What is a good temp to run at

[USA1]

i finally got my truck tuned, amost... i just need to know whats a good temp to run at.. im thingking it should be around the low two hundreds... my problem was that i was runing super rich, wich is why it kept stalling, and after i killed it it woulnd start back up, simply cuz i kill it by blocking off air in the intake, wich makes it run even richer, and thus flooding the system... :D well just need to know what is a good temp to run my .21 ofna hyper...

[Mr-Tamiya]

probably min185 to 210max really depends on ambient air temp out side but a fluctuation between what i said is usually safe

[USA1]

thats kool my temp maxses out at 220F... good to know where i am just by pullin over. thanx.

[matt1049]

thats usually around the best temperature zone, my thunder tiger pro .21s seem to make the most power right around 240-245

small blocks like to run hotter, seems you have it solved for yourself though so im just babbling on here

[Balact Man]

my ofna hyper .21 engine is collecting DUST at the moment. i have 5 Ofna engines 3 new and 2 slightly used. i just never seem to get a good idle, temp, or run time with the 2 ofna engines i attemped to use. i love ofna products but not their powerplants. but to answer your question i think whenever i tried to run the hyper .21 it ran around 255-269 degrees.

[Kiiski]

A couple of things, first you don't want to tune for a specific temp, tune for power and keep an eye on temp. Don't let it get too high or too low, too high, 275 or so will cause the sleeve assembly to warp and you won't be getting enough lubrication and will damage the engine. Never let it run below 200 either, as the sleeve won't expand enough and will cause the piston to score it.
Kiiski

[Mr-Tamiya]

A couple of things, first you don't want to tune for a specific temp, tune for power and keep an eye on temp. Don't let it get too high or too low, too high, 275 or so will cause the sleeve assembly to warp and you won't be getting enough lubrication and will damage the engine. Never let it run below 200 either, as the sleeve won't expand enough and will cause the piston to score it.
KiiskiI dont agree with your under "200" theory, When breaking in an engine the proper way it barely cracks the 200 mark by a long shot, And it doesn't score the piston, as a matter of fact running that fat(rich) to get the temp down that low, there would be so much extra lubrication in the cylinder and block during the combustion process that it wouldnt allow such a thing, I have only ever seen scoring from excessive temperature, Never to low a temperature. And yes you can tune for all sorts of things, Temp, Performance, longevity, ect ect.... Thats why it takes so long to break in, because its so rich and well lubricated and low temp, and thats why they(manufacturers) want you to do it that way. thats enough engine theory for one day :D

[Kiiski]

In over 25 years of RC engine and car/truck design, manufacturing, research & development and racing, I have seen literally thousands of piston and sleeves destroyed by running too cool. Regardless of the amount of lubrication. When the sleeve doesn't expand properly, and due to the inequal strength of the sleeve because of the porting, the excess oil will simply be pushed to the "weak" areas of the sleeve and scoring will result in the still overly tight areas, this is a form of thermal distortion. The old theory of running an engine blubberingly rich to break it in is seriously outdated, in the old days of cast sleeves and even the early ABC designs, this was the correct way to break them in, often taking a gallon or more of fuel. In a modern ABC engine, the only "proper" way to break in an engine is with getting them quickly up to an operating temperature that allows equal thermal expansion, running at this temperature for a short period of time, then shutting it down and letting it cool completely. After running the engine through a series of heat cycles, the engine will be broken in, much quicker and with less damage than with the old ways. Look around at the high end (often Italian) manufacters to see what their break in recommendations are. In the not so distant future, carbon-carbon and carbon-composite assemblies will become available, allowing a very short break in (just a few minutes), very lightweight engines capable of 60,000+ RPM's.
Kiiski

[Mr-Tamiya]

In over 25 years of RC engine and car/truck design, manufacturing, research & development and racing, I have seen literally thousands of piston and sleeves destroyed by running too cool. Regardless of the amount of lubrication. When the sleeve doesn't expand properly, and due to the inequal strength of the sleeve because of the porting, the excess oil will simply be pushed to the "weak" areas of the sleeve and scoring will result in the still overly tight areas, this is a form of thermal distortion. The old theory of running an engine blubberingly rich to break it in is seriously outdated, in the old days of cast sleeves and even the early ABC designs, this was the correct way to break them in, often taking a gallon or more of fuel. In a modern ABC engine, the only "proper" way to break in an engine is with getting them quickly up to an operating temperature that allows equal thermal expansion, running at this temperature for a short period of time, then shutting it down and letting it cool completely. After running the engine through a series of heat cycles, the engine will be broken in, much quicker and with less damage than with the old ways. Look around at the high end (often Italian) manufacters to see what their break in recommendations are. In the not so distant future, carbon-carbon and carbon-composite assemblies will become available, allowing a very short break in (just a few minutes), very lightweight engines capable of 60,000+ RPM's.
KiiskiWhen you say research and development of RC engines/ and car and truck design, Who do you work for? Just curious, Even Traxxas still reccomends that break in procedure, i fly planes as well and run some italian motors in those and some nitro vehicles and non of them say break it in hot and fast, Nova Rossi, Super Tigre(i know they are made in China now) and the the like. i mena your theory sound decent but do you have factual proof? Like pictures of a "cold" Scoring.

