R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro On-Road > Onroad Nitro Engine Zone

Reply
 
Thread Tools Search this Thread
Old 12-16-2003, 11:00 PM   #16
Tech Addict
 
icon's Avatar
 
Join Date: Feb 2002
Location: Boston
Posts: 527
Send a message via AIM to icon
Default

wow, i didnt know that. i bought a zac racing head for my novarossi and was even planning to buy the optional 11 fin head. would i still be able to use my zac/kawahara racing head. its still a 9 fin stack but has slightly wider top fins with broader opening to the glow plug near the top than compared to the stock unit. also do you know the shims/head clearance on the RR12L5?

Quote:
Originally posted by Corse-R
Just some warning about the 'small' heatsink of the NSR and RR models. THEY NEED IT.

Because the different composition of the piston, he likes to go hotter than previously and works fine hotter, thus why is he uses the smaller cooling head. So don't change it. He loves to go at 140 - 150ºC as I did on one of mine usually.
icon is offline   Reply With Quote
Old 12-16-2003, 11:09 PM   #17
Tech Addict
 
icon's Avatar
 
Join Date: Feb 2002
Location: Boston
Posts: 527
Send a message via AIM to icon
Default

whoa, 140 to 150 deg C??? thats 284 to 302 deg F!!! i didnt know they can run that hot.
icon is offline   Reply With Quote
Old 12-16-2003, 11:09 PM   #18
Tech Fanatic
 
Join Date: Mar 2003
Posts: 783
Default Re: rs12s5 w/ mt12 crankshaft

Quote:
Originally posted by thefuzzclub
a few weeks back i posted if this is possible. well, based on my experiment i would say that mt12 crankshaft perfectly fit in rs12s5 engine. however, these are my findings so far:

PLs check again the crank timing, if this feel weird for you, just measure (use caliper please) the widht of both crank opening. Its a square hole below the carb that acts like rotary valve.
If it within 2-3mm diff., should be OK. But if more than that you have a problem. It will be difficult to tune the engine properly if port and crank timing does not match.

Try to alter this parts:
- Pipes, use turbo dont use EFRA one
- Shorten the pressure line (pipe to tank)
- Use hotter plugs
- tighten your clutch

Reset the carb to factory standard and tune again from rich to lean.
From your description, your engine is having a "fake" top end mixture. It was to rich low and mid mixture so in the beginning of full throtle the fuel left in the crank is still enough to supply. But the truth in the end is too lean.

I solve my tuning problem backthen after i read this theory from parisracing site. Spend some of your time to browse there, it will make your (RC)life easier.

Try to learn how to "read" your plug, this is the ultimate and easiest thing to do if you want to know how health is your engine.

Have Fun!
GoldFinger is offline   Reply With Quote
Old 12-16-2003, 11:34 PM   #19
Tech Addict
 
thefuzzclub's Avatar
 
Join Date: Nov 2002
Posts: 704
Default Re: Re: rs12s5 w/ mt12 crankshaft

Quote:
Originally posted by GoldFinger
PLs check again the crank timing, if this feel weird for you, just measure (use caliper please) the widht of both crank opening. Its a square hole below the carb that acts like rotary valve.
If it within 2-3mm diff., should be OK. But if more than that you have a problem. It will be difficult to tune the engine properly if port and crank timing does not match.

Try to alter this parts:
- Pipes, use turbo dont use EFRA one
- Shorten the pressure line (pipe to tank)
- Use hotter plugs
- tighten your clutch

Reset the carb to factory standard and tune again from rich to lean.
From your description, your engine is having a "fake" top end mixture. It was to rich low and mid mixture so in the beginning of full throtle the fuel left in the crank is still enough to supply. But the truth in the end is too lean.

I solve my tuning problem backthen after i read this theory from parisracing site. Spend some of your time to browse there, it will make your (RC)life easier.

Try to learn how to "read" your plug, this is the ultimate and easiest thing to do if you want to know how health is your engine.

