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Old 07-25-2009, 08:03 PM   #1
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Default Hyper 21 Engine problems

Hi just thought i'd get some opinions on a problem i'm having.

I've got a hobao hyper 7 tq sport black (my first nitro, had it for a month or so) with a hyper 21 3 port engine. i've run it in and such with no problems. yesterday was the first day i took it out to a field and gave it to it. I didn't WOT it (well i did, but only in 3-5 second bursts) but yeah was just driving around on a flat grass field. My problem is this;

I had a Number 8 glow plug while running it in.. was no problems... and i thought i'd replace the glow plug before i took it for a drive yesterday (so i put in a number 7 which the guy at my hobby shop said was good to use). I put it in and all was well... About 2.5 tanks into my driving the car just stopped... i tried to start again and nothing (i have a pull start). Checked glow plug and realised the coil from the glow plug was no longer there. Looked inside piston and there it was, sitting inside the engine.

I tried to take off the cylinder head, but i only have the hex keys you get with the car, and i couldn't undo the head screws (i tried but just stopped after it wouldn't turn the first time). I took it back to the hobby shop i bought it from and they tried to take the screws off there too but couldn't. They say the only option left is to cut the top off, and of course replace the top. They said this will probably covered under warranty, since the screws shouldn't be that tight, and one of them is totally rounded (we didn't do it in our attempts to undo them.. it must've come like that).

My questions are;

1) is the glow plug coil falling into the engine a common problem? What would cause it? The engine wasn't running hot or anything... it's running slightly rich at the moment.

2) What do people think are my chances with the manufacturers replacing the head (i don't think i've done any damage to the engine itself but we'll see once we get it open)? Does Hyper have a website or something i can contact them through?

Let me know.

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Old 07-25-2009, 09:08 PM   #2
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1) no, that's not a common problem...could have been a bad plug (which does happen from time to time)...could have been a sudden compresion jump (to much fuel in the combustion chamber possibly, you did say it was running a lil rich) that broke the spring loose hence it falling into the motor...

2) look in the paper work that came with the car, there should be a number to call for assistance....if not go to ofna.com, the info should be there....

I hope this helps you and i also hope your local hobby shop stays behind you all the way!!!
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Old 07-25-2009, 09:21 PM   #3
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thinkin that the best option would be to see if you can get it replaced. guy at last race has to replace his engine because the glow plug coil jamed the motor and destroyed it. but if it turns over you should be OK. just don't turn the motor over. company should fix the problem for you due to the nature of the problem and ofna is a comparny with good customer service so you should be right. plus even if you have to cut the head off they only cost loike $40 and the screws are easy to replace so...... ya

hope this helps and good luck to ya.
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Old 07-26-2009, 12:16 AM   #4
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Can someone please explain to me what OFNA is? Their webiste FAQ doesn't work so i can't figure it out... does OFNA make the Hyper 21 engine? Thanks for all the advice... i just wanted to know if my problem was common or not.
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Old 07-26-2009, 04:33 AM   #5
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They are the same company. OFNA is the brand in which Hobao markets its products in America. Im guessing that you live outside the US?

Check out the ofna website, your car is here:

If you live outside the US i think your best option is to contact the local distributor (ask the local hobby shop where you bought the car).
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Old 07-28-2009, 10:59 PM   #6
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Unhappy Bad news

Just an update... not very good news unfortunately. Turns out after drilling out the screws (was easy enough to do and didn't damage the engine top) an inspection of the internals showed the piston and sleeve were gone. Most surely due to the glow plug coil... So yeah up for a piston and sleeve replacement. Not having much luck with my first nitro RC... becoming an expensive hobby indeed... and I haven't even really started !!!!
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Old 07-29-2009, 12:32 AM   #7
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Sorry to hear that mate. Stay with it, usually these things are very reliable.

Did you end up trying to get any of it covered under warranty?
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Old 07-29-2009, 12:46 AM   #8
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Upon talking to the suplliers here they said that they'd be happy to replace head if it got damaged during the removal. Since no damage was done during removal haven't really checked with them. Do you think they would cover me in any way given that there is no engine damage (well i suppose replacing piston and sleeve is engine damage). Also the fact that a glow plug did the damage, would I have any grounds to follow up on this? I mean i'll be paying for this new sleeve right now.. but they may be willing to throw me a piston/sleeve for the future. I guess there's no point in asking the question is there?

Let me know what you people think are the chances of getting anything out of the manufacturer/warranty.

I have just sent an email to Hobao Directly, via their website. I don't know if they'll respond to that email (sent to [email protected]) but we'll see what happens. I've detailed my situation and i'll let you folsk knwo if I get a reply.

Last edited by LordAnubis; 07-29-2009 at 01:23 AM.
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