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-   -   Anyone "Give Up" on An Engine That Won't Run Right? (https://www.rctech.net/forum/nitro-road/578484-anyone-give-up-engine-wont-run-right.html)

Jake C6R 12-16-2011 05:49 PM

Anyone "Give Up" on An Engine That Won't Run Right?
 
I know the answer has to be yes...or at least I think so!

I got this OS .12TR used as part of a sale. It was supposed to be lightly used and the pinch was really tight. It always gave me problems with flaming out. I took it apart and everything looked good. I sealed everything up (neck, carb bolts, backplate, fuel inlet) and there were no leaks. I pressure tested it and all is good.

When I got the tune right it would run awesome...but at times it started flaming out. I finally solved that problem with a new tank, or so I thought. New tank, new fuel lines, sealed engine, tight pinch, no internal signs of trauma, bearings were good, crank had no signs of wear and fit tight, no issues with the piston or sleeve, they looked new...and it ran great for a short while...

Temps were good, it would run great for a short while, then just when I thought I had it down, it would act up again. I am positive the HSN and LSN were dialed in as all the indicators of a good tune were solid.

Then same old crap. Would flame out at random. I gutted the thing and looked at every needle and seal, air filter, glow plugs and my underwear. I sacrificed a couple of chickens and still nothing.

My motivation was not to save money on a new engine, but to beat this thing! In the end I got so frustrated it was replaced with an engine that runs flawlessly every time, with the same tank, fuel lines, clutch, drivetrain...you get the picture.

So it beat me down. And it still sits on my workbench mocking me because for some reason I can't throw it away...LOL

Anyone have one of these?

valk 12-16-2011 06:55 PM

Sell it to me lol. I love my 12tr.

My novamega sx12 is like that but i cant find anything on that motor. Funny. My 12tr will run for days without problems. Only changed the plug twice even.

Jake C6R 12-16-2011 06:58 PM


Originally Posted by valk (Post 10047850)
Sell it to me lol. I love my 12tr.

My novamega sx12 is like that but i cant find anything on that motor. Funny. My 12tr will run for days without problems. Only changed the plug twice even.

This one has a turbo head and the rotary carb - you want it?

scary_jerry 12-16-2011 07:19 PM

while i was reading your description of the motor problem, i see that you might have a buyer. i just wanted to say try 1 more chicken (crispy) and maybe a new front bearing/seal. i'd be thinking of leak after motor heats up, you've pretty much covered all other bases.

formerly of Sunnymead.....:cool:

Jake C6R 12-16-2011 07:55 PM


Originally Posted by scary_jerry (Post 10047933)
while i was reading your description of the motor problem, i see that you might have a buyer. i just wanted to say try 1 more chicken (crispy) and maybe a new front bearing/seal. i'd be thinking of leak after motor heats up, you've pretty much covered all other bases.

formerly of Sunnymead.....:cool:


Sunnymead! I grew up in O.C. and spent a lot of time in the inland empire! Had a good buddy in Moreno Valley. Thanks for the tip, it's a good a theory as any at this point! If I keep this turd it might be worth a shot because I can't let a little engine win! LOL

If Valk wants it, I will send it to him for $5 express shipping in a padded USPS envelope or small box - maybe I can learn something when he figures out what is wrong with it!

Jake C6R 12-16-2011 08:04 PM

Found a front bearing for $16 on eBay...

valk 12-16-2011 09:08 PM

$5 for the engine? yes please! what you want for it though? my spare is the sx12 that i cant keep running. mine is a slide carb non turbo, but i bet the crank is all the same.
mine has a busted carb insert. the one that goes into the crank case between the carb and the motor. i tore a chunk out of it, flipped it around and it works, but i doubt it seals right. dont have money to buy a new motor, but the 12tr isnt slower than the newer novas at our track. track is too small for those cars to really sing, and my 12tr with massive low end is easily able to keep up to them.

scary_jerry 12-17-2011 01:21 AM

Jake, i'm hoping you tame the gremlin in that little motor just for the principle of the thing! I had a used motor i bought and did the best i could to clean it out and reoiled before firing it. The motor had moments of brilliance but i had to start chasing needle valve settings and then it went berserk......front seal.

Roelof 12-17-2011 03:10 AM


Originally Posted by Jake C6R (Post 10047672)
I got this OS .12TR used as part of a sale. It was supposed to be lightly used and the pinch was really tight.

This with all the problems does raise me a Question: you are sure it has the original piston and/or sleeve?

Mixing piston and sleeves from different brands or production series can cause bad running/adjusting engines.

stefan 12-17-2011 04:17 AM

A few questions that haven't been asked or answered:
  1. What plugs are you using?
  2. What's the head clearance of the engine?
  3. Have you tried a different carb on it?

