2LikesGo-Tech Engines Thread
03-22-2010 | 08:45 PM
Tech Elite
Joined: Nov 2007
Posts: 2,983
From: Auckland, New Zealand
Put the .2mm shim in for break in, and remove it when the pinch starts to ease. Don't leave it in there for too long. Couple to three litres is plenty.
Break in procedure on the Tech Tips page of www.go-racing.co.nz
03-25-2010 | 07:09 AM
Tech Fanatic
Joined: Aug 2008
Posts: 891
From: Texas
now that the news has broken...
http://www.neobuggy.net/modules/news...p?storyid=7921
I'd like to welcome Ryan Lopez, Daniel Ornelas, and Glenn Williams to the team. These three guys are in addition to our current factory team, consisting of Kendall Welch and Matt "Puddin'" Sistrunk.
http://www.neobuggy.net/modules/news...p?storyid=7921
I'd like to welcome Ryan Lopez, Daniel Ornelas, and Glenn Williams to the team. These three guys are in addition to our current factory team, consisting of Kendall Welch and Matt "Puddin'" Sistrunk.
03-25-2010 | 07:05 PM
Tech Regular
Joined: Feb 2006
Posts: 307
Hi all
Sorry folk’s long post.
I have a Go Gen 4, 3PT, which I purchased a few years back new, broke it in by starting and putting it straight on the ground doing figure eights up hill and on grass.
I still have a lot of pinch very difficult to turn motor by hand, motor has 22 litres of fuel through the engine, worn out a rod and rear bearing in the process.
I have experimented with 2 other carbs, Nova and OS, the problem is that it lean bogs once I lean it out, If I lean bottom end do pinch test, as posted few pages back, then lean on HS needle it lean bogs once it gets to a race track, ideal cap is 0.5-0.7.
I can lean top end from flush 2 full turns with OS carb and 1.5 full turns on Nova carb. I can tune the motor in the park, it goes good, put once at the track after 5mins, ½ way through a qualifier it starts to carry on and lean bog.
If I tune the motor so that it does not lean bog , thus bottom end turned correctly then tune HS needle I have ok bottom end but down the straight I am lacking power dramatically, tuning in this manner does not get the motor hot at all, max temp would be 70c and does not produce sufficient power.
This motor does not exceed past 80c in temp max, leaned out.
My possible solution is to wrap the head in foil then put a heat gun on it till it reaches 150c to try and loose some pinch. Crazy! What do the Go experts think?
I have tried 3 different brands of plugs, LRP (6), Nova (C6), OS (P4), and will try OD(97T).
I have tried blowing this thing up by mixing my own fuel, using a 1 litre beaker used in environmental analysis labs +/- 5ml. I have played with 9-11% oil content 25-30 nitro and further purchasing premixed race fuel from the factory, none the wiser.
Am I correct in assuming that once the pinch gas gone then I will be able to gain optimum power and temps to lean out top end so I get it going moving down the straight without lean bogging. I presume because of the pinch its restricting me from gaining maximum power.
I don’t use temp guns I use the old spit and sizzle, problem is it does not sizzle, just sits there.
If anyone can help me getting this thing to about 120c without lean bogging, you would have greatly solved a tuning mystery.
Sorry folk’s long post.
I have a Go Gen 4, 3PT, which I purchased a few years back new, broke it in by starting and putting it straight on the ground doing figure eights up hill and on grass.
I still have a lot of pinch very difficult to turn motor by hand, motor has 22 litres of fuel through the engine, worn out a rod and rear bearing in the process.
I have experimented with 2 other carbs, Nova and OS, the problem is that it lean bogs once I lean it out, If I lean bottom end do pinch test, as posted few pages back, then lean on HS needle it lean bogs once it gets to a race track, ideal cap is 0.5-0.7.
I can lean top end from flush 2 full turns with OS carb and 1.5 full turns on Nova carb. I can tune the motor in the park, it goes good, put once at the track after 5mins, ½ way through a qualifier it starts to carry on and lean bog.
If I tune the motor so that it does not lean bog , thus bottom end turned correctly then tune HS needle I have ok bottom end but down the straight I am lacking power dramatically, tuning in this manner does not get the motor hot at all, max temp would be 70c and does not produce sufficient power.
This motor does not exceed past 80c in temp max, leaned out.
My possible solution is to wrap the head in foil then put a heat gun on it till it reaches 150c to try and loose some pinch. Crazy! What do the Go experts think?
I have tried 3 different brands of plugs, LRP (6), Nova (C6), OS (P4), and will try OD(97T).
