Hello All,
Haven't had my LST for long and it is a new model SN#15xxx. Unfortunately this truck has been a major PITA and I have not had a single day of fun with it since I got it Anyway, I have been trying to get this thing running so it will run with good performance and not overheat (see [link=http://www.rcuniverse.com/forum/m_3111029/tm.htm]previous post[/link] for some background). Anyway, I was still messing with the settings yesterday when I couldn't get my engine to re-start. After about 1 minute I finally decided to check the plug. The little coil in the plug was all bunt up looking and pushed up into the body of the plug. I also see allot of small silver slivers of metal. So I tried another plug, this one failed really fast with the same problem. So I pulled off the heat sink and then the piston sleeve. inside the sleve I found some fairly good sized pices of copper\gold color metal at the top of the sleeve (inside the sleeve) along with more silver shavings. I haven't fully gotten the motor apart yet to see what is broken. Any idea what this is and why it happened? It shouldn't be the washer that I read about because my model is so new it shouldn't have one. I am ready to sell this thing on Ebay and get something else, i have had 3 Traxxas trucks with no problems at all. This was the first non-traxxas truck I ever owned. I have never run more than 1/2 tank before it acts up on me. I really don't want to gove up on this truck because it looks so awsome, but it is really trying my patience.

So question 1, what should I use to properly clean the engine from metal shavings?
2. what parts need replacing?
3. This is a new truck, should I keep this engine or go with a better one? This has been a PITA to tune.
4. What should I use to reseal the engine mounts and sqrews? I removed the engine mount sqrews from the bottom of truck (first time I tried to remove the motor).
5. How in the heck does the exhaust come off the engine?
6. Anything else I need to know while I have this engine apart?

Thank You

Uggg. I hate to tell you this but I believe that you may have had the dreaded Conecting Rod problem that seems to be more and more common with the newer Machs. I honestly wouldn't pull the engine apart any farther. Just remove it and send it back to Horizon. They seem to have been pretty good about fixing them for no cost to those that have had problems. Good luck and don't give up. It's a great truck. I have 3!

Do you think the connecting rod could have cause the performance issues I described in my other post (link was posted above). Also, how long does it take to send\receive the engine? Would it not be quicker to just replace the connecting rod myself? If the rod is going to keep failing, maybe I should just replace the engine instead of sending the engine back every month.

Thanks

It may be possible, but I wouldn't say it's likely. The issue, I think, is something with the tolerances on the crankshaft. Mine, though, seemed to be running fine before it blew...

The problem with replacing it yourself is that the engine is now full of metal. You need to replace more than just the rod... bearings... crankshaft, piston & sleeve, head button... when they repaired mine they put nearly $200 worth of parts in it.

I sent mine back through my lhs, and it took about 7 weeks. Most other people though, haven't had it take that long. I think Horizon may be getting bogged down by so many returns with this problem. Now, the engine *should* be ok after they rebuild it. They told me that they did the rebuild rather than giving me a new engine to avoid having the same problem again. Whether you want to get another engine in the mean time is up to you. Plenty of people love the Mach and it sounds like a good engine, but personally I went with a Picco .27.

How much did the Picco .27 cost? Is it as powerful as the Mach? I heard other talk of something like a Collie .30, is that a good one? I was reading another post on here of people that have had to send the engine back up to 4 times, this is not very good sounding. I think instead of paying $200 for another engine I would rather just buy a Savage or Revo for around $450. I am extremely dissapointed with all the problems I have seen with the Mach. I just wish I found this forum before I bought this truck.

If you go to tower hobbies the Picco is about $175, and they currently have a deal to get $10 off. I've been extremely impressed with its power and the ease of breakin and everything.

Remember, if you decide to go with another engine you can send the Mach back (and don't need to worry about how long it takes) then when they return it just drop it on eBay.

The LST is really a great truck when you actually get to run it.

