4 stroke fuel anywhere from 15 to 20% oil and anywhere from 0% to 50% castor. There are bigger differences in 4-stroke fuel than 2 stroke fuel.

(in reply to RaceCity)

Post #: 3

RE: 4-stroke fuel--Does anyone really know? - 1/5/2004 3:12:00 PM

Hobbsy

Posts: 10554
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline

Throw, I have never agreed with that idea, I ran my Enya .46MKII, Saito .80 and 150 for about three years on Fox 15% fuel with 20% castor with no ill effects at all.

_____________________________

"I have gone faster backwards, upside down and on fire than most people have gone at all" Don Garlits

(in reply to 3d-aholic)

Post #: 4

RE: 4-stroke fuel--Does anyone really know? - 1/5/2004 11:06:36 PM

Bax

Posts: 12269
Joined: 4/26/2002
From: Champaign, IL, USA
Status: online

Four-stroke engines tend to run a much lower temperatures than do the two-strokers. This means that you can use synthetic oil quite well. With rich running, synthetic oil will greatly reduce the varnish and carbon buildup you'd see in two-stroke engines.

Also because of the lower operating temperatures, you can get away with a bit less oil. With a few exceptions, all of the O.S. Max four-stroke engines can be run on fuels with the oil content as low as 16%. With hotter-running engines, the oil is used to help carry away the engine's heat. Synthetics will do this nicely until the engine gets too hot, where it vaporizes and, PRESTO!, no oil. Castor will start to turn to varnish, but will still protect the engine somewhat.

We have no problems with anyone using a fuel with all-synthetic oil in a four-stroke engine. The main thing to consider is that most fuels with synthetic oils do not provide the corrosion protection the lower-end of your engine needs. This means that you have to make sure you get a LOT of a good-quality after-run product into the lower-end of the engine at the end of the flying day. You'd be surprised to see how fast the bearings and crank can corrode if you don't.

For convenience, though, we'd suggest that you use the same 18% oil-content fuel in your four-stroke engines as you do in your two-strokes. If you use a synthetic-castor blend in your 2-strokes, then it won't hurt your four-strokes.

Good-quality fuel is the main requirement. If you use a good-quality fuel, you should have no engine problems caused by the fuel.

_____________________________

Bill Baxter, Manager Hobby Services/Futaba Service/North America
3002 N. Apollo Dr. Ste. 1 Champaign, IL 61822 USA
Service Phone: 217 398-0007
Email: hobbyservices@hobbico.com

(in reply to Hobbsy)

Post #: 5

RE: 4-stroke fuel--Does anyone really know? - 1/5/2004 11:17:21 PM

3d-aholic

Posts: 1992
Joined: 10/7/2003
From: Austin, TX, USA
Status: offline

quote:

ORIGINAL: Bax
If you use a synthetic-castor blend in your 2-strokes, then it won't hurt your four-strokes.

Well my TT .91FS is choking up gobs of black tar/soot into the tank from the muffler on Powermaster. So something in the fuel is burning up besides the Methanol and creating soot. Supposedly that can't happen to castor (not hot enough)...so it has to be the synth.

[But thats a guess.....seems no-one knows for sure.]

< Message edited by 2MuchThrow -- 1/5/2004 6:22:00 PM >

(in reply to Bax)

Post #: 6

RE: 4-stroke fuel--Does anyone really know? - 1/5/2004 11:28:48 PM

3d-aholic

Posts: 1992
Joined: 10/7/2003
From: Austin, TX, USA
Status: offline

quote:

ORIGINAL: Bax

Also because of the lower operating temperatures, you can get away with a bit less oil.

This is what I mean by no-one agrees.

Granted what you say is true. But, according to Wildcat, the only way oil can get to the bearings/crankcase for instance is blow by....so you need more oil to compensate for the fact that there is no direct fuel/oil mix pumping to that region of the motor.

http://www.wildcatfuel.com/fuel_24cycle.html

"First - Four stroke engines require more lubrication than do 2-stroke engines. This is do to the number of moving parts. Unlike a 2-stroke, a 4-stroke does not have the benefit of raw fuel and oil pumping through its crankcase for lubrication. A 4-stroke draws it's fuel in from the top of the cylinder by the down stoke of the piston. Lubrication is accomplished by blow-by at the BDC (bottom dead center) and run-down of oil through the lifter tubes. This oil must migrate to the bearings as well, therefore, volume is essential. (See disassembled 4-stroke -vs- 2-stroke below for comparision). Yes, despite the nonsense that some would try to get you to believe it's that simple."

