savage s25

[weezracen]

All I ever owned was traxxas. My buddy wants to sell me his savage s25 he says that it needs to either have the motor rebuilt or just replace the back plate. Since I never did that kinda work before how costly is it and how hard is it to do? He only wants 120 for it so it should be worth it right? But like I said I don't know anything about hpi or there models worth/specs.

 

[Rolex]

120? Grab it. You won't regret it. You'll never get a better deal, EVER!

 

[RC Addict]

+1. It is worth it, even if it needs a new mill.

 

[jnjritz]

Buy it man, And put a mill in it. You won't be sorry. You will be if you let that get away

 

[weezracen]

consider it bought!

 

[olds97_lss]

$120 for a rolling chassis with all the parts is not a bad deal at all. Personally, I'd consider the engine dead and start new. Trying to work on and bring a previously owned engine to life can be a real annoying ordeal.

If it comes with all the bits but a "working" engine and isn't totally trashed (blown diffs, busted axles, parts missing...) it's worth $120.

 

[weezracen]

so you think a new sleev and piston will be more trouble then there worth?
I always believe in new motors myself that's y I don't have any experience here. I guess a trx 3.3 won't replace that 25 will it?

 

[Rolex]

There are a couple of .28s out there that are even better than the stock mill.
Put in a new one, and do the rebuild as a spare.

 

[olds97_lss]

At most, I'd get the sleeve pinched ($25 at www.rayaracing.com). However, you said something was up with the back plate didn't you?

S25 Piston/sleeve $63+backplate only $14= $75

That's about half the cost of the engine. If the piston/sleeve is worn so bad that it won't run, there's a high likelihood the bearings have a lot of time on them as does the slide mechanism in the carb as well as the one way bearing. Adds up pretty quickly when your working with an engine that is used and abused.

Like I said, if it were me, I'd get it pinched and the new backplate. Then your only out $40 or so and if it craps out on you completely, who cares. Then you can get a new engine.

Or, you can just get a new engine now. There are a few for around $150 that aren't too bad at all.

Either way, $120 for a rolling rig in decent shape is a good deal.

 

[frickenjoey]

If you go to the for sale section in this forum we have a member (Racer1966) who is selling a couple .28 engines that will drop right in. But 120 is a good price for that I would say if it is in good shape.
https://www.rcnitrotalk.com/forum/showthread.php?t=71591

 

[weezracen]

ok I'm going to O "pinch" the motor and get a new back plate. Olds thankx for the link on that pinch I always thought that was just slang for a new sleeve. I learning hahahah! Then go from there. O he says that it got new tires/rims, dual pipe and other stuff I can't remember. When I get it in ill let ya know every thing about it. I'm so pumped!!!!!

 

[olds97_lss]

I wouldn't direct someone to something I don't know for sure is a decent product.

Here's a link of 3 I had done last by RayARacing:
https://www.rcnitrotalk.com/forum/showthread.php?t=56420&highlight=rayaracing

 

[weezracen]

O I see they do it for ya how nice! maybe ill try and sell the motor on ebay with the new back plate on there say that it needs a new pinch and use that cash for a new mill what's mill stand for anyway "motor"? either way I'm getting a savy!!!

 

[olds97_lss]

Yes. Mill = engine.

 

[weezracen]

Ok guys I just got my savy!!!!! Its in real good shape!! I spent about two hours taken it apart and cleaning it cause who wants to work on a dirty truck right? Took out servos motor gas tank sprayed it down with denatured alc and sprayed it with water twice then wiped it all down with my (special) wet wipes looks like new!!!!

Servos all work, diff all work, new spur gear, new 3 shoe clutch, new RD logics dual pipe, new tires and rims!

On to the motor he said he don't know what's wrong with it? It turns over and over but won't start. He thinks that the back plate leaks fuel out to his one way and it won't grab. So I took the the back plate off looked a little dirty. Its now soaking in denatured alc along with the one way. I took the head off to get a good look at the piston. Looks good its not black, pitted, scratched up,.

I think the one way was dirty and his gas was sitting in the tank for a bit before he tried to start it.

Tomorrow I'm going to finish putting it back together and see what we got!

I think its going to work just needed some love! It really needed that cleaning.

Nice rig tho waaaaay different then my revo little hard to get at something.

Ok ill update tom!!!!!!

how can u tell if the pisto is bad?

 

[olds97_lss]

If it has gouges in it or pieces of the skirt missing, that's bad.

Generally, if it's just worn, you won't see much damage.

If you take the engine apart, take out the piston/sleeve, then gently push the piston up in the sleeve from the bottom. If you can push it to be flush or past flush with the top of the sleeve, it needs a pinch. When it warms up, the sleeve expands and you will get a bunch of "blow by" which will cause it to constantly flame out and be hard to start until cold.

Similar to the first photo in that link I posted up above.
https://www.rcnitrotalk.com/forum/showthread.php?t=56420&highlight=rayaracing

You can see how I was able to push the piston past the top of the sleeve on two of them. With new or re-pinched, you can't get it nearly that far.

 

[weezracen]

Ok just to make sure I got this.

1.take the piston/sleeve out of the mill.
2.push the piston through the mill as far as I could with out excessive force.
3.if it goes flush or past needs pinch/replaced.
if not should be good.

what is a pinch another sleeve in side of the other? I know its a cheaper fix just not really sure how it works.

 

[xldriver]

well you will be able to tell if the piston and or sleeve are bad by checking for small pieces of grit or dirt that have found thir way into the engine and made bad scores or scratches on the sleeve, its hard to tell if the piston is bad without dissasembly of the engine. but checking the cylinder walls and turning the engine over by hand with the head on, and the plug in of course, check for good compression if its pretty difficult to tun over by hand then this is a good sign, if its really easy to turn over thats a good sign of wear and may still need pinched. hope this helps. its a good idea to use lock tight on the back plate screws or anything else on this rig for that matter, the savvy is famous for vibrating bolts and screws loose. oh and clean that one way up really good also, this will help it grab up when you put things back together again. Hope this is helpful.

too slow, got caught up, these guys are onto it. listen up

 

[olds97_lss]

1.take the piston/sleeve out of the mill.
2.push the piston through the mill as far as I could with out excessive force.
3.if it goes flush or past needs pinch/replaced.
if not should be good.

Yep, those are the steps. It's the best way to tell if your pinch is worn badly.

what is a pinch another sleeve in side of the other? I know its a cheaper fix just not really sure how it works.

Pinch is the taper of the sleeve. At the top of the sleeve, the ID (inside diameter) and quite possibly the OD (outside diameter) is smaller than at the bottom of the sleeve. As the piston travels up, it is basically wedged into the sleeve wall causing a seal, which will hold the explosion when combustion happens.

As an engine wears, the piston wears as does the coating inside the sleeve. In my mind though, the piston would be more prone to wear as it's aluminum which is soft whereas the coating of the sleeve is chrome, which is very hard.

Anyway, when an engine is "re-pinched", the sleeve is basically compressed at the top ever so slightly in a die machine. Being as thick and heavy as it is, it stays compressed and then gives you your pinch back.

Ray does a two stage compression I believe. Right above the exhaust port is a more mild compression and a bit further up is a more heavy compression. This helps to make the taper a bit more gradual so the piston slides smoothly and isn't hitting the equivalent of a ledge as it travels up the sleeve.

Better engines can be re-pinched 2+ times. Cheaper engines may not be able to withstand it either due to the thinner chrome coat, thinner piston walls or quality of alloy used in the components.

Did I make any sense or is this just mindless ramblings.

 

[RC Addict]

That made a lot of sense to me! Great info!!!