My T-Maxx's 2.5 head might be bad
 

I think I've located the source of my T-Maxx's irratic idling problem. While it's running, you can watch fuel bubbling out around the glow plug. I think I can rule out a bad glow plug and the brass glow plug rings because I've tried several different ones and it happened with all of them. I know I'm getting the plugs in tight enough without over torquing them. I think I've ruled out everything down to the head. The only thing I can think of is the glow plug mounting surface on the head wasn't formed correctly, allowing compression to leak out around the head. I don't know what else it could be.

My T-Maxx's 2.5 head might be bad
 

Sounds logical to me.....nothin is perfect.

My T-Maxx's 2.5 head might be bad
 

take the head off and check it out... look for warping and whatnot.

make sure the shim is in place and not damaged. and check the glowplug hole to make sure its sealed.

if you can see anything reasemble the head and make sure to tighten the nuts across from eachother (tighten one.. go across and tighten that nut, move over one nut and tighten then go across from that one etc) to make sure the head isnt warped due to uneven head bolts.

let us know what you see.

My T-Maxx's 2.5 head might be bad
 

I pulled the head, cleaned it up really well, and everything looked fine. It acts like the surface of the head, right around the area the glow plug is supposed to seal to is not pefectly flat like it should be. The fuel bubbles are definitely coming from where the plug should be sealing to the head.

My T-Maxx's 2.5 head might be bad
 

the washer from the glow plug should seal any small defects in the socket there so it sounds like something is wrong.

sounds like you need a new head. try this one :bananahea
oh wait that one is warped too :p

My T-Maxx's 2.5 head might be bad
 

I just ordered a new head from Tower. The good news is they're only $21. The bad news is they're on back order. :(

My T-Maxx's 2.5 head might be bad
 

If the truck is new you should call Traxxas. They will send you new head free.

Joe

My T-Maxx's 2.5 head might be bad
 

Dont mess around with another stock head, go with this one

http://www.novarcproducts.com/images...5sidesmall.jpg

It is made of high quaility 7075 aluminum, I run one on my XTM .247, not only is it strong, it will cut down on the heat by alot, I went from running 250 on my .247 to running 215-220 under extreme conditions. THis will cure all your problems, and they wont happen again!! The head along with some other goodies can be found at www.Novarcproducts.com , they are great people to deal with and thier products are top notch.

My T-Maxx's 2.5 head might be bad
 

I'll try contacting and see what they say. The worst that can happen is they'll say no.

My T-Maxx's 2.5 head might be bad
 

That's a nice looking head, and I'm sure it's more efficient than the stock one, but it's a bit pricey for me.

My T-Maxx's 2.5 head might be bad
 

Those Nova heads are really nice. I got lucky and happened to pick one up used for $35. It's still in great shape. Keep your eyes peeled another one might come up. There are also a lot of other alternatives to the Nova head. Do some shopping around. You might find one in you price range....

My T-Maxx's 2.5 head might be bad
 

Hey grampi, I had one do that to me.There was just a very light inperfection around the glow plug hole.I took off the head and put a small buffing wheel on my cordless drill and buffed on it lightly for a while and it worked great. Maybe it will work for you maybe it wont. Nothing to lose since you orderd one.Beats waiting on other to come in the mail...

My T-Maxx's 2.5 head might be bad
 

Ok lol, I hear that alot, "its a little pricy" alot of people spend $400-$500 on a nice Rc and then cant fix it when it needs repairs, I never understood that. But I can relate in some cases. Anyways hope things work out, TRX will more than likely send you a brand new head!!

My T-Maxx's 2.5 head might be bad
 

It's pretty tough to justify to the wife, after just 2 weeks ago, plopping down $400 for the Maxx, then having to turn around and buy a head for it already. Some things are expected costs, but replacing a head after just 10 tanks of fuel is totally unexpected.

My T-Maxx's 2.5 head might be bad
 

I can sympathize with you on that one Grampi. The wife asked me what the heck I needed a new engine for when the Maxx never even made it out of the box and had the Sirio on order. Funny thing is the 2.5 I pulled off of the Maxx has never had a drop of fuel in it..

My T-Maxx's 2.5 head might be bad
 

LOL like i said before "I can relate", I just got back into the hobby after a few months cause the wife said "its the toys or me" so I sold all my maxx's/ buggies, and projects(gotta love them women) But anyways the first maxx I bought when they were released back in Dec of 99" which I paid a whopping $507.88 for, I ran it for a month and had to replace the engine, then the diffs, and then the tranny, and then the suspention and so on. Then for the next three years I just slowly upgraded, and at one point in time I had roughly 7 Tmaxx's, and a couple emaxx's and some other toys, and my wife was completely supportive of it for the most part. Now I am pretty much starting over, and have one Tmaxx and a hole lot of space on my work bench!! Anyways have fun with what ever you do, but we should meat up some time and go bash. BTW do you have a track up there to run at or do you just bash in the fields. Ive got a buddy that runs a hyper .21 maxx that might want to work something out. We both moved down here from Denver, and frankly folks in wyoming have a very scarce knowlege of these Rc's, but a couple shops and tracks have opened up in casper and theres alot of guys up there with the 2.5 maxx's. Im probably gonna go to the track on saturday, but well see how things work out!! Anyways if your interested in getting together some time email me.

My T-Maxx's 2.5 head might be bad
 

Really? Casper isn't far from us. Where are their HS's and tracks?I'd like to check it out sometime. vwtrey has access to a machine shop at his inlaws. He's gonna take my head over and stick it in a lathe to see if he can true up the area around the glow plug. If he can't get it to seal, so what, it's no good as is. If he can then he just saved me some money and some down time. We'll see.