Nitro Engine Restoration

[RC10th]

I've done a fair few OS engines which have come up really well, soooo, I thought I'd start a thread documenting the tear down and clean up of a nitro engine. I'd rather rebuild an OS but have this pretty rough Hyper .12 should clean up well. It is locked solid and I know nothing about it.

This will either be a success or a failure.... we will see....

[RC10th]

It's your typical nitro engine, run and put away neglected without being run out of fuel or ever cleaned. All I've done so far is use some brake cleaner to remove the loose junk off the case. I've pulled the head off to see what condition the engine may be in, surprisingly the top of the piston looks good. I suspect by the old fuel on top of the piston that it has gummed up seizing the engine. I also pulled the carb and pull start. These will be cleaned later.

[Incredible_Serious]

You should have asked mate. Could have sent you a half dozen Irvine .15 2.5cc engines from my Schumacher Nitro 10 pile!

Watching with interest. Maybe I will learn something (there's a first for everything!).

Alex

[RC10th]

Eventually got all of the internal bits out. The rear bearing was disgusting and needed some WD-40 soaking to release its grab on the crank. I used a heat gun to get the bearings out, check out how fresh they are....

[RC10th]

Crank case all cleaned, believe it or not a bath in warm soapy water was the most effective followed by a scrub with a heavy brush. I also had to scrub a few areas with scotch brite to clean a few stained areas. All in all the case came up pretty good.

The front bearing is ok and the rear bearing is a bit worse, but it will still work ok. If it were an OS or a more significant engine I would have ordered a new bearing.

I used a heat gun again to install the bearings and also lightly polished the crank to remove a bit of tarnish.

[RC10th]

Next was to clean the piston, rod and liner. A bit of polish on the outside of the liner removed the tarnish and brought it back up like new. You can really see the difference if you compare it to the photo above. A quick clean of the rod and piston with brake cleaner was all that was needed. I also used a bit of piano wire to make sure the oiling holes in the rod were clear.

Something to take note of is the oiling hole on this style of rod faces the crank. OS's oiling hole is dead on the bottom of the rod, so if you seperate the piston from the rod make sure you mark which way it goes. Also take note of the cut in the piston skirt, this is to clear the crank at the bottom of the stroke. OS pistons have a large hole in the side that faces the front of the engine.

This little engine looks quite nice inside, the knife edged rod os a nice touch

[RC10th]

Install the piston and rod onto the crank, this can only be done (or removed) with the crank at top dead center without the liner in place. Once the rod is securely on the crank pin coat the inside of the sleeve with after run oil and carefully slide the liner down over the piston, make sure you also line up the sleeve with the locating pin.

This engine has a turbo fan which helps to swirl fuel inside, the one way bearing is also incorporated into this fan. At first the one way bearing didn't work at all as it was gummed up and needed a good soak in brake cleaner to free up the rollers. Eventually it came good

I also tidied up the pull start a bit, a little polish on the aluminum collar and an overall good clean is all it needed.

[RC10th]

The last bit for tonight, a nice clean engine head installed. I will rebuild the carb another night. I do need to buy a new exhaust gasket as the one on the engine was torn.

So far the engine is turning out pretty good and I have no doubts it will run, but how good you never know till you fire it up. I wouldn't mind trying it in a GT or something.

[Incredible_Serious]

Just..... WOW!

[RC10th]

Thanks Alex.

This wont fit a GT unless I convert it to bump start. Maybe I should make a nitro powered pencil sharpener ?

[Incredible_Serious]

Thanks Alex.

This wont fit a GT unless I convert it to bump start. Maybe I should make a nitro powered pencil sharpener ?

Come to the dark side. Get yourself a Nitro 10...

[RC10th]

Carb stripped down......

With my good friend polish I cleaned up the brass fittings, they will eventually tarnish back to a more natural finish. With everything cleaned the carb is ready for assembly.

I do need to buy a new carb mounting o-ring as it was quite dry and cracked. Other than that so far so good

[RC10th]

Engine all finished aside from the o-ring. The big question now is what to do with it. Maybe Alex will donate a Nitro 10 for a good cause

[DaveM]

Hi RJ,

Great post!

Do you need to oil any of the parts?

Especially if you don't plan to run it straight away?

Like Alex said,

Learnt something new today!


I knew a Guy in Mt. Gambier and he flew model aircraft.

He said he used oven cleaner on the outside of the engine.

It has to be the one that is suitable for aluminum ovens.

Cheers, Dave.