.15 hpi problems... and .12R ss help

[jakester]

Hiya fellas, first post here(I'm pretty much a noob as well)....

i did a search and couldnt find results so i figured i post it, to get a quick question....

First off i bought a RS4 2 a couple years ago... got the hpi .15 motor in it.... i never really drove it that much ... but when i busted the car out this summer and tried to start it i couldnt get it going.... I've only had about 1/2 to 2/3 of a gallon through the engine so I'm not sure what is wrong with it..... i do know for a fact that when i used to drive it in the past it would over heat like crazy... (knew this from the patented spit test)... but i really couldnt get it tuned correctly so it wouldnt over heat...

any help on what to do about the .15 would be greatly appreciated... i did however get a good link off this site that shows step for step how to rebuild a motor... so i may look into doing that.....

btw with the .15 i have changed glow plug, checked fuel lines, checked glow started. all fine.... one thing i considered is maybe the fuel is too old..... only 2 years old.. but is sealed with a lid....its 25% nitro i believe if i remember correctly

but meanwhile i have purchased a .12R SS hpi motor..... i got it off of ebay new.. but it didnt come with original tuning instructions or break in information.... if any of you could give me a link or some info i would be much obliged....

Also if anyone has any suggestions to how i can prevent killing this engine in less than i gallon please feel free to comment.

 

[Candyman]

If you're just busting out your car for the first time in a few years, I would basically start from scratch. First, I'd thoroughly clean the engine. Including the carb. Just to make sure all the passages are clear and there's no gunk in them. Start with a fresh glow plug. AND a fresh gallon of fuel. Act like this is day one with it. You've already checked the lines and that's good. If all the lines are clear and the engine is clean, this thing should fire right up. If you've been running it excessively hot, it may be in need of a rebuild. Check your compression and see if you've scorched any of the internals.

Now as far as the SS, go to http://www.hpiracing.com/index2.htm which is the HPI homepage. Click on "Instructions" on the side. Then click on "Nitro Star Engines Tuning and Assembly Sheets". There you'll find tuning instructions for your .12R SS. It's the 3rd one down.

 

[Nitroaddict]

First off - welcome to the greatest nitro forum on the planet!

What you have described regarding the .15 is the telltale signs of an improperly broken in engine. There is no cure for that, other than a rebuild of the piston/sleeve.

As for the .12ss - make sure you break it in SLOWLY AND CORRECTLY. Since you have no manual - here is the online version of the tuning guide and break in proceedures. FOLLOW THEM TO A T!!!! You should break in the engine by following these instructions, and running VERY RICH for at least 5-6 tanks of fuel - GOOD LUCK AND HAVE FUN.

BTW - better safe than sorry - buy some new fuel. nitro fuel is hydrogyscopic, meaning that it attracts water and u dont want water in the engine, that would be bad! below are the .12ss instructions.

BREAK IN & TUNING INSTRUCTIONS:
http://www.hpiracing.com/graphics/instr/1626-7_12rss/1626-1_pg1.jpg

EXPLODED VIEW AND PARTS LIST:
http://www.hpiracing.com/graphics/instr/1626-7_12rss/1626-1_pg2.jpg


Hope this helps!

- Anthony

 

[jakester]

thanks guys great info.... .. .. the .15 was broken in correctly.. i did follow the instructions to a "T".... i think i let it idle rich for an extra couple tanks too when i first got it .. just to be sure i didnt do something wrong.... How do i test compression btw??? i would like to repair the .15 just for a back up... or to sell..... I'm going to take it apart when i have time and learn to rebuild it..... might as well start learning... I'm very interested in this hobby...

also thank you very much for the .12 instruction links......

jake

 

[Nitroaddict]

per the compression test on the .15 - u can use a compression gauge from a full size auto, but that might be a lil overkill. just turn the flywheel over with your hand, it should be VERY tight. if it is easy to turn over, then u have compression loss. replacing the piston & sleeve will cure it though, and is not too expensive.

 

[mcvickj]

Do you still have the stock carb on that .15FE engine? I have a RS4 RTR and the engine is a bear to tune sometimes because the carb only has one needle. Does it also have the stock cooling head? When I was running the RS4 I purchased a new cooling head from HPI and that really helped with the heat issues.

Oh by the way...welcome to RCNT.

 

[jakester]

when i turn the flywheel i get plenty of pressure... so i dont think that is the case(lack of compression that is).....

and no i never replaced the stock cooling head... just cause i didnt want to pay the 50 dollars or whatever the purple aftermarket head cost.... the whole motor is stock including carb... thanks

 

[HumboldtBlazer]

that old of fuel is toast buy some new fuel first.

 

[Nitroaddict]

Originally posted by jakester
when i turn the flywheel i get plenty of pressure... so i dont think that is the case(lack of compression that is).....

even still - most likely might need a rebuild, as it is fine now, but when it heats up - the parts expand, and u get blowby. Try new fuel first though.

 

[jakester]

ok thanks .. ill try the new fuel and let you guys know how it works out

:devil: :OMG: :flaming: :transform

 

[Maxxcrazy88]

The .15FE has less compression than most engines brand new from the factory
because it has some messed up sleve materials...... ( can't remember the exact stuff)

BTW I got this info off of hpi's site.....:mex:

 

[jakester]

Also what type of glow plug should i use in the .12??? brand, type, ect.....

I'm going to try using after run oil in the .12 since i will prolly only drive it but once a week or so..... in the .15 i never used oil...

 

[mcvickj]

I am currently using OS #A3 glow plugs in my NTC3.

 

[Nitroaddict]

I recommend OS A3