Jake C6R 12-17-2011 06:51 AM

Thanks everyone for trying to solve this. As to the questions. I am not 100% sure it is the original piston and sleeve but based on the diagrams they look right to me. The piston is tight in the sleeve and has plenty of distance from the top when you push it inside the sleeve. Maybe you can tell from the pix is it looks right to you.

I am running OS RP6 plugs and 20% Byrons Race Gen 2. There is the one head gasket. I have not tried a different carb as I don't have access to one, but if all else fails I may try that.

You guys have inspired me not to give up on this thing just yet! I tore it down completely and took some pix. Before I did I tested the front bearing again and there is a small air leak. It is almost nothing but who knows when it heats up maybe it is getting worse. At this point I think I will find some new bearings, clean and reseal everything and see what happens! It is just not in my nature not to figure things out if I can!

I will post some pix in case anyone sees anything. Honestly I inspected it carefully and the only potential issue I think is left is the bearings. They are not completely smooth spinning, but no worse then bearings I have used with no problems in other engines. At this point I think that must be it based on process of elimination. Edit - OK that rear bearing is $62!!! We won't be replacing that one LOL, the front I can get for $16 so that one is good to go.

Jake C6R 12-17-2011 06:58 AM

Here Are The Pix...
 
http://i33.photobucket.com/albums/d8.../OS12TR005.jpg
http://i33.photobucket.com/albums/d8...S12TR004-1.jpg
http://i33.photobucket.com/albums/d8.../OS12TR002.jpg
http://i33.photobucket.com/albums/d8...S12TR003-1.jpg

Jake C6R 12-17-2011 04:14 PM

Ordered the front bearing and also the carb gasket and HSN and LSN o-rings just for good measure. I'll still seal everything up. Added a couple glow RP6 glow plugs as well, so I can try it with a brand new one.

Cleaned every little part and then dried them with the compressor, so just need the bearing and gaskets and we will see.

Any other ideas after looking at the pix?

fairgo 12-17-2011 05:08 PM

Front Bearing
 
Front bearings in onroad engines do not have an airtight seal. If you get a new bearing wash it out and hold it up to the light, you will see what I mean and the ones with the biggest gaps are the metal sealed.

quadracer111 12-17-2011 06:07 PM

Damn traxxas 3.3 engines. Such a piss off. Make it half way across the track, flame out. Take it off the track, try to replicate the issue, wont do it, throw it back on the track, flame out.

A picco .26 solved that issue. And when that kicked the bucket I just went brushless.

scary_jerry 12-17-2011 06:29 PM

Jake, great resolution on the photos. With that much detail i'd give Neil at Clockwork Motors a call and ask him to give an assessment. I'm drawn to the 'scuff' on the cylinder wall. Had a cylinder like that after my 2 speed stopped shifting in a main and i was not about to lift off the trigger.

(remember rc a\c at 'riverside raceway',
i ran 3.5K&B tunnel hulls at 'fairmont park'
and actually got to see action at 'thorp raceway'
as a spectator...almost forgot my first rc flight
at 'mile square park'). :cool:

Jake C6R 12-17-2011 06:40 PM


Originally Posted by quadracer111 (Post 10050792)
Damn traxxas 3.3 engines. Such a piss off. Make it half way across the track, flame out. Take it off the track, try to replicate the issue, wont do it, throw it back on the track, flame out.

A picco .26 solved that issue. And when that kicked the bucket I just went brushless.

I agree 100%, mine crapped out after the circlip came loose - Picco .26 red dot in my Revo is working awesome!

But this thread is about O.S. .12TR problem I am having for my onroad car - I put a Picco .12 in it which is running flawlessly but I still want to get the O.S. going if possible, when it ran well it would go like a scalded dawg!

Jake C6R 12-17-2011 06:42 PM


Originally Posted by scary_jerry (Post 10050860)
Jake, great resolution on the photos. With that much detail i'd give Neil at Clockwork Motors a call and ask him to give an assessment. I'm drawn to the 'scuff' on the cylinder wall. Had a cylinder like that after my 2 speed stopped shifting in a main and i was not about to lift off the trigger.

(remember rc a\c at 'riverside raceway',
i ran 3.5K&B tunnel hulls at 'fairmont park'
and actually got to see action at 'thorp raceway'
as a spectator...almost forgot my first rc flight
at 'mile square park'). :cool:

Thanks, Jerry! What did he say about yours? I don't see any scuff, maybe it's the pix because it looks pretty good in there. I even asked my wife to look at it and she said it looks fine so there you go! After all wives know everything!

Jake C6R 12-17-2011 06:49 PM


Originally Posted by fairgo (Post 10050656)
Front bearings in onroad engines do not have an airtight seal. If you get a new bearing wah it out and hold it up to the light, you will see what I mean and the ones with the biggest gaps are the metal sealed.

