FULLYGROWNKID

This is a vid of me trying to start my 5.9. It sounded this way Thursday, Friday, and again today. I have went through everything as normal but it just won't fire. I make sure all batteries are charged and ready to go. I preheat to atleast 200 everytime (today it hit 223). I primed by blowing in line until fuel hit the carb. Truck used to start quickly with this routine, but not anymore. I took the motor out and went through it, but couldn't see any broken parts or damage. I cleaned it and reassembled and sealed it Saturday morning, and i made sure it had 24hrs for everything to set and dry before i tried again Sunday night. Can anyone give me any suggestions of what to try or is this the sound of a blown engine? Maybe this is my opportunity to send it back to HPI and get something different.


http://www.youtube.com/watch?v=n1gfmR3FMpg


sounded the exact same way the whole weekend... even after tearing down, cleaning, and resealing.... PLZ HELP!!!!!

BudBud

Sounds like you are not getting fuel. Try blowing directly through the main needle with a section of fuel line or taking the needle out and looking inside for debris. A lot of times part of the o-ring will slice off and plug the orfice. Glen

bigwaltc

I know you said you checked every thing but take out the glow plug and check it one more time with the Glow igniter just to make sure its glowing nice and hot [sm=shades_smile.gif]

FULLYGROWNKID

Okay, i've just blown through the needle with a fresh piece of tubing and air went through pretty easy. I will take off the needles and inlet and check the orings but i'm not sure. I've been using a C cell glow igniter with a fresh battery and the glow plugs are glowing bright, but i'm not sure if its bright enough, maybe i need a new igniter? I've tried the original glow plug and 2 brand new ones and they all glowed the same way to me.


Also, fuel is still coming from the pipe. Even tho i switched to 30% nitro, i've kept it running rich. I'm not sure if its visible in the vid, but fuel is coming out onto the top of the bucket as I run the rotostart.

rcnitrohead

It really sounds like its not getting fuel. I know you said fuel is coming out of the pipe, but here is what I'd check first. Based on fuel coming out of the pipe, maybe the mix is too rich for it to fire. Maybe there is something really weird going on and you really aren't getting fuel into the engine? Take the filter off and have someone drip some nitro down the carb throat as you spin the roto. If it doesn't fire and you don't have an air leak, and providing the needles aren't too out of wack, and providing you have a good spark from the plug, then its toast. Your plugs just need to glow orange, don't have to be ultra bright. Though did you actually try a different plug in the engine? You never know when they foul up, sometimes they can be tricky buggers.

TOm.

SLAYERDUDE

Did you check the pinch while the engine was apart?

You can pull the glow plug after trying to start and put it on the ignitor if it sizzles it's getting fuel.
Basically try starting it for a bit and then pull and read the plug, if its dry your not getting fuel.

FULLYGROWNKID

Okay so today i picked up a new glow ignitor, 2 new glow plugs (4 new in total now) and new fuel line. I tried all 4 new plugs with new line and with both ignitors, same results. And yes after trying to start it up, all 4 plugs were wet and bright orange. As far as the pinch goes, I think its still good, but i don't really have enough experience to tell. The other 2 nitro mills I have are still going strong and still have to be pre-heated or the plugs loosened up just to pull the cords. I've sent an email to hpi about an hour ago. But if anybody has anymore suggestions please let me know.

SLAYERDUDE

:O Sounds like you run really rich.
Keep an eye on them rods!


Here's a pic of decent pinch-


These one's - not so good.[sm=lol.gif]

FULLYGROWNKID

personally i think it's blown... but i sent it in to HPI this afternoon... so i'll have an answer and let everybody know what the verdict is

SLAYERDUDE

Awaiting the outcome.
But why did you not recheck the pinch?
It takes less than an hour and you know where your at.
Guess I wanted to know more than you.

FULLYGROWNKID

actually i did, but when i compared it to the pics you posted... it only was popping out like maybe a quarter of the way it is in those pics. I thought it had to pop completely out of the top to be blown?.... either way i will know for sure soon enough. but when the tech from hpi saw the vid, he said the way the rotostart was turning so fast that it couldn't have any compression left. this is my first rotostart mill so i wasn't sure.

SLAYERDUDE

Cool, if it goes to the top the pinch is shot.
Doesen't have to go thru at all.
When the sleeve warms up it expands and all compression is lost.

davidaxper

I still wonder why it wouldn't start. Even if the engine's pinch is gone it should still start while it's cold. You should have tried dropping 5-6 drops of fuel into the carb and tried.

rcnitrohead

Pinch and compression are 2 different things.. My STS has 0 pinch, the piston goes up to the sleeve, I could probably push it out if I wanted to. It has very low compression as well, but runs like a raped ape.. It all depends on how it runs at operating temp under those conditions.

SLAYERDUDE

You are correct, pinch and compression are 2 different things.
I could see having good pinch with poor compression due to a gouge on the piston or cylinder wall.
But I'm confused, are you saying you have no pinch but enough compression for the engine to be okay?
Does that STS hold an idle at 1-2mm gap at full operating temps?
I have worn engines that run great for the first 5 minutes but as soon as they get up to temp they die and will not run at all until they cool.
Here's a T-maxx I got for free-
[youtube]http://www.youtube.com/watch?v=GBJn09k6T4g[/youtube]

HPI Nitro MT-
[youtube]http://www.youtube.com/watch?v=ru3C0TKlgL4[/youtube]

rcnitrohead

I mean there is close to 0 pinch, and you can turn the flywheel with your pinky when its cold. The engine will idle all day and shows no symptoms of giving up, almost 9 gallons and freshly modded and it runs better than ever. I guess its perfect once under normal operating temps.

