# Rebuilding nitro motors



## cypressvendetta (Nov 9, 2008)

I've got a OS vspec vzb i need to know a few things.... the previous owner put the motor up with some fuel in it.... what is the best things to do? rebuild? If so, what is the best way to remove the cylinder wall so i can remove the piston, crank and bearing?


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## Gary (May 21, 2004)

Try different temperatures to remove the sleeve. Toss it in the freezer, put it in the oven...


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## cypressvendetta (Nov 9, 2008)

well most important if it was setup with feul in it, does it need to be rebuilt?


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## jelias (Sep 7, 2004)

I just recently pulled my gas truck out of my closet that was put up without running all of the fuel out after the final run. One of the things that I noticed was that the oils in the gas were the only things left inside the motor and made it difficult to turn over. Don't know if running the motor would have cleared all the old stuff out but being that it's only a .12 motor and I already had the new piston and sleeve, I went ahead and rebuilt it. I guess it all depends on how much runtime the current piston/sleeve combo have on them.


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## Courtney Vaughan (Apr 11, 2007)

Does it turn smoothly with a flywheel on it by hand? Does the carb slide move easily? If so, then fire it up and try it out. 

If not, flush some fresh fuel down into the carb and move the slide in/out a bunch of times and I bet it'll free up a lot. If it does, you're on the right track. Pull the backplate and flush some fuel inside the case of the motor and turn it over at the flywheel by hand for a little while and let it smooth out a little as well. If you do both of those things and it loses some of the "gummy-ness", then put a LIGHT coat of after-run oil or the like around the rod & crank. Put a fresh glow plug in it and if it has decent compression, fire that bad boy up!

Again, if it's not gummed up, then just start with a fresh glow plug and fire it up!


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## cypressvendetta (Nov 9, 2008)

well i think the motor has about 1 or 2 gallons through it and he takes very good care of everything he owns, i removed everything (head, backing plate and carb) and cleaned it out with carb cleaner then put a couple of drop of trinity bearing oil in the inner bearing, spun it multiple times to spread the oil then closed the motor back up followed my a small shot of wd-40.... its been sitting on my workbend head down to let any excess drain.


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## Courtney Vaughan (Apr 11, 2007)

There's no reason not to fire it up then. Don't be surprised if you foul a glow plug or two. Let us know how it goes.


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## cypressvendetta (Nov 9, 2008)

i will, im still waiting on the clutch parts to come in to i can fire it, so hopefully my the end of this week i'll be able to let you guys know. I'm dying to get this thing on the river track


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## kstoracing (Oct 30, 2008)

Cypress, as long as your bearings aren't junked up it will be ok. I would just clean out the oil residue and go with it. Invest in some denatured alcohol cheaper than the motor spray and cleans just as well. New glow plug, new fuel, go time.


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## cypressvendetta (Nov 9, 2008)

already blew it out with motor spray hah


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## cjtamu (Sep 22, 2004)

What ksto said. I use denatured to dissolve the gunk, then just drop after run into the bearings. It's easier if you pull the crank.

Don't listen to Biff, there's a reason he gave up nitro, ha ha ha. To remove the sleeve, just run a ziptie through the exhaust port. Then turn the flywheel by hand and it will push the sleeve up a little. From there you can just pull it by hand. After that you can remove piston, crank, etc. Just be sure you pay attention to how the piston and rod are oriented. The heating the crankcase and freezing the bearings are for removing/installing crank bearings.


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## Todd Claunch (Sep 5, 2006)

WELL CHRIS I HAVE BEEN UNDER A ROCK, BUT I HAVE HAD A FEW THAT THE
OLD ZIP TIE METHOD DIDNT WORK..... WELL


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## cjtamu (Sep 22, 2004)

Todd Claunch said:


> WELL CHRIS I HAVE BEEN UNDER A ROCK, BUT I HAVE HAD A FEW THAT THE
> OLD ZIP TIE METHOD DIDNT WORK..... WELL


Hit the gym. :doowapsta


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## kstoracing (Oct 30, 2008)

Depending on the cost of a new pistion and sleeve tells weather you want to replace them or the engine. I wouldn't replace it more than once on the same crank case.


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## Courtney Vaughan (Apr 11, 2007)

I've actually had a couple of them cut the zip tie. My best tool for the job has been a wittled down toothebrush end.


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## cypressvendetta (Nov 9, 2008)

old shock piston..... worked perfectly


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## cjtamu (Sep 22, 2004)

Courtney Vaughan said:


> I've actually had a couple of them cut the zip tie.


Spend less time in the gym. :biggrin:


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## cypressvendetta (Nov 9, 2008)

I need to go to the gym..... or fat camp.... lmao


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## katjim00 (Jan 8, 2009)

I plan on making the next HARC race as I won't be able to make the big race this weekend. If you need any help with the motor let me know, I can inspect it all for you and see how things look. The biggest problem with the Vspec was the crank pin would wear quickly and cause lots of rod slop. That caused many problems which are more than I wish to type. Let me know if you need help.


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## cypressvendetta (Nov 9, 2008)

I appreciate it, we plan on going out to mikes this sunday to get stuff ready for next weekend


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## Big Phil (Apr 27, 2007)

Bump


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