Hello all this is my first post and I have a few years experience with nitro. now I just started using a temp gun on this O.S. Now I realize that the temp method is just a guidline but my question is where exactly should the reading be taken from? I have herd 2 ways and they are at the plug and on the side of the motor about half way up the cooling portion of the head. Here is my problem or not.. Once the motor is warmed up to where I can make a couple of good high speed passes and I pull it in the plug reads like 300 and the side of the head reads like 260. Now if I try to tune the motor so it reads 250-270 at the plug it just wont run right. Way to rich and it wont even shift into second gear. Oh by the way the motor that I speak of is in a Revo. So what I am thinking that the correct place to read the temp is on the side? Anyone?.. Thanks..
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O.S. 21 Max VG Temps.
- Thread starter Farbzilla
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Turn your HSN back to where it runs good, and start to richen the LSN. If that's too lean, nothing you do to the HSN will bring the temps down.
Oasis TR
RCTalk Basher
I'm not sure on the "chosen" method but I have always aimed at the plug..250 to 300 seems high..but It's your temp gun and not mine (meaning that they read differently) I have always been told to use temp as a reference and not tune by it..With that said, I go by how it feels and the smoke out of the pipe, I try to run a bit on the rich side..Like I was saying I would go by how it feels on the track and the smoke..use temp as a reference and not to tune by..
- Thread starter
- #4
No I know that. I know how to tune a motor but thanks. i really want to know where is the correct place to take a temp reading..
Actually 250 is not high. as far as my temp gun goes its dead on because i test it with boiling water. And I also stated that i know that the temp thing is just a guidline. But thanks though..
I know 4 or five people that run O.S. motors in their trucks and all of them seem to run beat at around 240-260..
bnrpat09
RCTalk Qualifier
ya 300 is definately high, like rolex said tune your low speed needle rich, and runs your high speed needle where it gets enough power for you...
and aim it at the plug and make sure you are reading in fahrenheit not celcius because that woulkd be a first for reading high temps!
and aim it at the plug and make sure you are reading in fahrenheit not celcius because that woulkd be a first for reading high temps!
Oasis TR
RCTalk Basher
Did not mean to offend..By the temp gun I meant more My temp gun may not be the same as Yours..And the preferred method is aim at the glow plug..But since it's just a reference point why would it really matter where you aimed it at..More of a question than a smart azz remark..:LoL:
- Thread starter
- #7
You temp. it at the plug.
BOUTCH
Hardcore RCTalk User
Directly at the plug...the temps reading
I'm surprised it's running that hot. What fuel/GP are you running? High/low gearing? Balls out on pavement or general off-road bashing?
In a revo, a 21 (especially that 21) should be running at or below 250F all day long. I've never had an OS that ran (or liked to run) about 250F for very long before it got weird on me. Most liked to run around 220-240 during heavy off road bashing in grass. All in the following bashers: t-maxx 21, t-maxx, revo, savage, 1/8 buggy and aftershock (doesn't really count since it was winter
).
I temp mine beside the plug as best as I can down in the head through the top. OS 15 CV-R, OS 18 CV-R, OS 18TM, 3 OS21RG's. All ran great between 220-250 all day long running 20-25% nitro with a hot plug in the SB's and a OS 8 in the RG.
When their temps climbed much higher than that, I had a bearing dragging (or some sort of drag) or the pinch was getting to weak and causing flameouts.
In a revo, a 21 (especially that 21) should be running at or below 250F all day long. I've never had an OS that ran (or liked to run) about 250F for very long before it got weird on me. Most liked to run around 220-240 during heavy off road bashing in grass. All in the following bashers: t-maxx 21, t-maxx, revo, savage, 1/8 buggy and aftershock (doesn't really count since it was winter
).I temp mine beside the plug as best as I can down in the head through the top. OS 15 CV-R, OS 18 CV-R, OS 18TM, 3 OS21RG's. All ran great between 220-250 all day long running 20-25% nitro with a hot plug in the SB's and a OS 8 in the RG.
When their temps climbed much higher than that, I had a bearing dragging (or some sort of drag) or the pinch was getting to weak and causing flameouts.
- Thread starter
- #12
Yeah if i take the temp from the side about as high as the plug I get around 250. But if point it down the center of the head into the plug it reads 290-300. So thats what I was sayin b4 is it down the center of the head of on the side level with the plug? With the temp taken at the side like I said it reads like 250 and it runs fine no sputtering breaking up or anything? Thought i got my question answered until olds97 chimed in and said that he temps his motor like me. I am just gonna just start from the beginning with tuning and tune LSN a bit rich then HSN and however it runs best than so be it. Temps or no temps... We will see..
Oasis TR
RCTalk Basher
On the point it at the plug..I have always been told that it's the hottest point on the motor..
I have one engine that's really easy to tell where the "hot spot" is. It's a new OS21RG with a really open head.
Old Head with little room around the plug:
http://home.comcast.net/~98gmarquee/pics/misc/2008-0407-OS21RGHeadOld.jpg
New Head with lots of room to find the hot spot:
http://home.comcast.net/~98gmarquee/pics/misc/2008-0407-OS21RGHeadNew.jpg
The best I could tell is that the engine was hottest right near the glow plug over the exhaust port with the newer head. It would be a ~10 degree difference vs the other side and possibly 15-20 degree difference compared to the side of the crank case.
So now I do my best to take the temp by the glow plug with my temp gun angled toward the exhaust port on all engines as a base. If you have a temp gun that has the sensor out on a tip (kind of like mine), it allows you to rotate it around the glow plug area and find the hottest spot anyway. It was just easiest to see the difference on that open bowl head.
Old Head with little room around the plug:
http://home.comcast.net/~98gmarquee/pics/misc/2008-0407-OS21RGHeadOld.jpg
New Head with lots of room to find the hot spot:
http://home.comcast.net/~98gmarquee/pics/misc/2008-0407-OS21RGHeadNew.jpg
The best I could tell is that the engine was hottest right near the glow plug over the exhaust port with the newer head. It would be a ~10 degree difference vs the other side and possibly 15-20 degree difference compared to the side of the crank case.
So now I do my best to take the temp by the glow plug with my temp gun angled toward the exhaust port on all engines as a base. If you have a temp gun that has the sensor out on a tip (kind of like mine), it allows you to rotate it around the glow plug area and find the hottest spot anyway. It was just easiest to see the difference on that open bowl head.