I have tried blowing this thing up by mixing my own fuel, using a 1 litre beaker used in environmental analysis labs +/- 5ml. I have played with 9-11% oil content 25-30 nitro and further purchasing premixed race fuel from the factory, none the wiser.
Am I correct in assuming that once the pinch gas gone then I will be able to gain optimum power and temps to lean out top end so I get it going moving down the straight without lean bogging. I presume because of the pinch its restricting me from gaining maximum power.
I don’t use temp guns I use the old spit and sizzle, problem is it does not sizzle, just sits there.
If anyone can help me getting this thing to about 120c without lean bogging, you would have greatly solved a tuning mystery.
03-25-2010 | 07:22 PM
jesussaves, sounds like an air leak to me. also try an os-p3 plug. Make sure your head is on tight and shimmed correctly. I had a gen4 5 port that did that to me. Was an air leak at carb pinch bolt. Also check the needle seals. I would seal it up, put in a p3 plug, check needle seals in original carb and put it back on. and try again. Also preheat engine. Set idle gap at .1mm hsn flush/lsn 2 turns in on original carb. Oh and one last bone head thing I once did,forgot to put carb restrictor in place!
03-25-2010 | 07:44 PM
Tech Adept
Joined: Mar 2008
Posts: 130
From: Northwest WA
Hi all
Sorry folk’s long post.
I have a Go Gen 4, 3PT, which I purchased a few years back new, broke it in by starting and putting it straight on the ground doing figure eights up hill and on grass.
I still have a lot of pinch very difficult to turn motor by hand, motor has 22 litres of fuel through the engine, worn out a rod and rear bearing in the process.
I have experimented with 2 other carbs, Nova and OS, the problem is that it lean bogs once I lean it out, If I lean bottom end do pinch test, as posted few pages back, then lean on HS needle it lean bogs once it gets to a race track, ideal cap is 0.5-0.7.
I can lean top end from flush 2 full turns with OS carb and 1.5 full turns on Nova carb. I can tune the motor in the park, it goes good, put once at the track after 5mins, ½ way through a qualifier it starts to carry on and lean bog.
If I tune the motor so that it does not lean bog , thus bottom end turned correctly then tune HS needle I have ok bottom end but down the straight I am lacking power dramatically, tuning in this manner does not get the motor hot at all, max temp would be 70c and does not produce sufficient power.
This motor does not exceed past 80c in temp max, leaned out.
My possible solution is to wrap the head in foil then put a heat gun on it till it reaches 150c to try and loose some pinch. Crazy! What do the Go experts think?
I have tried 3 different brands of plugs, LRP (6), Nova (C6), OS (P4), and will try OD(97T).
I have tried blowing this thing up by mixing my own fuel, using a 1 litre beaker used in environmental analysis labs +/- 5ml. I have played with 9-11% oil content 25-30 nitro and further purchasing premixed race fuel from the factory, none the wiser.
Am I correct in assuming that once the pinch gas gone then I will be able to gain optimum power and temps to lean out top end so I get it going moving down the straight without lean bogging. I presume because of the pinch its restricting me from gaining maximum power.
I don’t use temp guns I use the old spit and sizzle, problem is it does not sizzle, just sits there.
If anyone can help me getting this thing to about 120c without lean bogging, you would have greatly solved a tuning mystery.
Sorry folk’s long post.
I have a Go Gen 4, 3PT, which I purchased a few years back new, broke it in by starting and putting it straight on the ground doing figure eights up hill and on grass.
I still have a lot of pinch very difficult to turn motor by hand, motor has 22 litres of fuel through the engine, worn out a rod and rear bearing in the process.
I have experimented with 2 other carbs, Nova and OS, the problem is that it lean bogs once I lean it out, If I lean bottom end do pinch test, as posted few pages back, then lean on HS needle it lean bogs once it gets to a race track, ideal cap is 0.5-0.7.
I can lean top end from flush 2 full turns with OS carb and 1.5 full turns on Nova carb. I can tune the motor in the park, it goes good, put once at the track after 5mins, ½ way through a qualifier it starts to carry on and lean bog.
If I tune the motor so that it does not lean bog , thus bottom end turned correctly then tune HS needle I have ok bottom end but down the straight I am lacking power dramatically, tuning in this manner does not get the motor hot at all, max temp would be 70c and does not produce sufficient power.
This motor does not exceed past 80c in temp max, leaned out.
My possible solution is to wrap the head in foil then put a heat gun on it till it reaches 150c to try and loose some pinch. Crazy! What do the Go experts think?
I have tried 3 different brands of plugs, LRP (6), Nova (C6), OS (P4), and will try OD(97T).