Does the Picco .27 has as much power as the Mach? Or is it more powerful? I looked on ebay, doesn't look like I could get much for a used Mach[&o]

OK, I finally opened up my Mach and to my suprise the connecting rod look to be in good shape. However, there is a a brass washer that fits into the end of the connecting rod that goes on the crankshaft. I see that about half of this has broken off, thus the pieces of brass I seen at the top of the piston sleeve. There is allot of "play" between the connecting rod and the crankshaft. I think that this is allowing the connecting rod to scrape the bottom of the crankcase which is chere the silver slivers are coming from. Maybe this is how the rods on the other Machs start to go. Any thoughts on this? Can I save this engine myself?

So my question is this: Would you rather by a new engine for $200 or buy a revo for around $470? Seems like it would make more sense to buy a whole truck than just a motor. Is the LST really that much better of a truck to invest in another engine? Without looking at money, would you choose to buy an new engine for the LST or buy a revo?

Ahhhh "the washer." What serial number is your truck? This was an issue with Machs up until about the 11xxx LSTs (for more info see the "remove the washer" thread at the top of the LST section). Basically that little washer isn't capable of withstanding the stress that it goes through in the engine, and sooner or later it flies apart. Horizon will definetly replace it under warranty.

As far as Machs on ebay... remember, if you're getting it replaced by Horizon, it's a new engine. I don't exactly follow ebay on a daily basis, but if you start the price out lower and let people bid up, I'd expect to get $75-100 for it. It's certainly better than geting nothing for it.

Well no, I don't really follow that logic. You seem to be complaining about having to spend $150-200 on an engine, but you also seem to be ready to drop $500 on a Revo. Not only are you spending more if you do that, but you're going to lose a whole lot of money on that LST.

I'll just say this. You have an excellent truck sitting there right now. If you feel that you would prefer a Revo, or that you should have gotten a Revo to begin with, it's your money and your choice. Personally, I had to choose between the Revo and LST when I decided to get a MT. I choose the LST, and I'm going to stick with it.

The brass washer that he is referring to isn't a washer at all and is not THE washer that everyone has problems with. It's the bronse connecting rod bushing and it almost always fails before the connecting rod it's self and that causes the con rod problem. The bronse bushing is the weak link in the system and is being chewed up by the poor tolerances on the cranks of late.

Yes AKFireMedic, I was referring to the bronse bushing, but I didn't know the name of it. In my original post I said my serial is #15xxx. Do I have to completely blow the engine before they will replace it? Right now the bronse bushing is starting to come apart but has not completely broke, and the rod "looks" ok.

ncgrunt, my logic is this, If I am going to drop $200 in JUST a motor, why not buy a WHOLE truck for $500. The money isn't a problem except for the fact I just spent $600 on a truck that I'd expect to actually USE without constanly sending the motor in for a replacement. If I buy a motor, then that is $800+ for this truck. I too had to choose between the LST and Revo, and you see what I picked. I was a loyal Traxxas user owning a T-Maxx, Rustler, 4-Tech, and Stampede. All of which are still using the original motors with no major problems other than "normal" wear and tear.

Ok, forget what I said about the washer then... either way, the engine is toast and Horizon will replace it under warranty.

It'll come out basically the same either way:

Spend $200 on an engine, and you've spent $800 on the LST. But, you can get say $80 back through reselling your Mach after you have Horizon replace it. So the total comes to roughly $720 spent.

If you buy a Revo, I assume you'll try to resell the LST. Even if you get Horizon to replace the engine and add that back in before reselling, I would be pretty surprised if you got more than $400 out of it. So here you've spent $600 for the LST, plus $500 for the Revo, minus $400 for selling the LST. Total spent? About $700.

Aside from pointing that out, I'm not really going to say much else. Like I said before: your money, your choice.

When these little engines start spitting chunks of metal out...no mater how much or what color. They are already circleing the drain. Send it back to Horizon now and they will take care of you.

ahhhh a thread that sheads a little light.

skyodyssey i had the same problem today. it tool me 1 year to finally fork over the money for a LST. this was after messing with a on road car that i only felt safe using on a race track. about 3.5 tanks into my normal motor break in procedure the motor quit on me and did not start up again. curiosity got the best of me i ended up pulling the head to find a piston that was pretty hbadly chewed up on both sides with metallic gunk everywhere. great looks like the pistons i pulled out of my blow motor on the real car. i have always used novarossi motors in my on road car and had nothing but good experiences with them.

my question is i do not feel like burying myself to bad by having to buy another motor. if i just sit and wait for the mach to come back from warranty. how reliable is it gonna be????


man o just bought this thing on friday on my lunch break. []

jdmmax,
i'm not sure what to tell you, but I have heard that the Mach is really nice WHEN it runs. [link=http://www.rcuniverse.com/forum/m_3095734/tm.htm]This post[/link] is another that speaks of our problem and some have sent back 2 or more engines[X(] I do not want to mess with swapping engines every time it breaks, so I just want to get a RELIABLE engine.

