kennyz

Well my new magnum xls 52 showed up yesterday. It looks like a nice motor. Before I even turned it over I completely disassembled it. I've heard lot's of horror stories about chinese motors being full of metal shavings. I'm happy to report none were found! There was a fair amount of tooling marks on the crankshaft. Also their was a large burr inside the engine case which was partially blocking one of the transfer ports, I also felt that the ports inside the cylinder were a bit sharp. So I broke out the 2000 grit wet/dry and my dremel with some hard rubber polishing bits, a sanding disc, and the mini buff wheel and the jewlers rogue. I took me a hour to clean up and reassemle the whole motor. In my mind..time well spent. The crankshaft now looks like a chorme bumper (mind you I mainly just polished..do not remove too much material..you'll throw it out of balance) I also cleaned up the intake port inside the crank. The cylinder just got a few light turns with the 2000 grit..that felt much better. I removed the casting burr on the transefer port and polished them with the hard rubber bits on low speed...nice and shiny! I also knocked out the front bearing and cleand up inside the intake journal. I cleand every thing when done, and reassembled the motor lubeing everything with pure sig castor oil. I put her on the test bench and ran it this moring. It seems like a good strong motor. I am using the stock carb (at this pont), and after just a few 2.oz header tanks of fuel she'll fire up with just a flip. (I should note I had to and, was able to,flip start from the beginning..my battery was dead). All being said did I have to do everything I did to this motor..no..would it have run right out of the box...yup...do I feel better about what I did...Yup...Do I think this motor will have a better break in...Yup..am I happy YUP! When I get some more run time on it I'll thorw on my tuned pipe and get her all tweaked out!

Motorboy

The polished surface will make more worst in fact, it will not blend the fuel and air mix so well before entering into the cylinder. Also you get coarse fuel mix into the cylinder, more fuel drops instead the fuel drops splitted in smaller drops (improved atomized fuel) by surface roghness.

The normal are to remove the lose casting flake, remove swarf, rest of grinding paste, wash the engine parts clean and quality control before use. This is a job for the operator in the model engine factory.

Very rare we can find the swarf in the engine. One in the forum had the bit of staple in the engine when he inspected the engine.

When the engine are new, do not dismantle the engine in case the engine are damaged by strange matter, fault production method by operator in factory (Fault use by owner not protected by warranty) or the warranty will be void.

bigedmustafa

My Feedback: (2)

kennyz obviously knows his way around a glow engine. If polishing and inspecting his engine parts before running it for the first time makes him happy, then what's the harm? Of course kennyz understands that Global Hobby can't be held accountable for warranty support of an engine he has already taken apart and modified.

Motorboy's advice is sound: don't take your engine apart and start polishing it unless A) you are experienced with such things, and B) you don't expect warranty coverage.

Most RC pilots can trust the manufacturer to put a quality engine together so they don't have to strip it before breaking it in. If the manufacturer didn't do a good job, then they get to fix it under warranty if there is an issue with it later.

Some folks just love to play with their engines, like kennyz. One of the nice parts about picking up a Magnum XLS .52A for $69.99 on sale, you can feel free to take it apart, inspect it, polish it, and modify it to your heart's content. If it all goes horribly wrong, you're only out $69.99. It doesn't sound like kennyz's engine is any worse for his inspection and polishing.

A lot of the guys who post here in the glow engines forum are like kennyz.

gunneredwards

My Feedback: (4)

If it aint broke, dont fix it. I have never found foriegn material in an engine from the factory. I have not had good luck with the magnum engines though, and would rather spend a little extra cash and get a quality engine for my plane. If you get cheap components, you will have more problems in the long run and will probably not be satisfied with the experience. Cheap parts are just that... Ever see someone win a competition with cheap components?
dan

asmund

If it aint broken, refine it I do it alot myself, it is time well spent, and it is the only way to learn more about these little engines

