Bad day in 3.3 land

[Bkyd Basher]

Hey guys, so it seems something went down in the cylinder of my new 3.3 and i believe wiped out the inner bearing after it beat the hell out of the top of the piston. Questions are, how do i remove the sleeve and whats ur thoughts in what i should do. The sleeve it self looks ok,no big scratches or dig marks or anything. Just super tight to turn it overThanks

 

[moe7404]

save your self some work. get a O.S. 21tm. mine was a bolt in. it was flying out of box. my guess is the con rod snaped. if it damages so much stuff its easier to replace the whole engine. but if you really want to learn go to a good shop to get the parts. OR get parts from traxxas. just note what way the con rod faces and the piston.

 

[Punisher]

Take the back plate off and have a look at the connecting rod - as has been suggested your con rod has probably broken.

I broke a rod in my last engine - the sleeve and piston was ok so I simply replaced the rod with one from a spent 2.5 and I was able to save the engine with zero spend.


If/when you need to take out the sleeve, use a piece of wooden rod (chop stick I used!) to push the sleeve out from the bottom - and/or put a piece of wooden rod through one of the ports, then move the piston up the bore until it hits the wood and apply pressure - the sleeve is a bit of a bugger to get out, but you just need to persist.

Use wood though, as a metal rod or screw driver will stuff the sleeve - it's very soft.

If your bearings are ok, you can get a rod, piston and sleeve for around $60 - you will have a new engine.

Or Davis do a HD rod for the 3.3 . . . around $50.

Or you can get a new 3.3 for a little over $100.

If you are entertaining a new engine, save a bit more and put the $ towards an OS or Picco 26.

 

[mrbones]

You can also double up a zip tie and stick it in the exhaust port and turn the flywheel to push the piston and sleeve up. I'm about to order a new connecting rod and I think I'm going to spend the extra $15 to get the heavy duty one. It's better than replacing the piston and sleeve the next time the stock con rod breaks, which is just a matter of time because they all break. There is no brass bushing in the top hole of the stock rod and it is a weak point that always breaks. Heres a link to the rod on Ebay for about $41.
http://www.ebay.com/itm/330769476774?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

[Bkyd Basher]

nope, like i said the connecting rod is not broke, sleeve looks fine but the top of the the piston has a ton of imprints in it like something beat the crap out of it. It still goes up and down smooth but just super super tight. The wand wont even come close to turning it and its tough just turning the flywheel by hand. I may be wrong but the sleeve has to come out to get the piston and rod out so i can pull the crank and check the inner bearing. If it is just the bearings i can replace them for 20 cause i have another piston. I get the 3.3s for 90$, which is a long stretch away from an os or picco. This motor is not even two weeks old. Any ideas what could have happened? It never ran hot on the temp gun. Could a glow plug filimant do this if it fell down in there?Ihave no problems rebuilding it but if it comes anywheres close to 90$ its not worth fixing. I would like to try new bearings and piston that i have. Logical or not?

 

[Punisher]

sleeve looks fine but the top of the the piston has a ton of imprints in it like something beat the crap out of it.

Seems odd - unless you have dropped a little stone down the plug hole when you removed the glow plug . . .

Detonation maybe?

I may be wrong but the sleeve has to come out to get the piston and rod out so i can pull the crank and check the inner bearing.

You are not wrong - sleeve needs to come out to get the piston and rod out.

If it is just the bearings i can replace them for 20 cause i have another piston. I get the 3.3s for 90$, which is a long stretch away from an os or picco.

Fair call.

This motor is not even two weeks old. Any ideas what could have happened?

Detonation/Pinging - unlikely though.

If you haven’t taken out your rod you can't confirm it isnt broken . . .

It never ran hot on the temp gun. Could a glow plug filament do this if it fell down in there?

Yep

Ihave no problems rebuilding it but if it comes anywhere close to 90$ its not worth fixing. I would like to try new bearings and piston that i have. Logical or not?

If she is only two weeks old the problem is unlikely to be the bearings.

You can't really just replace the piston - piston and sleeve are married as a pair.

My suggestion would be to take her apart and see what is what.

Reckon the worst case scenario is you will may have to replace the rod, piston and sleeve - $60.

 

[Bkyd Basher]

ok thanks alot. I just meant the rod is not visually broken unless its around the wristpin, cause i havent got it totally apart yet. But logically if it was broken there it probably wouldnt continuously move the piston up and down.But the top of the piston has like pin size marks around the outside edge. Not holes just dents and marks(i will post a pic soon).The sleeve is nice and smooth with no scuffs or deep scratches. It is just very stiff turning over from bottom to top.I was thinking,(not sure if it could happen) but maybe something was in the combustion chamber bounceing around and went down in the case hurting the bearing. And i saw some pictures of piston b4 showing what it would look like in different circumstances, anyone one know where that was?

 

[moe7404]

as allways, my friends have great ideas.

 

[Bkyd Basher]

So kinda as i figured, i got the sleeve and piston out. Popped the crank out and all the ball bearings spilled everywheres.Should i pop a new set of bearings in and try it, even though the top of the piston is a lil beat up? Or should i use the piston and rod as a keychain and buy a new Motor? It sucks that the rebuild is so close to the price of a complete new motor.

 

[jerzey10]

I would replace the bearings & see what happens.

 

[Punisher]

I would replace the bearings & see what happens.

I would do the same

 

[Bkyd Basher]

Just ordered the bearing. figured the worse case scenario will be I'm out 20$ worth of bearings.

 

[Bkyd Basher]

Just got the 3.3 back together. Its Alive again!! Runs pretty good. Just havin a lil hard time with gettin it to idle for more than 3-4 seconds. But still has good power.

 

[Punisher]

Just got the 3.3 back together. Its Alive again!! Runs pretty good. Just havin a lil hard time with gettin it to idle for more than 3-4 seconds. But still has good power.

Well done.

 

[Bkyd Basher]

Ya thanks. So happy it worked,way to new to be in the junkyard just yet. Took it out on our track and gave it a good beating tonight. Got dark and the moon was shining bright so we just kept goin. What a blast. How lean in ur opinion is to lean on the LSN? 1 turn out sound to lean in an average situation?

 

[jerzey10]

I just use the pinch test for the lsn. it should idle for 3 to 4 seconds before it dies.

 

[Bkyd Basher]

it never seems to work for me.It runs strong but just will not idle for nothing. I started at 1.5 out on lsn 3 out on hsn and a paper clip width on idle adjustment screw. T o get it respond and run descent i am at 2 3/4 out on hsn 1 out on lsn. And pretty much as soon as it stops it wants to stall. It seems if i leaned the lsn it would idle better but it already idles kinda high.

 

[Punisher]

it never seems to work for me.It runs strong but just will not idle for nothing. I started at 1.5 out on lsn 3 out on hsn and a paper clip width on idle adjustment screw. T o get it respond and run descent i am at 2 3/4 out on hsn 1 out on lsn. And pretty much as soon as it stops it wants to stall. It seems if i leaned the lsn it would idle better but it already idles kinda high.

1 out on the LSN doesn't seem much - it may be idling high as the LSN is lean - try richening the LSN up a little - if the idle rpm drops having richened up, increase the idle gap (idle adjustement screw)

HSN is is not real rich either - but whatever works aye.