Time for an upgrade!

[andydrew39219]

I was bashing yesterday with my pede, just another normal day. I was gonna do a WOT pass down the street and all of a sudden *SNAP*.

Got to my buddies house and stripped the engine down. I snapped my conrod right above the loop that connects to the crankshaft and some bottom parts of the piston broke too. (I will add pictures soon)

What caused this? The only thing I can think of is not running up to temp. Yesterday it was running around 170-190 (high 30s for outside temp, running rich). I always put ARO in when I'm done, I actually just switched over to using MMO.

I have a brand new sealed 2.5R that was supposed to be going into my tmaxx. I see 2 different options, but another 2.5R, put in pede. Or what I am considering, buy a 3.3, put 3.3 in tmaxx and 2.5R in pede.

What kind of upgrades is my stock 2.5 tmaxx gonna need for a 3.3? is it just the driveshafts and axle carriers or am I looking at needing a ton of new parts to get the 3.3 in there?

 

[Childresshunt]

If you wanna put the 3.3 in the 2.5 go for it theres no upgrades needed and its a direct swap. I have a 3.3 on my 2.5 right now the only thing with it is i after like 3 gallons of fuel my stock drive shafts are slightly twisted but when i say slightly i its just a little bit the only reason i knew they were was bc i was changing bearings and i couldnt slide the shaft all the way in

 

[andydrew39219]

If you wanna put the 3.3 in the 2.5 go for it theres no upgrades needed and its a direct swap. I have a 3.3 on my 2.5 right now the only thing with it is i after like 3 gallons of fuel my stock drive shafts are slightly twisted but when i say slightly i its just a little bit the only reason i knew they were was bc i was changing bearings and i couldnt slide the shaft all the way in

Really? I get so confused because there are so many different tmaxxs. I could have sworn I read you needed a few things to get the 3.3 to work in the tmaxx, maybe it was about an older version? Mine is the 2.5 with the wide arms on it, but I don't think it is the tmaxx classic. But mine still has the black 2 speed with rev. Can I keep the reverse with the 3.3 or is that a bad idea? I would really like to keep reverse.

I feel like I should have gotten more life out of my .15 pro. I had around 4 gallons through it. What could have caused this so early in it's life? I do know I did some damage to it running it lean when I was trying to tune it for the first couple times. The top of the piston looks burnt, but I know that it has been that way for a while and there is no damage (other than that) to the top of the piston. I can't even find 1 scratch on the inside of the sleeve.

Here's the pictures, sorry they are low quality and awkward because all I have is an old android tablet that only has a front facing camera.

The first is just showing how bent the con-rod is, and where it broke

This one is showing the damage to the piston. I guess you would call it the skirt?

 

[Childresshunt]

I also have the wide maxx the 4910 version with black tranny. And its bone stock besides shocks and the 3.3 and i havnt had any problems out of it besides normal stuff. if It the .15 version of the maxx i would put a 2.5 and i think thats still a drop in maybe a new motor mount I'm not sure tho i dont really no anything about that maxx. If you put the 3.3 in the wide tho i would put a FOC in it to keep the truck from bucking like it does with reverse so you dont have so much stress on the driveline

---------- Post added at 9:41 AM ---------- Previous post was at 9:40 AM ----------

Deff snapped that rod how many gallons were on it

 

[andydrew39219]

Deff snapped that rod how many gallons were on it

Yeah lol! That's what I'm saying. What did I do wrong? It has around 4 gals on it and that's being generous...Could it be from flooding it with ARO (not intentionally) and then turning the motor over with the ez start and having it lock up? or could it be because it was running around 170-190F?

 

[Childresshunt]

170 to 190 is a little low but not bad low or anything. You said you were running in 30 degree weather did you have your head wrapped

 

[andydrew39219]

170 to 190 is a little low but not bad low or anything. You said you were running in 30 degree weather did you have your head wrapped

No, I didn't think it was necessary because it was getting up to temp. Honestly, if I had it tuned right it probably would have been more like 200. But I got it running good (and rich) and didn't want to start leaning needles out and messing up my tune. Now that I think about it, it would have probably been a good idea to cover the hole in the windshield. It still would have had plenty of air because the back of the truck body is cut open pretty well to get to the needles, ect.

 

[Snook Man]

It’s hard to say what came 1st the chicken or the egg. The rod could have broken and caused the damage to the piston skirt or the piston skirt could have broken and caused the rod to break. (Piston skirt would be my guess having about 8 of the pro.15 engines have the same failure).
Running too cool, excessive rpm’s at any time, running too lean etc.etc could all play a part in the failure.
4 gallons is not bad for a pro.15, if you run them hard that’s about average or even less.

 

[Childresshunt]

Myself i wont run my nitro's if the temp is lower than 50. although i do run old tired motors in the cold

 

[andydrew39219]

It’s hard to say what came 1st the chicken or the egg. The rod could have broken and caused the damage to the piston skirt or the piston skirt could have broken and caused the rod to break. (Piston skirt would be my guess having about 8 of the pro.15 engines have the same failure).
Running too cool, excessive rpm’s at any time, running too lean etc.etc could all play a part in the failure.
4 gallons is not bad for a pro.15, if you run them hard that’s about average or even less.

I was thinking that the con-rod broke first and when I went to turn it over to see if it would start up it probably drove the conrod into the skirt. I was thinking that if the skirt broke first it would have scarred up the sleeve pretty bad and I cannot find any scratches on the inside of the sleeve. But anythings possible.

I was certainly hard on it, I love to rip that thing around on the dusty roads we have out here (trying to) drift, do doughnuts, ect. I also had it in my tmaxx and ran it a couple times, but I think it is harder on the engine in the pede because I can just spin the tires with no effort. I'll just chalk this up to a learning experience. I'm going to assume that it is not worth the effort to rebuild that engine.

I got really antsy and wanted to drive my nitro around, I have been a few times now. and it's certainly warmer than it was in previous times.

 

[Snook Man]

I'm going to assume that it is not worth the effort to rebuild that engine.

IMO, it’s not worth it. I consider them throw-a ways. Nice paperweight for the desk when you kill them though.

 

[Childresshunt]

If the head isnt beat up to bad you could sell it on egay. Maybe the crankcase to but it may be damaged from when the rod broke