dabro15

I run McCoy MC-8 in mine and those work great. Any long plug will work. As far as heat ranges for the plug go with medium for 20% and cold for 30%. The more nitro content in the fuel the colder the plug.

46u

My Feedback: (3)

I have the STS D21B RBmods and run a hot McCoy number 59 on 30% fuel. Before you ask why I run a hot plug is because that is what Rick Brake at RBmods said to run with this engine he modified. Now running a hot plug on 30% you have to keep your eyes on things. Sorry to say I am not sold on RBmods or Rick’s recommendations or his work. I know one thing I am sure glade I did not have to pay for him to modify my engine I would sure enough be up set!!!!!! I am thinking about trying a medium. I have over 3 gallons on this engine. I ran a medium in my stock STS D21B on 20% and have well over 4 gallons on it. Next time I run my stock engine I will be going to 30% fuel.

TGreg

why are you saying your not happy with it? my next engine was going to be the modded mkII.

46u

My Feedback: (3)

One other thing if you know what you are doing you can fine-tune your engine by what heat range glow plug you run. A hotter plug advances the timing. Now if you are not sure I recommend running a medium or a medium cold.

46u

My Feedback: (3)

A little back ground about me first. I have only been into RC for about 8 or 9 years and only racing for about a year and seriously for about 6 months. I have been a motorcycle mechanic and machinist for over 35 years. I have my own little machine shop here at the house and can do more to a motorcycle then most dealers can with out subbing it out.

When I got my STS D21B RBmods engine of coarse I took it apart to look at. The work on the sleeve and crank looked OK but where it was put back together on the lower part of the rod and the bushing it was beat up pretty bad! It has held up fine but being I work on motorcycles that cost as much as $60,000 or more I sure would not do work like this. As far as the way it runs I do not see a whole lot of difference between my stock B and the RBmods B. I did every thing just like Rick Brake recommend even thaw I was not crazy of his recommendations including break in. I sure do not see where it is worth the money and sure would not pay to have it done!

As far as the STS D21T MKII it is all ready factory modified and sure would not spend the money to have it modified, as most the work is all ready done. Being I do not have one cannot say how far or what other work could be done as far as modifying. I do hope to have one with in the next 2 or 3 months. If I ever mess with modified engines again I will do the work my self.

I have talked to many other races at some fairly big races and there is very mixed emotions about RBmods.

JB COMP

RBmods are a little pricy. any one know how good http://www.abmods.com/index.html or http://www.ceopowermods.com/store/ is?

46u

My Feedback: (3)

Unless you are a pro driver need a couple hundreds of a second off your lap times I do not see much need in modifying a high performance engine. If you have a sports type engine then I recommend up grading to a race type engine. The only thing I see in modified engines is being smoother through the RPM range.

sputnikxxx

Hey guys my motor when I started it up today was acting funny and I was wondering if anyone could tell me the cause of this?... when I fire it up and give it throttle it seems to bog out, but when I let it idle for a sec and give it just a little bit of throttle it seems to bog down.... and the only way I could get it going to a decent speed was if I let on and off the throttle real quick in a repetitive sense but at any point if I gave it wot it would bog down and almost shut off?....

I am guessing 2 things its the glow plug or my low speed or hi speed is too rich... but im concerned about adjusting these because the motor is already hitting the 200 temp area's... and I don't want to over heat it..

JB COMP

its sound like two thangs. 1. your LSN is too lean. 2. your LSN is too rich.

Mine was doing the same thang once, and it was because of having my LSN too rich. so set your LSN at 4 turns out from closed, and work from there.

SManMTB

Your LSN setting is funky.

To see if it's too rich or too lean you should just pinch the fuel line close to the carb. If it revs up after a while and tghen dies you know the setting is to rich. If it dies almost imediately without increasing in rpm it's borderline lean. Go from there.


Your plug could also be going bad. Take it out and check if it glows as good as a new one. A fouled plug will make your engine run real bad.

46u

My Feedback: (3)

sputnikxxx I am guessing you still are breaking in the engine and have less then a gallon on it? Sound to me you are still running rich but until you get at least a gallon on it do not tune for performance. You can try leaning it out a hair.

MT

Great suggestions guys! I just found this thread, the search button really does work!
I have a RB modded MKII on the way, may even get here today.
After I bought the engine, I have heard mixed feelings about STS in general, and now reading some skeptisim on the RB side. I will just have to find out for myself I guess.
Now, I must go get that heat gun!

46u

My Feedback: (3)

I got a STS D21T MKII stock factory modified recently but have not had time to break it in. I will more then likely finish this race season on my D21B.

MT

So far, so good, the motor started right up. There was a ton of pinch, but my Mugen box had no problem turning it over, but I did preheat using a hair dryer. After idling through and cycling a couple of tanks, I did have to lean some to keep the motor running, so I could drive the trug to continue the break in process.

46u

My Feedback: (3)

Make sure you put the piston at BDC while cooling between cycles. How hot does a hair dryer get the engine when preheating? I use a heat gun and get my engine up to at least 190 degrees before starting while breaking in. Keep us posted.

MT

Thanks, I did put the piston at BDC.
My GF's hair dryer is 1875 watts, so it was able to get the engine to about 190, I just had to leave it on there for a bit longer than a real heat gun.
I can usually tune, but I did not turn down the help of a 15 year veteran sponsored driver, for it's first tune. He still tuned it rich, and said to start leaning for performance after another 1/2 gallon.
This STS motor is actually in my 8-T, but I started with the Mach427 engine that I stole from my rtr buggy. To be honest, my Fioroni clutch is engaging way to soon, there for I have no low end punch. Needless to say with I was not impressed, but I did not expect the .21 to have the low end of .28. I will get new shoes and harder springs and try her out again.

46u

My Feedback: (3)

STS engines have a very thigh pinch and do not tune for performance till you have at least a gallon through it. All my STS 21 engines took 1 to 1 ½ gallons to come alive. As you can see I am sponsored by STS.

MT

Yeah, after break in a some runs, I have about 1/2 gallon through it, that is why that guy was saying wait at least another 1/2 gallon before I start to lean.
I hope this engine lasts a reasonable amount of time, I have heard very few good things about RB or STS. We all know how opinions are though

poe

How are the STS 12's?

46u

My Feedback: (3)

My STS D21B has at least 5 gallons on it and still runs great. As far as the STS small blocks I do not have one but some of my fellow team drives do and they like them a lot. Here is a good place to check them out.
http://www.stsmicroengines.com/

MT

I have almost a gallon run through and started to lean it out a little tonight. It has started to come to life, my temps are around 190 and still lots of smoke. I think I have lots more of leaning/perf. tunning left to do, I took the glow plug out and turned it over and there is still a lot of pinch, but no where near when the engine was new.

46u

My Feedback: (3)

On my STS D21B when cold I had to loosen the glow plug to start it up till over 3 gallons on my 12-volt Ofna chrome top starter box. I have 4 STS engines and they did not wake up well till all most 1-½ gallons. If you are running only 190 it is running to cold. Yes lean it out some more and tune for performance. Let us know how it goes and what you think of the engine. Are you running the standard or turbo plug?

D.A.M.

I put 8 cycles of idle through my new STS D21T today, I plan on putting several tanks through it tomorrow at 50% to 80% throttle as per Instruction Manual. Do you think I will be able to race this engine on a small track on Saturday? You would probably never use more than 80% throttle on this track anyway.
Thanks for any opinions!!

46u

My Feedback: (3)

I would not race any STS engine till I had at least a gallon of run time on it. I would not even recommend to tune for performance before then as well.

D.A.M.

Thanks! I'll just keep plugging away at it.