bluemagic98

Hi
I have a Evolution 58GX2 and its been sitting around waiting for a plane to be flown It has broken a few. I was wondering if any one knew what the flashing ment when you first turned on this engine. When i power it up I get one long flash and 3 short flashes. Last i recall the thing only had 3 short flashes on power up. I dont have a choke servo conecter to this thing so following along the instructions to reprogram it is a bit of a task I know i could mange to reprogram it but the code its flashing has to have some meaning.

Ive run this engine in 2 differant planes and its failed me both times. allways has good power and good transition on the bench but after 8-10 min in the air it will act like the low end setting has leaned out and fail to spool up after a touch and go. Failing me in a low hover has happened 2 times rtesulting in a loss. and both times it was after i had been compleetly satisfied with the settings and have had many good flights. Sending this back to Horizon wont help I can tune this thing and make it run good for a few flights but it wont last. I dobt Horizon will test fly this thing for 4 or 5 flights. If i run the low end needle setting ritch it wont do this if i pick up the throttle slow it wont do this but i think thats asking a lot more out of the pilot and a lot less out of an engine that is supposed to be top shelf. Ive also run the plane without the coweling so it isnt heating up thats doing this Horizon has offered to look at it but truth is i doubt they have the time to realy test it as its had some days when it runs flawless all day and on the last flight it it eather destroys a prop or worst I have lost many props and 2 air craft. Loosing shipping cost and finding out that they are unable to reproduce the failure dosent exactly make me feel overly confident that shipping it out will solve this. Ive repaired the last plane it managed to leave in the bushes. and its destryed another prop due to loss of power on a touch and go and yes it was the first flight after the last repair about the 4th touch and go. It has new tank lines and clunk line. I would like to get to the bottom of this myself It would go a long way in allowing me to trust this motor with a new plane. Im going to run this ritch for a few more tanks before I attempt to reset the needles. Ive been a mechanic all my life and I have some experianc e with small engines Most flyers trust me to tune there engines. But as allways I keep my ears and mind open to Ideas and this one has me 2nd guessing myself.

Thank you all for reading this Hope some of you have had this experiance and have found its cause. Or have some possative Ideas.

pe reivers

It seems to me that your engine is running way to hot.
Normal two strokes will give warning by sagging in rpm. This is not the case with MVVS, because of the piston plating with graphite.
The increased problem with 3D flight shows in that direction.
Advise for the time being is to run the engine extremely rich.
But in the long run, I think you need good cooling by air guiding and air extraction to run these powerful engines up to their capability.

bluemagic98

I agree i was running a 24-10 msc and now im running a 24-A vess however it sure dont like to be leaned on the low end enough to get the burble out Maybe a 23X8?

bluemagic98

A pic of the cowelling

Bass1

I'm with pe on this one. From the photo, it sure looks like your lacking quite a bit in the "outflow" department!

bluemagic98

At one point i felt the same way and the out going whole is a bit bigger i should have got a updated photo. Eather way as i mentioned in my first post Ive ran this without a cowelling on the plane with the same results. This is why Im thinking a 24X10 MSC is a tad to big for this engine. However I will make a serious atempt at enlarging the out going if you still feel its the issue but here is a 3 min old pic sorry to have ussed an older pic

pe reivers

look at the sketches, and choose your cooling system. Then you will see that a lot of air can circulate inside your cowl, but it is not set to work on the required cooling business because the air is not forced to go through the engine cooling fins.
Powerful engines need a powerful cooling system. Lack of proper cooling makes itself noticed especially in upline verticals and hoovering.

bluemagic98

Now this is good information thank you very much

dcs155

My Feedback: (2)

I had a similar prob with the evo 58, took the cowl off.............prob solved!!!!! so I made a much bigger outlet and the 58 is now fine

negy1

i have got 35 cc and 58 cc mvvs and have had dead sticks mostly from being to lean but because the filters wer blocked be warey because when you land the crap in the filter relaxes gives you enought time to get flying untill it cloggs the filter again so i now run two filters lean equals heat this was m y experience hope it helps negy1

bluemagic98

i havent made any changes to the airflow as of yet but this last weekend the temp's where in the low to mid 70's and the Evolution 58 was running awsome. I ran a vess 24X8 prop and we tached it at 6700rpm and it just impressed the hell ou of me. I will do my best to make up some additional changes to the air flow befor I push the 3D envelope. Ihave to admit the lack of any sag in uplines and the large amount of open space at the front of the coweling had me thinking that this was being cooled enough. I do hang on the prop alot and hope to get this cooling under control.

