View Full Version : what are the signs of a engine about to go? what to look 4?
11-17-2010, 09:32 PM
new to this and think this might be my problem tried tuning and no luck or just dont have it right yet.(more detail in my revo post) if motor is bad would a 3.3 go in the place of the 2.5r ? this is a 5310 model it had about 1/4 of a gallon run through it just broke in the man said and it looked brand new but he said it set up since he broke it in and he said he done it right.when i got it had a good trail of smoke and still does but was dripping fuel out the tail pipe so i leand it out a little seemed like it run hot so went back it factory settings and still does the same, runs great for little more than a 1/2 tank and it idles down and then burrrr. and dies then it takes a while b-4 it starts back up, done this b-4 and after i tried tune n it
11-18-2010, 12:16 AM
Everyone that sells a nitro truck has little use on the engine which was broken in to a "T". If the engine stalls when warm and will only restart when cool it is gone. Disassemble the engine and try to push the piston up through the sleeve. If it stops before the top they are still good. If the piston reaches the top or goes through then time for replacement. If the engine is still good you'll need to check every other part attached to it to make sure there is no tiny air leak someplace. And if you have the 5310 the drivetrain should be able to handle the additional power.
11-18-2010, 07:47 PM
i must be the lucky one cause every used engine i have bought after tuning right ran great, but yeah, all other normal running engine factors being good, double g is right!
11-18-2010, 08:21 PM
now does these engines have rings or is it just piston and sleeve ? comparing the 2.5r and the 3.3 what is the better one and the differnce on the track? or bashing? because 50$ sounds better than over a 100$ on the traxxas program.
11-19-2010, 03:06 AM
Traxxas motors do not have piston rings. Most if not all nitro engines made for cars or trucks are ABC engines meaning (Aluminum piston Brass sleeve with Chrome plating). The cylinder sleeves in these motors are slightly tapered which creates the seal like a piston ring would. As the piston travels towards the top of the sleeve you will notice it gets tighter when you push the piston towards the top by hand. The tightness of this is also referred to as "pinch". To check the pinch you need to dis-assemble the motor, then put the piston in the sleeve and push it towards the top lightly until it stops. Like DoubleG said it should stop with the piston being below flush with the top of the sleeve and not pass all the way through. If the piston goes all the way flush with the top of the sleeve or goes all the way through then it's shot.
If it does come down to you needing a new engine, bigger is always better.:D
11-19-2010, 02:45 PM
dripping oil or fuel out of the tail pipe does not mean that your engine is running rich. in fact dripping oil or fuel is a good thing. if it was running good before you leaned it you should have NOT touched the needles. sounds to me that maybe you made a mistake. can you undo what adjustments you made?
IMO the 2.5r is a great engine!
11-19-2010, 02:53 PM
Here are some tell tale signs your engine may be on the way out.
1. Not maintaining a tune while being used.
2. Drop in performance.
3. Engine stalling once reaching operating temps.
4. Whining sound coming from the bearings of the engine (very specific sound).
Like said if you experience any of this 1st check the compression of the engine when it is cold. With the glowplug in turn the flywheel counterclockwise, you should feel a good deal of resistance as the piston reaches to thop of the sleeve, if not then the compression is gone and chances are you either need to rebuild or replace the engine.
You can also remove the glowplug and again rotate the flywheel counter clockwise, you won't feel the compression but you shodl feel a little bit of resistance as the piston reaches the pinch at the top of the sleeve, if the flywheel rotates complete turns and very little to no resistance tear it down and check if the piston can be pushed through the sleeve. :cool:
11-19-2010, 04:08 PM
i think it is shot when i took apart the lower end it looked chocoholic milk and looked to be some what tarnished inside (rust looking) and the piston goes to the top with ease (not all the way out but about a 1/16 past the jug) now would it setting up for so long cause this because he said it just set for 3+years .... i guess i am going with the 3.3 its 110.$ and the 2.5r is 104.$ at my hobby shop, thought about just rebuilding but like having the new better.
11-20-2010, 01:52 AM
well i got the 3.3 and loving it so far just got it broke in done it by the book so i hope it lasts, now the old 2.5r was ether not broke in right or the guy run it alot more than he said because it took me almost a quart of fuel and about 2 hours the fuel that came with the truck was over 3/4 of a gallon and he said thats all he ran it....so u tell me.....now did not burn out a glow plug on tuning is this a good thing or could it end up being bad? or does this happen very often
11-20-2010, 12:30 PM
Plugs should last if your tune is good, a bad/lean tune can kill plugs rather quickly.
Not burning out the plugs ok.
Change the plug after break in is done, then tune. It will save you some headaches.
I personally like the Traxxas heavy duty plug TRA #3232X, it has a heavier heating element.
I generally I get a gallon or so use out of this plug if I'm getting a good tune.
Below are two great pages of helpful info:
Helpfull Tuning Tips (http://traxxas.com/forums/showthread.php?334452-New-to-Nitro-Helpful-Tuning-tips).
Glow Plugs & Tuned Pipes (http://traxxas.com/forums/showthread.php?261817-Tuned-pipes-and-glow-plugs-updated-1-14-05)
~~Hope this helps~~
11-24-2010, 09:00 PM
what exactually do you have to to to tear apart the engine i suspect that my pro .15 is on its last legs; it stalls when it is warm. also does the whining sound very loud mine somethimes does it, but it also sounds like there is something caught in the weel.
11-29-2010, 10:31 PM
just take out screws
11-30-2010, 05:22 PM
It does the whining sound very loud mine somethimes does it, but it also sounds like there is something caught in the weel.
Maybe a bad bearing, you'll have to dissemble the engine to see.
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