• 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

seized 3.3 after 1 gallon?

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
rak12

rak12

RCTalk Addict
Supporter
Messages
514
Reaction score
0
Points
601
Location
North Texas DFW
RC Driving Style
  1. Bashing
as the title says my tmaxx 4908 with the 3.3 seized mid run after about 30 minutes moderate running. I put about 1 gallon thru it so far. Noiw on some other sites I've found similar stories after about 1 gallon. I've done the break in accorinding to traxxas guidelines. my question is this: is this not that uncommon for the 3.3? I trust and put more faith in the members here than other websites hence why I joined here and not there. My goal is build up some knowledge of this senario before hitting up the traxxas warranty dept begging and pleading!

I forgot to mention, I have tuned it within spec, maybe even a little on the rich side for safety, my head temps are around 190-200 using a temp gun. during the last run, no major tuning changes were neccessary.
 
You should see a doctor for those head temps.....JK it probably spun the crank bearings. I haven't been able to keep a set of them together on my worn out 3.3's.
 
Running rich probably caused premature wear on everything. Every engine has to be kept in it's own sweet spot. Running rich is as bad as running lean.
 
Oh no! that unfortunately is not good news for me. I suppose we sometimes have to learn the hard way. Well maybe if Traxxas is feeling generous they will help me out, If not I'll be exercising their exchange program. Thank you for the help and advice. Also what is the typical operating temps for the 3.3?
 
Every engine is different,i have two and 1 runs real good at 260, the new one likes 270-280.
also it might be cheaper to rebuild it.
 
Last edited:
Did you pull it apart to see why it seized? Did it seize while running? Or did it become seized when you tried to start it between runs?

Ezstart or pull-start?
 
Well I tore down down the engine and the con rod is split in half from the wrist pin down to the crankshaft connection., the piston is also chipped along its lower edge. When I first had the troubles mid run, it "stalled" and I attempted to restart. It would not turn over giving me the impression it was seized. I removed the glow plug and saw metal chips sitting on the piston. I knew I had major problems So i packed up and went home. I then tore down the engine and found the damaged con rod and piston. After teardown it became apparent that the con rod was just jammed into the bottom of the piston giving me the impression it was seized. the sleeve looks good no gouging or scratching. I called traxxas and described the damage, told them it was 1 month old with only a gallon thru it. They responded send them the engine with a copy of the receipt showing its 1 month old. I felt comfortable after talking with them. Its an EZ start
 
Don't break the new one in so cold. You want to be getting near 200 and above to 220 or so by the time you get to tank 4-5. You may need to lean it a bit once you get into tank 2 to get the temps up. Don't go nuts, but really by 4-5, you should be able to tune it lean enough to hit 220-240 without much hassle.

Breaking in at a lower temp causes too much fuel to sit in the combustion chamber, liquid doesn't compress. With the pinch tight when new, that already puts a heavy load on the con-rod.
 
rak12 said:
Well I tore down down the engine and the con rod is split in half from the wrist pin down to the crankshaft connection., the piston is also chipped along its lower edge. When I first had the troubles mid run, it "stalled" and I attempted to restart. It would not turn over giving me the impression it was seized. I removed the glow plug and saw metal chips sitting on the piston. I knew I had major problems So i packed up and went home. I then tore down the engine and found the damaged con rod and piston. After teardown it became apparent that the con rod was just jammed into the bottom of the piston giving me the impression it was seized. the sleeve looks good no gouging or scratching. I called traxxas and described the damage, told them it was 1 month old with only a gallon thru it. They responded send them the engine with a copy of the receipt showing its 1 month old. I felt comfortable after talking with them. Its an EZ start
Click to expand...

Same thing with mine (T Maxx 4908) Had it for 2 months and had 1 and 1/2 gallons run in it, they told me to send it in so it will be off this week. I have heard great thing about there service, so who knows if they fix then I'll have a spare. Good luck
 
I dropped mine off at traxxas 2 days ago and waiting for an answer. They said it will about a week. I having extreme difficulty waiting. This id going to long quiet weekend!
 
every one has there own ideas, and thats a good thing. my advice is: dont run it at top rpm for more than 30-40 ft, then let it cool down some before cranking the rpm up again
 

RC Builds

Back
Top