Arrow Racing GTR .21 Engine Thread
07-23-2012 | 01:17 AM
#931
Tech Adept
Joined: Oct 2011
Posts: 189
From: norway
A little trouble will my new Arrow Gen II today at Thunder Alley.
Here's the scoop:
-Broke in using heat cycle method. (Pre heat to 200* and do 5, 3 minute runs. Then 3, 5 minute runs. Getting up to 250 each time, cooling between each run. Then tossing on track and running easily for 5 tanks. Then Tune.)
-The motor is about 3 tanks shy of a gallon.
-Stock New Agama 3 shoe clutch with 1.1 springs.
-Go EFRA 2072 pipe (ran on my last Arrow and it ripped)
-Stock Carb.
-Break in shim left it
Now the problem is. It runs good for about 3-4 minutes then randomly I have NO bottom end what so ever. It bogs and runs poorly until the mid range kicks in. Then it pulls for days. There are no leaks, idles great, sounds good on the bench and top. I don't think it's a problem with the motor, but maybe the carb? I ran an OS carb on my last Arrow from day 1 and it was awesome.
Has any one had this problem? And can someone offer any advice onto what it could possibly be? The motor rips when it's running but getting there seams to be a problem at the moment.
Here's the scoop:
-Broke in using heat cycle method. (Pre heat to 200* and do 5, 3 minute runs. Then 3, 5 minute runs. Getting up to 250 each time, cooling between each run. Then tossing on track and running easily for 5 tanks. Then Tune.)
-The motor is about 3 tanks shy of a gallon.
-Stock New Agama 3 shoe clutch with 1.1 springs.
-Go EFRA 2072 pipe (ran on my last Arrow and it ripped)
-Stock Carb.
-Break in shim left it
Now the problem is. It runs good for about 3-4 minutes then randomly I have NO bottom end what so ever. It bogs and runs poorly until the mid range kicks in. Then it pulls for days. There are no leaks, idles great, sounds good on the bench and top. I don't think it's a problem with the motor, but maybe the carb? I ran an OS carb on my last Arrow from day 1 and it was awesome.
Has any one had this problem? And can someone offer any advice onto what it could possibly be? The motor rips when it's running but getting there seams to be a problem at the moment.
It had good idle. But when giving full throtlle it did stay on idle for a while
And then it slowly started to rew upp.
After changing the position on msn it was good,did never touch it again.
I must say that my exsperience is that this carburator is more easy than the nova to make adjustment.
07-23-2012 | 06:10 AM
#932
Tech Elite
Joined: Jan 2009
Posts: 2,005
From: Florida
Thanks guys. I got my MSN set where it should be, and clutch is fresh/ broken in.
What would be the "carb insulation issues" .. I put a different Arrow carb on the motor and there was no possible way to catch a tune with it. It would spool up at idle no matter what. I will get my OS carb (friend has it -___-) and slap it on and see what happens!
What would be the "carb insulation issues" .. I put a different Arrow carb on the motor and there was no possible way to catch a tune with it. It would spool up at idle no matter what. I will get my OS carb (friend has it -___-) and slap it on and see what happens!
It sounds like your bottom end is too rich or the top end is too lean.
07-26-2012 | 10:29 PM
#933
Got my OS carb back today. Going to slap it on and do some testing tomorrow. I'll be back with results.
07-27-2012 | 11:35 AM
#935
The new Arrow-Racing GTR-21 Ver III .21 engine is now in stock at Hobby Pro USA.
The engine has been redesigned to have less mechanical pinch to make engine break in easier and allows the engine to be started the first time with less effort. This also puts less stress on the con rod and allows a race tune to be put on sooner.
