rcguy1979

Hey Guys,

I have my Losi LST XXLup and running and completely broken in with 5 tanks throughherand noticed this thing shoots up in temp pretty damn fast on the Telemetry display after full break in. I have heard these 454 engines run alot hotter then the avg 220 degrees Farenheit and was wondering what is considered a good engine temp to maintain at?Mine seems to hang around 238 Degrees rolling and at idle will try and climb up even higher with noair rolling through the engine head. All my Trims are set at 0 and there is absolutely no binding taking place on any of the gears and the thing holds a idle like a champ. My needle setting is 3 3/4 turns out on my HSN which is rich 1 full turn fromfactory (2 3/4)and the lsn is still set at factory settings.After 5 tank burn in I have replaced theGlow plug with anew medium plug by HSI. The tempdefinitely has me worried a little, so some feedback would be awsome and wouldease my mind If I know this engine naturally runs warmer thennormal. Thanks!!

Mclovin350z

You might as well unhook the telemetry. Do you have a handheld temp guage?Anything 220-250 is fine. What fuel are you using?

rcguy1979

Yeah Im running between 238-242 on the Temp Gun and the Losi built in Telemetry reads about 10-15 degree's higher. Im running 20% Fuel right now but if she will run better on another percentage let me know. Also I here if you swap out the stock Exhaust with something better you getbetter powergains and it tends to run cooler. Going to check more into aftermarket Tuned Exhaust. Thanks for the feedback...

Mclovin350z

Before you spend the money on an exhaust you should try a fuel with less oil content. What brand fuel do you have?

CR500rider

You asked for good advice from a nitro veteran, so here it is..... Hook the telemetry back up and put the handhelp temp gun in your toolbox as a backup. Use engine temp as a GUIDE only. Tuning by temperature is retarded and will drive anyone crazy. As you drive the truck more the temps will come down, just because you have ran all the break-in tanks through it does not mean it is broke in yet. After about a gallon of fuel has run through it the engine will really start to wake up, it will run cooler, better, faster and harder!

Try tuning for power, NOT for temperature. I was going crazy when i got into nitro because everyone said to tune for about 200-220 degrees, well a lot of engines run like complete shiz at those temps! I learned to tune an engine by performance and i couldnt be happier. Some of my engines ran best at around the 270-280 mark., there was good smoke and no bogging so i knew everything was ok. All engines are a little bit different. All you have to do is make sure the engine leaves a nice smoke trail, will not bog going from idle to WOT, and will not lean bog on the top end. Sure there is a little more to it than that but this is the basics. If you really want to learn how to tune there are much better places to look than here on the noob forums.

1QwkSport2.5r

What many people dont realize with ABC engines is because the cylinder is tapered, the engine has to work harder to drive the piston to Top Dead Center. Because of this extra friction you have some extra heat. Like CR500rider said - it takes quite a bit of fuel to get the engine to be fully broke-in. As long as the mixture is slightly rich and you dont beat the ever loving tar out of it, it'll run-in and the temps will stabilize. Tuning by temp alone will wreck an ABC engine PERIOD. I have a SH .28 P6 in one of my LST2's and I dont even have a full gallon run through it yet and the hottest its gotten is 304*F. The engine was running fine and had no detonation. The Mach 427 in my other LST2 is at about the 1 gallon mark and temps out around 250-280. As far as I'm concerned, I won't worry about it until it hits 310*. On the contrary to some folks' belief, a richer mixture will result in lower engine temps.

Mclovin350z

310 are you nuts? No freakin way are any of my engines gonna be allowed to run that hot, especially a BB. I would compare the telemetry to the temp gun, my telemetry was off by about 10-15 degrees.Who believes that a richer mixture will run hotter?It seems pretty obvious that a richer mix will run cooler. My engines all hit max performance by no more than 270. BTW cr500 that is great advice, I've been using the temp guage as a too hot / too cool indicator for quite some time now,it's all they're good for.

rcguy1979

Thanks for the feedback and Im not a total noob with RC NItro. I am a noob with Losi Products that have Telemetry though,so I have to ask some questions so I dont tear **** up. Speaking of tear **** up the damn pullstart already screwing with me and not grabbing on right. Roto works fine so I guess I will fork out the loot in time for a new pullstart unless something just came loose within the mechanism somewhere. I guess I will see whats up once I get the damn thing off of the engine. Always something breaking it seems, but thats to be expected in this hobby.Fun Fun Fun......

