Rawlpower

Can I drop an OS engine into my Revo 3.3 without any modifications? Any advice most welcome please!!

After having has an OS on my model heli, I am really surprised at how temperamental the TRX is. Maybe I'm spoilt?

I really like everything about my Revo (suspension, handling, looks) except the motor.

My first TRX 3.3 lasted less than 10 tanks. Piston failure. Traxxas sent me a new engine under warranty, casting issue with the piston head. (Which I applaud.)

My second TRX 3.3 was great for the first 15 tanks or so. Started easily, idled nicely, and smooth powerband. Then, the other day, I took the thing to the track and like nobody's business it started eating glowplugs, idling erratically, and generally acting like it had PMS. I took it apart and noticed pit marks on the cylinder head. Which means in theory it was running too hot/lean. Which I find surprising as the HSN was more than 4 turns out and the LSN was flush with the plate and gave me about 5 seconds on the pinch test. I took the car out again today and it starts easily when cold, then after less than 1/2 a tank it eats the glow plug. Put a new plug in, and the engine refuses to start again until it cools down. So basically the engine is toast.

How many TRX's must a man buy in his lifetime?

leroycool1

i have a os18tm in one of my revos and it is the best thing i have ever done to the truck

that motor is hard to find now ( its not made anymore )

but there is a os21tm that would drop right in yuor revo and make you happy

DaveG55

The OS .21 TM is a direct drop in but OS is a bit proud of it, price wise. I understand that people have been having pretty good luck with the Picco Maxx red dot engine too. If you can find an OS .18TM you'll get about the same performance as the 3.3 but with OS tunibility and reliability - unfortunatly they are discontinued and getting really hard to find. Personally I think that OS made a major marketing error when they brought out the .21TM and discontinued the .18TM. I know that I won't go to the .21 TM when my .18TM dies. I'll go Picco or RB or maybe even a true big block before I buy the OS .21 TM simply because I feel like OS is trying to take advantage Traxxas owners by discontinuing the .18 version.
But enough ranting, there are several drop in - or very close to drop in - engines out thatwill fit and be an improvement for your Revo.

sb13

My Feedback: (52)

I have a new OS .21 that I'm about to install. I got a great deal on it and it was well worth it. It's a drop in and I'll be using my THS pipe. Can't wait to get it done. I'm really wanting to know if I should upgrade the clutch or use the stock one since I'm going to be in there anyway. Thats really my only hold up, once decided I'll get on it. I'm off tomorrow and should just install it and break it in.

dirtpile

I'll second the .18TM. They are still out there. I checked Ebay and there are a few there NIB. A couple of them are llisted with sellers that have a lot of good feedback. Just make sure to contact the seller and make sure it's part number is OSMG2112 so you get the right header.

I also definitely agree about the price if the .21TM. I understand that it likely costs more to produce but not $100 more than the .18.

newgst

well personally i havn't had any problems with the trx3.3 except for the fact that it needs to be sealed. After about a gallon it developed a nasty air leak that needed fixing and i didn't know what to do until about 6 tanks later. well anyways it is working great now for over 2.5 gallons! O and while i had it apart i deceded to port and stuff the crank with silicone and flow mod the sleeve which made a huge difference in fuel economy and performance!

BADBIRD

My Feedback: (1)

can you elaborate a little for us noob's
I just broke my 3.3 in and now need to start tuning and making power

Ron

matts6887

So far, I have not had any problems with my 3.3 either, other than it has been known to be a little tempermental at times; but thats ok with me as I guess one may have to expect that from any given engine at any given time

Rawlpower

After much consideration, I have decided to simply do the following in order to relaunch my Revo:

- put a new piston and sleeve in my TRX3.3
- seal the backplate and carb using some gasket cement

It will definitely be the cheapest option, as I don't really want to invest in a brand new engine and pipe etc if I can help it.

The TRX has caused me a lot of pain but I feel like I'm getting to know it, if you know what I mean.

matts6887

Yes, most people know it by now and know how their particular engine "reacts" to adjustments in needle settings, etc; anyways, good luck with ur decision to put a new p/s in it. However, while u are at it, I would also replace the connecting rod if I were u, so that u dont have 1 part that is wearing unevenly compared to the rest....

ChaosEngine

The TRX 3.3 can be an awsome little engine. It can be a little fussy at times, but once you spend some time twisting some needles, finding her turn ons, and turn offs, it can be pretty rewarding for you in the end I just got into the hobby in may or june, and I'm on my third motor The first died on its 4th tank dureing break in, my bad.. RTFM!!! My second lasted through about 5 gallons of hard running, half of the time over heating abuse, and now I'm almost done my second gallon with my third TRX. This one is a gem But in the end.. They are a throw away motor, unfortunately. But!! When they live, for what they are, they are little fire breathers, you just have to tune em right