Picco 26 Red Dot leak

deanwrx said:

Hi,

I have a new Picco red dot in my Revo with a Dynamite side pipe. This motor used to run perfect and extremely strong (I had originally sealed it but kept the original front bearing in it). After about 12 runs, it started running erratically - high idle, rpms all over the place and running extremely hot. I simply could not tune it. I took the engine out and tested for leaks. Only leak i could find was with the front bearing.

I got a new Boca ceramic bearing, installed it and resealed the entire engine. I tested for leaks and the only leak was the new front bearing (i also tested gas tank). I read that some leaking was normal from the front bearing and heat would get it to seal - i don't know if this is true or not.

So i ran my Revo. It started right up, but instantly started running horribly. Same symptoms. Could not get a tune and rpms are all over the place. It will idle extremely high or not at all. No in-between.

Oddly it has great power - low and top end.

Could the problem be the front bearing, even though its new? Should a new bearing leak at all? Or do I have some other issue?

Thanks for your help.

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I have a similar problem with mine, it will not run past 1/2 throttle. I do know that some amount of leaking from the front bearing is ok. My other engines have that and run fine. I even have another .26 max that runs great. Someone made a post in the classified forum about using a mid range pipe? That doesn't explain why my engine was running fine before on trx resonator pipe. I am kind of stumped but i do know that most front bearings leak a little air.

Jerboybikes73 said:

I have a similar problem with mine, it will not run past 1/2 throttle. I do know that some amount of leaking from the front bearing is ok. My other engines have that and run fine. I even have another .26 max that runs great. Someone made a post in the classified forum about using a mid range pipe? That doesn't explain why my engine was running fine before on trx resonator pipe. I am kind of stumped but i do know that most front bearings leak a little air.

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I'm using the Dynamite 053 which is the mid-range pipe. I've done some more exploring and some leaking from the front bearing is ok. But i know mine is leaking way too much. I can acutually feel the air coming out.

I'm calling Boca tomorrow and I'll see what they say. They have good customer support.

Boca is great. I told them about the leaky front bearing and they sent me 2 for free (the ceramic ones). I'll install the new bearing this week.

Have you tested it yet? Help?

did the new bearings they sent you fix the prob ,would like to no in case this happins to my picco .26 jl red dot with same pipe as you ,Thanks

Seal the carb with some lucky seven wicking sealant. The carbs will leak around the seam where composite and aluminum meet.

Sorry for the late response - my rcnitrotalk emails have been going to my spam folder.

The bearings did not work, i.e. - they all leaked. I called Boca and they said i was using the wrong one, so they sent me different ones. I installed the newest bearing last night but after burning hands in so many places, i didn't get a chance to reassemble the whole engine. I'll reassemble it tomorrow night and test for leaks. I'll also list the part numbers of both bearings for reference.

I've sealed my carb with the Right Stuff sealer and green slime in the needles. So far no leaks with the carb.

So I installed the 3rd Boca bearing, part # SMR697C-YZZ and this bearing is leaking too. The first 2 (wrong) bearings were MR697C-2RU.

I posted a video of the leak. If anyone thinks this amount of leaking is acceptable, please say so. I didn't put a ton of suds on top of the bearing so that it is clear where the leak is coming from (its from the metal bearing shield). I checked the entire engine and there are no leaks anywhere else.

[ame="http://www.youtube.com/watch?v=Ct972wJa2Z0"]Picco 26 red dot jl front bearing leak - YouTube[/ame]

You're never gonna find a bearing that doesn't do that.....it's a bearing, it goes round and round and can never seal completely.

2revo1maxx said:

You're never gonna find a bearing that doesn't do that.....it's a bearing, it goes round and round and can never seal completely.

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haha. Good point. I really wasn't sure if the leaking I'm seeing is a problem. I'll just fire her up and see if she runs right.

Started up the Revo and its doing what it has always done. Runs perfect until it reaches full operating temps. Then the idle starts to increase and decrease on its own, then the idle just keeps creeping higher and higher until it is screaming without giving it any throttle. Doesn't matter how much i close the carb, the idle will not go down once it starts increasing on its own.

I called Ofna and they said that a little air leak from the front bearing is normal and my motor may simply need to be fully broken in until it runs right. They recommended another 6-10 tanks of gas. I also confirmed my needle settings.

Then i called Boca and they said that the front bearing should not leak and if I am getting a leak from the bearing seals, it could mean my crank is misaligned.

I'll try running it for a few more tanks, but its kind of hard when the idle increases and temps start soaring.

Anyone have any ideas on what else could be the problem? Or does anything Ofna or Boca said sound right? Again, this is the 3rd bearing i've put in. I've sealed the entire engine/carb and tested everywhere for leaks. None found except from the front bearing.

Thanks.

Did you seal the carb where the composite and aluminum meet? I'd forget the bearings and crank, that's not it.

Thanks 2revo -

I've sealed the entire carb (needle housing base, base of carb where it attaches to block, put green slime into needles). But i will check again. I also need to check my fuel lines and cooling head. I haven't checked those areas yet.

Is it okay to submerge the entire block in water (while sealing off carb base and exhaust) and blow into it? Seems like most foolproof way to look for leaks.

2revo1maxx said:

Did you seal the carb where the composite and aluminum meet? I'd forget the bearings and crank, that's not it.

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That's what I do.

Any news on the 26? Sounds like maybe you got a lemon. I'm thinking of replacing the 3.3 in my REVO with the 26. When yours runs right whats it like?

I don't really know if its a lemon. But i'm taking Ofna's advice and running it more, hoping that after breaking it in further, it will be easier to tune. After 5 more full tanks, it actually is running better. The idle is not as erratic. Temps are no longer reaching 300 - they are now stable around 230. And outside temp only dropped around 10 degrees since the temp readings. When it was running right, it was incredible. It had insane, crisp throttle response. 1/2 throttle pulled the front wheels up in the air, and I'm running the traxxas extended rear a-arms (extends wheelbase by 19mm). The motor still has tremendous pinch, but no as snappy as it used to be. I'm hoping it wakes up soon.

But in all honesty, i'm done with nitro. I'm selling this and moving on to the brushless revo.

Thats crazy that your talking about quiting NITRO. I've been thinking the same thing after going through a number of nitro engines. I've had a lot of luck with nitro but i have bought a few OS upgrade engines and they be total garbage. the support for them has always been great and the engines were replaced at no cost, but i think the simple idea of charge, plug, play and repeat is starting to apeal to me.

Have you tried a new glow plug or different fuel.

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When metal gets hot, it expands. So at operating temps, most of that gap would be gone. All my motors leak out the front. After every run the back of the flywheel is always wet.

deanwrx said:

So I installed the 3rd Boca bearing, part # SMR697C-YZZ and this bearing is leaking too. The first 2 (wrong) bearings were MR697C-2RU.

I posted a video of the leak. If anyone thinks this amount of leaking is acceptable, please say so. I didn't put a ton of suds on top of the bearing so that it is clear where the leak is coming from (its from the metal bearing shield). I checked the entire engine and there are no leaks anywhere else.

Picco 26 red dot jl front bearing leak - YouTube

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