When is it time for new piston/sleeve?

[RCDad]

I just pulled my k4.6 out of the Savage, and I was turning it over....it seems to turn over soo easy. I mean, I have .12 engines with more compression. How do you know when it's time for a new piston/sleeve or could this mean that the engine needs to be sealed?

I'm wondering if the Nova cooling head needs to be sealed somehow?

[rocco79]

Pull the piston an sleeve out... Push the piston up through the sleeve if you get to the top of the sleeve your worn out and need a pinch or a new sleeve/piston/rod.... or i guess you can try getting it pinched....

You really can seal the head... it seals through the tightness of the head bolts and the shims....

[RCDad]

So the piston should never be able to pass through the top of the sleeve? I've never heard that before.

[rocco79]

So the piston should never be able to pass through the top of the sleeve? I've never heard that before.

You never have? Yes, if the piston can make it almost to the top (1-2mm) without very much resistance . Your engine is cashed.... Now if you can get the piston PASTED the top of the sleeve you surely need a rebuild! Engines work off of taper and a very tight fit... If you can push it up that far when the engine is cold imagine how big the tolerances grow at operating temps.

[RCDad]

How does an engine act when it's worn out? Mine is running really hot and it does not seem to want to run very long.

[rocco79]

does it run and quit for no reseason??? Just pull it apart and test it the way i told you

[RCDad]

Ok, got it completely pulled apart (and praying I get it back together), the piston will not go through the sleeve at the top so they must still be good. The Nova head was definitely not as tight as it could be.

I'd like to soak everything in some kind of cleaner, should I use gass or nitro fuel? I've got the carb completely apart also.

[Mr. Tune]

Don't soak any part of the motor in cleaner. Leave all the internals as is.

Tex has told me why before (I had asked the same question before), but I forgot how he explained it. I'm sure he'll chime in soon.

[rocco79]

Well if the head was loose that MIGHT have been your problem. But remember the piston doesnt have to pass all the way through at room temp.. It just has to gey close to the top. because when the sleeve heats up it will get bigger and allow for my "blow bye" to occur...

No reason to clean the oil off ethier , it protects the metal from oxidation.....

All i can say is put it together, seal it up and make sure the head is tight... if it still runs like a turd go buy a mach .28 or a xtm24/7pro LOl!!!

[RCDad]

Ok, I'll just reassemble everything as it is and seal where applicable. Thanks all!!

[Tex]

the oil residue in the motor keeps it lubed and protects the inside of the motor. Also it makes the seal of the motor better and compression stays tighter.

[RytM1]

If the flywheel is offering up little resistance when turning by hand, you may want to start considering a pinch. Especially if its not running consistent. I smoked a new piston/sleeve last summer at Nitrofarm by sucking a little dirt, and next thing I know, the engine won't stay running, and there is no pinch. I have only seen one engine (and I wish I remembered who had it last summer) that screamed with no pinch. I couldn't believe it.

[RCDad]

Well if you can't push the piston through the sleeve could it still be bad (or needing a pinch)?

Haven't had time to mess with this all week, Saturday I'll begin reassembling this engine.

[RCDad]

I saw something that did not look right when I reassembed the engine this morning, it looks like a small piece has broken off from around the bottom edge of the piston. I bet that's why it lost so much compression.

I'm going to see how it runs later, I may have to put the HB .26 on.

[Tex]

that would be a blown engine. I would just throw the .26 on now.

[RCDad]

I sealed up the .21 and put it on, it fires right up and sounded real good. I'm going to try it tomorrow and see how I like running with the smaller engine. I took the HB .26 apart and cleaned it all up and resealed it, I'm going to take it as a spare

Tex, I got that rear end dialed in now, had to take the rear carriers off and turn it. The turnbuckle just was not even on both sides.

I also ground down my front carriers n stuff so I have a lot better turning radius.

I'm looking forward to tomorrow!

I saw a new piston & sleeve for the 4.6 on eBay is only $40.

[rocco79]

wait... Im confused... Did you mean you sealed the .28 (instead of .21) and it runs fine????

[RCDad]

I took the k4.6 apart and during reassembly this morning I noticed the piece broken off on the bottom edge of the piston. I went ahead and sealed the engine up and tried it out but it wouldn't even start.

I took the .21bb apart, cleaned and sealed everything up, it's running great, so I put it in the Savage to run tomorrow.

I also took the HB .26 apart, cleaned and sealed it up, I'll take it as a backup.

[rocco79]

OMG a .21 BB!!! Wow!! I didnt now there were any left around!!!!

Cool!!!! Hope it runs well for you tomorrow!!!!

[RCDad]

I don't care if its a 21 or a 51 as long as it runs good.

[Czech-it-Out Graphics]

if u really want to u can clean the internals of the motor in diesel fuel

[rocco79]

@ 3.00 a gallon! LOL!

[RCDad]

I've been using WD40 to clean the engine internals.

[Michowski]

well denturated alchohol is like 8 bucks a gallon. You can get 2 and a half gallons of deisel fuel for the price of just one gallon of alcohol.

[Czech-it-Out Graphics]

never use wd40, it is bad for o-rings and seals. If you have a modified motor that has putty in the crank, it will break that down as well