Losi XXL question

[Greywolf74]

So I have upgraded my LST 2 into an XXL and bought the stock 454 engine for it because I really liked my Mach .26 that I had on my lST2. I'm trying to break it in using Squirrels method (if you dont know squirl he runs an RC forum and posts alot of how-to and review vids on youtube) and he says to keep the engine temp between 195 and 205 when breaking in a new engine. Heres my problem. The damn thing wants to run hot as a fire cracker. I had tons of smoke, and kept increasing the richness of the model until it wouldnt run anymore, and the damn thing still climbed up to 280 degrees. I just dont get it. I started at stock needle settings and I did the first tank idling at about 202F. On the next tank when I am doing 1/4 throttle bursts for 2-3 seconds thats when the engine temps just kept climbing. I kept making it more and more rich but still the temps climbed. I finally made it so rich it wouldnt run anymore. I had plumes of smoke billowing out from underneath the thing. ummmmmm HELP? lol

 

[Chucksolo69]

Are you sure your drive train isn't binding somewhere. Is your clutch bell gear mesh to tight. If you have good airflow to the engine I would definately start with a binding drivetrain. Have you checked the airfilter?

 

[srusinek]

You might have an air leak

You might want to invest in some rtv sealant and some green slime. Before you do that take the carb out and re seat it in the block. Then remove the backplate carefully and check the back plate for looseness. My mgt 8.0 was running out of line and I sealed mine. While taking off the backplate the screws were loose and that's where my problem was. I have not ran my MGT yet but when I do I'll post here with an update.

 

[Racer 1966]

Two things to try, first is to seal the engine. An air leak can definitely cause your problem. Second would be fuel/plug combination.

 

[Greywolf74]

Two things to try, first is to seal the engine. An air leak can definitely cause your problem. Second would be fuel/plug combination.

I should have pointed out that prior to break in went through Squirrels guide to sealing an engine on youtube and i checked the gas tank for air leaks as well as replacing all the fuel line. so I dont think its that. when I upgraded my LST2 I put a brand new XXL transmission in it so I dont think its anything binding in the drive train. Gear mesh should be fine its fairly snug but there is the tiniest amount of play in it. I've done the paper test and it crinkles the paper pretty heavily but doesn't tear it so I think thats ok as well...slipper is set at factory setting, 1 turn out. the second gear setting is set at factory which is 5 turns out...

My carb had about 1 or 2mm gap and I richened the LSN so the engine would idle what i thought was a good rpm level and it idled at 202F. Once I started running it however thats when I had the problem. I kept richening the HSN in about 1/4 turn increments until the thing just died so not wanting to risk damaging the engine I packed it up for the day so I could come home and ask some questions.

I have read alot on the internet that alot of people have had problems with the 454 running extremely hot and most people that I've seen say that the engine is a POS. Anyone actually have one of these engines and what was your expierence with it?

Oh I almost forgot I'm using sidewinder fuel...20% nitro 12% oil. How much of the oil content is castor IDK. doesn't really say on the bottle it just says "racing blend" for whatever thats worth. I bought it because it was the one of the cheaper ones but it seems to do just fine in my rustler.

Also i didnt even have the body on it so airflow wasn't the problem. It was very hot and humid out yesterday so I'm sure that didnt help but I dont think that would be the issue.

Getting back to the drive train though... it made me think of something. when I just try and roll the XXL back in forth the drive train is engaged and you can hear the gears all moving in it but when I do the same thing to my Rustler is rolls freely back and forth...When my XXL was an LST2 I can't remember if it rolled freely or not. Does that sound like an indication of soemthing?

 

[2revo1maxx]

Make sure you have a good medium plug in there. Plugs won't really help the temperature, but they can improve performance and idling. I use O'donnell #99 plugs in my 454 and they work great.
As for the temp issue I think my 454 likes a smaller than 1mm idle gap, and it seems like your problem is on the low end needle and/or idle. I would also try to confirm that it really is running 280 by using a different temp guage or at least the spit test. If you're using the dx3s telemetry temp reading then forget it, those are rarely ever accurate.

 

[Greywolf74]

Make sure you have a good medium plug in there. Plugs won't really help the temperature, but they can improve performance and idling. I use O'donnell #99 plugs in my 454 and they work great.
As for the temp issue I think my 454 likes a smaller than 1mm idle gap, and it seems like your problem is on the low end needle and/or idle. I would also try to confirm that it really is running 280 by using a different temp guage or at least the spit test. If you're using the dx3s telemetry temp reading then forget it, those are rarely ever accurate.

I dont have the telemetry rig. Thats one aspect of my LST2 I didnt upgrade into the XXL. I took the temp with a temp gun and I'm fairly certain it was accurate because you could just feel the heat radiating off that thing....it was hot as hell so i dont really doubt my temp gun. If it happens next time I can try to spit test ( didnt really think of it at the time) but hopefully I can get this thing figured out so it doesn't happen again.

I will try making the idle gap smaller and adjusting the LSN to compinsate and see if I see an improvment. could very well be my problem was on the low end.