[centermass]

There was an article in one of the nitro car magazines this last winter about running engines in cold weather. They measured the piston and sleeve cold and then heated it up. I dont recall the exact temps but I think one was below 200 and the other was above 200. They were able to show that the sleeve expansion was greater on the higher temp. The auther said that this was the reason that the engine would wear faster in cold weather conditions. I run my .21 at about 230-260 and it seems to have a ton of power. It is also a Works Racing L. Collari motor with a ton of HP.

[Mr-Tamiya]

I fully agree with the warmer temp the engine wil lrun a lot stronger, for one its running leaner to get the higher temp, lean engines are fast to apoint, but dont last long, i will have to look for that article because they/you are correct on one part, the sleeve distortion which is normal, thats basic thermo dynamics, just look at the space shuttle for example, the tiles that protect the shuttle have large gaps in them until re entry when temps climb to ridiculus levels, then they expand forming a prefect fit, So I dont disagree with your theory there, its just the part where you say its " old school " to break in an engine that way(when every RTR truck out there tells you to do it that way) and the fact that it causes friction damage in the cylinder.

[Kiiski]

When you say research and development of RC engines/ and car and truck design, Who do you work for? Just curious, Even Traxxas still reccomends that break in procedure, i fly planes as well and run some italian motors in those and some nitro vehicles and non of them say break it in hot and fast, Nova Rossi, Super Tigre(i know they are made in China now) and the the like. i mena your theory sound decent but do you have factual proof? Like pictures of a "cold" Scoring.

I work for whoever will pay me! :D I am an alloys stress/fatigue contractor specializing in tribology analysis (the technology concerned with interacting surfaces in relative motion, concentrating on lubrication, friction and wear) currently working for General Dynamics, and have worked for Team Associated, Team Losi, HPI, OS engines, Lamberto Collari, Rossi and Kyosho on the RC side and for Boeing, General Electric aircraft engines, Lockheed-Martin and Raytheon in the aerospace-military industry and Ford Motor Company, BMW and Volvo in the automotive industry (You asked! :D). I would be more than happy to dig up some photos for you, I might even have some PV and ultrasonic images. I also have access to considerable amounts of data that I, understandably, cannot share. Most manufacturers stick with the “run it rich” method of break in because it is safer for an RTR type of user who probably doesn’t even have a temp gun or loop type of monitor, and frankly, most people, especially beginners, don’t have access to the sensors and interfaces that the manufacturers and factory racers have, where you can have very accurate data on head, exhaust and intake temps, RPM’s and intake air volume and you certainly will damage an engine more quickly with excessive heat than running it too cool. You might want to check out Andrew Coholic’s article in the June 2005 issue of Fly RC magazine on ABC engine break in, keeping in mind his article stems on forced air wash engines with standard cooling heads, where temps at the plug should hit 300 deg during break in, whereas you should see 60 to 75 deg lower with a head that relies more on surface area than airflow.
Kiiski

[Mr-Tamiya]

Most manufacturers stick with the “run it rich” method of break in because it is safer for an RTR type of user thats what I was looking for! I am contracted to Raytheon myself as we speak, as well as a few other aerospace companies. Took you a few days I was wondering if you were going to respond, Very glad you did! ;)

[Kiiski]

thats what I was looking for! I am contracted to Raytheon myself as we speak, as well as a few other aerospace companies. Took you a few days I was wondering if you were going to respond, Very glad you did! ;)

If you do have the "tools" necessary, even a decent temp gun, it would be preferred to break in "hot" so to speak.
What are you contracted for? I have a contract with Raytheon starting in November, what campus are you at?
Kiiski

[Mr-Tamiya]

If you do have the "tools" necessary, even a decent temp gun, it would be preferred to break in "hot" so to speak.
What are you contracted for? I have a contract with Raytheon starting in November, what campus are you at?
KiiskiI am an Inventory control analyst, I am in Cleveland, I try and keep my contracts local, I also work PT at Hobbytown USA here when i have time. Prior to The analyst job, I was in the Automotive field for 15 years. And Steady Hobbyist for 25yrs.

[Kiiski]

Did you go to the ROAR nationals in Toledo last year? What a great track! A ton of great drivers. I was very happy with myself being in the "D" main!
Kiiski

[Mr-Tamiya]

No I went to The ROAR carpet Nats in Cleveland though! I am not a big nitro guy! I am an electric racer!

[KasperE]

Kiiski,

Your desckription of break-in is indeed very interesting. Could you, in a bit more detail, outline the break-in procedure. Im in denmark and I dont have access to the mentioned issue of Fly RC (checked the libraries)?