He is the explaination from the manufacture:
We have done a number of minor adjustments to help with the initial start-up process for end-users. But ultimately this was done without affecting the engine's overall lifespan. The idea was brought up long ago but it was only until the beginning of the last production schedule, we were able to bring this element in. From our drawings and the actual sample, we were able to locate a slight increase of 20 microns in tolerance at 2 points of the surface between the sleeve and piston. The tightness has since been eased off by 0.1 mm with standardized insertion pressure. In the end result, the engine is easier to start and this slight increase also promote a more sufficient clearance during operational heat expansion. Thus, in general the new engine requires less time, effort and money to complete the breaking-in process.
I have not had time to break in my new one yet, but I took it apart and the piston can now be pushed up into the sleeve much farther. I compared it to a new OS XZ-B piston and sleeve and I was able to push the piston up the same distance on both engine (both new never started). So it should break in much easier now, probably half the time (.75 gallons vs 1.5 gallons).
Hobby Pro USA has sold out of Ver II engines, so all engines ordered as on today will be the new Ver III engine.
The engine has been redesigned to have less mechanical pinch to make engine break in easier and allows the engine to be started the first time with less effort. This also puts less stress on the con rod and allows a race tune to be put on sooner.
He is the explaination from the manufacture:
We have done a number of minor adjustments to help with the initial start-up process for end-users. But ultimately this was done without affecting the engine's overall lifespan. The idea was brought up long ago but it was only until the beginning of the last production schedule, we were able to bring this element in. From our drawings and the actual sample, we were able to locate a slight increase of 20 microns in tolerance at 2 points of the surface between the sleeve and piston. The tightness has since been eased off by 0.1 mm with standardized insertion pressure. In the end result, the engine is easier to start and this slight increase also promote a more sufficient clearance during operational heat expansion. Thus, in general the new engine requires less time, effort and money to complete the breaking-in process.
I have not had time to break in my new one yet, but I took it apart and the piston can now be pushed up into the sleeve much farther. I compared it to a new OS XZ-B piston and sleeve and I was able to push the piston up the same distance on both engine (both new never started). So it should break in much easier now, probably half the time (.75 gallons vs 1.5 gallons).
Hobby Pro USA has sold out of Ver II engines, so all engines ordered as on today will be the new Ver III engine.
Previously the V2, we would have to heat it up 212+ degrees F ( 100+ C ) to get it start up for break in.
Now with the newest engine V3, we manage to get it start up at 150 degrees F
( 70 C )
It is much easier to break in, uses less fuel and time. Thumbs up !
Last edited by Danny Teh; 07-27-2012 at 11:54 AM.
08-01-2012 | 07:30 PM
#936
Ran a Arrow for the first time today. Ran awesome, these definately have some power. Came back to idle really nice in the turns, really did run like the blue head V-spec. Now that I have a baseline time to pull it apart and do some modding!
Rex
Rex
08-04-2012 | 06:32 AM
#937
Tech Adept
iTrader: (4)
Joined: Aug 2011
Posts: 239
From: Santa Cruz, CA. USA
V3 Engines..........
Previously the V2, we would have to heat it up 212+ degrees F ( 100+ C ) to get it start up for break in.
Now with the newest engine V3, we manage to get it start up at 150 degrees F
( 70 C )
It is much easier to break in, uses less fuel and time. Thumbs up !
Previously the V2, we would have to heat it up 212+ degrees F ( 100+ C ) to get it start up for break in.
Now with the newest engine V3, we manage to get it start up at 150 degrees F
( 70 C )
It is much easier to break in, uses less fuel and time. Thumbs up !
Does the new V3 come with a break in shim for the head?