bluemagic98

Well it seemed to get hot and loose transition today it was a tad warmer out so i added this cooling setup ( see pic ). Ill be out with it tomorrow and run her hard see what gives.

bluemagic98

The cooling was a marked improvment thank you. Flew the plane all day and she never quit. I was wondering if you knew how much end play you should have in the crank shaft? seems a tad excesive to me. Im going to put a dial indicator on it tomorrow.

bluemagic98

Well a few things have changed. One I lost a prop due to some radio glitch issues and i fixed that with a new DX-7. the new prop is a 24 X 10 I dont think the motor liked this Prop. I started it up and it failed to transition untill I backed out the low speed screw and the burbling is back with a vengance. Some one on the wildhare forum suggested fliping over the reed block so the carb would be facing up when the motor is mounted inverted. This has made improvments on other engines. I thought I would ask here If this was a good Idea?

Also the end play is 0.10" depending on the clock position of the crank it will drop to 0.05" at the bottom of the stroke TDC is 0.10"

pe reivers

0.1"end play? axial or radial or rotational.
for axial play that is excessive. Come to think of it. it is very much excessive for radial play as well. For rotational play in the prop tip it seems OK. Just a very slight play in the bearing-ring land combination will show this kind of play when moving the prop tip slightly.
normal values:
Axial play, just noticeable
radial play, nil.

If an engine gets (too) hot, the crankcase expands more than the bearings, and a loose running fit will result. This causes the bearing to spin in the crankcase where it should not. If left alone, this will damage the outer bearing ring fit to the extend, that the crankshaft will start to rub excessively in the shaft bore and maybe even start fretting, under generation of even more heat. (da capo)

bluemagic98

No this is end play forward and backwards of the crank shaft right at the prop nut. As for left and right of the shaft there is nill, as well as the prop tip. It is just in and out of the crank shaft.

How do you feel about flipping the reed block? Is that advisable?

pe reivers

Yes. It helps very much in starting. The carb is angled, and a downward slope spills the drawn fuel into the cowl instead of letting it enter the engine.

duber3

I have the Evo58GX2, it's brand new, the motor is on a Top Flite GS Corsair, after the break in, I maked some test
to find what's the best way to start the motor when it's warm, if I let the throttle at the idle position, the motor won't start
and a lot fuel came out of the carb, I found that if I put the throttle at 1/3 the motor start at 3 or 4 flip and I have'nt flip
the reed block.

nonstoprc

My Feedback: (90)

Pe,

Always enjoin your informational posts. One question through. On my SD Extra 260, because of the wrap-around muffler, it is difficult to build internal shield(s) to guide the air flow around the engine. In that case, can the air-dam along improve the cooling a lot?

Thx.

pe reivers

The air dam will improve flow through the cowl. On one side, the wraparound muffler will guide the air through the fins. The other side needs the baffle. in short, close all openings that let air bypass the cooling job to be done.
Closing the gaps has a double function:
it improves cooling, and because less air flows through the cowl, it reduces the plane's air resistance.
(Besides the much neater look of a well designed cowl)

bluemagic98

Well I flipped the reed block and she starts one flip when warm or even close to warm and the transition was greatly improved. I can reduce the ritch low speed mix to a smooth mid range with out loosing the transition. I will still have to reduce the prop pitch some. When I reduce the idle to dead slow it will lagg a bit without ritchening it up but it wont die and 2 clicks of up idle trim and she snapps to full speed like a champ. Im going to run it hard this next week end. I wanted to thank you Pe for all your time. It has helped me rebuild my confidance in this motor.

nonstoprc

My Feedback: (90)

Thanks. Appreciate the feedback.

maxhell

Change of Subject. I have the 3w150 have changed the cowl setup, will post a picture or two. Now im finding that my needle setting are all out. Please can you explain what is going on.

RTK

My Feedback: (1)

If adjusting the needles does not fix your situation, try running a line from the diaphragm vent into the fuse or in a a place of dead (unchanging pressures) air. If you have the snorkel with the line attachment I would bet all you need to do is re-tune.

closetguy

My Feedback: (13)

Bluemagic,just wonder if you ever had anymore trouble with the end play on the crank shaft.i have the same with my 58,no side to side like you would see in a bad bearing just a little in and out. i was going to tear it down just to see where it was coming from.