GRP .28 Issue
05-05-2008, 09:19 AM
#1
Member
Thread Starter
Join Date: May 2007
Location: San Diego,
CA
Posts: 49
Likes: 0
Received 0 Likes
on
0 Posts
GRP .28 Issue
I've got approximately 8 tanks heat cycled through my GRP .28. I've been breaking it down every couple of tanks to make sure everything is wearing well (which it was). So this weekend I decided to take it out for it's first bit of track time. I'm running Nitrotane 30% using an OS P-3 plug with my head shimmed at .5. I chased a tune for the first part of the morning, but I believe it was because the outside temp was rising so fast. The outside temp stabilized around noon at about 90 degrees and I was able to finally get a proper tune. The engine was consistently temping between 185 and 195, which is consistent to what I've heard this engine runs at.
Good news first: The power delivery for a .28 is as smooth as it gets! It wasn’t overpowering and I didn't feel like it would get away from me as I opened her up. I was definitely happy with the power delivery and this is my first .28
Bad news: Take a look at the pics showing both sides of the piston. I broke it down this morning to see how everything looked and this is what I found on the exhaust port side of the piston. The cylinder is showing wear in the exact same place but I can't get a good pic of that area.
Not sure what my warranty options are here, but I hope I'm able to get the piston and cylinder replaced. It had to happen at the track this weekend because I had it taken apart Friday night and everything looked great. Could using to hot of a plug (P-3) have caused this?
Any ideas or opinions on what could have caused this would definitely be appreciated.
05-05-2008, 09:22 AM
#2
Senior Member
RE: GRP .28 Issue
that damage is likely from leaning down the motor before it was ready...that piston is scuffed, which is usually from someone rushing the motor and leaning it down while its still too tight... Or revving the engine too much while its still tight...that damage is from lack of lubrication........ GRP may warranty it, but to me it looks like user error, rushing break in and beating on a motor too early !!!
05-05-2008, 11:13 AM
#3
Member
Thread Starter
Join Date: May 2007
Location: San Diego,
CA
Posts: 49
Likes: 0
Received 0 Likes
on
0 Posts
RE: GRP .28 Issue
ORIGINAL: supertib
that damage is likely from leaning down the motor before it was ready...that piston is scuffed, which is usually from someone rushing the motor and leaning it down while its still too tight... Or revving the engine too much while its still tight...that damage is from lack of lubrication........ GRP may warranty it, but to me it looks like user error, rushing break in and beating on a motor too early !!!
that damage is likely from leaning down the motor before it was ready...that piston is scuffed, which is usually from someone rushing the motor and leaning it down while its still too tight... Or revving the engine too much while its still tight...that damage is from lack of lubrication........ GRP may warranty it, but to me it looks like user error, rushing break in and beating on a motor too early !!!
I imagine you’re correct. I felt that 8 tanks heat cycled was enough. I broke this mill in the exact same way as my JPX .21 which is still flawless inside after 2 gallons. It’s a costly error on my part.
05-06-2008, 12:20 AM
#4
Senior Member
Join Date: Jul 2005
Location: Torchy the Fiery Fast RC Turtl
Posts: 10,544
Likes: 0
Received 0 Likes
on
0 Posts
RE: GRP .28 Issue
The U-shaped divots on the piston, that is the exhaust side. It looks like the tip of the piston lip caught the middle of the wiade exhaust port. This means you sleeve might have suffered similar damage just above the middle of your exhaust port as well. Unfortunately, you will have to acquire a new piston & sleeve at the very least. Maybe GRP will waranty it, maybe they will not. But GRP, being a Rossi engine, just might cut you a break in effort to maintain a good customer service reputaion. So asking will not hurt.
As for breaking in any engine, to releave that dreaded pinch, did you preheat your engine to as close to 200degrees F before you tied to start if for the first time? Most engine stresses come from starting them cold. And staring a brand new engine without heating it puts tremendous stresses on the innards. Even though most engine manuals do not ven mention preheating, it is a very important step to take on any engine, especially a $300 Rossi engine. (I do not mean to sound like a broken record by saying the "always preheat a brand new engine," but unfortunately, most engine makers do not even tell their customers to preheat their brand new engines before even trying to start them.)
As for breaking in any engine, to releave that dreaded pinch, did you preheat your engine to as close to 200degrees F before you tied to start if for the first time? Most engine stresses come from starting them cold. And staring a brand new engine without heating it puts tremendous stresses on the innards. Even though most engine manuals do not ven mention preheating, it is a very important step to take on any engine, especially a $300 Rossi engine. (I do not mean to sound like a broken record by saying the "always preheat a brand new engine," but unfortunately, most engine makers do not even tell their customers to preheat their brand new engines before even trying to start them.)
