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  1. #1
    RC Racer
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    how do i tell if a nitro engine is worn out?

    ok so i just finished replacing all my parts and i put a trx .15 in my tmaxx i got the engine used but it all looks great inside and out so anyway i turn it on get it nicely tuned and i start running it out on my street i get it to top speed a few times and drive it for about a minute then while im still pulling the throttle it cuts out . i have sneaking suspicion its near death please help how do i tell if it is worn out?
    2001 tmaxx, 2012 1/16 erevo vxl

  2. #2
    RC Racer
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    Sign of motor being lean. Check temps, and make sure a trail of blue smoke from the exhust while at WOT. You can check the compression as well...should be hard to spin past TDC
    Jato 3.3 Pede 2.5R Rusty 3.3

  3. #3
    RC Champion
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    Being lean on the top end can also cause a engine to cut out
    Spin the flywheels to check the compression.

  4. #4
    Marshal Double G's Avatar
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    With the engine torn apart: push the piston up through the sleeve. If it stops flush or above the sleeve it is worn.
    Engine intact: spin the engine by hand using the flywheel. You should feel resistance and then a pop as you spin past TDC. Also while running if the engine stalls when warm only to restart when it is cool then it is done.
    You can purchase new parts to rebuild or if the sleeve and piston are in decent shape you can have Ray A Racing repinch it for around $25 (which may be the price of a new piston/sleeve--I haven't checked).
    The Super Derecho

  5. #5
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by Double G View Post
    With the engine torn apart: push the piston up through the sleeve. If it stops flush or above the sleeve it is worn.
    Engine intact: spin the engine by hand using the flywheel. You should feel resistance and then a pop as you spin past TDC. Also while running if the engine stalls when warm only to restart when it is cool then it is done.
    You can purchase new parts to rebuild or if the sleeve and piston are in decent shape you can have Ray A Racing repinch it for around $25 (which may be the price of a new piston/sleeve--I haven't checked).
    When turning the flywheel make sure the glowplug is in and the engine is cold,,, turn the flywheel counterclockwise since that is the natural direction it spins in.
    Founder of H.U.A.
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  6. #6
    RC Racer
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    Quote Originally Posted by Double G View Post
    With the engine torn apart: push the piston up through the sleeve. If it stops flush or above the sleeve it is worn.
    Engine intact: spin the engine by hand using the flywheel. You

    Tshould feel resistance and then a pop as you spin past TDC. Also while running if the engine stalls when warm only to restart when it is cool then it is done.
    You can purchase new parts to rebuild or if the sleeve and piston are in decent shape you can have Ray A Racing repinch it for around $25 (which may be the price of a new piston/sleeve--I haven't checked).

    Thanks it doesnt go above the sleeve but wont restart when warm
    2001 tmaxx, 2012 1/16 erevo vxl

  7. #7
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by nathan8856 View Post
    Thanks it doesnt go above the sleeve but wont restart when warm
    What are the running temps?

    How many seconds do you get with the pinch test?

    How many gallons are on this engine, worn engines will lose compression and not want to run when the piston and sleeve are worn.
    Founder of H.U.A.
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  8. #8
    RC Racer
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    Quote Originally Posted by Nitronaught View Post
    What are the running temps?

    How many seconds do you get with the pinch test?

    How many gallons are on this engine, worn engines will lose compression and not want to run when the piston and sleeve are worn.
    idk i got it used the temps are 300 witch is normal for 3000+ feet i just re pinched it but now it wont start and i get about 3 and a half second (well i did when it wanted to turn on)
    2001 tmaxx, 2012 1/16 erevo vxl

  9. #9
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    Quote Originally Posted by nathan8856 View Post
    idk i got it used the temps are 300 witch is normal for 3000+ feet i just re pinched it but now it wont start and i get about 3 and a half second (well i did when it wanted to turn on)
    ok update i found out that one of my engine block screw holes is stripped so the head wont go on all the way preventing it from starting. yesterday i took it all apart and the piston went through the sleeve so i re pinched it and it seemed to have good compression but what good is that with a screwed up block, this truck has been a huge disaster and money hole for me the first engine came with the truck and during break in i ran it without the air filter thinking nothing of it 2 quarts later its destroyed so i buy a used engine off eBay with "good compression" that's the one i re pinched that wont start iv replaced all the servos the rims tires shocks 3 pull starts 2 fuel tanks all the fuel line the transmission 3 spur gear and many other things and the longest its run is 2 and 1/2 weeks i love nitro rcs but i think im gonna have to leave the hobby .
    2001 tmaxx, 2012 1/16 erevo vxl

  10. #10
    RC Racer
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    do not leave i had thought about it and did not do it because in the end it will come back and make you hate yourself for stoping




    it keeps us all out of moms,wifes hair

  11. #11
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by nathan8856 View Post
    ok update i found out that one of my engine block screw holes is stripped so the head wont go on all the way preventing it from starting. yesterday i took it all apart and the piston went through the sleeve so i re pinched it and it seemed to have good compression but what good is that with a screwed up block, this truck has been a huge disaster and money hole for me the first engine came with the truck and during break in i ran it without the air filter thinking nothing of it 2 quarts later its destroyed so i buy a used engine off eBay with "good compression" that's the one i re pinched that wont start iv replaced all the servos the rims tires shocks 3 pull starts 2 fuel tanks all the fuel line the transmission 3 spur gear and many other things and the longest its run is 2 and 1/2 weeks i love nitro rcs but i think im gonna have to leave the hobby .
    Nitro will not forgive those who do not pay attention to detail... Running wihtout a filter is a sure engine killer...

    A helicoil kit can fix it but they are like $30.00.. At that price you can buy a new block.

    Buying used engines,,,,, Unless it was someone I know, I won't ever do it... So many out there ruin their engines and sell them saying,,, 1-2 gallons use... Yeah right!
    Founder of H.U.A.
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