jscamry

iTrader: (5)

Hey all I am looking to get a new engine. I cant seem to make up my mind as to which engine i want. I am looking towards the Mugen MT12, since i hear very good things about it, But i have been reading the posts on here about how good STS products are. However i just want to get a more personal and experience anwsers from you all.
Thanks Jason

cybertoolzz

i have the sts12 3 port sg crank motor - my limited expirence with nitro engines is that this motor is at least equal to and better, imho, than many motors costing far more. i have 2 gal. of 30/10 thru it with no probs at all - i added the turbo head for 25 bucks and i run #8 or #7 turbo plug. i bought this motor thru ebay (directly from frank calandra, jr.) for 100$ - the best money i have ever spent in this rather expensive hobby.

jscamry

iTrader: (5)

cybertoolz what do you mean 30/10 fuel?

cybertoolzz

30% nitro with 10%oil - i broke the motor in using 20/12 and switched to 30/10. the motor likes the higher nitro content although i have heard that higher nitro tends to reduce the life of the motor, i havent seen ANY reduction of performance/compression so far...

jscamry

iTrader: (5)

so have you seen any mugen mt12's run? how come you just dont use full 20% or 30% nitro. I think that the only way the higher nitro will runin the engine is that if you dont watch the temps.

Thanks Jay

cybertoolzz

Jason,

today i have run into the first real issue with my sts12 - it appears that the front seal bearing has become loose - there is some quite noticeable wobble in the crankshaft - it produces a visible separation at the gear mesh. this i discovered just today and I'm sure it is very recent as i have been looking very closely at the motor after every run. the motor still makes great power and works as good as ever - but this issue is alarming.

tear down analysis...

there a slight wearing on the back plate - this wear was there before and shows no signs scoring - only a very slight circular impression on the plate evidently from the rotation of the crank stud - can't really determine if the discovered bearing wear has added to this;

visual inspection of the crank shows no real damage or prominent wear at the contact points of the motor bearings - no serious wear of the stud - the crank appears to be okay;

the con rod too appears to be okay - fit to the crank stud is not tight by any means but i cant detect any appreciable play. there is a good amount of lateral play in the con rod to piston connection - the con rod can swing about 5-10 deg side to side as i hold the piston head - note that the play is LATERAL not vertical. vertical play is minimal - detectable but very slight.

no scoring on the case where the con rod rotates - no evidence of damage to the internal surfaces of the crank case.

the main bearing seems okay - the outside seal bearing seems to be culprit - there is very detectable play to the inside bushing of this bearing - the seal looks fine, no marring whatever - the motor doesn't leak fuel at all.

what to do...

1. buy new motor bearings - 32$ for boca bearings at my lhs - these boca bearings look to be a pretty std size and i think they would fit the sts12;

2. call CRC - i talked to John at CRC - i basically got the std line that motors wear out BUT he said he would talk to the guys at STS to see what he could do. i asked him if he had replacement bearings - yes - 25$ EACH. i asked him if anybody else has had this issue - he has never sold a replacement bearing set. i asked him if he could tell me what SIZE the motor bearings are - no - his info didn't list the size.

bottom line...
1. buy a new motor? at this point i am RELUCTANT to buy a replacement sts12 - as i have had only this motor IF i were to buy a replacement motor now i would get a diff make - PRIMARILY to get experience with a diff motor mfg

2. replace with the bocas and hope it holds up thru a few races? good money after bad? suppose it doesn't last for more than 1-2 races - i would feel like i have wasted the money AND i will have to buy a new anyway.

3. pester CRC and STS to see if i can get them to help me out - send me the bearings or send me a new motor and i send mine back. see IF the support at CRC/STS is any good at all.


i am posting this EXACT reply at the CRC forum.....

Ron C.

iTrader: (2)

Hello jscamry,

I personally have used both these motors and
am still using them. I would recommend you go
with the Mugen MT12.

jscamry

iTrader: (5)

thanks for the input all. man cyber sorry to hear the bad news.Have you decide that you are going to do? If you would get a new engine which engine would u get??

Thanks All, jay

cybertoolzz

i posted it at crc's forum - i will wait to see if crc/sts can do anything - meantime - i am fubar'ed....

Ron C.

iTrader: (2)

cybertoolz,

I hear you on that.
My buddy had the same issue.
When he emailed CRC, he got a response back from
Mr. Calandra requesting a summary of what had
happened in order for him to get a picture of the scenario.

My buddy, hoping that he was going to get some
assistance from them, had sent him more than a paragraph
email reply. What he got back was a one liner "Will research
and get back with you".. Guess what - HE JUST VANISHED!

Mind you that the motor was just broken in and not even
leaned out nor raced. We all got them together and he
unfortunately got the worst of it. I may understand that
there may be lemons during the manufacturing of these
motors but since the topic of "Customer Assistance" was
brought up in this thread, I just thought of sharing this
with you guys. Please also note that we had gotten a total
of 5 motors in one order, which I think would somewhat
entitle us for some attention from them.

Good luck and please do let us know if something good
happens or any assitance at all is recieved from CRC.?

cybertoolzz

not hoping for much from crc - but i posted my analysis at crc forum - stsdino - he IS sts - reads all the posts there and MAYBE he will help out... i'll let u no....

TheRagunCajun

I have the STS 3 port legal engine. Runs great. Has lots of power. It is also fast. Pics in my signature link. Also check out the previous STS threads...they are more than 1. I also have the STS pipe, works awsome.

InitialD

You can go to any bearing shop and ask them for a rubber sealed bearing of this size;

7mm x 19mm x 6mm (inner diameter x outer diameter x thickness)

Part number is 607 2RS1. These front bearings are the same ones used on the Novarossi and RB varients. It's pretty cheap and I don't think it will come up to USD 25.

Once you get the bearing, take one side of the rubber seal off the bearing and install this open side facing the crankshaft for lubrication purposes.

cybertoolzz

man Initial - u DO know ur stuff! - that is the correct bearing size thx. my main lhs dosen't have that size - i will chk the other lhs around here -

i am "communicating" with CRC/STS on this issue at their forum - u might find it interesting;

http://www.teamcrc.com/phpBB2/viewtopic.php?t=498

ya' know - just once i'd like a company to say "yeah - u spent ur hard earned money on our products - here - we're gonna back it up and take care of you"

i realized they can't give away stuff - but so many companies FAIL to realize the power of word of mouth - i can get on 15 r/c forums - not to mentiuon all the ppl i talk to at lhs, tracks, locally and say STS motors are great or that they stink... u'd think they would rather i say the former...

dino.tw

If you don't mind to pay for the postage.You can send the motor to the address as following.....

YIEN BONG HARDWARE INDUSTRIAL CO., LTD.
No. 2, Lane 29, Chiungtai Rd.,
Hsinchuang City, Taipei Hsien, 242,
Taiwan R.O.C.
To: Dino Lee
Tel: 886-2-8201-7432

I repair it for you personally.