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So I found this HPI Nitro RS4....

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Old 07-05-2011, 05:34 PM
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Default So I found this HPI Nitro RS4....

Okay well I bought a slash 4x4, so my dad was like "ohh I have this bitchin RC down at the shop it's been there for like 5 years if u can find it" so I went down there and got it. It was an RS4, with a brand new clear body, but the car itself was pretty well used. I went and bought some traxxas 20% nitro, but the car is too gunked up to start. I've never had a nitro car, and my dad has never taken it apart. So how do I clean it out and get it running? Ohh yeah and I have no manual. And would it be possible to convert it to electric?
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Old 07-05-2011, 08:03 PM
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if you want to get rid of it let me know
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Old 07-05-2011, 11:40 PM
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Sure if u wanna buy it haha. Or have a slash 4x4, because my dad wants one...
But yeah if not I still need to get this running somehow.. Is there any good videos on how to clean this thing?
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Old 07-06-2011, 09:49 AM
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Well, define dirty and gummed up...

If you're talking extrernally, just hose it down with some motor spray. May need a couple of cans and a toothbrush to get the hard stuff out.

If the engine is seized you're going to have to take it apart. You'll also need to let us know what engine is in it. It could be the 12e if it is the original Nitro RS4 with the silver, no-countersunk chassis or the later Nitro RS4 2 with the 15fe and the purple countersunk chassis. Depending on which version you have will change what tips I can give you. The 15fe will say 15fe on the pull start case. The 12e will just say "Nitro Star". Both engines look almost identical with the only external difference being the 15fe has engine mounts built into the bottom of the case in addition to the normal engine mount tabs that are on the side of all small block nitro engines. The 12e just uses standard engine mounts.

First, NOTE: When taking apart the engines, be VERY careful. The screws most use are small and VERY easy to strip out their heads. This also goes for the screws holding the engine to the chassis. Use a screwdriver that fits the screw heads very well, press down hard to prevent the screwdriver from slipping, and turn slowly. At the first sign the screwdriver is slipping on the head, STOP! Also be sure to use the proper sized allen keys for all hex head cap screws. Most of the hardware is metric so be sure to have metric allen keys if your engine has hex head screws on it. (I'm pretty sure though the 12e and 15fe both used phillips head screws throughout...)

As for engine teardown, there are manuals on HPI's site.

http://www.hpiracing.com/instruction...Star%20Engines

The 12e is similar enough to the 15fe that you can use it's manual for the 12e teardown (they don't have one posted for the 12e). Also, the other 12s listed on their site are COMPLETELY different from the 12e so DON'T use them.

Now if the engine is locked up, you're going to need to take it apart. Here is where I'll need to know what kind you have to give you proper pointers. One thing you WILL need to know though is that you need to note how the sleeve is aligned in the engine case. The sleeve is ported and the ports need to line up with the ports in the engine case. (Except the exhaust port, you can't see the ports when the sleeve is in the engine case and the piston is at the top of it's stroke.)

Now, chances are the piston will be stuck at the top of the cylinder. To get it down, (after taking off the cyclinder head) first try pushing it down with the pull start off the engine. If that doesn't work, get a small screwdriver and place the HANDLE OF THE SCREWDRIVER on the top of the piston (DO NOT use the point of the screwdriver as it will damage the piston). GENTLY tap the tip of the screwdriver with a hammer to try and loosen the piston and get it to move down.

IF this doesn't work (and it should) try placing the engine in a small container of FRESH nitro fuel and letting it soak overnight and repeat the process.

IF it DOES work, continue to disassemble the engine. Take the piston, sleeve, case, connecting rod, and wrist pin and soak them in FRESH nitro fuel overnight. Remove them the next day, brush off any residue fuel varnish that didn't come off during the soak, dry them off, and reassemble the engine.

Depending on how used the vehicle is, this MAY or MAY NOT refresh the engine. If the engine was ran hard and has more than a couple gallons through it, it may be worn out completely.

