joy

Hi,

are the MDS .58 or .48 engine any good? Im interested in buying one cos i found a good price in my country.

Thanks

Joy

Alfaman

I too would like a definative answer on this as after much research, i can only get the following info.

1) Run them in caerfully
2) Don't use more than 5% nitro
3) Some are good un's some are bad un's.

Question is do I save a couple of quid on an MDS or go for the ASP 61 which has had good reviews?

rsieminski

Either get the .68 or get someting else. I can't say for sure the .58 will be problematic, but I have 2 .48's that are impossible. The 3 .68's I have are great running engines.

Homebrewer

My Feedback: (8)

The .58 is a great engine and I currently own two of them. Only one gave me problems due to a pitts style muffler not providing sufficient backpressure to the carb. I simply restricted one outlet on the exhaust and problem was fixed.

Never had any problem running stock exhaust or older style carb.
The price can't be beat either, 89 bucks new. If you can afford the extra weight on an airplane, the MDS .68 is also a great engine.

Alfaman

This is not filling me with confidence. Think i'll go for a sc .61 instead.

Gizmo-RCU

My Feedback: (27)

Good choice I have a Magnum 61a which I believe is the same as the SC? A great engine, trouble freeand ample power.

Homebrewer

My Feedback: (8)

I'll put my money where my mouth is. If anybody wants to borrow an MDS .58 from me to check it out for a week or two, email me. You pay for shipping each way. Only request is not to run the engine too lean, use Omega or Wildcat 10% fuel, and please return it after the trial period is over (or buy me a replacement).

I am that sure of the engine and am tired of hearing from people who have not been patient enough to break in a true chrome cylinder engine properly (takes 3-4 times longer than an OS and should last longer too).

GalenB

My Feedback: (18)

This is exactly my experience with my MDS 58. I ran it for what seemed like forever on my test stand and was not happy with the results. Then I put it on my SE since it is a good dead stick plane. Guess what -- 14 of the first 15 flights ended in a dead stick. Then I put it on my US 40 with a pitts muffler. By then it was starting to break in and it ran beautifully. Easy hand starting, lots of power, and very reliable. It only dead sticked once on the US 40, and that was because I forgot to fill the tank between flights... I bet I put two gallons of fuel through that engine before it was completely broken in... I also added a head shim and use my standard 15% fuel...

rsieminski

Homebrewer,
I have 3 .68's that I'd swear were a completely dif mfg from my .48's. I still have problems with transition, despite varrying nitro fuels, and a dozen types of plugs. If I spend more time breaking it in, do you think it'll fix the problem? It will hold a richened peak rpm for ever, and will idle forever, so I figured they were run in.

Gizmo-RCU

My Feedback: (27)

Homebrewer you might have the secret to breaking in an MDS? I got three crummy carbs, the first bound the barrel due to not cleaning up the threads on the idle stop screw, the engine would not shut down, period. The second was rough and binding ,would not transition. The third ditto. The second and third were the new design, so much for that. I used 5%, well over a Gal and a half. The bore was starting to show signs of scratching the piston and bore around the intake ports. Maybe I got a bad one and the rare bad carbs, I still can't justify spending $30.00 on fuel to brake in an engine that I saved $15.00 to buy. These engines may be great ,but not user friendly especially for a beginner(i'mm not)

Homebrewer

My Feedback: (8)

On the 48s, if it will idle forever and hold a peak rpm at full throttle then it is broken in. Sounds like you may be experiencing some of the famous MDS .48 carb problems. I do think that the MDS carbs are more sensitive to position and distance from carb and less forgiving in this regard.

What is happening at transition? Is it stumbling from being too rich or too lean?

w8ye

My Feedback: (16)

I have a 48, 58, & 68. Though I didn't have any trouble with any of the three, the 68 is my favorite but it took about 20 flights on it before I would say it was broken in. It never dead sticked but once. The 58 is not as powerful as a Supertiger 61 but it doesn't weigh as much either.

Enjoy,

Jim

cerecman

Just bought a used MDS 58 without a carb. Any suggestions on getting one? Is it worth the investment and the trouble?

1QwkSport2.5r

Measure the neck size. That is, the ID of the carb port. That will narrow it down as to what fits. I doubt you want an OEM MDS carb.

earlwb

Like he stated, measure the neck size or hole where the carb mounts, and then check the Perry Carb website out for one that will fit http://www.perrypumps.com/prod01.htm

You would want a carb in the .50 to .60 engine size range. Better fuel draw is with a smaller venturi bore carb versus the large venturi bore carbs. But too small of a bore would result in some performance loss, but if the smaller bore carb and engine works really good, it is worth it to lose a little performance.