Cheers
Brian
08-07-2012 | 06:18 PM
#939
Hi guys,
I have a generation 2 arrow engine, probably only had 8 litres/2 gallons fuel through it. I am running it without the breakin shim, the problem I am having is that after around 3 minutes driving, it will flame out. I start it on the box, remove igniter, it will idle fine, rev it, revs fine but once I let the throttle go, it will flame out. If I leave the igniter on the plug, it will rev and stay running when i release the throttle. I am using P3 plug, and 25 % nitro. Can anyone shed some light onto what I am doing wrong
I have a generation 2 arrow engine, probably only had 8 litres/2 gallons fuel through it. I am running it without the breakin shim, the problem I am having is that after around 3 minutes driving, it will flame out. I start it on the box, remove igniter, it will idle fine, rev it, revs fine but once I let the throttle go, it will flame out. If I leave the igniter on the plug, it will rev and stay running when i release the throttle. I am using P3 plug, and 25 % nitro. Can anyone shed some light onto what I am doing wrong
08-07-2012 | 06:28 PM
#940
Hi guys,
I have a generation 2 arrow engine, probably only had 8 litres/2 gallons fuel through it. I am running it without the breakin shim, the problem I am having is that after around 3 minutes driving, it will flame out. I start it on the box, remove igniter, it will idle fine, rev it, revs fine but once I let the throttle go, it will flame out. If I leave the igniter on the plug, it will rev and stay running when i release the throttle. I am using P3 plug, and 25 % nitro. Can anyone shed some light onto what I am doing wrong
I have a generation 2 arrow engine, probably only had 8 litres/2 gallons fuel through it. I am running it without the breakin shim, the problem I am having is that after around 3 minutes driving, it will flame out. I start it on the box, remove igniter, it will idle fine, rev it, revs fine but once I let the throttle go, it will flame out. If I leave the igniter on the plug, it will rev and stay running when i release the throttle. I am using P3 plug, and 25 % nitro. Can anyone shed some light onto what I am doing wrong
08-07-2012 | 06:38 PM
#941
It does this with an old glow plug, and also with new glow plug. It has got me stumped
if it stays running with the ignitor on it then your glow plug heating element is worn and cannot stay lit without the help of the ignitor. get a new plug! also look at the old one. is the tip of it whitish looking(too lean) or is it black and kinda wet(too rich) your plug can tell a story how your engine is running. try to get it in the middle.
08-07-2012 | 09:12 PM
#942
Hi guys,
I have a generation 2 arrow engine, probably only had 8 litres/2 gallons fuel through it. I am running it without the breakin shim, the problem I am having is that after around 3 minutes driving, it will flame out. I start it on the box, remove igniter, it will idle fine, rev it, revs fine but once I let the throttle go, it will flame out. If I leave the igniter on the plug, it will rev and stay running when i release the throttle. I am using P3 plug, and 25 % nitro. Can anyone shed some light onto what I am doing wrong
I have a generation 2 arrow engine, probably only had 8 litres/2 gallons fuel through it. I am running it without the breakin shim, the problem I am having is that after around 3 minutes driving, it will flame out. I start it on the box, remove igniter, it will idle fine, rev it, revs fine but once I let the throttle go, it will flame out. If I leave the igniter on the plug, it will rev and stay running when i release the throttle. I am using P3 plug, and 25 % nitro. Can anyone shed some light onto what I am doing wrong
You might want to do this to reconfirm. Leave your engine to cool down, then start your engine away. If the flaming out issue is gone then it is confirm you have a bad tune...............Try this.
http://www.rctech.net/forum/malaysia...pdates-21.html
08-20-2012 | 08:53 PM
#945
Race tune for Arrow engine
To all Arrow Engine users. Here is the tuning which we found to be close to what you might need.
Low Speed Needle: From Flush >> 1/2 Turn in.
Mid Speed Needle: From Flush >> 1 1/2 Turn Out.
High Speed Needle: From Flush >> 1 3/4 Turn in.
I tried these settings Danny posted a link to, ran awesome.
Rex
To all Arrow Engine users. Here is the tuning which we found to be close to what you might need.
Low Speed Needle: From Flush >> 1/2 Turn in.
Mid Speed Needle: From Flush >> 1 1/2 Turn Out.
High Speed Needle: From Flush >> 1 3/4 Turn in.
I tried these settings Danny posted a link to, ran awesome.
Rex