I don't think I have a big leak but I am out of ideas. If this doesn't work Valk will he be getting an engine for cheap! LOL:nod:

valk 12-18-2011 12:55 PM

no complaints here! i know my motor is leaking like a siv i just cant be bothered to spend money on the nitro car lol.

you could always use the method of checking for vac leaks on 1-1 cars. just get her on a stand running at med throttle and spray some soapy water around the flywheel and all the seals. you should know right away if its a bad enough leak to make it run screwy.

my 12tr has a cracked and chiped out carb seal that definitely doesnt seal properly. my exhaust mani gasket is worn out and ive never taken the carb apart to clean, yet it will idle all day and only sometimes dies on refuel stops. np. i just have my pitman lift the car, rev the piss out of it for a second to build up pressure and let it go.

your motor looks to be in better shape than mine.

scary_jerry 12-18-2011 04:35 PM

Jake, sorry if i wasn't seeing 'scuff'. I had already replaced that fried motor before i found 'Neal' at Clockwork in pursuit of monster mill.

Having wife to support hobby madness is good. I put her down as my 'sponsor' at Las Vegas Grand Prix (3d place A main IGT), but mine couldn't tell 'scuff' from micropolish. tsk tsk

Jake C6R 12-18-2011 06:28 PM


Originally Posted by scary_jerry (Post 10054072)
Jake, sorry if i wasn't seeing 'scuff'. I had already replaced that fried motor before i found 'Neal' at Clockwork in pursuit of monster mill.

Having wife to support hobby madness is good. I put her down as my 'sponsor' at Las Vegas Grand Prix (3d place A main IGT), but mine couldn't tell 'scuff' from micropolish. tsk tsk

Congrats on the 3d place! I am sure it was your wife/sponsor that got you the win! :sweat:

Jake C6R 12-22-2011 04:13 PM

Case is History - Anyone Have One?
 
Problem found. I removed the front bearing and saw a very small hairline crack in the case. So it's history. Just for laughs I removed the rear bearing and it wasn't exactly excellent either.

So now I have all the guts plus new parts on the way and no block. The crank, piston/sleeve, rotary carb, etc are good. Being delivered are a new front bearing, HSN and LSN o-rings and carb gasket.

The question is now try to sell the guts and new parts or try and find a OS .12TR block with at least a good rear bearing? It's not worth the money to replace the rear bearing - too expensive.

el salvador 12-22-2011 05:28 PM

Jake, you could load all the good parts into a TZ block if you had one handy.

Before you found the crack, I was going to suggest checking the Thermo Insulator on the Carb base (OS #21165010),
a common issue. I've had Two TZ's (sold one) and the "Old/TTrusty TR (w/TZ carb)
still runnin strong in the "Clubs RRR Loaner Car" that I own & maintain for the use of recruiting nOObs into Nitro TC Racing................:tire:

Jake C6R 12-22-2011 06:13 PM


Originally Posted by el salvador (Post 10071902)
Jake, you could load all the good parts into a TZ block if you had one handy.

Before you found the crack, I was going to suggest checking the Thermo Insulator on the Carb base (OS #21165010),
a common issue. I've had Two TZ's (sold one) and the "Old/TTrusty TR (w/TZ carb)
still runnin strong in the "Clubs RRR Loaner Car" that I own & maintain for the use of recruiting nOObs into Nitro TC Racing................:tire:

Thanks for that, bro! Good to know everything will fit. Looked on eBay and found a crankcase with bearings for $70 but I am hoping for a cheaper solution. Maybe someone will have a used one in good shape that they want to unload. Especially if I can use the new front bearing I bought.

Are all the .12 TZ models the same as far as the guts?

Roelof 12-22-2011 11:47 PM

Just weld or solder the crack? It is possible with aluminium or a more simple way: use a glue. I have done it in the past with a metal glue.

scary_jerry 12-23-2011 07:17 AM

Jake, good news you found the 'gremlin'.

I like Roelof's take on it...fix it. I'd check with a jeweler to see if they could suggest some repair method. But i would attempt a fix before 'teeing it up' on the back 9...

PINGGGGG>>>>>>>>>>>>>>>>>>(*%:#). :D

Jake C6R 12-23-2011 07:38 AM

Thanks for the suggestion guys! If I can't find a used case Valk wants to take it off my hands as he needs the internals.

As for the case, well let's just say it is not going to survive, it received the brunt of my frustration in my vise....CRUNCHHHHHH LOL

scary_jerry 12-23-2011 08:25 AM

I can relate Jake.....][:(][.......][.][. :ha:

valk 12-23-2011 10:03 AM

Happy to be getting the parts, though too bad you killed the case. I would have jbwelded the thing ad started it up lol

Jake C6R 12-23-2011 10:22 AM


Originally Posted by valk (Post 10074346)
Happy to be getting the parts, though too bad you killed the case. I would have jbwelded the thing ad started it up lol

I know, in hindsight that was dumb. But it felt good at the time! LOL


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