cv-r questions........

[Lason]

Ok, I just got my CV-R about a week ago and quickly broke it in by letting it idle for 6 tanks very rich (about 165-200 degrees) and running another 3 at about 1/2 throttle also very rich. Now I went to the track yesterday and it seemed like the only way I could get my truck running real good was leaning it out to about 275-300 degrees. After running 2 laps around the oval i took a temp reading and saw it hit 301 so I shut it off and richened it up a little till I had it about 240-255 and it still ran like crap and was sputtering gas out the pipe like it was way rich. I thought I may have had an air leak so I changed out all my fuel line and it still ran the same. I also sealed the craburator throat with silicone when I turned it 180 degrees to fit my GT. Any ideas on what could be wrong or better yet, who makes a correct head for a CV-R?? I see hardcore and crazynut both have heads for the os cv family .12's but I read the CV-R has a different head than previous versions, and if I use one of these heads I will lower my compression. Thanks in advance.
Lason

 

[NCNitro]

If you call OS and ask them they will tell you no two OS engines will run the same temps. They tell you to tune to performance and not temp, and that temps near the 300 mark is ok. Make sure you have a nice stream of smoke coming out the exhaust and you should be ok. Mine ran those exact same temps and did the exact same thing if I richened it up. I was not comfortable with that at all so I bought the Hardcore Mutant head for mine and it dropped my running temps down to the 220-250 range depending on how hard I am running it. OS also does not recommend an idle break in, your temps really needed to be higher than 160 to get the piston and sleeve to seat properly, you need to bring the temps up and down creating heat cycles during break in. Then letting it cool off completely between tanks.

 

[Lason]

Well as far as breaking in goes, I have always broke my motors in this way and they have always lasted me some time. The first 2-3 tanks I run, I run real rich around 160-180 just because I want as much oil as possible to get in there and keep it lubed during the initial break in then after that I run 2-3 more tanks at about 185-215 so I can get the temp up to do the actual breaking in. After all that I run it at 1/2 throttle for another couple tanks at around 225 just to finish off the break in then I just let her rip. As far as temps go, I have always had my motors run between 225-250 and they always ran like beasts. I have run everything from Rossi's to O.S.'s and they always did great at these temps, except for this CV-R. Also you said you have the mutant head on there, was it designed for the CV-R specifically or just the CV family and if the family did you notice it get slower? The reason I ask is because as I stated above O.S. even states the NOTHING on the CV-R can be shared with the CV family and I actually found a website a while back that sole CV-R specific heads but can't find it anymore. Of course if the CV-R is higher compression than a CV-Hyper for example then that would explain why your temps dropped about 50 degrees with that head, you just lost compression.

O and I did run 10 minute heat cyles between tanks with piston at bottom of bore.

 

[Rob D]

As for temps ill agree with NC os says tune for power not temps and here is a link to a head for os cv-r just happen to see review of it this am no pic on site but in mag its a huge head

http://crazynutracing.com/

goto the all availbe part# link and look there but the part # is cnr1200 and its 55$

 

[NCNitro]

Yes the Mutant will fit the cvr, a good friend of mine has one on his cvrx.

No my truck did not get slower because of the better cooling head, It actually was faster because I could lean it where it wanted to be run and still run cool. It is just a far better cooling head than the cv head. I have heard really good things about that Crazy Nut Racing head too.

Read the break in procedures from the OS website, it says they don't recommend break in at idle. I know some do, the instructions that came with my RS4 3 said to do it just like you did. I try to follow what each manufacturer recommends, and not just use a generic break in procedure. Just like the new 2.5 has its own set of break in instructions, so I would not buy that engine and break it in like my HPI or OS engines, I would follow the recommendations for break in set by the manufacturer.

 

[x_789]

AHH the break in routine. Man every one has a diffrent way of breaking in engines.. I heard 10 diffrent ways from 10 diffrent people when i got into the hobby I just finally decided to go with what the manufacture says like NC suggested. My fantom was diffrent from my OS which was diffrent from my dynmaite and on and on.. The one thing that does seem to be the same now is that most manufactures are recommnending getting engines above 200 asap and not just idling. This seems to have really taken off latley.. As far as running heads there is a diffrence in the CV and CV-R heads a CV head will lower Compresion on a CV-R head that is strait from OS... If you find some one that makes a head specifically for a CV-R please link to it. Because all I have seen is just generic heads that are for os .12 or .15 and they were all made for CV is my understanding. Anyway I run my OS around 230-250 and get good power from my cv-rx... X

 

[Rob D]

X posted a link to the cvr head above but here it is again

http://crazynutracing.com/

 

