New sleeve/piston?

[pitbull14218]

So my HPI MT1 has a .15fe motor, it seems a bit tired, I was debating just rebuilding it.

Can i use any .15 piston and sleeve or does it have to be the exact one?

Or just maybe another engine?

 

[Certified Mike]

You would Def need the same type of piston and sleeve. No such thing as a generic although you may find off brand replacement avail. for it, I recommend the real deal for the same performance and reliability.
You will need to break the motor in again.
Personally, I recommend ppl rebuild, esp with a small motor. This is assuming of course that The parts are available. The parts tend to be cheap and it's a good learning experience at least.
If it's just about cost for you, it's a simple comparison of parts cost vs replacement cost. So really, you need to anseer your own question. Rebuilding is certainly a common practice though.

 

[ninnon]

You need the same piston and sleeve from the same engine. Does the engine still have compression/

 

[pitbull14218]

You need the same piston and sleeve from the same engine. Does the engine still have compression/

It has resistance when I pull the starter, when it's warmed up it's definitely easier to pull.

 

[cbaker65]

I would definitely be shoving an 18 in there!...

 

[pitbull14218]

I would definitely be shoving an 18 in there!...

An hpi .18 Or what brand? Any recommendations?

 

[cbaker65]

An hpi .18 Or what brand? Any recommendations?

There is several brands of that size that I seen on ebay recently was an AE 18 which is common for the mini Mgt which I have ,
very easy to tune!
Then you have the Hpi 3.0.
An Ofna has an 18 if you can find one ,which I have!
An acource ,there is the Traxxas 3.3 ,but rather have a OS 18 for that price!

 

[BurningRain]

I'm going to rebuild my other engine soon, for ease i've just gone for standard replacement parts.

 

[cbaker65]

I'm going to rebuild my other engine soon, for ease i've just gone for standard replacement parts.

Yea ,take your time an shop on E-bay ,you should be able to find a new descent engine for less than a &100.00 bucks.

I seen a few engines ,for a 100 ,I wouldn't do anything less than an 18 size engine!

 

[pitbull14218]

If it's cheaper to rebuild I might go that route because I just bought a savage x lol... So no need to make 2 crazy nitro rigs.

But today I decided to take a part the old .15fe, and she is very tired!

The front bearing the crank rides in has no up down or side to side play, but in and out it has some. So I guess that means the bearing is worn? What do I replace it with?


The rear engine plate with the pull start the bushing the other piece of the crank goes in has some play causing lol to leak into the pull start which then leaks out from the rest of the Engine. Is that bushing or bearing replaceable?

Also I'm thinking of repinching the sleeve and porting it myself for fun, do people repinch the sleeve with a hose clamp still?

Pics

 

[Certified Mike]

@pitbull14218
If you go on the AE site, there is a.18 bearing avail. With a lil research (if I got it right for another person here) I believe you will find it's the same bearing for .12, .15 and .18 motors. PLEASE check the part numbers, sizes etc... I am not 100% on this... But 75% at least. Please let me know if I was right about the bearings. Although I don't own an AE nitro motor, I have a few of their cars and will likely own one sooner than later. Thanks! Good luck!

E-bay seemed to be the best pricing on the parts... So shop there, but AE site for info. on sizes as well as your manuals.
@BurningRain
Unless you got extremely lucky, putting a different piston and sleeve in would have likely resulted in broken parts and almost Def no run situation. The sleeves are cut per motor case design. Good call and good luck! Let us know how it goes! Don't forget you will need to do the break in process again!

 

[pitbull14218]

So I was going to try to re-pinch the sleeve myself but when I googled repinch ing nitro engines I found a guy local to me that does it. So should cost about $24 to get the sleeve re-pinched. I'm gonna see if he does porting and polishing as well.

I also just bought on eBay the backing plate for the pull start which has the bushing, so I'll take care of some areas where there could be vacuum leaks.


What about carborator modifications?

I notice the throttle bore is a bit bigger than the actual rotating throttle blade, could I port it to match? It seems like it would have to help performance.

 

[Certified Mike]

I have done a TON of research about modifying nitro... If you have lots of knowledge and experience, you can play with boring out the intake BUT I strongly urge you to KNOW what you're doing before you start cutting... Unless you don't mind replacing a case. If this place does mods, ask them about it... I'm sure they can tell you. My guess is that rather than doing a bigger carb, that are gonna recommend cutting the sleeve ports and doing timing work etc... It's not a simple thing. You may want to read about sealing a motor if you have leaks. There is a post about it in the nitro forums I believe. No matter what you do, please post about it and GOOD LUCK!

 

[pitbull14218]

I definitely plan to seal everything up once I get the sleeve and piston back.

I have some carb sealant in a tube, I'll see what people think about before i use it, in case I should consider another product.

 

[cbaker65]

I definitely plan to seal everything up once I get the sleeve and piston back.

I have some carb sealant in a tube, I'll see what people think about before i use it, in case I should consider another product.

The best stuff to seal is that copper sealer ,I forget the name!..

 

[Certified Mike]

You need a sensor safe rtv.

 

[pitbull14218]

The best stuff to seal is that copper sealer ,I forget the name!..

I'm glad you said that, I do have some in the garage!

 

[cbaker65]

I'm glad you said that, I do have some in the garage!

Sealing an engine is controversial ,But I do it anyway for a piece of mind!
One of the most important things ,is to make sure the fuel tank holds pressure ,that the lid seals an
it receives the pressure from the muffler.
If the line connects to a pre-tap nipple that comes out of the muffler ,make sure its tight an not plugged.
If the fuel line simply goes through a hole in the muffler ,My trick is to cut the tip of the line in an angle
so the tube doesn't bottom out in the muffler an plugging up...

 

[Certified Mike]

Make sure it is sensor safe... And be careful not to goop it all over the place... It's a sensitive thing in that you don't want loose pieces of that inside the motor at all... Also, be very careful if you're sealing the carb. You don't want that in the tube or in the carb... VERY careful!!

 

[GAJ]

Permatex Ultra Copper RTV sealant is what you want.