I got my rs4-3ss last year for christmas. It has the 12rss engine in it, and for the last couple of months it seems to be loosing more and more compression. Sooooo how long do engines usually last before a rebuild or befor getting a new one? I have been putting after run oil in it and everything. It has had about 2 gallons of gas put thru it.

most .12s will last 4-6 gallons. It all depends on how rich/lean you run it though.

hey guys what about using airplane fuel like the omega 15%nitro and 17%oil?
I think they will last longer cause the airplane fuel have more oil or I am wrong????

Airplane fuel is useable in an rc car engine, but you should really use fuel thats made for the car.

mines (.15 abc piston) gone for 3-4 gallons of fuel and is still going strong

What kinda mileage can I expect to get out of the .25 that comes in the savage SS...

They've still not arrived over here yet, so I guess I'd best make sure I'm not buying no lemon

everytime i pull the pull start there is like a hissing sound it sounds like an air leak....i replaced the glow plug and it still makes it and still little to no compression....anybody got any ideas on what i can do??

Hmmmmm. Any ideas where the "hissing" is coming from?

Have you stripped the engine down to inspect the state of the piston / sleeve?

I haven't yet reached the point where a rebuild is necessary, so I can't really advise you on how to tell when one's needed, but if you have no/little compression then I'd say you're there

I know that with mine it's VERY hard to turn the flywheel manually through a complete cycle - give yours a try...

the hissing seems to becoming from where the glow plug is.....and the flywheel turning it manually, its almost as easy as picking up the car and turning a wheel

What I do to check the compression of my engines I take the engine head off and I turn the flywheel. The piston sleeve should lift a little bit but if it doesn't lift than it needs a rebuild.

HPIRS4-3SS - I'd say you definately need a rebuild if the flywheel moves so easily

Try taking the head off your block and check the condition of the parts - make sure you need a rebuild before investing in the parts and all

condition of the parts.....what exactly will i been looking for? this is still my first engine, first problem with it to

i took off the head....i move the flywheel and the piston sleeve moves

I'm not the most experienced person myself on this one to be honest

Still on my first engine too - lol

It's a good sign that everything's moving (from a diagnostics point of view), but from what I know, it's sounding more and more like you need a rebuild...

well if it sounds like it's coming from your glow plug.. and you can see the piston sleeve move up on it... your head on your engine is loose I bet... make sure you line up the sleeve right on the piston.. and make sure you put some BLUE loctite on the screws of the head and screw it down, DON"T STRIP THE SCREWS though... make sure it's tight.. I think that's where your loosing compression.. I had that happen on my Hyper 21.. It needs to make the Pop pop noise... no hissing noise.. pop pop pop..... and if you want to see if you got good compression.. hold a finger over the carb... and pull the starter cord... sucks your finger pretty hard.. your good.. it doesn't suck on your finger.. you got a rebuild coming up..

i can see the sleeve move when i take the head off......not whiles its on

do u mean put my finger over the carb with air filter goes.....cause if u mean that i dont fell anything at all

Since the piston sleeve moves take the engine apart and check the con rod and the crankshaft for scratches. You could also need new bearings.

thanks ill do that later today....but if i rebuild it what would i need?

You would need a head shim and gasket set for your engine and you would need the piston and sleeve set for your engine. Before you order your parts though you should check to see if you need any other parts.

ok im taking it apart right now....i have the whole back off i can see the rod, nothing looks scracthed and everything is moving smoothly......do i have to take the flywheel and all that other stuff off?

Its back to normal now, im not quite sure what i did to it. All i did was take it apart and look at it, then put it back together. So i am guessing maybe a screw was not tightened or something. Thanks for all your advice and tips, im sure i will be able to use them when the engine does need a rebuild

Cool - nice to know you got it sorted

Have fun