Some help here???

[TheFixxer]

Hopefully you guys can help me. Tired of getting a million different pieces of advice on the Traxxas forums, not to mention they are a bunch of jack wagons. Nothing like you guys here....you guys are dang near family. Ok, so now that I have buttered ya up.......;

My TRX 2.5R on my my revo (converted to a 3.3 minus the engine) is eating glow plugs like crazy. Ran half a tank of fuel a little while ago and burned through 3 of them. Came in the house and started doing some research. Mostly getting the "it is too lean" story from just about everywhere I look. But, I had my needles set to factory and burned the 1st one. Richened it up some and burned out the 2nd. Fattened it up just a tad more and was getting the nice smoke you are suppose to get and it was running great....then burned the 3rd. At that point I gave up on it and did after run care and shelved it. It was hotter than a pistol and I should have grabbed my temp gun but was so aggravated at that point I didn't care.

I don't believe its an incorrect tune issue but I do believe it is lean. A few sources I found suggested air leak. When I rebuilt the revo a few weeks ago I installed a new fuel cap 0 ring, new fuel lines and new fuel filter as well as new fuel line clamps. I do not recall seeing any air in the lines while it was running. That is something know to watch for whenever I am running any nitro.

So, I am inclined to think I got an air leak in the engine itself and it is causing a severe lean running engine. Now a lot of what I read by Traxxas and Traxxas fan boys say never ever need to seal a TRX engine. But for everyone that says not to there are 10 that say you should. What are your guys' thoughts? Found a nice write up on savagecentral reposted on rcnitrotalk on how to seal it up right. http://www.rcnitrotalk.com/forum/showthread.php?t=60832#sealingnitro

 

[griff7373]

Quick question have you checked the fuel tank lid on the first Revos that came out the o-ring on the cap of the fuel tank was defective so it wouldn't seal causing it to leak. I can't remember which color was the defective one I will have to walk to my garage in a bit and look it was like the nitro caused it to start to come apart.

 

[TheFixxer]

Quick question have you checked the fuel tank lid on the first Revos that came out the o-ring on the cap of the fuel tank was defective so it wouldn't seal causing it to leak. I can't remember which color was the defective one I will have to walk to my garage in a bit and look it was like the nitro caused it to start to come apart.

It is red and brand new. Also, I did not see any air bubbles in the fuel lines while it was running. I knw to see air there would indicate an issue orginating from the fuel tank or lines/fittings.

 

[Jam Racing 1]

sounds like they hit all the bases in that article...

 

[X]

Wow, that tutorial has surfaced again. It is an excellent method and is what I modeled mine after. Definitely give that a shot.

To also help trouble shoot, what fuel and glow plugs are you using?

 

[TheFixxer]

Wow, that tutorial has surfaced again. It is an excellent method and is what I modeled mine after. Definitely give that a shot.

To also help trouble shoot, what fuel and glow plugs are you using?

The revo does not run well on anything but Traxxas 20% and I use the stock TRA3232X plugs.

 

[TheFixxer]

Today's project;



Hopefully this will solve the issue. I did test the fuel tank, lines, clamps, O ring. No air leaks so I am convinced it is the engine itself. The Green Grease you see is the exact same as TA Green Slime. I read the MSDS for both and they are identical chemically. The awesome part was that stuff came in a 3 pack for $6 at Autozone so I have enough to seal needles til the end of time. Oh yeah...I will still be RC'ing then.

Changing out the carb too with a Losi 3.4. The carb that is on it sure looks like a Losi but I don't know the history of the vehicle all that much from the previous owner. Better safe than sorry.

 

[TheFixxer]

Engine all torn down.


Went a bit farther than the guide for 2 reasons. 1st, never torn down a nitro motor and wanted the experience. 2nd, thought it wise to check over all the parts since I didn't know the whole history of the engine. Everything looks good to me other than being a little dirty. Wish I could find what the dimension should be at the top and bottom of the bore. I have a digital micrometer. Just want to know before I put this all back together if my sleeve is in spec.

PS. That is not a Losi 3.4.

 

[TheFixxer]

Ok, followed the guide to the letter and I am happy with it;



Now for some follow up questions and an observation. And this thread might be better suited if it was moved to the Nitro Engines, I started it here because I referred to my Revo. Anyway, first the observation; I either have a screwed up exhaust pipe header or Traxxas designed the dumbest set up ever. The bottom retaining bolt on the header flange is not accessible with any sort of driver because the pipe is in the way. I had to tighten down a little at a time with a needle nose. Dumb. The flange and the header pipe seem to be one piece because the flange does not turn on the pipe like one would expect. Maybe it's just stuck and I am an idiot.

Now the question. I know I gotta let this baby sit for 24 hours and I will be counting the minutes as it gets closer to go time. The problem is I have blown all my TRA3232X plugs and oddly enough do not have time to swing by the LHS. In my bins of stuff I found a plug NIP http://www.foxmanufacturing.com/index.php?main_page=product_info&cPath=202&products_id=1431 . Would this be a suitable plug to use in my TRX 2.5 running 20% nitro?

 

[Jam Racing 1]

I think you have that manifold on upside down, it will go either way.. and to remove the pipe from the header just cut the zip ties and it comes right off there,
here is a link to the Revo manual , in the pic there on page 6 you can see both header bolts and they are accessible... so try flipping it over and reattach.....

http://traxxas.com/sites/default/files/53097-OM-KC2054-R00.pdf

as far as that plug working , yes it will although it may be a bit hot for that trx engine, but I would try it anyway and see....

 

[Jam Racing 1]

if you look at where the header mounts there are 4 bolt holes and if using the wrong set the header will not be on right....

 

[TheFixxer]

I think I have it on right. The bolt on the left is the one I am talking about. No way to get a driver on it to tighten it. The flange is tight on the header and wont rotate.



I know it looks from the picture one could get a driver on it but just no way no how. If you mount it using the other 2 holes it puts it at a goofy angle plus you can't attach the EZ drive doing it that way.

 

[TheFixxer]

Found a spring mount for this engine. Might just scrap the whole above assembly and go that way. Still seems stupid that bolt is hard to get at. Doesn't come down to which two hole I use, that bolt stall can be accessed with a tool because of the curve of the exhaust header. Flip it over, use different holes makes no difference.

 

[TheFixxer]

as far as that plug working , yes it will although it may be a bit hot for that trx engine, but I would try it anyway and see....

Yep...too hot. Called Traxxas support and was told it was not a good idea and that a medium temp plug the best way to go. Just wanted to be safer than sorry. I'll have to wait til I get a minute to stop at the LHS to get the right plugs. Spring mount manifold ordered.

 

[X]

For me, I don't run anything that I would bother putting a hot plug in. Below 25% gets a medium. 30% gets a cold.

 

[fz1dave]

That header looks bent and if you cant get at the screw it must be, maybe its cracked somewhere causing an exhaust leak. I had a revo awhile back and cant remember not being able to get to that screw.

 

[TheFixxer]

That header looks bent and if you cant get at the screw it must be, maybe its cracked somewhere causing an exhaust leak. I had a revo awhile back and cant remember not being able to get to that screw.

I am pretty sure it is bent as well. The spring mounted header will be here tomorrow.

It turns out sealing the engine did the trick. Couple with using a Losi 3.4 and it runs fantastic now. I think I am just gonna tear all my engines apart and do the same thing on all of them.