Have Fun!
GoldFinger,
this is what i like about this thread, LEARNING and getting others point of views. i have printed the above would also try it. many thanks....

thefuzzclub is offline   Reply With Quote
Old 12-17-2003, 08:36 AM   #20
Tech Master
 
tIANcI's Avatar
 
Join Date: Jul 2003
Location: Kuala Lumpur, Malaysia
Posts: 1,737
Default

Quote:
Originally posted by icon
whoa, 140 to 150 deg C??? thats 284 to 302 deg F!!! i didnt know they can run that hot.
Its ok ... I used to run up to 160/170 and as you will know ... the engine did not last all that long. But it was hardy ...
tIANcI is offline   Reply With Quote
Old 12-17-2003, 08:10 PM   #21
Tech Addict
 
thefuzzclub's Avatar
 
Join Date: Nov 2002
Posts: 704
Default Re: Re: rs12s5 w/ mt12 crankshaft

Quote:
Originally posted by GoldFinger
PLs check again the crank timing, if this feel weird for you, just measure (use caliper please) the widht of both crank opening. Its a square hole below the carb that acts like rotary valve.
If it within 2-3mm diff., should be OK. But if more than that you have a problem. It will be difficult to tune the engine properly if port and crank timing does not match.

Try to alter this parts:
- Pipes, use turbo dont use EFRA one
- Shorten the pressure line (pipe to tank)
- Use hotter plugs
- tighten your clutch

Reset the carb to factory standard and tune again from rich to lean.
From your description, your engine is having a "fake" top end mixture. It was to rich low and mid mixture so in the beginning of full throtle the fuel left in the crank is still enough to supply. But the truth in the end is too lean.

I solve my tuning problem backthen after i read this theory from parisracing site. Spend some of your time to browse there, it will make your (RC)life easier.

Try to learn how to "read" your plug, this is the ultimate and easiest thing to do if you want to know how health is your engine.

Have Fun!
Bad news!
my crankshaft got broken!!! cut into 2
i don't now what happened, what i know is my setting is still rich and i don't abuse my engine by pulling the throttle in a long time, not to mention that our track is small so there are no long straights. it's the 2nd time i encountered this. the same problem the same engine where i first broke the original crankshaft, now it happened again. i know there is something i'm doing wrong, i just know what that is.......


thefuzzclub is offline   Reply With Quote
Old 12-17-2003, 08:51 PM   #22
Tech Fanatic
 
Join Date: Mar 2003
Posts: 783
Default Re: Re: Re: rs12s5 w/ mt12 crankshaft

Quote:
Originally posted by thefuzzclub
Bad news!
my crankshaft got broken!!! cut into 2
i don't now what happened, what i know is my setting is still rich and i don't abuse my engine by pulling the throttle in a long time, not to mention that our track is small so there are no long straights. it's the 2nd time i encountered this. the same problem the same engine where i first broke the original crankshaft, now it happened again. i know there is something i'm doing wrong, i just know what that is.......
... Ooopss
Most common engine part that could be broken is the con rod. Usually after 3-4 galons it will deveoped too much play. Small detonation or bit overeving will broke it.
But if broken crankshaft, only too much overreving (higher than states in the manual) will broke it. Or you have a mechanical / installation problem.
Can describe where is the exact spot that cut in 2 ?
GoldFinger is offline   Reply With Quote
Old 12-17-2003, 08:52 PM   #23
Tech Prophet
 
InitialD's Avatar
 
Join Date: Feb 2002
Location: MORDOR
Posts: 19,679
Default Re: Re: Re: rs12s5 w/ mt12 crankshaft

Quote:
Originally posted by thefuzzclub
my crankshaft got broken!!!
Sorry for the bad news... Did you check to see if the broken point of the MT12 crankshaft the same as the one that broke on your original crankshaft?

It may be coincidental that this one broke but my guess is that it probably has got something to do with the misalignment of the main bearings that the crankshafts broke. Did you ever take out and dissassembled the bearings out of the crankcase?
InitialD is offline   Reply With Quote
Old 12-17-2003, 08:53 PM   #24
Tech Prophet
 
InitialD's Avatar
 
Join Date: Feb 2002
Location: MORDOR
Posts: 19,679
Default Re: Re: Re: Re: rs12s5 w/ mt12 crankshaft

Quote:
Originally posted by GoldFinger
[BBut if broken crankshaft, only too much overreving (higher than states in the manual) will broke it. Or you have a mechanical / installation problem.[/B]
Somehow, I suspect mechanical installation problem as two crankshafts broke in the same crankcase.
InitialD is offline   Reply With Quote
Old 12-17-2003, 09:45 PM   #25
Tech Addict
 
thefuzzclub's Avatar
 
Join Date: Nov 2002
Posts: 704
Default Re: Re: Re: Re: Re: rs12s5 w/ mt12 crankshaft

