Nitro engine getting stuck at TDC

[mzanzirc]

Howzit guys

So I got this nitro. Secondhand. When i got it, i could easily pull the pullstart and the engine would turn over very well.

Today though when i finally got my fuel and whatnot, the damn engine gets stuck at TDC. I pulled slowly on thr pullstart and it snapped.

So i took the engine out and repaired the pull start. Good. But turning the flywheel i could hardly do it by hand.

Took the cylinder head off and this is what i see when i turn the engine by hand.

The piston sleeve comes out by a few mm. As if the piston is getting stuck in the sleeve and pushes the sleeve up. When turing it the sleeve goes down again. It turns nicely at the bottom.

Any ideas? And I ruined my pullstart. Spring inside came out. Ffs.

 

[Chubaka]

If the engine is still like new, I would say the sleeve coming up is normal with no head. Alot of new engines need the head warmed up prior to starting because the pinch is so tight.

As for the stuck at tdc, maybe it hrdrolocked or a colbination of hydroloc and a tight pinch?

The reason behind that is fluid does not compress, and it may help seal the piston also.

I would use a heat gun or hair dryer to warm the block. Igmf ots a heat gun, maybe wrap the engine in foil as to not melt plastic or dicolor it.

 

[mzanzirc]

If the engine is still like new, I would say the sleeve coming up is normal with no head. Alot of new engines need the head warmed up prior to starting because the pinch is so tight.

As for the stuck at tdc, maybe it hrdrolocked or a colbination of hydroloc and a tight pinch?

The reason behind that is fluid does not compress, and it may help seal the piston also.

I would use a heat gun or hair dryer to warm the block. Igmf ots a heat gun, maybe wrap the engine in foil as to not melt plastic or dicolor it.

Thanks for the reply.

Maybe I should calm down first. hahaha.

Right, so it's a secondhand RC. I'm not sure as to the age of the motor.

When I got it about two or so weeks back, I could happily pull on the pullstart and it would turn over freely. It would "feel" very tight, but a quick yank and she would keep turning over.

It's not hydrolocked or anything. Sorry if I didn't make that clear in my first post. lol. There was no fuel in it. nothing.

I will try the heat gun trick and see if that works. But should I do that every time before I run the car? Or only for the first could of times?

New to nitro. Although learning all this stuff is awesome, I'm almost starting to regret it. hahahaha!

 

[TRAT]

Sometimes I’m not saying this the case but if it new yes heat will help as it brakes in. I have a built big block that’s pinched sleeve for higher compression so the understanding what’s going on is the fact that if it’s new the brake in process has not been done correctly.
And I’ll give this advice as we’ll Nitro is pain in the ass sometimes climate weather all those things come into a factor. Mine well some like my TRAT doesn’t like hot weather.

 

[mzanzirc]

Sometimes I’m not saying this the case but if it new yes heat will help as it brakes in. I have a built big block that’s pinched sleeve for higher compression so the understanding what’s going on is the fact that if it’s new the brake in process has not been done correctly.
And I’ll give this advice as we’ll Nitro is pain in the ass sometimes climate weather all those things come into a factor. Mine well some like my TRAT doesn’t like hot weather.

Thanks.

I did heat up the engine and it got better. I sew on youtube they recommend around 80° celcius? I'm not sure what mine was at.

I also rewound my pullstart spring. Luckily it is working again.

So what should have been just me putting in fuel and trying to start it ended up in me learning to take a nitro engine apart and completely overhaul a nitro rc pullstart. And one big mess of parts all over my bench.

I'll put the cylinderhead back on and heat it again. Hoping just to get it started so the engine can loosen up a bit.

 

[mzanzirc]

So the seller tells me the engine is still new and all the posts on forums confirms this is a classic symptom of a new engine.

The seller also told me as you guys have said, to heat the engine up and then start it.

I made a silly mistake last night. I put some nitro in it, and the only heating tool I had was a dremel soldering iron. Removed the tip and started to heat the engine. The nitro fuel started to burn. Wasn't bad. But it was cool. hahaha!

I picked up a heat gun this morning and will proceed to heat the shyte out of it until I can pull the pullstart!

 

[mzanzirc]

Well well well. The seller advised me the engine is new (weird as it doesn't look new - He might have put one tank through it?) and he says I still need to run it in.

So all my effort and struggles were for nothing. Why couldn't he just say, it's new, it needs to be run in and heat it up before you yank on the pull start.

So I guess I will be doing that now. LOL!

 

[mzanzirc]

I have good news! After I blasted her with the heatgun, she fired right up. I did loosen the glow plug a bit just to make sure she has every possible chance of turning over. Voila. Glad I'm sorted. Now I can relax! hahaha. But now I'm on the hunt for a replacement pullstart. Anyone know what to look for? I'm ok with getting a generic one that will fit. Or perhaps I might look at going to a rotostart backplate.

Ok, nitro makes one helluva racket! Me likey....

 

[500 Mike]

Glad you had success in getting it started. Using the heat gun on it ahead of time has helped me a bunch. Much easier that way. Being a noob I had a steep nitro learning curve as well. I'm still learning all the time too. Enjoy the racket as well as the drive!

 

[mzanzirc]

Glad you had success in getting it started. Using the heat gun on it ahead of time has helped me a bunch. Much easier that way. Being a noob I had a steep nitro learning curve as well. I'm still learning all the time too. Enjoy the racket as well as the drive!

Thanks man.

Yeah I didnt think I will be rebuilding pullstarts and taking the engine apart so soon.

If the seller told me (i guess i should have asked too) the engine is new and i should probably use a heatgun on it. Could have saved me tons of time and effort, buy i guess i dont learn that way. Lol.

Feels lile a huge weight off my shoulders. Hahhaa.

 

[johnnydmd]

I had similar issues with a brand new OS .12, it was super tight.

 

[mzanzirc]

I had similar issues with a brand new OS .12, it was super tight.

This thing is tight like a tiger.