There is an incredible amount of disagreement in this area

(in reply to Bax)

Post #: 7

RE: 4-stroke fuel--Does anyone really know? - 1/13/2004 2:12:53 AM

RCXPLANES

Posts: 535
Joined: 1/5/2003
From: Central Point, OR, USA
Status: offline

2MuchThrow,
I couldn't agree with you more. I can't even get past the "To Castor Or Not To Castor" question concerning four stroke motors let alone how much nitro or oil content. I was running CoolPower 15% in my Saito and then was told that 18% oil was not enough. Oh my goodness it is all synthetic as well. I know better than to overheat a 2 stroke so, for me synthetic was fine. Besides, Castor in a 2 stroke ringed motor just means you will gum it up and spend more time sooner fixing that.

I think we need a manufacturers rep from all of the four stroke companies to recomend at least a safe percentage of castor/synthetic/nitro blend without the wishy washy this is ok and that is ok and no real recomendation. To complicate things, some fuels are great about telling how much of what is in which products in their line. Others are not so good.

So what is the best fuel for our nitro swilling bump stickers? Is Blow-By a really good lubrication method for a crankshaft? With that much Blow-By, arn't we loosing some of the power potential? Seems to me that my four stroke is bordering on if not surpassing my 2 strokes in fuel inefficency when you compare how much raw fuel and oil are deposited on the Ultracoat.

_____________________________

Life is short. Fly hard and enjoy.
Bud Wilkinson, RC-Xplanes, www.rcxplanes.com

(in reply to 3d-aholic)

Post #: 8

RE: 4-stroke fuel--Does anyone really know? - 1/13/2004 4:46:24 PM

3d-aholic

Posts: 1992
Joined: 10/7/2003
From: Austin, TX, USA
Status: offline

quote:

ORIGINAL: errolw98
To complicate things, some fuels are great about telling how much of what is in which products in their line. Others are not so good.

And the most secret of all mixes are the 4 stroke combinations. Sig, Powermaster and many others completely secret on the 4 stroke mix question.

(in reply to RCXPLANES)

Post #: 9

RE: 4-stroke fuel--Does anyone really know? - 1/13/2004 5:29:44 PM

RCXPLANES

Posts: 535
Joined: 1/5/2003
From: Central Point, OR, USA
Status: offline

Makes it easy dont it.

_____________________________

Life is short. Fly hard and enjoy.
Bud Wilkinson, RC-Xplanes, www.rcxplanes.com

(in reply to 3d-aholic)

Post #: 10

RE: 4-stroke fuel--Does anyone really know? - 1/13/2004 5:43:45 PM

3d-aholic

Posts: 1992
Joined: 10/7/2003
From: Austin, TX, USA
Status: offline

Its obvious to me no-one really knows.

I think everyone is just pretending like they know...

(in reply to RCXPLANES)

Post #: 11

RE: 4-stroke fuel--Does anyone really know? - 1/13/2004 6:17:21 PM

Hobbsy

Posts: 10554
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: offline

This fuel thing is just like the glow plug thing, some guys say the OSf is the only way to go, I have ten Saitos, three YSs and two Enya fourstrokes that say different. The Fox Miracle plug and the H9 SuperPlug work just as well except in my Saito .30 in which the H9 plug works best. I've used Wildcat fuel for several years now and have had zero problems, so I think I know. But some guy whose run a 12x4 on his Saito .72 is going to fry the bearings and blame the fuel or the bearings or both and he'll say that I don't know jack stuff. So where does that leave us? Simply put, run the fuel you like.

_____________________________

"I have gone faster backwards, upside down and on fire than most people have gone at all" Don Garlits

(in reply to 3d-aholic)

Post #: 12

RE: 4-stroke fuel--Does anyone really know? - 1/13/2004 6:24:35 PM

3d-aholic

Posts: 1992
Joined: 10/7/2003
From: Austin, TX, USA
Status: offline

So TRUE....I hear what you are saying. I agree. I use the Fox Miracle plug too and have to listen to folks say it won't work...you have to be using a $9.00 OS plug or your engine will explode or it won't work.

I just say "Yeh, your right and then tighten up my Miracle plug and go flew".

With the fuel thing, I was trying to make my own and so its a bit more complicated. I guess I will need to try and experiment with several blends and find out what works best for myself. I'm fairly sure that just about any kind of oil that is at least 12% or better is probably fine for a short decision making process anyways.

(in reply to Hobbsy)

Post #: 13

RE: 4-stroke fuel--Does anyone really know? - 1/14/2004 3:26:31