1LikesGo Engine USA 2011 Thread
03-27-2012 | 04:14 PM
#2374
Tech Regular
iTrader: (4)
Joined: Oct 2010
Posts: 260
From: johnson city ny
i bought one of amain for 149 a few weeks ago have alittle under half gallon still a tad rich on top thing moves my truggy with a werks 2013 pretty good should have even more power once its fully broken in , i would def buy one of theese for 139.00 mite get another for back up or for a buggy
03-27-2012 | 05:05 PM
#2375
Tech Elite
Joined: Nov 2007
Posts: 2,983
From: Auckland, New Zealand
Hell yeah. Buy up big time at that price.
Hope it didn't come across like I was bagging the 2 needle version. They are a brilliant motor, and the 2 needle is a very nice carb too. Very much a "set and forget" carby on race days.
You can always grab a 3 needle at a later date when they become available in the US and just change it over if you want. The rest of the motor is identical.
Hope it didn't come across like I was bagging the 2 needle version. They are a brilliant motor, and the 2 needle is a very nice carb too. Very much a "set and forget" carby on race days.
You can always grab a 3 needle at a later date when they become available in the US and just change it over if you want. The rest of the motor is identical.
03-27-2012 | 08:39 PM
#2376
Tech Master
Joined: Jan 2006
Posts: 1,977
From: Sydney
All MG and Zilla engines are hand built and piston matched. This means no more than 1 litre of run in before racing it. Much less stress on rod and bearing as a result and an engine that wont break your starter box :-)
Pm for details :-)
M
03-30-2012 | 04:22 AM
#2378
+1 Flanno. It sound like it might have had a bit of a short, sharp and cold run in.
It would be hard to know if the rod / crank pin wear came first, or it was caused by the stuffed bearing.
Either way it doesn't sound too healthy. The front bearings will weep if your running rich, or put heaps of after run in, but it sounds like a serious bearing failure (or two !!).
Check the wrist pin. See if there is any lateral movement of the pin in the seats on either side of the piston. If there is movement there, or ovaling of the wrist pin retaining holes, then I would suspect a very harsh run in has left some play in the wrist pin and big end, thus probably causing the bearing wear through excess play.
It would be hard to know if the rod / crank pin wear came first, or it was caused by the stuffed bearing.
Either way it doesn't sound too healthy. The front bearings will weep if your running rich, or put heaps of after run in, but it sounds like a serious bearing failure (or two !!).
Check the wrist pin. See if there is any lateral movement of the pin in the seats on either side of the piston. If there is movement there, or ovaling of the wrist pin retaining holes, then I would suspect a very harsh run in has left some play in the wrist pin and big end, thus probably causing the bearing wear through excess play.
I did notice though that the 2 x holes in which the wrist pin goes into is oval on the top and bottom (holding the piston upright), has this been damaged even through the pin has no play? The holes are not as round as the other 2 x holes on the piston.
I cant upload pic.
03-30-2012 | 10:17 AM
#2379
Tech Master
Joined: Sep 2006
Posts: 1,919
BTW, some people have reported wrist pin looseness because of piston ovaling. Haven't seen it myself.
03-30-2012 | 12:43 PM
#2380
I have taken the piston out the motor, when I hold it up right and move the rod up/down, there is no movement of the wrist pin. There is movement of the rod left/right along the wrist pin, is this normal? Yes normal
I did notice though that the 2 x holes in which the wrist pin goes into is oval on the top and bottom (holding the piston upright), Is ok as long as the lottle G clips are still there has this been damaged even through the pin has no play? Is ok as long as still retainiong the little G clips The holes are not as round as the other 2 x holes on the piston.
I cant upload pic.
I did notice though that the 2 x holes in which the wrist pin goes into is oval on the top and bottom (holding the piston upright), Is ok as long as the lottle G clips are still there has this been damaged even through the pin has no play? Is ok as long as still retainiong the little G clips The holes are not as round as the other 2 x holes on the piston.
