I bought a tmaxx used with a drop in os engine already installed on it.. it runs good, seems about the same as the stock engine.. probably a .15 but i can't decide for sure bc os offers so many engines that fit the tmaxx.. i took a few pics, all it says on the right side of the crankcase is cv-r and os on the other side.. os offers a cv-r .15 and .18 and maybe others that are cv-r but these are the only 2 i know about.. anyway, please help id it! it has a broken high speed needle valve so i can't use it til thats fixed, but i don't want to order the wrong part! plus i want to get the sullivan start system for it, but again, i don't know what engine i have..

Looks like an .18 CV-R to me from looking at the carb.

I think there's a number on the carb so if you check on the OS web site you'll see what carbs are available on that engine,but I'm fairly sure it's the .18 from the blue heat sink as well.IIRC the .15 has a black heatsink.The .12 I had had a blue heatsink so it could even be a .12.

You could find that the needle housing is the same across several carbs,when I broke one like that I fitted one from a redundant OS.12 CV-R.

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thanks bikeracer seems more likely that it is a .12.. it doesn't have any extra power over my brother in law's factory tmaxx.

anyone else like to take a stab at identifying this engine? i need to know for sure b4 i order the parts for it.. thanks

please help, i need to get this bad-boy back up and running, but i can't without knowing what to order! please help!

i'm wanting to say .18 as well...the heat sink looks a little different than the one on the .12 (the cut outs on the .12 are straight up and down...not at a slight angle like on yours)  all else fails, take it down to the lhs and have them take a gander at it

I think its an 18 as well... I have one of them and its close... the head is different, but yours may be an older one.. Mine is a couple of years old and the head is all blue... can you possibly remove the engine, clean it up and take some new pics... the header is also in the way making it tougher to ID the motor... Mine has the # 18 stamped above the CVR, but can't see that on yours... maybe dirt or stuff in the way... You really need to clean that off to get a good idea what you have there... Let us know... OS doesn't make a 15 CVR anymore and I don't remember a 12... There are a couple of carbs used on the CVR depending on application.. Side or Rotary style.. can't tell from the pics what that one is... should be slide in a Maxx, but who knows what was in there... A properly tuned 18CVR will smoke a traxxas .15 all day....

I did a little digging and found this on the discontinued OS engines.... here is a link http://www.osengines.com/parts/images/21254000.jpg

this is from a OS 12CVR and its long discontinued... the carb is a #10 series, but you have to look at the carb to tell... Hope this helps you... If you want.. go to the os engines webpage and type in discontinued engines in the search... scroll down to car engines and look at the list ..... alot of the parts have pics to help with your search...

thanks so much guys, i will get this bad boy cleaned up! no one at my lhs knows what this engine is, which is why i came straight here.. i will look through that link you posted cen.. thanks!

also mine does not smoke a stock tmaxx so that makes me think it is the .12, plus that discontinued head you linked is my exact head/heatsink.. also mine has a rotary carb if that helps id it! thanks again for the help guys!

Here is the carb you should have on the engine... if its a 12 vcr then this is the carb..
http://www3.omnimodels.com/cgi-bin/w...I=OSMG2440&P=7

Here is a link to the part that you need to replace....
http://www3.omnimodels.com/cgi-bin/woi0001p?&I=OSMG6993

when you remove the carb, the stock number will be stamped on the side... should say 10E.... if not go back to chart and find the correct one... Ive ordered from omni models before... they are good....

100% sure its a .12. That was a pretty good motor upgrade from the Pro .15

I've just checked a couple of my .18 CV-Rs and they've both got eleven fins,yours looks like nine fins so it's more than likely a .12

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hey guys thanks so much, after reading what you all had to say and looking at a few outdated engine pictures from os i feel pretty confident it IS in fact the .12.. thanks so much for all the help!