Quote:
Originally posted by InitialD
Somehow, I suspect mechanical installation problem as two crankshafts broke in the same crankcase.
InitialD,
I want to believe that its a mechanical installation issue, probably the allignment of the bearings and you are absolutely right, the 2 crankshafts broke exactly at the same area. I never tried disassembling the bearings, but it looks alligned the way i look at it. well i'm not an engine expert so i guess i'll just consider this as a learning experience....huhuhuhuhu. now this engine will turn to be a spare part engine for my other s12s5....huhuhuhuhu... crankshaft is very expensive to replace!!!!!.....
thefuzzclub is offline   Reply With Quote
Old 12-17-2003, 09:59 PM   #26
Tech Prophet
 
InitialD's Avatar
 
Join Date: Feb 2002
Location: MORDOR
Posts: 19,679
Default Re: Re: Re: Re: Re: Re: rs12s5 w/ mt12 crankshaft

Quote:
Originally posted by thefuzzclub
I never tried disassembling the bearings, but it looks alligned the way i look at it. well i'm not an engine expert so i guess i'll just consider this as a learning experience....huhuhuhuhu.
It is difficult to determine if the crankshaft and the bearings are aligned properly. Perhaps during assembly in the factory, the bearings were fitted with a minute misalignment which will only be amplified and further exaggerated at high revs. I guess it's a draw of luck. A guy at the track broke 3 crankshafts on the same engine at the same place.

I also know a few people who when they break a crankshaft in their engine, they try to get a spare crankshaft in and sell it as a 2nd hand engine to another unsuspecting person or just sell the other parts of the engine.

Anyway, it would be great if Dino, Top Gun 777 Grinder or Motorman could shed some light on how to detect and know if the crankshaft is installed correctly and aligned in the bearings...
InitialD is offline   Reply With Quote
Old 12-18-2003, 01:05 AM   #27
Tech Champion
 
Manticore's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2001
Location: Heaven
Posts: 9,999
Default

Since when TG777 and motorman has a spoke person? now what? master of spoke person?
Manticore is offline   Reply With Quote
Old 12-18-2003, 07:19 AM   #28
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,781
Default

I had the same problem some time ago with an RB X12 engine. Mine broke the crank in two just at the edge of the front bearing. At the begining I thought it was a worn bearing, I changed it and ¡¡¡bang!! it did it again (2nd crank).
Carefull inspection determined it was the Centax clutch bell that was slightly ovalized because i did a bad operation trying to change pinions thus creating a high rev vibration(I asume) that affected the crank. When i changed the Centax bell, checked the rest of the clutch assembly, the problem was solved.
Hope this helps.
AFM
afm is offline   Reply With Quote
Old 12-18-2003, 07:28 AM   #29
Tech Champion
 
Manticore's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2001
Location: Heaven
Posts: 9,999
Default

Quote:
Originally posted by afm
I had the same problem some time ago with an RB X12 engine. Mine broke the crank in two just at the edge of the front bearing. At the begining I thought it was a worn bearing, I changed it and ¡¡¡bang!! it did it again (2nd crank).
Carefull inspection determined it was the Centax clutch bell that was slightly ovalized because i did a bad operation trying to change pinions thus creating a high rev vibration(I asume) that affected the crank. When i changed the Centax bell, checked the rest of the clutch assembly, the problem was solved.
Hope this helps.
AFM
one great insight to share with ! thanks ! but I do have pinion tool !
Manticore is offline   Reply With Quote
Old 12-18-2003, 12:46 PM   #30
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,781
Default

Manticore
Yeah, I also have a pinion tool, the problem is that the bell fell off my hands and believe or not it hit the floor, and at that moment I never thought it had slightly bended, it cost me a new crank and the bell aaagggggghhhh!!!!
A buddy of mine broke his crank because he overtightened the nut that holds the flywheel and apparently it created a stress at that point, and during the race the whole clutch assy past every car at the track, jajajajajaja.
Stupid experiences...... but real man.
AFM
afm is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Sirio engines thread EVOLUTION Offroad Nitro Engine Forum 2824 04-29-2014 11:58 AM
Axial Engines thread Axial Racing Onroad Nitro Engine Zone 164 10-06-2008 06:48 PM
RB engines thread CraigM Nitro Off-Road 7 01-05-2008 11:57 AM
JP Engines Thread DOMOisCOOL Onroad Nitro Engine Zone 2 02-16-2004 06:00 AM
OS engines thread EVOLUTION Onroad Nitro Engine Zone 44 02-11-2004 07:28 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 08:16 AM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net

SEO by vBSEO 3.5.0