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OS 21 RG-X... they suck!

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olds97_lss

olds97_lss

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  1. Bashing
Well guys, I have read many a post saying how good and solid this engine is, but I fail to see it for real.

I'm posting this thread on behalf of bomber's most recent meltdown. So far, I've seen 3 of the engines break badly around the 2 gallon mark. I just don't get it. I recommended this engine to bomber and now I feel partly responsible for his crappy experiance. He had another one blow up the exact same way. I had one blow up as well, but mine was a bit different.

Anyway, on both engines of his that blew, the lower end of the connecting rod just shatters. So, it's hard to tell what happend since the lower half is completely gone. Also, both times, it was just going about 1/4 to 1/2 throttle through some grass on a 21 maxx. His trans is lasting him longer than his stupid engines!

On my engine that blew, the crank shaft snapped into two pieces at the induction port right below the carb neck inside the engine.

Both of us take what we think is good care of our engines. We do everything we can to make them last. Such as not running them over 250. Letting them warm up to about 200 before we start driving hard. Cleaning the air filters or replacing them pretty often. Using ARO religously. Running mildly rich on both high and low sides. Running 20% trinity MHP fuel.

I ran 6 gallons of the same fuel through my OS 15 cv-r(x) and it still ran strong when I just recently traded it.

If anyone has any idea why we have had 3 break badly around the 2 gallon mark, please respond. Also, all three broke while around 1/4-1/2 throttle. Not even during WOT runs!

Thanks.
 
Check out paragraph 3, (about O.S. engines) this might be your problem. I don't know for sure, but read it see what you think.

This is the Stephen Bess method of break-in.

If you are still idling at least a tank through during break-in, you're using the old-school accepted method (still works well for some!) but it's not the method that the top engine guys (Ron Paris, Dennis Richey, Rody Roem, Michael Salven are just a few I've spoken personally with about this) recommend anymore.

From the very 1st time you start your engine, plop the car on the ground & begin running it in a parking lot in 2-3 minute intervals, tuned only *slightly rich* getting the temps up in the 200F range on a normal day. Every 2-3 minutes, shut the engine down & let it cool completely with the piston at BDC, and then fire it back up; continue this cycle until you've run 15 min or so, and then bump up to 3-4 minute intervals. Vary the RPM and don't be afraid to get the temps in the 200's. What you want is heat cycling of the components without the incredible stress that comes with breaking an engine in when it's overly rich & cold. After cycling the engine in this manner for about 20-25 total minutes, it'll be ready for the track and race tuning. I realize this method goes against the old-school "idle on the box" routine, but you'll be amazed once you've completed this break-in routine, your OS will still have amazing pinch w/out sticking at the top AND your OS's compression will last far longer than it will with the "old school" method.

You say you run the engine at "factory settings" for the first FIVE tanks? That alone causes lots of stress, as the factory OS settings are very rich on every OS I've ever owned or tuned. The piston & sleeve haven't expanded to operating temps, and every time the engine turns over, the piston slams into the pinch zone at TDC. The not-so-surprising result can be a cracked con-rod at the crank pin--that's where the majority of the stresses occur as the engine turns over. I've only heard of about 6-8 OS engines breaking con-rods, and they're ALWAYS during the first gallon...and almost every time it's because the guys have performed the break-in procedure you described. Doesn't seem like a mystery as to why it's happening. Drawing out the break-in routine really stresses the engine & actually wears away compression along the way. This method I've outlined will feel weird at every step, but after you try it once, you'll notice a big difference in your engine's performance & lifespan.

Hope this helps; give this break-in method a shot--you have nothing to gain except longer life & more power :)
 
Well, I break my engines in the way he describes is his right way. And so did bomber. We both got the engines up to 180 in the first tank and by tank 3 (after shutting down every 5 minutes to cool, piston at BDC), we were at the 200 mark.

By the time we both hit gallon #2, there wasn't a ton of compression and minimal pinch left in the sleeve. Although, there was enough power in the engine, that if you tuned it to run around 240-250 it would pull wheelies with 72/20 gearing.

I just don't think it's what is described in your post. But, thanks for the info anyway.
 
Sorry to hear that, I just got an RX broken-in yesterday. It seems to be holding at around 210, so I guess I'll see how long it lasts.
Seems to be alot of problems with engines these days. I hear all kinds of stories on the forums about pistons wearing out early, rods breaking early, bearings burning up early, cranks exploding early. I realize that alot of people don't keep their engine as clean as it should be, but there are just too many stories of early failures.
I wonder if the engine manufacturers are starting to cut corners to bring prices down and thereby lowering quality? That seems to be what is happening with a lot of manufacturing in other industries.
 
just a though

Something to look into, “check the oiling hole in the big end of the rod once and a while.”
I have done many engine mods to O.S. RG 21 motors with very good results. But, I have found one big flaw and that is the connecting rod can not get enough lubrication through the one small oiling hole causing the bushing to spin. Fix, enlarge the one hole and add a second one directly opposite.
 
i did it the old school method and ran rich all the time and my 15fe was gone at 1/2 gallon and ya i sucked up a little dust but before i did that it had little compression and never held a tune and never really ran more then 2 tanks at a time . but this was my first nitro engine and i let it idle to Two rich tanks and fuel spit out of the pipe all over the place lol ill do the new method next time .
 
thats too bad about your rg's, my rg has had dirt and TWIGS cleaned out of inside it two different times from the air filter popping off and i didnt know it...and one time leaving it laying around found out it had froze up completly from rust...after soaking the internals in wd-40 i was able to get it clean enough..and till this day at about 4 gallons it still is able to scream up and down the street full rpm. compression is pretty low..but still idles decently and makes good power...especially after what it has gone thru.
 
