grant-RCU

My Feedback: (10)

I read the magnum 4 stroke post in the forum and everyone seems to think these are great engines.
However i have read a few posts claiming these are not the best engines. A few people said 20% nitro will melt the piston. The other comments were (you get what you pay for.)

I ordered a magnum .30 4 stroke. just got it in the mail today. its a nice looking little engine. Does anyone have any experience with this engine? I also have a magnum 91 4 stroke. I've ran about 1.5 gallons of fuel through it and it seems to be a good engine. I run 15% synthetic fuel in it. cool power and magnum fuel.

Do you guys run castor in your magnums? I have 10% omega but the 15% synthetic make more power and less mess. I have always heard that castor will gum up a 4 stoke.

Ed_Moorman

My Feedback: (1)

Grant,

I have magnum & Saito 4-strokes and I have had great luck with both. I generally put the lighter Saitos in fun fly type planes and the Magnums in sport and scale planes. This is not because the Saitos are more powerful, it is just that the Saitos are lighter for a better power-to-weight ratio. In the Magnum line, I have the .91 in a scale Nieuport 27, the .70 in a Sea Monster flying boat and the .61 in a Cessna scale. My buddy has a .52 in an SE-5 and 2 of the .30s, also in scale planes. We love the darn things.

We normally run Omega 10%, although I have tried 20% heli fuel.

I would imagine that the probablilty of getting a low quality engine is greater with any of the Chinese engines, but Global Services for Magnum is excellent so you won't get stuck. My club's experience is that they replace the engine rather than fix it. One of the guys sent one in after a crash, asking for an estimate and they sent him a new engine, no charge, no questions. Beat that.

They are a little rougher than an OS so they will take longer to break-in and get tuned right on, but well worth it for me. As with all ringed engines, they will need some running to seat the ring. If you are expecting to mount the engine right out of the box, lean it out and get max performance, you'll be disappointed. Break them in like the instructions say. The .70 and the .91 in particular are excellent engines. If I get a 1.20, it will be a Magnum. For the price, they are hard to beat.

Rodney

Many Magnums in our club, all very good engines with no problems.

w8ye

My Feedback: (16)

I have several also

Enjoy,

Jim

jessiej

I have the Magnum .30 and like it fine. Break it in carefully and I am confident you will be well pleased.

jess

yard-dart

My Feedback: (35)

I had a .61 and sorta hate I got rid of it. The guy I sold it to put it on a .40 sized Stick and loves the combo. The engine runs great, so don't let people give you crap about Magnums. Sure, they're not as light and as nice looking as my Saitos, but for the money, you can't go wrong. And for the comment about running 20% in these engines, I do it every day in all of mine, even when I had my Magnum. It actually ran better on 20% than any other mix. The current owner is still running it on 20%, and guess what, no piston meltdown. Whoever told you that is an idiot. And about running all synthetic as opposed to a Castor "blend", as long as your not running a fuel that is "all castor" based, your engine will definately not gum up. In fact, I went from running all synthetics to a Castor blended fuel. That's all I'll put in my engines now.

jessiej

yard-dart is correct about the castor. Won't hurt anything and gives an extra bit of protection.

jess

grant-RCU

My Feedback: (10)

Thanks guys! Whats the best prop for the .30? My plane is going to come out around 3.5 to 3.75 lbs AWU. I was hoping to get it to hover or at least be a hot sport plane. I have some 8x5 props , 10x6, 9x8, and 8x4s.
It says to use a 9x6 i think to break it in. can i use the 8x5 instead since i dont hav a 9x6?

I am going to stick with the omega 10% for a while until i have some good run time on it.

William Robison

My Feedback: (3)

Your 8x5 wont be much load on the engine. Better to use the 9x6 or even the 10x6. When run in the Saito FA-30 spins a 10x6 very nicely, I'd think the Magnum should do so as well.

Bill.

hondaguy

My Feedback: (1)

I have a 91 4stroke. Many hours of flying time. Only problem I've had is the throtle arm on the carb barrel is a staked on fit. They stake 4 places around the barrel. Mine worked loose, had a lot of play. Thank goodness I caught it before it came completly off.[X(] Could of bin a real problem in the air.[:'(]

Engine has always ran good outside of this.

grant-RCU

My Feedback: (10)

I ran the magnum 30 today for the 1st time! Its a sweet running engine despite the rich setting. I found a 10x6 zinger wood and a 9x6 zinger wood. I ran it the 1st time with the 10x6 and then i saw the 9x6! LOL I changed it to the 9x6 for the 2nd run.

