TM323

this is kind of a way to vent my frustrations so bear with me. I bought the rbtm323 in june it is the best engine I ever had in the 3 1/2 years I have been into nitros I usually buy a new engine when the old on wears out but in this case I rebuit because like I said it is a hell of an engine. I did not replace the conrod though and after half a gollon it snapped. I thought it was just my one way bearing acting up but when I went to clean it that is when I realized it was the conrod this is the first time I have ever seen one broken before. I have dumpe over $200 into this engine(p/s set, crankcase, carb retainerbolt, back plate) and refuse to spend another penny so I am waiting till march for the 523 and in the mean time I'm going to get the mach 28 and see what that is like. to make a long story short when you rebiuld an engine should you always replace the conrod? I,ve heard some people say after every other rebuild you replace it? is there a rule of thumb to go by? Well thanks for listening and rember to breathe between sentences

DaveG55

Well, I'm no expert but it seems to me that the conrod is the one part in the engine that takes the most abuse in just normal running. So you take a part that has been stressed and worn and then rejuvinate the parts that stress it, ya gotta figure that part may give up.
I've rebuilt engines that had the sleeve scratched after about 1/2 gallon and reused the conrod with no problem. But, if an engine is in need of a rebuild from long use and wear, I'd say the few dollars the conrod costs is not worth the risk of it failing and trashing a fresh rebuild.
Anyway, that's my thought.
I've got 2 Mach26's and so far they've been great. Don't know about the 28 but I've heard it's good too. For what it's worth($0.00 ) I've heard that it's a rebadged SH28. I don't know but that's what I've heard.

TM323

well i went and purchased the mach .28 I have not ran it yet probably will break it in this week end. had to go and buy the new era BB kit looks weird as hell to see a nitro engine almost laying flat like that. what gearing are you running with your .26 I was using 15/38 with the wide ratio 2 speed the rb still was yanking the wheels off the ground (till my conrod broke) so should I go lower for the .28

DaveG55

Sorry, cannot help you with the gearing. My Machs are in an LST and a Savage. I'm using stock gearing in both of those but I'm gonna have to change the Savage, I cannot keep it from flipping onto its back - some problem, huh????
My T-Maxx is the old Pro.15 bumped up to a 2.5r - I wish I'd went with one of the OS.18's. I may still drop a TM in it. Not that the 2.5 is bad, just that I think there's more potential there.
Or I may sell the T-Maxx, get a Revo and then BB it.