Pinched Sleeve Advice

[sweetdiesel]

Hey guys,

I had my sleeve resized from my Collari .30 about a month or so ago. After putting the engine back together I rolled the flywheel slowly and noticed that the normal pinch at the top is now split into two pinches, one pinch that is about 3/4 to TDC followed by a pinch that is about 1/4 after TDC. Did my sleeve resizer guy go too low on the sleeve when he did the job? Or is this normal for a pinched engine to behave?

 

[Plaidfish]

as long as it doesn't give a real hard thump on the first one I wouldn't worry.....he will releive it if it's too much pinch....I set mine on a box and see if it turns over nicely for my test....USE ARO FOR THIS as your sleeve and piston are probably fairly dry by now....I have mine pinched in 3 steps but they rarely have a heavy enough pinch (on the lower stages) to affect the piston too much...it's supposed to create a more dense area in the sleeve that way....I can't image the collar putting enough force to change the metal but this what I was told...the dense ring created is like a band around the sleeve helping to "squeeze" the pinch and keep it.....

 

[sweetdiesel]

Thank you for the advice Plaid. I am going to start it tonight and re-break it in, I was afraid of ruining something if my condition was unusual.

 

[Plaidfish]

you don't need to do a full break in...I run 2 tanks and do the 1/4, 1/2, 3/4 throttle spurts and then the last tank do all WOT spurts.....that's a funny word to type "SPURT"....

 

[.21Rc10GT]

that's a funny word to type "SPURT"....

uhuhuhuhuhuh, you said spurt... beavis, huhuhuhuh

 

[Plaidfish]

R-UthreatningME...

 

[olds97_lss]

I Am The Great Cornholio!!!! I Need Tp For My Bung Hole!!!!

 

[Tweak]

Het... just a dumbass question. What exactly is "pinching" a sleve?

 

[AC48]

Once an engine gets old and the pinch wears out (tightness of piston/sleeve, pinch is the tightness you feel when there is no gloplug in) they will actually put a ring around the sleeve and clamp it down making the sleeve smaller. That makes for a nice tight fit of the piston and sleeve again, and the engine will run like new again to some extent. At least thats my understading, please correct me if I am wrong.

 

[beason]

you put it in a vise and squeeze it so that it gets its pinch back..

 

[Plaidfish]

it's a little more to it than that man......my guy had special tools made to do .21 engines....he spent like 600 bucks to get a whole bunch of sizes for .21, .12, .15, and some .18 engines I think.....real precision tools....3 different size shims for each type to do 3 stage pinches......it's pretty cool what you can do with some really crappy engines and a little modding......if you can get stuff pinched it's a little easier to experiment..........saves from HAVING to buy a new mill when you roast your current one......but one guy from teh track and his son said they tried using a vise grip and it worked.....I'm skeptical about that but they both say they did it to an engine I knew he blew up and didn't replace the sleeve......

 

[sweetdiesel]

Frustration

Well I tried to get the engine started last night and she just wouldn't turn over. 3 Hours of heating up the head, ARO, loosening the glow plug all resulted in nothing. Needles were also reset to factory specs.

If anyone knows how to relieve some of the pinch from a sleeve please chime in. Thanks!

 

[Plaidfish]

gotta send it back to have it done......are you using a starter box????
if so what box??.......it would suck to have to send it back now.....cause once you run it fro a little while it just releives itself.....is it stuck at TDC now???? or is it jamming into it when you try and turn it over???

 

[sweetdiesel]

It's a pullstart engine. At one point I heated up the heat to almost 200 degrees and it still wouldn't fire, it keeps jamming into TDC when I try and turn it over.

 

[Plaidfish]

your pull starter cord just slips then huh???
can you run a starter box on the RC it's in or at least mount it in one you can turn over w/ a box????you could get it up and going like that probably...I can't tell w/o rolling the Flywheel as to whether it's too tight....that's a knowing what to look for issue...you either do or you don't......I'd try and bump it before sending it back if you can......

 

[sweetdiesel]

Last night I was sure the pullstart cord was going to snap...I probably pulled with more than 50lbs of force. The sleeve is way tighter than when it was brand new.

I'll throw it in the buggy and see if my friend's starterbox will turn it. The only problem I see is the starterwheel reaching the flywheel. With the pullstart housing in the way, I have to use a taller mount.

 

[ImBroken]

If possible, remove the pullstart, and try to get the chuck of a drill on the shaft. Use the drill to turn it over a dozen or so times, till it loosens up.

 

[sweetdiesel]

I'm going to try that, thanks for the help gentlemen.

 

[olds97_lss]

Don't do it on the starter shaft!!!!!

Take off the CB and flywheel. Tighten the chuck down on the crank shaft on the front side of the engine.

I did what ImBroken suggested first and it marr'd up my starter shaft. It's not as hard as the crank shaft. With the starter shaft marr'd up, it messed up my one way when I finally did get it started. In about 1/2 gallon the brand new $25 one way was junk.

I basically "releaved" mine with a non-cordless drill that was variable speed. I pulled the glow plug, the carb and the starter assembly. I chucked down on the crank shaft where the CB goes, sprayed a few shots of WD down the carb and in the GP hole, then slowly pulled the trigger on the drill. After almost breaking my wrist, (doing it with the engine in my left paw and the drill in my right paw), it finally started turning over... 30 minutes of WOT with the drill and a half can of WD later, it was loose enough that I could get it to start with the pull start. But, for about the first gallon and a half, I had to carry a fat screwdriver to pry the flywheel through TDC almost at least once every time I started it (hot or cold). It would just get stuck.

Now, I'm on gallon 4 after the pinch and it still gets stuck at TDC, but not stuck stuck to where I have to use a tool to get it over the hump.

 

[sweetdiesel]

I'm planning on clamping the engine down on my bench vise. Just need to borrow a neighbors drill since all mine are cordless and have a keyless chuck. Thank you for the additional information olds.