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Thread: Cooling head

  1. #1
    RC Racer
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    Cooling head

    Let my Lil brother run my maxx for a while. He rolled it pretty good and bent the cooling head up pretty bad.
    I was able to straighten it up a bit but cannot get it to run cool enough. I assume any damage to the had will affect the cooling?

    Going to pick up a new head tomorrow. Are they hard to Change out?

  2. #2
    Marshal Double G's Avatar
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    It will have effect on cooling but also look to see that it is sealing against the block properly and also there is no damage anywhere else.
    The Super Derecho

  3. #3
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    Is there a better aftermarket head out there?

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  5. #5
    RC Turnbuckle Jr. fallonguy's Avatar
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    Do you have the 3.3 engine or the 2.5? Also check the header for damage.
    I wanted to put a really cool signature but I ran

  6. #6
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    I would stick with the stock head and yea the're not to hard to change out.

  7. #7
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    I also recommend to stick to stock head. A larger one is unnecessary. Also when you remove and bolt on the head make sure you unscrew it in a star pattern.
    TRXnot so Newbie21

  8. #8
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    I have 2.5 engine on my TMAXX and it has an aftermarket cooling head that says "TRX 2.5 Nova Race Pro". I cant seem to find another one anywhere. I have another 2.5 engine that I was thinking of getting an aftermarket head like the one I already have or just pick up a 2.5R cooling head instead. Also... I was wondering if the cooling head is the only difference between the 2.5 and the 2.5R?
    Traxxas Nitro Sport w/ TRX 3.3 Racing Engine

  9. #9
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    Quote Originally Posted by Monte_1977 View Post
    I have 2.5 engine on my TMAXX and it has an aftermarket cooling head that says "TRX 2.5 Nova Race Pro". I cant seem to find another one anywhere.

    Ive got a couple Nova rc products myself. Thier stuff is well made but unfortunately
    they went out of business a few years back.

    I see the Nova rc cooling heads listed on ebay once in a while.

    Crazy Nut Racing makes a nice cooling head too but I dont know if they're still in business.
    Bash, Crash, Upgrade, Repeat..

  10. #10
    RC Turnbuckle Jr. fallonguy's Avatar
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    Quote Originally Posted by Monte_1977 View Post
    I was wondering if the cooling head is the only difference between the 2.5 and the 2.5R?

    Yes the cooling head is the only difference and you can use the 2.5R head.
    I wanted to put a really cool signature but I ran

  11. #11
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by lowrhadur View Post
    Let my Lil brother run my maxx for a while. He rolled it pretty good and bent the cooling head up pretty bad.
    I was able to straighten it up a bit but cannot get it to run cool enough. I assume any damage to the had will affect the cooling?

    Going to pick up a new head tomorrow. Are they hard to Change out?
    I bet if you cleaned up the mating surfaces of the head and the block/case with some denatured and replaced the head shim yo umight get away with it...

    I ran this engine a week after this in the State Races, ALLLL weekend long... It got me to 15th place out of over 80 entires...

    If you have a leak from there you can tell, you will see brownish coloration from between the block and the head, if it seals there you should be OK. Oh, and I live in SoFla,,, Heat, not a problem...


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  13. #13
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    Yeah IDE go with the RBI mods cooling head myself. Supposed to drop running temps up to 40 degrees cooler and gain up to another 1000 rpm.

  14. #14
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    I have a good 3.3 cooling head I'm not using.

  15. #15
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    Quote Originally Posted by fallonguy View Post
    Yes the cooling head is the only difference and you can use the 2.5R head.
    Awesome... thanks Fallonguy. Kinda figured that the cooling head was the only difference. I just bought one today and a new piston and sleve. It's time for a rebuild too.
    Traxxas Nitro Sport w/ TRX 3.3 Racing Engine

  16. #16
    RC Turnbuckle Jr. Nitronaught's Avatar
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    Quote Originally Posted by zdragon71 View Post
    Yeah IDE go with the RBI mods cooling head myself. Supposed to drop running temps up to 40 degrees cooler and gain up to another 1000 rpm.
    Yeah, and if it works too well you will be wanting to either run the engine too cool or run it too lean trying to attain your temps.... Also,,, it's the port timing that makes the major changes in rpms.... Not combustion timing, that gives you more power and that's what changing the compression of the engine does (hence the different thicknesses of head shims and different heads providing different compression).

    Do you have the RB Mods cooling head? How's it working? I'd like to know form someone who is actually using it. I know the Nova cooling head worked well for the 2.5 engine, but that was the last aftermarket head I dealt with that was worth anything... I've seen engines take an early life with some cooling heads..... Rick over at RB knows his stuff. But 40 degrees cooler? I don't want my engine running 40 degrees cooler at all. My best performance is working below 260 and above 210 on all 3 of my TRX engines and my other RC engines, 2 of them fairly well modded but Non-Traxxas. Still using the factory heads though. In fact I don't know anyone at the offroad track where I race that uses aftermarket cooling heads... But Onroad cars, pullers, cawlers, boats and planes they seem to be more common.... I'm pretty sure it has to do with air flow along with load and oil content as well as the functional rpms that all play in that factor... Probably the alignment of the stars too .. j/k
    Last edited by Nitronaught; 05-25-2012 at 07:52 AM.
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  17. #17
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    I just ordered the RB head(for my 3.3), so I will report back once I receive and install it...

    Sent from my SAMSUNG-SGH-I727 using Tapatalk 2

  18. #18
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    Quote Originally Posted by Nitronaught View Post
    Yeah, and if it works too well you will be wanting to either run the engine too cool or run it too lean trying to attain your temps.... I don't want my engine running 40 degrees cooler at all. My best performance is working below 260 and above 210 on all 3 of my TRX engines and my other RC engines, 2 of them fairly well modded but Non-Traxxas.
    Yeah I'm with you on this one. There's not too many aftermarket heads on the market
    these days, but in thier heyday there were several models available
    and most claimed 40 dgrees cooler or more.

    Its best to tune by smoke trail, performance and sound when tuning these engines.
    Leave the temp gun in the tool box.
    Bash, Crash, Upgrade, Repeat..

  19. #19
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    Quote Originally Posted by fallonguy View Post
    Yes the cooling head is the only difference and you can use the 2.5R head.
    the sleeve is also ported slightly differently

  20. #20
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    The 2.5 and 2.5r are the same everything except the cooling head. The early 2.5 before the 2.5r came out was different porting on the sleeve. Once the 2.5r came out they only offer the sleeve that came out in the 2.5r. So if you have an early 2.5 the sleeve will be different, until you order a replacement.
    T-maxx 3.3
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