Rebuilding My Old Savage 21

[monstertruckier15]

If there is some scoring on the 4.6 engine I suspect the bearings could be bad. More oil lube will help with that problem. It will also help when starting and promoting a good pinch. I suggest you get a temp gun and watch the temperature Not to exceed 225 degrees. That is a medium number! I would have ran 14% oil lube based on the condition of you motors. More oil lube can bring back compression on a used engine.

Curious to where the high speed needle is set after to had it tuned at the store? Factory high needle setting start is 2-1/2 turn out from closed and 1/2 turn in is the danger zone 2-1/4 out is fine.

 

[D3MON]

225F is barely operating temperature, the materials haven't even completely expanded and seated to mate fully. ABC (aluminum, Brass, Chrome) construction sleeves are completely fine at 240-270, that is their operating temperature, much over that and it starts to degrade the metal integrity, and 300F is where damage starts setting in.
ABN (aluminum, Brass, Nickel) is a bit lower temperature bracket, and more susceptible to damage if it does overheat, whereas ABC "might" survive overheating a few times and still might run right, but lifespan definitely compromised.
but still 220+ minimum, neither of the HPI engines are ABN, think the last ABN they used was the 15FE? (please correct me if I'm wrong).

 

[Dizzyotes88]

Well we ran thru about 4 tanks of fuel. Adjusted the brakes. Had to change out the spur gear as we totally stripped it down to no teeth. Lol. Put a 52T spur gear on from my original savage and man! That low end torque is totally sick! It was killer. And I'm not sure yet if I have the 3 speed transmission or not. I'm starting to think it does, I'm just not totally sure. But either way it was so much fun running it up and down the street for awhile. A neighbor came out and said he was charging his electric battery for his car.

I'm going to order another spur gear online that's metal but it's only the 47 or 49 tooth. They are sold out of the 52. My new motor is already on its way. It'll be here in a couple days. Then we will get to work on the other truck to have both up and running. And I'll tinker with the 4.6 motor and get it going so we will know for sure if it's dead or not. The shims will be here about the same time as the new motor. And what's messed up is I looked in my big bag of parts and found shims. Problem is they aren't the right size for the 4.6.

 

[Dizzyotes88]

Also it doesn't turn very well right now. I moved the shock position on all 4 corners. Which stiffened it up and I'm happy about that. We got it to endo flip once. Got it to drive on 2 wheels a couple times. Which was alot of fun. I just want to take it to the park by my house and play with it over there.

 

[monstertruckier15]

a Smaller clutch will help. 2 teeth down
GENUINE HPI SAVAGE HEAVY DUTY STEEL SPUR GEAR 52T RARE | eBay
Team integy steel spur Gear for Savage 51T | eBay
GENUINE HPI SAVAGE X Spur Gear 52 Tooth (1M) - Savage SS / 4.1 / 4.6 / 77097 | eBay
GENUINE HPI SAVAGE X HEAVY DUTY STEEL SPUR GEAR 52T | eBayRobinson Racing Mod 1 Hard Steel Clutch Bell/Spur Gear Combo (52T/14T) [RRP7052] 719696070524 | eBay

 

[Dizzyotes88]

Smaller clutch? What do you mean exactly as far as to what I was talking about?

 

[monstertruckier15]

Smaller clutch? What do you mean exactly as far as to what I was talking about?

Most engines you can change clutch bells to change gearing along with the spur gears The motor will slide to adjust.
Robinson Racing Mod 1 Hard Steel Clutch Bell/Spur Gear Combo (52T/14T) [RRP7052] 719696070524 | eBay
I see 13-20 tooth clutch bells

 

[D3MON]

Smaller clutch? What do you mean exactly as far as to what I was talking about?

smaller clutch is going to gear it down to go slower, and a larger spur gear is going to do the same, so to compensate for the smaller spur gear, id recommend to gear down the clutchbell a tooth or two to be closer geared to stock.