I just recently purchased a .21RG-X for my Storm Pro. The first time I ran it was at the Winter Bash. I was really happy with the way it ran.

I just dissembled the engine last night for the first time since I ran it in January to inspect it and everything looked fine.
 
I know of the 3 I talked about that all blew up before hitting the 2 gallon mark. It was about 1 a month for 3 months.

We were discussing it recently that maybe it was due to us running hot plugs (OS A3), which would in turn advance the timeing of the engine since the manual for the engine recommends an A5, if I remember correctly. Having the timing to far advanced would put all the bang of combustion on the piston rod way before it hits TDC. I know having it hit just a single degree or so is preffered for 1:1, but I'm not sure for these.

Anyway, I did notice a huge difference in power on my Omega 21 when I went from an A3 (hot) to an A8 (medium) plug. With the A3, I wasn't producing near the power I produce with the A8.

Any thoughts?
 
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i have always ran odonnel 99 (cold) plugs in my RG...I've never try'd any other plug with that mill...but i can say that I'm very pleased with how the motor ran with that plug. i own xtm 24.7's, hyper 8-ports and an s-25 and the rg has always held its own compared to my other mills, an so i never needed to try any other plug. those plugs last forever also.
 
Olds - My bash buddies 0.S. mill like yours has blown up @ the 2.5 gallon mark. WHat's the cause....the Conrod is poop it appears.
 
**chris73** I would also like to see exactly where the other oil hole is drilled. Do you mean on the bottom of the con rod or the back side?
First all the OS guys were complaining about the VZB wearing out too soon and now the RG has exploding con rods. Boy I hope that I don't get to enjoy that (probably will if it is happening that often). Has OS gone to hell? I have a few of their old engines from around 90 or 91 and they are now all worn out, but they lasted forever.
 
My buds and I have had probably 10 rgxp's between us in the last 3 years. The Cybermaxx was originally designed around them. Sometimes they last forever - you practically have to deliberately kill them. Others will blow a conrod at the slightest mistake, like running lean momentarily, or holding it pinned for a backflip attempt.

It is normal for a nitro engine to need more fuel for extended high speed running. For example, if you have it tuned to run clean on a tight track, you will need to open it 1/4 turn or more to blast across an open field. I seemsto me the 21 rgx needs more extra fuel than most, when going from tight tract to open track. I had one seize on the big end rod bushing for that reason.

It is best to warm any new engine with a heat gun before starting to expand the sleeve and reduce forces on the rod. Perhaps the big end gets stretched out during breakin, causing excess clearance. That will cause any bearing to fail quickly.

I think the idea of expanding or chamfering the oil hole may be a good idea. If anyone gets a new engine, let us know if you try it.
 
WWWWeeeeeeeeeeeellllllllllll GGGooooooooooDDDDDDDD FoOOOOOOOr UUUUUUUUUUU...

Just kidding. I don't know why ours died so early like i said. But I doubt I'll ever buy another one. 3 in a row is just retarded. We didn't run WOT hardly ever (at least I didn't). We also ran rich with temps around 220 all the time. ARO after every run. 20% nitro only.

Don't know, don't care really any more. I was just curious what others have experianced. Maybe engines are only supposed to last 2 gallons for a typical basher? I can't imagine so, but maybe.
 
I agree with you olds97_lss engines are supposed to last much longer than 2 gallons. If mine only lasts that long I will be done with OS. I have been running them exclusively since I got into RC, but as of recently I have heard nothing but bad news about them.
Matter of fact I bought a VZB and heard so much bad news about them that I sent it back and eventually bought a Novarossi Top P-5.
 
We have both tried different brands of engines that we haven't found much info for. I bought one on accident and pretty much so did he. By accident, we both researched for engines we wanted, but our LHS didn't have them in stock. So we picked something around $150 and said f'it. It's got to last as long as the OS, so what does it matter?

I ended up with an Omega 21 Comp w/PS. He got a Hot Bodies 26 powerhouse (i think). I guess we will see what happens.

I just cranked through about 1.5 gallons in mine and it still has hard compression. The piston top is still nice and shiny like the day it was new. He barely has his broken in (10-15 tanks). What ever happens I'm sure we will both post how they turn out just to let others know either about 2 good engines or 2 mistakes not to make.

The major trade off for me is the Omega cranks out 2.4hp which is .6 higher than the OS. It's very evident that it's more powerful. I can't keep it off it's roof. I really had to lean out the OS to pull a good wheelie. With the omega, I run pretty rich (temps around 230 aft WOT) and I still can't keep the front down.
 

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