[x_789]

Originally posted by Rob D
X posted a link to the cvr head above but here it is again

http://crazynutracing.com/

All I see is a CV head. And a .21 head ... I don't see a cv-r head ...X

I foy go here http://crazynutracing.com.futuresite.register.com/_wsn/page9.html you will seeexactly what I Was talking about they have the same part numbers for a cv and a cv-r

O.S. 12CV $50.00 #CNR2000
O.S. CVR12 $50.00 #CNR2000

This is exactly what I was talking about using the same head for a cv and cv-r If you use a head that is made for a CV on a CV-R you will lose compression... X

 

[NCNitro]

I dont know X, my buddy has a Mutant on his cvrx and it runs like a raped ape. That just might be a cover their ass thing. I have heard several complaints about the cvrx though, either you get a real good one or a lemon. I dont know, I have been using my CVX for a while now and I love it, when it went I was thinking about going up to the cvrx but I may have to rethink that. I dont know if this still holds true but the CVRX did not have a warranty either because it was their "racing engine" but the CVX does have a warranty. They may have revised that but I know thats how it used to be.

I have also heard alot lately about getting the engines in the 200+ range during break. If the engine and piston do not get hot enough during break in how are they supposed to seat properly. This is why I follow exactly what the manufacturer says.

 

[Rob D]

sorry it was for the 15 they had diff head forgot we were looking for 12 my bad

 

[x_789]

Well there was a email posted on the old maxx trax site from os talking about how putting a CV head on a cv-r that iw would lower the compresion and there were some people that complained about it also that is where I got my info I contacted OS about this and never got a reply. X

 

[NCNitro]

Here is the head and description I got from Hardcore Racing's site. Like I said I have a friend running one on his cvrx and it screams!


OS .15 Mutant Head

Superior design leads to superior cooling! Our Mutant Heads are machined from solid billet aluminum for maximum performance. A unique heat sink design provides more surface area for superior cooling that other heads simply can not match. A recess in the base allows for easy idle access. A perfect fit every time. Fits all OS .15 CVX, CVR, & Hyper engines.

They also make one for the new 2.5.

TRAXXAS T-MAXX 2.5 Mutant Head

Superior design leads to superior cooling! Our Mutant Heads are machined from solid billet aluminum for maximum performance. A unique heat sink design provides more surface area for superior cooling that other heads simply can not match. A recess in the base allows for easy idle access. A perfect fit every time. Fits any new T-Maxx 2.5 engine.

They come in silver, green, purple, and blue.

 

[Bash_N_Thrash]

X_789,

As far as running heads there is a diffrence in the CV and CV-R heads a CV head will lower Compresion on a CV-R head that is strait from OS...

OK so what your saying is the CNR1200 for the OS .15 CVR from Crazy Nut would fit the OS .15 CV-X engine and would raise compression? Just the opposite of the quote above, right?.
Then it sounds like it would not be a good idea to put a CVR head on a CV engine. Please correct me if I'm not getting it. I wanted to purchase a cooling head that would keep the temps down on my OS .15 CV-X. Currently I have the O'Donnell head. Tuned for good power with good smoke it will go to 300+ degrees while bashing around in my T-Maxx. This seems to be quite hot, but maybe according to OS its not a concern to worry about temps just performance.

 

[x_789]

Well considering that head is actually made to spec for a cv-r then yes bash that would be a correct hypothisis...X

 

[Lason]

I see everyones points and they are all taken into consideration but one thing I want to point is just because O.S. says not to tune by temp doesn't mean I should lean it out till I get that lil booger just flat screaming because at that point my mill would be hitting the 400 degree mark (trust me I have done it in a previous mill) and I dont know of any ABC sleeve that can handle that. I will continue to tune with my temp gun handy but I just wanted to make sure these temps I was taking were in the norm with these motors. I have always been the type of person that really takes care of his things and if I would loose a little performance running at 250 then so be it as long as I knew my motor would last a couple more gallons before needing a rebuild. So no one knows where I could get head for my CV-R that is CV-R specific huh? I might just go ahead and pick up a mutant head and measure my compression before and after and see what I get.

 

[Çh®i§tiªñ]

Temps of 300 on an O.S. are not uncommon and I havent seen bad results yet because of it. Now if you run at 500 on an O.S. I can assure you that you will need a new piston and sleeve, QUICKLY! As I did.....

300 is good but there are some other heads that will reduce it for certain. You should be able to control compression to some extent with the right number of spacers. Just watch for Plug impact if you dont use any.

 

[Lason]

Ok guys, I appreciate all your input! Have a good one