 

[Dizzyotes88]

Oh! I totally got ya now. So having the larger spur gear makes it slower? Cause it was flying. Let me tell you. Lol. That low end torque is very nice. I guess I'll just get that 47T metal gear. I want it to go faster. But I love that torque. I would love to have both.

 

[Dizzyotes88]

Ok so did some teeth counting. 52T spur gear with a 14T clutch gear. I have a 17T clutch gear. What would that do? Would it change much?

 

[D3MON]

stock:
52T Spur & 17T CB = 3.056 ratio the clutchbell/gear needs to rotate that many times to spin the spur gear.
so to get close to that to stay similar with a 47T
47T Spur & 16T CB = 2.9375 ratio, so going to be (very) slightly higher geared than what you have now.
47T Spur & 15T CB = 3.1333 ratio, which is going to be a (very) slightly slower.
if you are happy with the speed and wouldnt mind sacrificing a little bit and want maybe slightly more torque, i would get the 15T, if you want maybe a bit more speed (like in the .0X MPH range) and dont really care to have more torque, get the 16T.
if you are going for a steel spur gear, make sure to get a hardened clutchbell, like from Robinson racing, or another higher quality brand, not all metals are equal. if the clutchbell isnt hardened, and the spur is (very rarely if ever they are not hardened), the teeth will get eaten off the bell gear, i think i still have pictures when i was testing that out to prove a point lol

 

[monstertruckier15]

Usually you don't change the stock spur gear size. To get more torque without loosing speed you change the clutch bell 2 teeth. You can get the metal spur gear. You can get a 15 tooth clutch bell.

 

[Dizzyotes88]

Alright so between talking on my other thread about my new trucks, I went outside to run my HPI. Was running great, got it warmed up. And then the throttle went wide open, and nothing on the remote would stop it. So I shut it down, look at it inside and nothing is stuck. I'm going to change the batteries in the remote and see what that does. The throttle trim is set correct on the remote because I even played with that as well.

I also had a body on it for the first time. Not that it should matter.

 

[Dizzyotes88]

Well, I think I burnt up the spur gear, or close to it. Stupid plastic gear.....

 

[monstertruckier15]

Well, I think I burnt up the spur gear, or close to it. Stupid plastic gear.....

Alright so between talking on my other thread about my new trucks, I went outside to run my HPI. Was running great, got it warmed up. And then the throttle went wide open, and nothing on the remote would stop it. So I shut it down, look at it inside and nothing is stuck. I'm going to change the batteries in the remote and see what that does. The throttle trim is set correct on the remote because I even played with that as well.

I also had a body on it for the first time. Not that it should matter.

Time to get the fail safe and this wouldn't happen. The the truck would have just stopped. if signal lost or low voltage loss.
4.8-6V Fail Safe Suit for RC Nitro Cars Accelerator Brake Protection | eBay

 

[Dizzyotes88]

The spur gear is toast. Figured out the issue. I guess one to many hard launches. Fun while it lasted until the metal 47T comes.

 

[monstertruckier15]

That will do it but you better get some fail safe's in all your trucks.

 

[Dizzyotes88]

So what does that do? I read the description. It doesn't say what it does. I get the concept. Just want to understand better.

 

[Dizzyotes88]

So the first 2 pictures are the 49T spur gear. The third picture is my current 52T spur gear. And the last 2 pictures are of my original 47T spur gear.

Is there a way to get that 49T gear on my truck? We had tried that one first but it wouldn't go as far as setting it right to tighten it down.

 

[D3MON]

So what does that do? I read the description. It doesn't say what it does. I get the concept. Just want to understand better.

what failsafe features are designed to do is to return the electronics to "idle" or "brakes" position in case of lack of communication between the RX and TX. bear in mind, this ONLY works in cases of lack of communications between them, if power is lost between the RX pack and the servos/receiver, the failsafe will do nothing. use a spring on either the linkage or the throttle slide itself that puts tension to close the throttle linkage. make sure that the spring has enough tension to overpower an unpowered servo, but not too much that the servo has to fight the spring to function.