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Need some help (engine)

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H

hammertime

RC Newbie
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  1. Bashing
Need to know if some one can gimi a little input, and here is the deal with out writing a small book. I received a used Classic Tmaxx .15 from a friend over Christmas. First i tried to start it and failed, it was leaking fuel from the front crank bearing by clutch and believe it wont hold crankcase pressure because of this leak . broke down completely front bearing seal was toast so installed some new bearings and the thing still leaks? could the crank possibly just be worn out, and is this a common problem with these engines?
 
hammertime said:
Need to know if some one can gimi a little input, and here is the deal with out writing a small book. I received a used Classic Tmaxx .15 from a friend over Christmas. First i tried to start it and failed, it was leaking fuel from the front crank bearing by clutch and believe it wont hold crankcase pressure because of this leak . broke down completely front bearing seal was toast so installed some new bearings and the thing still leaks? could the crank possibly just be worn out, and is this a common problem with these engines?
Click to expand...

I don't know much about the traxxas .15 motor.. but I'd take it over to you lhs and see if you can exchange it.. I know traxxas offers an engine exchange program. You trade in your old engine and get menoy off a brand new one. I have a gut feeling that dosent apply to the .15, but it's worth a shot.
 
You did use the correct bearing right? Try again before condeming it.
 
A .15 isn't worth messing with for a maxx. The newer 2.5 and 2.5r are too weak, too. They're all .15's. Get a 3.3(.19) for it at least. An O.S. .18 or .21 are way nicer and hold a tune better. Last longer as well. But they come with a steeper price.
 
But you can't really put a .18 or a .21 in a MAXX with out having to do a ton of work to it and spending a lot of money on new transmissions and stuff!

Would it be worth it if you have the money?
 
I currently know that the .15 isn't the best choice for the tmaxx and was really looking to do a rebuild to get a little extra time out of it, however it doesn't seem practical so may do the exchange or kick it across the yard not sure yet... but if i decided to spend the money on the os will i need the big bore upgrade kit i have seen mentioned in these treads?
 
hammertime said:
I currently know that the .15 isn't the best choice for the tmaxx and was really looking to do a rebuild to get a little extra time out of it, however it doesn't seem practical so may do the exchange or kick it across the yard not sure yet... but if i decided to spend the money on the os will i need the big bore upgrade kit i have seen mentioned in these treads?
Click to expand...

I think it depends on the engine size.. but I think it's referred to as a "big block conversion"
 
Hey hammer time. it would be worth it!

If you have the money to do it then definitely go for it!
 
When you switch engines you'll have to watch for carb type and exhaust location. The .15 is rotary carb/side exhaust.
I put an HPI .18 in my Maxx with very little and simple mods.

The 3.3 is a .20(not .19 Matt) and requires a conversion kit,readily available from Traxxas. The conversion kit can be used for other slide carb/rear exhaust engines.

If you just want to run cheap for a while, I have a spare .15 I'll sell for $35 shipped assuming your addy is CON USA.

pro15.JPG
 
IMO if you are just getting into nitro id stick with the pro 15, its slow and very easy to drive.
 
Hey I really would like to thank all you guys for your help... I'm not so much new to the sport because i have a plethora of stuff such as a trx nitro sport, hpi rs4 2, and hpi rs4 evo, rc10gt and they all run pretty good with a .15. So getting this thing running just really seemed like a debacle and wanted to get a few opinions. And Racer1966's thanks very much for the offer and ill let you know what i decide after i do some more tinkering but once again thanks for all the help guys.
 
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I have a first gen. T-Maxx and currently I have the OS .18 CVR in it and IMO this is the best engine for this truck. It drops right in because it has a rotory carb and side exhaust. Perfect match for this old truck.

You can hear in this short video how well the .18 runs.
[ame]http://s208.photobucket.com/albums/bb193/durwank/?action=view&current=MVI_0868.flv[/ame]
 
I just had the same issue on my pro .15 tmaxx. The leak is from the crank bearing right behind the flywheel. it has a plastic seal build into it. If u just want to repair the engine u have u can buy the bearing(comes in a 2 pack with
the inner crank bearing 16 bucks at the local hobby).

The bearing is a little difficult to replace u need to heat up the engine block to
get it out due to the bearing being a press fit. then carefully remove it with
a right angle pick. To put the new one in i had the best luck with putting
the bearing in the freezer and heating up the block it slid most of the way in,
i gently tapped it the rest of the way in with a socket the same size.

It was a fun repair i would go for it if u feel good about your mechanical skills
 
The Pro .15 is such a POS IMO. I wouldn't bother with fixing it. Trade up for the 2.5 or 3.3 if you can. It will cost you a little but it will be well worth it.
 
$90 dollars later and I have a factory running TMAXX would have sprung for the O.S. However it was $130+tax so a little out of my scope... I think the .15 pro runs pretty dam good in such a big truck but just my opinion. Only complaint is once tuned after breakin still runs pretty hot don't have digital temp gauge but use the good old lick the finger and touch the head method and still boils so? Time to do some more research......... Once again thanks for the help everyone
Mark
 
The best thing to do to combat the heat from a .15 is gear it down a little, run a lighter wheel/tire combo and make sure it gets plenty of air. I suggest picking up a temp gun asap. Keep it under 285. That's a little on the hot side, but you still want some performance. Richening it to keep it cooler will start to kill your power. Find a happy place for you and the engine.
 

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