I cant upload pic.
03-30-2012 | 12:45 PM
#2381
03-30-2012 | 02:24 PM
#2382
Tech Elite
Joined: Nov 2007
Posts: 2,983
From: Auckland, New Zealand
I think that's probably it Flanno.
On the GXII-5RHO the wrist pin holes are slightly chamfered, which gives the impression of them being oval.
The actual seats for the G clips are perfectly round (as you would expect), but the edges have been chamfered slightly top to bottom - I am guessing as an aid to lubrication of the outer pin edges or something similar, not 100% sure.
I don't think RCNitro13 was talking about the GXII though from memory, and I am sure all previous models prior to the GXII were not chamfered.
On the GXII-5RHO the wrist pin holes are slightly chamfered, which gives the impression of them being oval.
The actual seats for the G clips are perfectly round (as you would expect), but the edges have been chamfered slightly top to bottom - I am guessing as an aid to lubrication of the outer pin edges or something similar, not 100% sure.
I don't think RCNitro13 was talking about the GXII though from memory, and I am sure all previous models prior to the GXII were not chamfered.
03-30-2012 | 02:58 PM
#2383
I think that's probably it Flanno.
On the GXII-5RHO the wrist pin holes are slightly chamfered, which gives the impression of them being oval.
The actual seats for the G clips are perfectly round (as you would expect), but the edges have been chamfered slightly top to bottom - I am guessing as an aid to lubrication of the outer pin edges or something similar, not 100% sure.
I don't think RCNitro13 was talking about the GXII though from memory, and I am sure all previous models prior to the GXII were not chamfered.
On the GXII-5RHO the wrist pin holes are slightly chamfered, which gives the impression of them being oval.
The actual seats for the G clips are perfectly round (as you would expect), but the edges have been chamfered slightly top to bottom - I am guessing as an aid to lubrication of the outer pin edges or something similar, not 100% sure.
I don't think RCNitro13 was talking about the GXII though from memory, and I am sure all previous models prior to the GXII were not chamfered.
I guess I'll just replace the front bearing (and the rear just to be sure) and take the advice of warming up and shutting down the motor and see how I go...
03-30-2012 | 04:28 PM
#2384
Tech Elite
Joined: Nov 2007
Posts: 2,983
From: Auckland, New Zealand
Replace the bearings and give it another go. The only other thing is possibly vibration from the clutch/flywheel etc that is toasting the front bearing ?
The fronts do go out from time to time due to dirt and dust being forced into the bearing through the flywheel cut out in the chassis, plus they do not like the shock loading from the starter box wheels (especially when cold). But having said that, they should last longer than yours have from what you have told us.
03-30-2012 | 10:21 PM
#2385
Tech Master
Joined: Jan 2006
Posts: 1,977
From: Sydney
The new model piston came out mid 2010 as it was a new cast from the factory.
In the new cast they improved
Concentricity of roundness pt dia
Gudgeon holding stays
Front lip angle and thickness
Piston top thickness
Gudgeon hole chmpfer is for ease of removing andnreplacing the g clips. When you put in new g clips you place the elbow of the clip into the groove and push inward. Then to check its seated you turn it back wit a bit of prssure from a flat blade.
Hope this info helps
Oh ps
Forgot the piston maerial alloy was changed to a about 10 higer silicone content. This aids in the malleability of the cast. Ie lessesns the chances of pistons cracking.
Cheers m
In the new cast they improved
Concentricity of roundness pt dia
Gudgeon holding stays
Front lip angle and thickness
Piston top thickness
Gudgeon hole chmpfer is for ease of removing andnreplacing the g clips. When you put in new g clips you place the elbow of the clip into the groove and push inward. Then to check its seated you turn it back wit a bit of prssure from a flat blade.
Hope this info helps
Oh ps
Forgot the piston maerial alloy was changed to a about 10 higer silicone content. This aids in the malleability of the cast. Ie lessesns the chances of pistons cracking.
Cheers m