Mclovin350z

It's the one way bearing inside the motor. Take off the pullstarter and pull out the starter shaft. Then use600 grit sandpaper to lightly scuff the shaft. Clean it and re-install, the owb will grab better and no harm done to anything.

rcguy1979

Yeah sounds like these pullstarts are a piece of crap on these things.. I will try what you said and hopefully I wont have to remove the whole engine to do so. Thanks for the info....

Mclovin350z

Mine's been good.....since I did that to it.I almost always use the roto. Unless it stalls when I'm out in the yard or something. Fortunately the 454 runs like a champ, IMO the best 'rtr' engine money can buy.

1QwkSport2.5r

yup, I'm nuts. I like it that way.

Mclovin350z

To each his own.....lol

1QwkSport2.5r

I have always gone on the premise that: if the engine sounds right, and there is enough oil and smoke coming from the exhaust, that it doesn't matter and to just run the darn thing. All this hub-bub about engine temps being super critical isn't as critical as it's made out to be. If the temp stays above the say- 280 threshold for a long period of time can be bad but small spikes aren't the end of the world. I'm not a preacher by any means, and not paranoid either.

CR500rider

That is exactly right. If it runs good then run it! Regardless of temps. Good smoke, good power, no boggs, you are good to go! 310 degrees? If 310 is where it runs good then why not? No reason to have a blubbery sluggish engine just because someone told you anything over 220 is destructive.

Mclovin350z

I'm just gladmy enginesalways run their best at about 230-270. I agree, if it's not getting hurt at 310 then run it, but 310 is excessive no matter what it is. You have absolutely no room for error at that temp. On some engines the fuel will boil in the carb at lower rpm's. Aluminum melts at 1220 f, so I guess it'll hold.....lol

rcguy1979

Got my Losi up to 46 MPH today on asphalt and was rock steady running like a champ 268 degree's. What's the top end suppose to be able to hit on this XXL? Im sitting pretty rich on my HSN approximately 3 turns out. Curious what you guys have your hsn set at and what kind of top speeds you all are hitting? Keep the good post coming... Ohh yeah can the Pull starter be replaced on this thing without removing the engine. Looks like the top 2 screws are no isssue to get out but the bottom ones look like a biotch to remove without having the motor lifted out some. Happybashing!!!!

1QwkSport2.5r

This has always been the opinion war in the nitro world. What so many "experts" dont realize is the metal needs to expand and since ABC engines are 3 different metals they all expand at different rates. The tighter engines absolutely need more heat than 220 to expand right. Those TRX 3.3's are one of the notorious ones with pistons getting stuck at TDC, etc. Get that thing of to 240-250 and it doesnt get stuck. I've had 3 3.3's and this is what I had to do to get it to quit sticking at TDC mid-tank. 220 wasnt hot enough.
Get the darn thing warm and go play for cryin out loud! <LOL>

Make no mistake - I dont like the idea of any engine getting that hot, but these chinese RTR engines run hot. They dont have insulated carbs so in most cases you have to run a richer mixture to get the fuel to not boil - something high end engines dont have a problem with. Up here in my neck of the woods, it gets hot in the summer and very humid and this type of weather undoubtedly will make your engine run hotter at optimum fuel mixture. If its running the way its supposed to aside from temp, I'll let 'er buck. As it is; 220 is the minimum temp which ABC engines need to run to have the cylinder expand properly. Any lower and you will wear it out sooner. When I broke my SH .28 P6 in, Running off the factory carb settings I couldnt get the engine to temp over 175 on the first tank. I had to lean it down enough to temp. (I had the head covered with a piece of a sock and a zip tie even.) It would not temp right. I only took it down enough to get it to

ntrain42

Using the stock "telemetry" temp sensor, the engine runs its best from about 250-290 degrees. Even at these higher temps the engine is still running a tad rich. I agree with a post above that if the engine hits around 300, its still nothing to worry about.