Now then they do not make the engines any more, haven't been for quite a while too. So parts are harder to get. Generally the engines worked Ok, but there were some duds though. Usually it was the carburetor that was causing the problems. So going with a better carb on the engines is a plus.

dennis

My Feedback: (90)

I've had a few of them back when they were available and still have a pair of 18's NIB. That said it is correctly pointed out that unlike OS engines which are fit up loose to minimize break in and accelerate wear out these needed to be broken in carefully. Castor oil was the preferred oil and I mixed it 50/50 with synthetic at 25% volume.I ran them in at a fast 4 breaking 2 cycle run for about 30 minutes before I even considered trying any idle adjustments. Incidentally it is not to be expected that any new out of the box will be consistently good at idle until it acquires some time on it. Run in was about an hour. Incidentally run in is not running an 8-10 or 12 ounce tank through each time you start it. It is a series of short runs with a complete cool down and repetitive repeats of this procedure with pinches to the line for leaning and then allowing it to settle back to your needle setting. Run a little faster as it sets up and when you can run a full tank through it at correct setting put it on the model and go flying. I realize that everyone has their own method of break in but 60 years of running these things makes you want to keep them running as long as possible without having continuous hassles trying to get a satisfactory run. All engines including Schnurle ported benefit from a run in done correctly for the engine type
Most of the carb problems the I encountered on many of them were the carb gaskets and needle gaskets. Russians really do make crap for their engines and the gaskets were right at the top.
incidentally you should ALWAYS take the head and backplates off and check for swarf. The machine work isn't bad but Russian production workers are really careless at times.
With all of that they ran fine and I eventually sold them to various club members and then sat back and watched some people who shouldn't be allowed near any tools or machinery just completely destroy them by ineptitude and then blame the engine for their stupidity. That incidentally is not a rant on anyone in this thread but simply the truth of the events that I witnessed and still do too many times.

1QwkSport2.5r

Same reason Fox engines always get bashed. There is very little instant satisfaction from an engine built well. I'll guarantee if cared for during a lengthy break in, any well made engine will run well and for a long time and likely better than the fast break-in engines that are sold today.

Mr Cox

The MDS .18 are real screamers, one can easily make a few extra head shims to lower the compression ration and use nitro in the fuel.
On one of my engines the ball bearings were not set up right, so that's something to check for too.
The chrome on the liner can be a little rough, so it needs running in, but at least you do get chrome...

Broken Wings

My Feedback: (20)

Running miniature engines is a hobby in and of itself. If you enjoy burning gallons of fuel on a test stand, GREAT!

Those fast break-in engines always get bashed because they work (actually fly a model airplane) right out of the box. All of my fast break-in engines last a very long time with proper fuel (at least 20% lube) AND the company(s) that make the fast break-in engines are still manufacturing engines and parts. (unlike Fox...and several others)

dennis

My Feedback: (90)

Running miniature engines is a hobby in and of itself. If you enjoy burning gallons of fuel on a test stand, GREAT!

Those fast break-in engines always get bashed because they work (actually fly a model airplane) right out of the box. All of my fast break-in engines last a very long time with proper fuel (at least 20% lube) AND the company(s) that make the fast break-in engines are still manufacturing engines and parts. (unlike Fox...and several others)