The XLS.52 is great. I own three of them, very very powerfull and reliable[8D]

kennyz

I'm sorry but I don't agree with the atomization theory. That's what your carb is for. I can speak from experience on this. My self and a buddy both had acrtic cat 97' zr 580 efi snowmobiles, his had 3k less miles on it but mine had new pistons (cylinders were orginal with almost 6k miles on them). . Upon my rebuild I polished all of the boost and transfer ports, and inside the crankcase. Just simply removeing factory casting burrs and the rough edges. This is something any 2-stroke racer will do. My sled had ALOT more power than his and he was never able to catch me, both sleds were stock and measured very close in engine compression. I was also a close second to my nieghbor's brand new $9000.00 ski-do 600 H.O. ! Any engine needs to breath properly, the easier it can breath the better it will perform. Look inside a 1/4 mile top fuel dragster..your going to tell me the int/ex ports aren't polish to a mirror finish? If it's good enough for them it's good enough for me, I'm just glad I don't burn nitro at 10gal in a 1/4 mile! To each his own just m.h.o.

kennyz

An Exerp from hot rod magazine..
..
Port Any Head Technical Article Engine Masters
Beyond the potential for flow gains, commercially ported heads need to have a nice uniform shiny finish to be acceptable for most customers. Polishing with cartridge rolls, and flap wheels finished these pro-ported Edelbrock 454-Oval heads. Port flow for these heads was an outstanding 350-cfm, intake, and 280 exhaust. Check out the short turn form

POLISHING FOR POWER

Once the heavy cutting is done with the carbides, the ports and chambers can be polished, using a combination of sanding attachments, flap wheels, or cartridge rolls. Often, the polishing process will uncover minor surface irregularities, bumps, and dips that are hard to see but typically present in the rough carbide-cut surface. Boundary layer airflow physics tells us there is little flow to be gained from surface finish, but in practice, significant flow gains are sometimes seen from polishing the ports. The polishing process does remove metal, making the port slightly bigger, and the removal of minor irregularities probably accounts for the balance of any improvements.

I rest my case.[8D]

jeffie8696

Kenny we have read the same magazines. Much like my Ported and Polished Thunder Tiger GP42 the gains were to be had at very little expense.
The ports dont need a mirror finish but a very high performance engine like a 2 stroke glow engine will provide enough turbulence in the crankcase (like 13,000 rpm worth) to mix the fuel quite well . Airflow doesnt like sharp corners. Blending and smoothing is all that needs to be done.
And Ihave seen first hand metal shavings inside a brand new engine. Luckily not a Magnum.
And here is a link for your viewing pleasure http://www.rcuvideos.com/video/Porte...ed-Thunder-Tig

kennyz

Sweet!

jeffie8696

Thanks dude.

ddavis60

My Feedback: (6)

Hey folks, I have a question concerning the Magnum .52 two stroke muffler. The muffler is too long and the exhaust hits the firewall. I found that the muffler can be taken apart and the middle, chrome section, can be removed and the muffler goes back together with a shorter center bolt. Will the engine still run as well with a shortened muffler?

estradajae

The purpose of that piece is to increase the muffler volume because of the larger displacement of the engine.

I haven´t tried it to tell you, but it may overheat the engine (muffler will be too restrictive).

You can alos modify your firewall to fit the engine..or install it in another way perhaps?

faulknej

My Feedback: (9)

Iput my Magnum .52 in my Revolver. Ihad to use the Magnum muffler extension to clear the firewall. Igot it from hobby people for not much, maybe5 bucks.

http://www.hobbypeople.net/gallery/280152.asp

NM2K

My Feedback: (14)

The old hot rodder point of view used to be that polishing the ports and tunnels was okay on engines that spent all of their time at W.O.T. The problems came into play (loading up/poor throttle response/stalling) when running at less than full throttle. Especially where crisp response to throttle was needed. Yes, that was with four-stroke automobile engines. I don't know if it applied to smaller two-stroke engines.

Anyway, it sounds as though you are having fun. Keep sharing the data with us!


Ed Cregger

Turk1

Be careful on your Magnum s carb screws.They are famous to leave on flight.Secondly I recommend you to take remote needle system on to carb.

jeffie8696

When Imade the vid of my TT GP42 the idle mix was slightly fat, I fixed it and it responds even better now.

Iflyglow

My Feedback: (79)

I did a little work to my Evolution .60NX, and it gained about 300rpm over a stock version. But I was willing to take the chances, if it backfired which it did not.

Iflyglow

My Feedback: (79)

Or you can install a Jett Muffler, and let it really scream.