05-06-2008, 09:25 AM
#5
Member
Thread Starter
Join Date: May 2007
Location: San Diego,
CA
Posts: 49
Likes: 0
Received 0 Likes
on
0 Posts
RE: GRP .28 Issue
ORIGINAL: SAVAGEJIM
The U-shaped divots on the piston, that is the exhaust side. It looks like the tip of the piston lip caught the middle of the wiade exhaust port. This means you sleeve might have suffered similar damage just above the middle of your exhaust port as well. Unfortunately, you will have to acquire a new piston & sleeve at the very least. Maybe GRP will waranty it, maybe they will not. But GRP, being a Rossi engine, just might cut you a break in effort to maintain a good customer service reputaion. So asking will not hurt.
As for breaking in any engine, to releave that dreaded pinch, did you preheat your engine to as close to 200degrees F before you tied to start if for the first time? Most engine stresses come from starting them cold. And staring a brand new engine without heating it puts tremendous stresses on the innards. Even though most engine manuals do not ven mention preheating, it is a very important step to take on any engine, especially a $300 Rossi engine. (I do not mean to sound like a broken record by saying the "always preheat a brand new engine," but unfortunately, most engine makers do not even tell their customers to preheat their brand new engines before even trying to start them.)
The U-shaped divots on the piston, that is the exhaust side. It looks like the tip of the piston lip caught the middle of the wiade exhaust port. This means you sleeve might have suffered similar damage just above the middle of your exhaust port as well. Unfortunately, you will have to acquire a new piston & sleeve at the very least. Maybe GRP will waranty it, maybe they will not. But GRP, being a Rossi engine, just might cut you a break in effort to maintain a good customer service reputaion. So asking will not hurt.
As for breaking in any engine, to releave that dreaded pinch, did you preheat your engine to as close to 200degrees F before you tied to start if for the first time? Most engine stresses come from starting them cold. And staring a brand new engine without heating it puts tremendous stresses on the innards. Even though most engine manuals do not ven mention preheating, it is a very important step to take on any engine, especially a $300 Rossi engine. (I do not mean to sound like a broken record by saying the "always preheat a brand new engine," but unfortunately, most engine makers do not even tell their customers to preheat their brand new engines before even trying to start them.)
05-06-2008, 10:29 AM
#6
Senior Member
RE: GRP .28 Issue
ORIGINAL: strngdze
That's the weird thing about this whole situation, I did pre-heat the engine during my 8 tanks of heat cycling. After every (2) tanks I would break down the engine and inspect everything. The piston and sleeve were wearing fine and everything else looked great. I had the engine apart Friday night and same thing, everything looked great. The one thing I did change on Friday night before this happened on Saturday at the track was change the stock #6 plug to an OS #3. I really never felt like I was running into a dangerously lean situation while tunning on Saturday. My temps were consistent at around 185/190, which might seem low, but these are the temps I hear most people are getting from this engine.
ORIGINAL: SAVAGEJIM
The U-shaped divots on the piston, that is the exhaust side. It looks like the tip of the piston lip caught the middle of the wiade exhaust port. This means you sleeve might have suffered similar damage just above the middle of your exhaust port as well. Unfortunately, you will have to acquire a new piston & sleeve at the very least. Maybe GRP will waranty it, maybe they will not. But GRP, being a Rossi engine, just might cut you a break in effort to maintain a good customer service reputaion. So asking will not hurt.
As for breaking in any engine, to releave that dreaded pinch, did you preheat your engine to as close to 200degrees F before you tied to start if for the first time? Most engine stresses come from starting them cold. And staring a brand new engine without heating it puts tremendous stresses on the innards. Even though most engine manuals do not ven mention preheating, it is a very important step to take on any engine, especially a $300 Rossi engine. (I do not mean to sound like a broken record by saying the "always preheat a brand new engine," but unfortunately, most engine makers do not even tell their customers to preheat their brand new engines before even trying to start them.)
The U-shaped divots on the piston, that is the exhaust side. It looks like the tip of the piston lip caught the middle of the wiade exhaust port. This means you sleeve might have suffered similar damage just above the middle of your exhaust port as well. Unfortunately, you will have to acquire a new piston & sleeve at the very least. Maybe GRP will waranty it, maybe they will not. But GRP, being a Rossi engine, just might cut you a break in effort to maintain a good customer service reputaion. So asking will not hurt.
As for breaking in any engine, to releave that dreaded pinch, did you preheat your engine to as close to 200degrees F before you tied to start if for the first time? Most engine stresses come from starting them cold. And staring a brand new engine without heating it puts tremendous stresses on the innards. Even though most engine manuals do not ven mention preheating, it is a very important step to take on any engine, especially a $300 Rossi engine. (I do not mean to sound like a broken record by saying the "always preheat a brand new engine," but unfortunately, most engine makers do not even tell their customers to preheat their brand new engines before even trying to start them.)
what brand of temp gun do you uses... and I pray you didnt just idle the motor for heat cycling..