My plane's AUW is 2.75 lbs. 400 sq inch wing with a 16 ounce wing loading. Now what prop should i try to get this baby hovering?

I am using 10% omega fuel. I check the head temp at the glow pulg and it was a wopping 103 degree at full throttle. i leaned the needle aboout a 1/2 turn for the 2nd run. The darn thing smoked out my shop! I had the door up with the engine blowing the smoke outside but it managed to smoke it out! LOL
I am really impressed with the pull it was making at such a rich setting. The sound is almost just like the magnum 91. All in all it awesome!

Thanks for the encouragment guys.

Grant

mentorman

My Feedback: (2)

I totally agree with Ed, My 61rfs is a great engine, I did send it back due to compression loss concerns with the exhaust valve, they replaced the piston, liner and the head, NO CHARGE. Well except i had to cover shipping, but the motor runs great on 10 or 15 percent powermaster. its all good

ZM2000

My Feedback: (1)

I have a dozen of Magnums and ASPs, never disappointed.

IronCross

I have had more trouble with my Saito .72's and that d*& plastic backplate then any of my Magnums... No more plastic Saitos for me... I love my Magnums...

submikester

My Feedback: (6)

When did you have this problem? I've always thought my 61 had low compression but it runs like a top and pulls the 4*40 I have it on straight up forever...hard to complain about that.

grant-RCU

My Feedback: (10)

On my magnum 30 what is the little hole for in the cylinder behind the intak pipe? I noticed oil comingout of it today. is this normal? the engine seems to run fine.

mentorman

My Feedback: (2)

Mine has that hole too, is covered up by the liner, i wouldnt worry about it. Sub, when I bought the motor, I would hear the exhaust valve make a hissing noise when I turned it over by hand, so I thought it was bad, global services took it and replaced a bunch of parts that I didnt even think they were a problem. However the compression still seems low, but it runs good, kinda jealous that you are running a 91 now...

Pilotsmoe

The .91's were on sale for $130 at tower a while back(yes, the four stroke)[8D]

Flyboy Dave

My Feedback: (21)

I'm rather fond of the Magnums myself, the Saito's are too expensive.
I've been running the .91's since they first came out.

FBD.

grant-RCU

My Feedback: (10)

I flew the plane today and found a weird nosie from the engine. When i started the engine for the 3rd flight it was hard to start with the electric starter. I kept spinning it over and then it made the loud knocking noise. I though the rod had broken! I turned it by had and it turned easy like normal. I then tryed starting it again and it finally started. Once it was running it made the nosie again. I ran it some more and took off. In flight i heard it 2 more times.
Any idea what this is? It sounds like a rod knocking when it does it.

mentorman

My Feedback: (2)

Sound like detonation, too lean or plug too hot.

Flyboy Dave

My Feedback: (21)

grant....

....[link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXAN96&P=0#tech]check here[/link] ...scrool down, and read what it says about the oil at "requires".

FBD.

submikester

My Feedback: (6)

Well - my LHS was out of my standard 15% nitro/18% oil fuel yesterday and I was plum out from flying the can dry that morning so I went ahead and bought some of that expensive 20/20 YS/Saito fuel... I figured a half gallon wouldn't hurt too much for my .91 and .61 and boy I tell you - those two engines loved it. Except for the .61's idle which has always been a little higher than I want it to be they ran better than ever. The .61 was pulling my 4*40 with a 13x6 prop straight up forever (I didn't get it on the tach but might do that if I have a chance this week) and the .91 pulled the Spacewalker through multiple torque rolls without hesitation (14x8 prop).

I'm really impressed with these engines and disappointed the .61 is no more.

Flyboy Dave

My Feedback: (21)

I think you can still get the .61 in the ASP line. I put some 20/20 YS Saito
fuel in my Magnum 1.20, and it loved it as well. I bought a gallon of straight
nitro to doctor up the regular 15% nitro to 20% to try and save a buck. I
get the 15% Powermaster on sale for 10 bucks.

FBD.

lynnpreston

What about 30% heli fuel in a Magnum .91? I like the 30% for my other engines, but I think it may be causing predetonation in my Magnum. I hear a knocking at certain RPMs.