Also, here are some manuals for the different Nitro RS4s.

http://www.hpiracing.com/instructions/#Kits

Hope this helps and if you have any more questions let me know.
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Old 07-06-2011, 01:05 PM
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Thanks a lot for all of that info! I can't check the engine out right now, but the chassis is purple if that helps. And yes the engine is internally gummed up, the car won't even come close to starting. Is there anything else besides the engine that I would need to take apart/clean? Also how much do you think it would be worth if I were to sell this car? (once it's running)
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Old 07-06-2011, 01:35 PM
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Originally Posted by iStubz
Thanks a lot for all of that info! I can't check the engine out right now, but the chassis is purple if that helps. And yes the engine is internally gummed up, the car won't even come close to starting. Is there anything else besides the engine that I would need to take apart/clean? Also how much do you think it would be worth if I were to sell this car? (once it's running)
If the chassis is purple and your father never did anything to it then it's almost definately going to be a Nitro 2 and have the .15fe in it. Should have asked if it's belt or shaft drive too...didn't even think about that...shaft drive would change everything...5 years, yea, could be a Shaft Drive Nitro 3 and at 5 years old it could have the newer T-15 engine or one of the .18 sized engines...Those I'm not familiar with as I am the .15fe. Getting the piston loose though would be the same for all of them.

As for what it's worth...hard to say. Really it comes down to what someone will pay for it. $100 maybe with radio if it's a Nitro 2. Maybe a little more if it's a Nitro 3 with the .18 sized power plant. Wouldn't be over $200 even it it was almost brand new with radio considering it's been sitting for so long unless you found someone that just HAD to have it. I'd say trading it, cleaned up, in running condition and in an RTR state, for a RTR Slash would be a fairly even trade.

For cleaning, figure you need to clean the whole thing. Bearings should be fine as they are sealed units. Diffs may need some new grease and I'm almost certain your shocks will need new o-rings, new bladders (IF they came with bladders...), and refreshed with new oil.
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Old 07-06-2011, 03:11 PM
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It's got the 15fe motor and it's belt driven.
Would an electric conversion be possible? If it's only worth $100-200 I'd rather just make it electric and keep it.
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Old 07-06-2011, 04:08 PM
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It's a Nitro 2.

As for an electric conversion anything is possible with money. Reality is that there is no cheap way to do it. No one I know of ever made an electric conversion for it as, when it was popular, brushed electric motors were the only option and not able to provide the power for adequate performance. Cheaper to either trade it for a Slash, get it running for cheap, or leave it as-is.
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Old 07-06-2011, 05:04 PM
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I'll just get it running and sell it so I can start my rally project.
I'll probably be back with questions in a day or 2.
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Old 07-07-2011, 08:32 PM
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tagged..
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Old 07-11-2011, 03:18 PM
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subscribed

I just got an RS4 in a trade...and I know nothing about it
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Old 07-11-2011, 09:28 PM
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Same question as the OP, what color chassis is it? What does the back of the motor say? Is it belt or shaft drive? Does it have upper arms or upper links? I can tell you which one it is from there and once you know that you can get the manuals from the links I posted above. From there, it's up to you to ask questions as for what you want to know about it.
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Old 07-12-2011, 07:51 AM
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Originally Posted by Robotech
Same question as the OP, what color chassis is it? What does the back of the motor say? Is it belt or shaft drive? Does it have upper arms or upper links? I can tell you which one it is from there and once you know that you can get the manuals from the links I posted above. From there, it's up to you to ask questions as for what you want to know about it.
I was only stating why I subscribed. the above info is plenty for me to determine what model it is. just wanted to stay on top of thread, lots of good info in here.
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Old 07-12-2011, 10:36 AM
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Originally Posted by apexslider
I was only stating why I subscribed. the above info is plenty for me to determine what model it is. just wanted to stay on top of thread, lots of good info in here.
So then you DO know SOMETHING about it. LOL

One thing I should mention on the RS4 Nitro and Nitro 2 kits (Super Nitros too but we're not talking about them...) is that they did make a "roll center kit" for them. If you see what looks like a thin aluminum plate between your chassis and the front/rear bulkheads and pully mounts (also should be washers under the upper deck posts), this is the roll center kit. It was a very worthwhile update for the Nitro and Nitro 2 but you'll probably only find them on kits that were raced. They are not common.
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Old 07-12-2011, 10:39 AM
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Want to get my rs4 racer up and running again too. Such a competitive little vehicle.

Anyone have any leads to 2-speed parts? I took mine apart years ago and lost a lot of my parts.
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