• Welcome to RCTalk! 🚀

    Join the #1 RC community where hobbyists connect, share, and get expert advice on RC cars, trucks, boats, drones, and more!

    • ✓ Friendly & passionate RC enthusiasts
    • ✓ RC tips & troubleshooting
    • ✓ Buy, sell & trade RC gear
    • ✓ Share builds & upgrades

Worn out Engine?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
N

NC Tmaxx

RC Newbie
Messages
7
Reaction score
0
Points
0
RC Driving Style
I’ve got a tmaxx I bought used, it runs good until it gets up to about 230 degrees then it dies. It will not crank back up until it cools down then its ready to go. Is this a sign of a worn out engine? I've sealed the back plate and checked for air leaks around the carb and tank. When I had the back plate off I did notice that who ever had this truck didn’t take good care of it, it had signs of rust in the crank case.

I'm new to the nitro engines and so far this site has been a wealth of information.

Thanks!
 
Hard to say if it is tuned wrong or worn out. A compression gauge will tell you, also taking the piston/sleeve out to see if the top of the piston come out of the sleeve. I would just "feel" for compression by turning it over by hand when it is cold. If you feel you have good compression then I would suggest setting the engine back to factory and tunning. The rust is what happens if you do not use After Run Oil. The little bit of fuel left in the engine attracks moisture and viola! rust..........

btw welcome to the board, and they have helped me a ton too. :cheers:
 
I had the same problem. I was just runnin' a little rich on the high-end. I got tired of tunning it casue my 2.5 wouldnt hold a tune for a week so i just got a new engine...
 
Normally, you can test compression by turning the flywheel over with your finger. If you can turn it over with your finger with the glowplug in while the engine is cold, it's time for a new piston/sleeve.
 
olds97_lss said:
Normally, you can test compression by turning the flywheel over with your finger. If you can turn it over with your finger with the glowplug in while the engine is cold, it's time for a new piston/sleeve.
Click to expand...

Really? I thought that i had good compression since it was hard to turn it over.
 
Why does everyone buy a Maxx, then get rid of the engine?? Is the 2.5 that much of a crappy motor?? Why wouldn't you just buy a different truck that has the motor you rather have, instead of spending $400 on a Maxx, then at least another $250 on a new motor??
 
rust in the crankcase? that shouldnt be there. more than likely ur tuning just needs to be messed with a little.

diavolos- people buy maxx's cause they can, and they are a good truck. as for the 2.5 they arent as great. i have never had a good 2.5 and prolly never will. and for $250 u can buy almost any engine for these things, except for RB concepts

bryan
 
I dont know. my 2.5 is great I can pull wheeles and have hit a average speed of 37 mph I agree with you I dont see why people put down $300 for a new engine. becaues if u race most tracks are not big enough so u can hit top speed but if your a back yard basher your not worried about top speed all u whant to do is jump and have fun.I think most people buy a new engine just to say I spent $300 on a new engine. And to be fair I know their are a few people who like to see how fast they go and thats fine but it seems that most peolpe are BYB
 
SuperMaxx97 said:
and for $250 u can buy almost any engine for these things, except for RB concepts

bryan
Click to expand...

You can fit a RB in one with an .21 concersion. There is a company making pull start conversion kits for a lot of sweet engines, and the RB's are included. I will look for the link. And of COURSE the rust shouldn't be there, but it is do to lack of engine maintenance by the previous owner.
 
Thanks for the replies. Before I label this one dead I’m gonna try a few more things. I took the hsn out and got some trash out of there. As far as how much compression it has, it turns over by hand with little effort. I’ll try some more this weekend, take the head off and such. Shorter days are cutting into by playtime minutes. :cheers:

If I need to replace this engine what would be a good choice within the same price range as the stock 2.5. I just can’t put a lot of cash into something that when it’s running I’m just trying to break it. :hammer:
 
Endless said:
Really? I thought that i had good compression since it was hard to turn it over.
Click to expand...
That IS good compression.

There's not a 2.5 at the local track that I haven't been asked to tune. They get a little pesky after the break in period, but then seem to level out. My ONLY suggestion for anyone with this engine is to get a good after market cooling head. I run the ACNCM head on mine.
The stock head is pitiful, and when the engine is tuned to run good, it gets too hot and quits.
With a good head on it, and proper tuning, it's proved to me to be a solid good running engine.

By the way, if you have lost a lot of compression, look up osrocket on Ebay. He'll pinch your sleeve for about $20. Like new.
 
So, if the Maxx 2.5 isn't getting around the 240-250 degree mark when warmed up, it's running lean?? I'm still learning to tune mine on my own, but it's running good from idle to a wot, at wot, good amount of smoke, about a 2-3 second delay on the pinch test, but the temp is only getting to about 200 when fully warmed up. I only leaned the hsn about a 1/4 turn from factory setting, after that it runs crappy at wot. I also have the lsn at 1 1/2 out from closed. I think I'm just making this more difficult than it really is, but it's easier to tune my damn Harley than this thing!!
 

RC Builds

Back
Top