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ACNCN Cooling head

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godale03

godale03

Awesomer!! Than Rolex!!
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Well Rolex, and Jon2, and of course all of my new friends out there have finally convienced me to get rid of that molded stock 2.5 head and replace it with a brand new ACNCM head. I have to say though, Ebay and paypal are just way to easy... I went on Ebay and found one brand new from some place in New York. $31 shipped. I hope this is a good price. I looked around and it was the cheapest I could find. I will have to pull the dremel out and get rid of my three point roll cage it looks like, but at least I should have an easier time tuning my mill.... of course I bought this against the advice of my LHS but who the hell cares.. .you guys know your stuff. Thanks again.

Tom
 
I was told by my LHS that adding a cooling head to the 2.5 would gain me no performance gain or help make tuning any easier. He told me that he would sell me one if I really wanted one, but he said I would be wasting my money. He said the 2.5 was enginered specifically for that mill and there isn't a better head out there.
 
Thats funny, changing the head will improve cooling and performance on just about all mills, and especially mills with tiny cooling heads!
 
You now what though, I find that my LHS gives me alot more different advice verses when I ask everyone here. For example, my LHS advised me to go with 33% nitro to improve performance, but they never said it will wear my engine faster as I found out here. I also got the same advise about replacing the cooling head. My LHS also is a little more expensive on cars/trucks and parts verses purchasing online. Online all the way for me and 99% of my questions get answered here. I hardly ever go to my LHS anymore because I tend to question what they give me advice on now. It would be nice though if this website had some kind of real-time help, sort of like using AIM/yahoo/MSN messenger to get help instead of waiting for a bit later. Just a thought.
 
godale03 said:
I was told by my LHS that adding a cooling head to the 2.5 would gain me no performance gain or help make tuning any easier. He told me that he would sell me one if I really wanted one, but he said I would be wasting my money. He said the 2.5 was enginered specifically for that mill and there isn't a better head out there.
Click to expand...


Freaking morons is what I say. The instant I put the Hardcore racing mutant head on mine the tuning was more consistant and didn't over heat! I know tha my LHS sucks ass as they promote HPI, Traxxas and XTM yet they say that ACNCM and Hardcore racing and ACNCM are just lame and over priced. The cooling head helps to cool the engine thus helping the motor run more efficiently. Its not a new motor or different gearing that can help make more power. The LHS needs to understand that even though it doesn't make pwer directly, it helps to the engine to run better due to the lower temps.Their cooling heads aren't any better than the ones stated prior. They just hate the products that they don't sell.

Get the ACNCM head. You won't be disappointed. RushRC has the nova heads on sale right now!! Go for it!!!
 
Went on Ebay last night and I have a brand new ACNCM cooling head on its way. Only $31 shipped. I don't think was a bad price at all.... The only problems I forsee is how much dremeling I will have to do, and I will probably have to get rid of my three point rollcage.
 
godale03 said:
He said the 2.5 was enginered specifically for that mill and there isn't a better head out there.
Click to expand...

I think he's quoting the advertisement or what he reads at the traxxas forum. I've read it as well. Supposedly, the 2.5 head has tapered fins which by physics draws the heat away from the center.

Regardless how it is tapered/shaped, the head is just to small for the kind of RPM's that engine cranks out. 40K rpm's makes for a lot of fire inside which makes for a lot of heat. My OS 15 cv-r(x) head was bigger than the 2.5 stock head and it put out less RPM's and HP (on paper) than the 2.5 and it still ran around 240-270 consistently.
 
Godale, I don't think much dremelling will be needed. It is huge, but i doubt the head will need to be mutated to fit with the roll bar.
 
How to install new Cooling Head (ACNCM) on 2.5 Maxx

Groovy. I was hoping not to have to mutate the cooling head. I hope I got a good deal on it though. Supposed to be NIB . Comming from PowerHobby-com. Seems to have a good seller rating. I just hope it comes soon. I am in MD it is coming from NY we shall see.

How does the old head come off? And how does the new head go on? Is there any mods that need to happen or is it a direct fit? Is there anything I should know before taking on the job?
 
Think I got my ACNCM head from the same guy in NY off of Ebay. I paid 21.50 for the head + shipping. The head is huge,just gota get me a Tmaxx now :shrug: LOL
 
the 5 screws on the inne part of the head around the glow plug need to be unscrewed, then the head just comes right off. you need to keep the seat area around the head clean so no dirt is in the seal area. You need to transfer all shims off the stock head and put them on the new one. Then just torque the 5 screws down in a star pattern and you are good to go.
 
.21Rc10GT said:
the 5 screws on the inne part of the head around the glow plug need to be unscrewed, then the head just comes right off. you need to keep the seat area around the head clean so no dirt is in the seal area. You need to transfer all shims off the stock head and put them on the new one. Then just torque the 5 screws down in a star pattern and you are good to go.
Click to expand...


When you say shims, what do they look like and are they put on in a particular order, or pattern? Thanks

Tom
 
godale03 said:
When you say shims, what do they look like and are they put on in a particular order, or pattern? Thanks

Tom
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They can be brass or gold colored. They are thin and are VERY FLIMSY AND BEND EASY! Don't bend them. Can't remember how many there are in the Maxx 2.5 but they will be either on the head or right on the block. Be careful not to get dirt in there while it is open. Whatever shims you have in there transfer them to the ACNCM head. Tighten the head bolts till they are snug but not too much where you stip the threading.
 
Is this something that a Newbie should try or is it something that I should take down to my LHS and have them do it? Just don't want to ruin anything. Thanks

Tom
 
godale03 said:
Is this something that a Newbie should try or is it something that I should take down to my LHS and have them do it? Just don't want to ruin anything. Thanks

Tom
Click to expand...
You are quite capable. Can you handle a screwdriver? If you can then this is not much different. Find the proper driver for the headbolts and turn them counter clockwise.

Just make sure the head is clean .

When you are done. look at the bottom of the new ACNCM head and see if the head has a certain pattern that it goes on. The stock head does. Look at the bottom of the stock head and you will see what I mean. If the ACNCM head is like it then just make sure it is aligned properly and place the screws back on.Tighten them in stat type pattern to get the head on evenly.

Let us know.

Jon
 
Yeah, you wont get more experienced if you don't do your own work. Besides, thats the whole fun about this hobby, is learning!
 
That is true, I do enjoy and look forward to getting better at wrenching I just didn't want to ruin a brand new motor. I am sure I can handle it. What does teh pattern look like? Do you mean that the head is "Keyed" which means it has only one way and one way only to go on, or do you mean making sure the head lines up with the screw holes? The head should be in today. Thanks

Tom
 
You tighten down the screws in a "star" pattern. The stock head has the slots in the sides for the engine mount screws to line up with it. I dont think the acncm head has anything like that (that i remember).
 
When you replace the head, use one hand to keep the head seated absolutely flat on the block. Drop the allen screws in, and spin them in with the allen wrench between your thumb and forefinger. Go back and forth, crisscrossing which ones you tighten, just a little more each time. I usually do it 5 or 6 times till it's completely tight. That method insures that the head is seated absolutely flat, with even pressure on the gasket, so you won't get any leakage.
If you start by tightening the first one all the way down, the head can end up tilted, and you'll be losing compression.
As far as LHS advise, always ask what MTs or buggys they drive. A lot of them are trying to sound knowledgeable, but if they don't own them or drive them, they are pretty clueless.
His comment on the cooling head was totally bogus.
 

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