RE: Official HPI Hellfire Thread
 

I could just squeeze an 18T CB with a 52T spur with an os28. The os started to struggle with that gearing (17T goes ballistic). You mite squeeze the 20 on with the 51 spur.

RE: Official HPI Hellfire Thread
 

thanks stussman. never thought about how much room id have using a larger cb. for some reason on hpi.com it does show spur gears just cb. so i was thinking i would be good with that 20.

anyone else have any other info?

RE: Official HPI Hellfire Thread
 

well the k4.6HO with the repinced sleeve locked up on me today. everything was running fine then stopped all of the sudden. i was still running it somewhat rich since it was a rebuilt engine. i'll break the engine down soon to see the aftermath. thanks peace

RE: Official HPI Hellfire Thread
 

Be sure to post some pictures of what you find.

RE: Official HPI Hellfire Thread
 

hello. in any way am i saying that the repinch was the reason for this damage.

the conrod broke at the top where it connects to the the piston. the rod passes through the piston and then hits the sleeve, causing the sleeve to crack and wedge material to the block. the sleeve will not come out because of this. [&o] so to the closet goes the HF. thanks peace
http://i134.photobucket.com/albums/q...IMAG0010-1.jpg
http://i134.photobucket.com/albums/q...IMAG0011-2.jpg

RE: Official HPI Hellfire Thread
 

Is the block damaged too?

RE: Official HPI Hellfire Thread
 

the block seems to be okay. some nicks from me trying to push the sleeve material back in place so it could be removed. crank seems to be straight also.

RE: Official HPI Hellfire Thread
 

You should be able to find a piston and sleeve online fairly cheap. If not its a good excuse to get an LRP :)

RE: Official HPI Hellfire Thread
 

well... in my persistence to remove the sleeve, I broke the top cooling fin. not where the threads are but to the side. lrp huh? you don't have one do you keithjv? haha thanks peace

RE: Official HPI Hellfire Thread
 

How did you break the fin when you were removing the sleeve? Wasnt the head off already?
No I dont an LRP... I have 2.. :D Great engines

RE: Official HPI Hellfire Thread
 

yes the cooling head was off. the fins on the block are whats broke. with the sleeve not wanting to just slide out. i used a flat head to pry it out some. sleeve is winning so far...

haha 2 huh? well if your ever looking to get rid of one, you know who needs one haha. i need my nitro fix! my crawler and ep boat aren't doing it!!!

RE: Official HPI Hellfire Thread
 

Did you try the zip tie trick to get the sleeve out?

RE: Official HPI Hellfire Thread
 

Vid of my Hellfire on wet road!


[youtube]http://www.youtube.com/watch?v=BgT9P9OktXA[/youtube]

RE: Official HPI Hellfire Thread
 

don't think thats gonna work. the bottom of the sleeve, where the conrod hit, has pressed part of the sleeve into the block. i'm having to use a mini pry bar to get up in there and press it back so i can pull it out.

RE: Official HPI Hellfire Thread
 

If the block has that much damage you're probably better off just tossing the hole thing and getting a new engine.

RE: Official HPI Hellfire Thread
 

ya i'm thinking i'll try some more. i hate to toss a decent block. but i am looking for a .28 lrp. i was comparing engines on rcu. and my question is, how can the lrp .28 spec 3 make that kind of power with that low of and rpm compared to the k4.6HO? with the lrp have a lower rpm does that mean higher gearing would be pointless?


Associated
LRP Z.28 Spec 3


Rating: 4.5 / 5
Type: 2-Stroke
Displacement: 0.279 cu. in.
Cylinders: 1

General Specs:
- Bore: 0.728 (in.)
- Stroke: 0.669 (in.)
- Shaft: SG
- Low RPM: 2000
- High RPM: 33000
- HP: 3.810 bhp@33000 RPM
- Weight: 15.90 oz.


HPI
K4.6 HO

Rate it | Details | Buy

Rating: 5 / 5
Type: 2-Stroke
Displacement: 0.280 cu. in.
Cylinders: 1

General Specs:
- Bore: 0.732 (in.)
- Stroke: 0.665 (in.)
- Shaft: SG
- Low RPM: 3100
- High RPM: 41000
- HP: 2.950 bhp@38000 RPM

RE: Official HPI Hellfire Thread
 

I know what the specs say but all I can tell you is that the LRP flies. I have the LRP .28 in my ST-1 and it will absolutely blow my hellfire away with the HO. The extra HP of the LRP allows you to gear it higher without having to worry about losing bottom end. It has so much power it even ate the teeth off a clutch bell on me when the wheels got caught up in some weeds. The metal spur would turn but the engine spun the CB clean. If you get the LRP you will NOT be disappointed at all. You might even want to try the Z.30 thats out now. It has even more power and higher RPMs. I do suggest you get the bump start version though because the LRP backplates and pull starts are very large and they dont sit right without changing the engine mounts. Or you can buy the LRP backplate that allows you to use the HPI roto start.