On a side note, have you uses the roto start for your NovaRossi engines? Would this design work in the LST? This is probably the only thing holding me up from buying. Also, is there a replacement that I could buy that would fit that engine? Could I buy the pull start version then use my LST roto start?

sky:

all the novarossi i had where i used started boxes. they were .12 for my touring sedan. i went and picked up a new motor today and droped off the mach to be replaced.
i ended up getiting a picco omega.26 i think it was called. i didn't have much time to break in the new motor today i plan on doing that tomorrow. thing cost me $160 so i was like eh oh well cheap enough. the LHS had the novarossi .28 motor in stock for $279 and if it were compatible with a rotor start i would have gotten it. the screws for the rotor start plate do not match up on the nova rossi motor. i ended up getting a hpi rotor start and converted the picco to a roto start it was an extra 50 but gives me the option off 2 different rotor star systems so i have more motor to choose from in the future. so far i burned about 800 for the LST & new motor. and i ran it for a total of 30mins tops. tomorrow should be a fun day. i sould be able to finish breaking in the motor tomorrow.


frank

edit: damn wish i would have seen this sooner i would have went with a novarossi motor.

[link]http://www.amainhobbies.com/product_info.php?cPath=23_79&products_id=3070[/link]

jdmmax,
thanks for the info, but I am a bit confused from your post. So after seeing the roto start system in the picture you would have gone with the nova? I seen that roto system and wondered how I would get the roto shaft into the starter. The current roto that comes with the LST would have the openening in the starter in about the middle of the "R" on the nova starter. Any thoughts?

Thanks You

yes i hate pull start motors i hate driving a rc car with a sore arm when the motor decides to act up on me. i used starter boxes on my on road cars. for the trucks the roto start would be best.

seeing as though nova rossi has a rotor start motor i probably would have gotten that instead of my picco .26
i have always used novarossi motors i like the way they run and they are easy to tune. never gave me any problems.



thats what the novarossi roto start looks like. looks like you access the roto start from the back.

i looks like it comes out of the back. but be carfeful different roto starts require the rotor start to spin a certain direction.
the hpi/ofna rotostart which i am currently using spin in the opposite direction(counter clock wise) from the losi rotostart( clockwise) thank god i figures this out before i tried to start the motor i do not know what would happen if the motor wer to spin the other direction.

jdmmax,
Forgive me for being thick headed, but I have one more question. I have seen a picture similar to yours and I was thinking the gas tank would be in the way, at least if it has the same dimensions as the Mach roto start.

Also, the Nova spins the same direction as the LST roto start? If not, I can use a drill and put it in reverse

You should be able to pull the rotostart off and have it pointing whatever way you want.

uhmm it looks like there will be two gears in there if there are it will require you to spin the roto star opposite direction of the losi rotostart.

jdmaxx,
Thanks for the info, amain hobbies was great! I ordered my engine at noon, and it shipped at 3!

did you order the novarossi ????

owwwwwww let me know how it runs. i was also looking at th rb concept motors to. i had a x12 5port and that thing hualed ***. i was able to keep up with a few 1/8 scales at the track i use to go to.

Actually that is called a Tider Drive

it is a tiger drive and it spins the same direction as a mach. I put one on a wasp .28 the drive is smaller so I used some of my older tools I have, cut up a allen wrench can't remimber the size now , and a 1/8' drive socket ( here's the had part) I had a 1/8" drive (square) by hex I ground all sides of the hex down to fit the losi starter motor heat shrinked it altogether. and I have a stater motor that works on 3 diff. engines very conveniant.