BudBud

We visited this topic recently and somebody who normally does not post in the Savage forums came in with tons of copy and paste from OS engine's web site. I have several Piccos that I can roll over easily with the plug out and they just scream on top end and will idle for extended periods. The argument was that without pinch, the sleeve would get hot and expand away from the piston. His claim was that the piston was an silica alloy that did not expand as much as the sleeve. According to his post, when the sleeve expands on an engine with little or no pinch, the compression gets too low to run. I never did get the answer from him I was looking for. According to his posts, I have a lot of engines that will not run....somebody forgot to tell them and I am not smart enough to figure it out. I am still running them, hard, lots of rpm and they idle....extended idle time.. Glen

SLAYERDUDE

Not starting a battle here, I'm always up for learning something new.
But the 3 engines that I have gotten for free that have little or no pinch all run the same.
As soon as they reach temp they lose power and die / will not restart until cooled.
The 2.5 T-maxx has the worst pinch of all 3 but seems to run the best/longest.

I thought the sleeve was supposed to expand more than the piston...
Like on a fresh engine with super tight pinch is very hard if not impossible to turn over but once warmed up it turns over considerably easier.

So my question is - if the piston goes to the top of the sleeve and has poor pinch the engine may still be fine and run good in some cases?

BudBud

I suspect all things are not equal among engine companies. I know that a tight Picco will stick the piston in the sleeve and it is horrible when it happens. You think you are going to rip the end of the rod off when trying to get it free. Heating the sleeve prior to starting helps a lot, but I have been through a couple of them that were so tight, you had to run pig rich to keep it rotating. I have several Piccos that one would think are worn out, but they run great. I also have the other problem too with some AE engines. Get them hot and the power goes down, eventually they die and will not start until cooled off. I disagreed with the blanket staement, not he theory. Glen

FULLYGROWNKID

okay here's an update. I got the engine back from HPI today. I was told it wasn't blown at all and still had a long life ahead of it. They told me it was the mid range needle and that all of the needles were loose. They replaced the carb and told me I have to repeat the break-in process. They told me to refer to the Savage XL Break-In vid they have posted on the sight and to follow it closely. I'm breaking it all down right now and sealing it and installing the pull start and 086 pipe that i ordered awhile back. Gonna let all of the threadlocker sit over night and tomorrow I'll try to start it up and see what happens. I'm not sure about going through break-in all over again just because of a carb replacement. I thought the reason for break-in was for the piston and sleeve, and if that wasn't replaced or touched at all, then why repeat the process? But if thats what i should do then fine. Better safe than sorry. Thanks for the info and suggestions from earlier. Keep them coming!

This is the video I was told to follow... maybe it can be helpful to others getting started with a 5.9 or Savage XL
[link=http://www.hpiracing.com/videoplayer/62/]XL Getting Started And Break In Video[/link]

HPI_Savage_RC

I don't know who it was that said that (Must have missed the argument), but he was correct. The sleeve is brass, and the piston is a silicon/aluminum alloy, which is designed to expand at a slightly lower rate than the sleeve. The pinch does decrease as the engine warms up. A broken in engine should have a near perfect fit between the piston and sleeve when at operating temperature, and some pinch when cold. Zero cold pinch means that you will leak compression past the piston when the engine warms up, and performance will suffer accordingly.

If you can push the piston to the top of the sleeve as you claimed in an earlier post, that is an outright lie.

FULLYGROWNKID

I hope HPI wouldn't lie about it, but i don't know enough about nitro engines to say myself. But before i sent it in i checked it and tried all or most of the suggestions given in this thread and in others. I did compare it to the pics posted here and it went to the top and came out ever so slightly. Nowhere near as much as in the pics but yes out of the top. I didn't check it again when i got it back today, but just went ahead and sealed everything up. I was only told the original problem was with the needles and that the carb was replaced and that i should repeat break-in procedure. So did HPI just tell me something just to keep me with the 5.9? Wouldn't they have just replaced it if it was dead or defective?

SLAYERDUDE

My guess is that HPI for PR reasons told the OP that it was just the needles.
That is what AE did to my LHS (and personal friend) when he sent my 8.0 back to them. (which I traded for the XL)
"the needles were set wrong and it is fine now"
Which was a bunch of BS.
I am an experienced tuner and work on weed eaters, chainsaws, etc...
My RC10GT is one of the fastest stock old school GT's out there with the OG stock engine.
.12 O.S. CV tub 10+ years old and still pulls wheelies.
LOT of runtime on that engine.
Believe you me the 8.0 was not a tuning issue.
Before sending the faulty engine in he marked it and it was a new engine that they sent back.
But they said- "the needle settings were incorrect and we tuned it for you other than that there were no problems"
"The head was scratched and we put a new one on because we are nice."
What a load of crap!

That's why HPI wants you to break in the engine again.
It may have had no pinch.
But if they want you to break it in again I would say they replaced some MOVING parts.
So do the break-in however you like but I would lean all your engines out a hair.
I watched your vid for the first time tonight and read the whole thread carefully and noticed you said all your other engines need to be heated or loosen the glow plug to even get them to turn over...
THAT is waay too rich!
Like I stated in an earlier post, watch them rods!
Running TOO rich is just as bad as running too lean.


WHEW, that was my 2 cents for what it's worth.

SLAYER

HPI_Savage_RC

Can't believe I didn't think of that initially. That's exactly what they did, replaced the piston/sleeve or the entire engine, and told you that it was only an issue with the carb. Covering their arses I suppose, but I don't know why they wouldn't just tell you outright that it was defective, instead of fabricating an elaborate story.

SLAYERDUDE

So why would they have any break in?
Moving parts are the only reason for any break in.
Hard to tell sarcasm on forums.