RE: Official HPI Hellfire Thread
 

Here is a short clip of my hellfire on my boot leg home made ramp.
http://www.youtube.com/watch?v=pQJb9pTB8jw

RE: Official HPI Hellfire Thread
 

[youtube]http://www.youtube.com/watch?v=pQJb9pTB8jw[/youtube]

RE: Official HPI Hellfire Thread
 

Alright I really need some help from you all, I just purchased a Hellfire RTR, Im very new to the whole Nitro RC world. After I purchased it, it came in and the remote that came with it was all messed up the crystals wouldn't work the tramsmitter was bad, now the worse part of it is I am in Iraq.......I contacted HPI they sent me a new one out. I broke in the engine as per the guideline set forth by HPI. After tuning the carb in and it starts running right, the rear Diff gears get stripped out? Now I am S.O.L, Listen I really need some advice, I am trying to upgrade this thing so I can enjoy it.I heard that the Savage Diff Gears will work, but will the Posi Diff work? also it is stock what spur gear should I be running? If anyone has any input I would really appreciate it, Mind you I am in Iraq so it takes along time to get parts so I dont have the resorceslike going downto the local hobbie store.

RE: Official HPI Hellfire Thread
 

First of all all welcome to the forum and thanks for representing us in Iraq.
Now for the problems. Are you saying the rear diff is stripped already or are you having a problem and asking if its the rear diff? If you can describe the problem you are having we can probably help you out.
I believe the savage diffs work as well as the CEN diffs. HB diffs should work as well.
A posi diff is going to reduce the turning ability of the truck. You can tune the diffs using different weight diff oils which I think is a better option.
The stock spur gear is fine. The CB gear can go a little higher, up to a 15 depending on your driving style and what you are looking to do. If you want pure speed then you want a larger clutch bell and a smaller spur. If you are looking for more torque then the stock gearing is good. If you want a happy medium then a 14 or 15 CB with the stock spur is a good choice.

RE: Official HPI Hellfire Thread
 

Ive had 2 hellfire rtrs. One was new, one used. I use the used one for parts.
The rtr has many faults, weak diffs, weak shock towers and shock caps, weak plastic braces. Unless you shim the diffs yor pinions will strip/wear out very easily. They will still wear out but last alot longer. Iam still using hellfire diffs but i regulary have to reshim them.I just bash so i dont care about bent shock towers or braces. The plastic shock caps will break when you have a hard front on collision. The aluminium caps are a good upgrade. I have rently ordered the cen diffs which the toughest to get. The stock spur of 52t is ok. The rtr comes with a 13t cb. I would upgrade to a 15t cb as the k4.6ho has lots of torque and the 15t will give it more top end while still having ample torque. The hpi transmittor is very crappy so expect interference. Get yorself a failsafe. I run the JRXS3 FM transmittor, Its an excellent upgrade without costing too much like the spektrums.

RE: Official HPI Hellfire Thread
 

If you are going to upgrade the radio you might as well go for a 2.4ghz system. They have a built in fail safe as well.
Stussman are you still running the stock pipe on your K4.6?

RE: Official HPI Hellfire Thread
 

Heres what it is doing, the Rear end is dragging, and my engine isrunning at a high RPM andslowly engaging, the only thing I have done is pulled the engine and installed the rotostart, I also tightened up the CB but not too tight, after this allhappenedI pulled the rear diff, the spider gears are stripped, the ring and pinion are fine, I have a couple other guys out here that are running the T Maxx and the Jato, we are building a track, remember we are in the desert so this thing is HUGE, big burms, and one 4 foot jump, I have replaced the Shock Caps but do I wanna waste money on the $89 Shocks? or can I get big shafts for the ones I have now and do a complete over haul on the stock ones? and if so what is the better size choice? I took the Posi diff off my wish list I dont want to compromise handling ability. I will order a 15TCB, also the HPI Diff conv set savage. Is there anything I can do about the transmission? I keep getting the feeling like its slipping, when I first start the car up it drags in the rear but the front wheels pull it, but as it warms up thats when it starts to Rev high and move slowly.

RE: Official HPI Hellfire Thread
 

At first i ran the stock pipe (crappy), then went to a 2035. I use the 2035 on all the engines i have used in the hellfire. I went from the k4.6ho to lrp 28 to os28. Iam currently using an 086 on the os28. The 2035 works great on it to.

Mcrazy30,
the helly shocks are actually quite good. Some people uograde to them for the savys.
To handle better change the diff grease to oil. 5/7/3 is a good starting point. Also toe out slightly on front wheels.
Iam not sure what you mean with the dragging rear. But check the grubs screws are tight in you couplings/drive shafts. Hold the spur gear tight while trying to roll the hellfire, make sure the spur doesnt spin. None of the wheels should spin when you push it.