Well it's an interesting point and your certainly entitled to your opinion as everyone is. But let me at least offer a rebuttal for your consideration.
I an certainly familiar with most of the engines manufactured in the last 60 or so years having owned most of them and probably bought a large share of them when they were new on the dealers shelf, no online buying in the dark ages.
That said, none of them were ready to run out of the box and all required running in including non iron/steel engines. The first Schnurle engines were fit so tight you had to heat them up to free them before running them and several runs were necessary to get rid of the excessive squeak. This type of porting was originally used in C/L speed engines by K&B and Super Tigre. When released for R/C they loosened them up so a starter could be used without stalling. Successive production runs of engines reduced the P/L pinch fits further to allow the instant gratification of ready to fly.
That said, it does not mean that you can expect to have these engines last as well as a fine fit engine. You have looser fits and it doesn't take a lot of abuse before they are over the hill. OS peeling liners are the result of lean runs and low oil fuels. I've never had one do it.
As to companies not making fast start instant gratification engines, Fox, for example, never did engines as their primary focus. It was always a side business simply because of Duke Fox's love of the engine business. They have ceased because of other more profitable business and that has priority. K&B, Super Tigre ,VECO, Johnson et all take your pick are gone for many reasons mainly death claiming the owners or declining market share.
The Chinese can make excellent engines if the buyer is willing to pay for it. You get to buy what the importer was willing to pay for at the factory. They have also made enough slag to make that instant starting engine a real lemon for your hobby money, Russians also.
I've not really bothered to get into your claim of long lasting engines because it is really moot. Engines last long when given proper care and run according to common sense. For what it is worth I have piles of engines that I bought in my teens and 20's that have lots of hours on them and have excellent compression and not a lot of slop in the plain bearing engines. What that means if that I have a fair amount of engines that I bought over 50 years ago and still use and that is what I call long lasting. Anything less to me is really not ready for prime time yet.
It's all about getting what you perceive as enjoyment in the hobby, don't take it too seriously.

Broken Wings

My Feedback: (20)

It's not my claim but I agree with your statement.

From various Fox instruction manuals.

BREAK-IN
Your Fox 40BB or Fox 45BB has been test run at full throttle with a full lean setting at the factory before it was shipped to you. You should not have to worry about it sticking or sagging. However, in the interest of getting the best possible break-in on the rod and ring it might be discreet to avoid over leaning your engine for the first few flights.


BREAK IN
All Fox 78RCs have been test run at full power before shipping. Prolonged bench running is unnecessary, however, we do recommend that you make your first few flights on the rich side.

BREAK-IN - Your Fox 60R/C or Fox 74R/C has been carefully made and tested at the factory. About the only practical purpose served by a break-in period is to familiarize you with the controls and adjustments.

BREAK IN:
Your Fox Eagle 4 has been test run at full power and should fly your airplane with no problem. The idle, however, will become more reliable as the motor accumulates running time. When you install the muffler, it is important that both screws be tightened tight. A bit of locktite on the threads isn’t a bad idea either.
Gaskets squeeze down with heating and cooling. For this reason it is important to tighten the head screws, cylinder base screws, rear cover screws and carburetor screws tight after a half hour of running time. We recommend you use a proto #9684 screwdriver for the cylinder base screws and a proto #8682 screwdriver for the other screws. Most cheap imported screwdrivers fit the recess so poorly that a stripped recess is often the result.


BREAK IN PROCEDURE

Fox 1.20 Twin
There is no need to baby this engine or have a prolonged break in. If you have an airplane to fly, then fly it, but bear in mind that until the rings seat, there is sufficient friction in the engine so that if it misfires on low speed, it will probably quit. For this reason, we do recommend you not get your bird out of landing range. As the rings become seated this tendency disappears.


BREAK IN

These motors have a closely fitted bronze main bearing, and an iron piston that requires running in to operate at maximum efficiency. Running in should be done with the mixture set richer than normal. Usually after a half hour running the motor will hold a maximum power setting without sagging or quitting. It is useless to try to fine tune your carburetor until the motor has been run enough to be freed up.

BREAKING IN
These motors have iron pistons which are a very close fit in the steel cylinder liner. They are as closely fitted as possible at the factory and for best results the motor should be run rich for 20 or 30 flights before you attempt to run it at full power. We feel however that prolonged bench running is not necessary.

dennis

My Feedback: (90)

Yes that was said many times by Fox, however quality control was really not their greatest selling asset and run in really was a necessity for iron/steel piston/liner sets. Run in was whatever it took to get the engine to hold a setting without overheating and then fly the engine without over taxing it. I wasn't unusual to go through a gallon or two between run in and flying in to get the motor where it needed to be. It also really paid you to look inside and make sure that they were clean. They did improve in the last few years when they got newer equipment and I really had no complaints for the last 10 years. my Fox twin took forever to get right with 2 trips back to the factory to have production mistakes rectified. There was a recall issued on the engine by fox for a free fix on one of the problems. It was also ran as a glow, ignition and diesel engine after it was running well and served well for a few years. It's retired now because it is a real fuel hog.

Broken Wings

My Feedback: (20)

Do you remember what serial number engines were affected by the recall and what the recall entailed? I have a fairly late serial number 1520.

1QwkSport2.5r

I'm sure if it has MkX carbs as yours does, it's likely already been back to the factory for the "modifications" Duke did to curtail the cylinder charging problem. Well, part of it.