I have tried blowing this thing up by mixing my own fuel, using a 1 litre beaker used in environmental analysis labs +/- 5ml. I have played with 9-11% oil content 25-30 nitro and further purchasing premixed race fuel from the factory, none the wiser.
Am I correct in assuming that once the pinch gas gone then I will be able to gain optimum power and temps to lean out top end so I get it going moving down the straight without lean bogging. I presume because of the pinch its restricting me from gaining maximum power.
I don’t use temp guns I use the old spit and sizzle, problem is it does not sizzle, just sits there.
If anyone can help me getting this thing to about 120c without lean bogging, you would have greatly solved a tuning mystery.
03-25-2010 | 07:56 PM
Tech Elite
Joined: Nov 2007
Posts: 2,983
From: Auckland, New Zealand
Remember - if you lean the top end needle you are also effectivly leaning the bottom end needle at the same time.
You say you set the bottom end right, then went and leaned the top end some. If you don't go back and richen the bottom end again to compensate, you will end up with a lean bottom end and lean bog.
Also - just very small adjustments at a time. No more than 1/8 of a turn at a time, or you could miss the tuning sweet spot and be chasing your tail all day for a tune.
What your describing also sounds like a rich bottom end disguising a wide idle gap - resulting in a way too lean top end. This will cause the motor to run OK, but it will run cool, then start lean bogging at around half a tank, then run really lean as the tank runs out. It's a classic mistake, made by pretty much every RC gas racer at some time during their learning curve. It's hard to pick because the motor will actually run not too bad, but nowhere near it's full potential.
Check that idle gap by pinching the fuel tubing off about 1" back from the fuel nipple when the motor has just started, before it gets too warm. If the idle comes up quite high, your idle gap is too big. Reduce it and pinch test again until the revs only rise up very slightly. This indicates a correct idle gap for your motor. If the engine won't idle for long at this setting, lean the botton end - DO NOT ADJUST THE IDLE GAP. Now tune bottom end, then top end, then re visit the bottom end if you made big adjustments to the top end needle. You should now have a ballpark tune. Fine tune from here.
You say you set the bottom end right, then went and leaned the top end some. If you don't go back and richen the bottom end again to compensate, you will end up with a lean bottom end and lean bog.
Also - just very small adjustments at a time. No more than 1/8 of a turn at a time, or you could miss the tuning sweet spot and be chasing your tail all day for a tune.
What your describing also sounds like a rich bottom end disguising a wide idle gap - resulting in a way too lean top end. This will cause the motor to run OK, but it will run cool, then start lean bogging at around half a tank, then run really lean as the tank runs out. It's a classic mistake, made by pretty much every RC gas racer at some time during their learning curve. It's hard to pick because the motor will actually run not too bad, but nowhere near it's full potential.
Check that idle gap by pinching the fuel tubing off about 1" back from the fuel nipple when the motor has just started, before it gets too warm. If the idle comes up quite high, your idle gap is too big. Reduce it and pinch test again until the revs only rise up very slightly. This indicates a correct idle gap for your motor. If the engine won't idle for long at this setting, lean the botton end - DO NOT ADJUST THE IDLE GAP. Now tune bottom end, then top end, then re visit the bottom end if you made big adjustments to the top end needle. You should now have a ballpark tune. Fine tune from here.
03-26-2010 | 05:56 PM
Tech Regular
Joined: Feb 2006
Posts: 307
jesussaves, sounds like an air leak to me. also try an os-p3 plug. Make sure your head is on tight and shimmed correctly. I had a gen4 5 port that did that to me. Was an air leak at carb pinch bolt. Also check the needle seals. I would seal it up, put in a p3 plug, check needle seals in original carb and put it back on. and try again. Also preheat engine. Set idle gap at .1mm hsn flush/lsn 2 turns in on original carb. Oh and one last bone head thing I once did,forgot to put carb restrictor in place!
. I don't think I have a air leak, as this is happening with all 4 carbs I have tried, 2 Go Carbs (Gen 4 and 5), 1 Nova Carb ( 2 needle on road), 1 OS carb.Engine is shimmed as per factory spec for using 25% nitro. Head bolts are tight, very tight.
03-26-2010 | 05:59 PM
Tech Regular
Joined: Feb 2006
Posts: 307
I don't have a 3 port but I've been running Nova carbs on my 7 and 5 ports for a while now and it sounds like you HSN is too lean which means your probably running it too fat on the bottom. Try resetting your Nova carb. Assuming your using a 2 needle carb, try these settings as a start point. Idle gap 1mm, HSN 4 turns out from bottom. LSN 2 1/4turns out from bottom. Adjust your idle with the LSN only.