05-06-2008, 01:45 PM
#7
Member
Thread Starter
Join Date: May 2007
Location: San Diego,
CA
Posts: 49
Likes: 0
Received 0 Likes
on
0 Posts
RE: GRP .28 Issue
ORIGINAL: supertib
what brand of temp gun do you uses... and I pray you didnt just idle the motor for heat cycling..
ORIGINAL: strngdze
That's the weird thing about this whole situation, I did pre-heat the engine during my 8 tanks of heat cycling. After every (2) tanks I would break down the engine and inspect everything. The piston and sleeve were wearing fine and everything else looked great. I had the engine apart Friday night and same thing, everything looked great. The one thing I did change on Friday night before this happened on Saturday at the track was change the stock #6 plug to an OS #3. I really never felt like I was running into a dangerously lean situation while tunning on Saturday. My temps were consistent at around 185/190, which might seem low, but these are the temps I hear most people are getting from this engine.
ORIGINAL: SAVAGEJIM
The U-shaped divots on the piston, that is the exhaust side. It looks like the tip of the piston lip caught the middle of the wiade exhaust port. This means you sleeve might have suffered similar damage just above the middle of your exhaust port as well. Unfortunately, you will have to acquire a new piston & sleeve at the very least. Maybe GRP will waranty it, maybe they will not. But GRP, being a Rossi engine, just might cut you a break in effort to maintain a good customer service reputaion. So asking will not hurt.
As for breaking in any engine, to releave that dreaded pinch, did you preheat your engine to as close to 200degrees F before you tied to start if for the first time? Most engine stresses come from starting them cold. And staring a brand new engine without heating it puts tremendous stresses on the innards. Even though most engine manuals do not ven mention preheating, it is a very important step to take on any engine, especially a $300 Rossi engine. (I do not mean to sound like a broken record by saying the "always preheat a brand new engine," but unfortunately, most engine makers do not even tell their customers to preheat their brand new engines before even trying to start them.)
The U-shaped divots on the piston, that is the exhaust side. It looks like the tip of the piston lip caught the middle of the wiade exhaust port. This means you sleeve might have suffered similar damage just above the middle of your exhaust port as well. Unfortunately, you will have to acquire a new piston & sleeve at the very least. Maybe GRP will waranty it, maybe they will not. But GRP, being a Rossi engine, just might cut you a break in effort to maintain a good customer service reputaion. So asking will not hurt.
As for breaking in any engine, to releave that dreaded pinch, did you preheat your engine to as close to 200degrees F before you tied to start if for the first time? Most engine stresses come from starting them cold. And staring a brand new engine without heating it puts tremendous stresses on the innards. Even though most engine manuals do not ven mention preheating, it is a very important step to take on any engine, especially a $300 Rossi engine. (I do not mean to sound like a broken record by saying the "always preheat a brand new engine," but unfortunately, most engine makers do not even tell their customers to preheat their brand new engines before even trying to start them.)
what brand of temp gun do you uses... and I pray you didnt just idle the motor for heat cycling..
No, I did not just let it idle. I was warming it up on the bench and figure 8's in a lot. It was defiantly difficult to get up to temp so I had to wrap the cooling head with some foil and a sock on top of that. My HPI Temp gun is accurate, I
gauge it of the thermostat in my home it's usually off by only +/- 1 degree.
05-25-2008, 04:20 PM
#9
Member
Thread Starter
Join Date: May 2007
Location: San Diego,
CA
Posts: 49
Likes: 0
Received 0 Likes
on
0 Posts
RE: GRP .28 Issue
I think the general consensus is that there really isn’t a “Standard” factory needle setting on these motors. Mike Truhe over at neo buggy said that each engine he has received has had different factory settings.
I got my GRP .28 with the following settings:
4 turns out on the HSN
4.5 turns out on the LSN
I got my GRP .28 with the following settings:
4 turns out on the HSN
4.5 turns out on the LSN
05-26-2008, 09:47 PM
#10
Senior Member
Join Date: Apr 2007
Location: richmond, VA
Posts: 1,053
Likes: 0
Received 0 Likes
on
0 Posts
RE: GRP .28 Issue
man that suxs! i have a new osspeed on the way next week and im gonna take my time driving it gettin up to temp the richining it back up to cool it then lean back out to raise temps again then repeat like that while driving it around for a few tanks then cu t off let cool at bdc then do it all again for about 2/3's of a gallon
