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nova rc cooling head - force 28-32

 
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andreas_h92



Joined: 16 Feb 2009
Posts: 63

PostPosted: Wed Mar 04, 2009 2:57 am    Post subject: nova rc cooling head - force 28-32 Reply with quote

does anybody tried the nova rc cooling head for the force 28 or 32? Dies they really reduce the 40% of the temp and perform better?
here is a link of the cooling heads: http://www.novarcproducts.com/coolingheads.html

Thanks
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Eggbert



Joined: 27 Jan 2006
Posts: 331
Location: Nova Scotia, Canada

PostPosted: Wed Mar 04, 2009 6:25 am    Post subject: Reply with quote

I did a lot of experimenting and calculating on cooling heads a while back. For the old Force 26, an aftermarket cooling head is a definite improvement. However the stock Force 28 cooling head is sufficient in my neck of the woods. I supppose if you live in Florida, or some other hot climate and drive on sun-baked hot asphalt, a better cooling head might help.

Mind you, I try not to worry too much about temps. Nothing in the engine is going to melt, even at temps well over 300F. However, I found that if an engine gets too hot, it can detonate. This occurred at about 325F on my old Force 26. And detonation causes damage.

I tune my engines as best I can, and then check the temps. If they are getting close to the 300F mark, I then consider an adftermarket cooling head. An easy mistake to make, is to have the HSN too lean and the LSN too rich.....can make very high temps after a bit of hard running.

Those after-market heads can help a lot in on-road touring cars where there may not be a lot of airflow. Typically the engines are covered by the body and the air-holes don't let enough air through to cool the engine.

Now, about that 40% temp reduction. No, I havn't found that. Maybe a drop from 280F to 220F which is much less than 40%. They may be touting that 40% based on the amount of surface area their heads have compared to stock heads, which you think would think would lower the temp that amount. Well.....it should lower the temp a lot on the head fins, but not necessarily at the glowplug, where one normally measures temperature. I find my glow-plug temp doesn't change much from winter to summer, yet the cooling fins are sure hotter in the summer.

Don't forget, the source of the heat is from in the combustion chamber, and that should be a certain temp for a perfect tune regardless of the rate the cylinder head dissapates heat. Problems arise when the combustion chamber temp goes high enough to cause detonation. Sometimes a BIG head can help, but only if the original head was poorly designed to begin with, or there are air-flow problems peculiar to your vehicle.

So I didn't answer your question, but hopefully I helped a bit.

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MotionMachine999



Joined: 20 Oct 2005
Posts: 1721
Location: Land of Oz

PostPosted: Wed Mar 04, 2009 8:13 am    Post subject: Re: nova rc cooling head - force 28-32 Reply with quote

andreas_h92 wrote:
does anybody tried the nova rc cooling head for the force 28 or 32? Dies they really reduce the 40% of the temp and perform better?
here is a link of the cooling heads: http://www.novarcproducts.com/coolingheads.html

Thanks



Cleaver marketing, omit the risks while greatly exagerating the benefits.

An aftermarket cooling head, by itself, will NOT improve engine performance. Sure aftermarket cooling heads can lower operating temps, but any performance gains are only achieved by allowing the end user to further LEAN, often excessively mind you, the engines fuel mixture that would otherwise quickly cause THAT particular engine to "melt down". However, in doing so, users also lower the amount of vital internal engine lubrication, less fuel = less lube. The fuel not only delivers the lube, but the nitro also doubles as an internal COOLANT. This "lean'er fuel condition" promotes engine wear and can significantly shortens the engines expected "service life."

Its been my experience that Force engines are notoriously hot blooded, meaning they perform best at temps of 260-280 degrees, often peaking out around 300 degrees. Yes, these temps appear dangerously high and YES, these temps can be lowered by the addition of an aftermarket head. However these temps are the norm for Force engines and after adding an aftermarket cooling head, the performance level then often directly reflects that of the lower temps (say 220'ish). SO folks start leaning the fuel mixture to further improve performance (squeezed to the last drop persay) and before they know it, there right back at the same temps as before with the stock head, only now the engine is being starved of fuel and vital lubrication while often producing more "work" than it was ever intended to deliver SAFELY. Eggbert makes some valid points, but I'd like to expand a bit further. This much lean'er fuel condition can further promote detonation which as he mentioned, should be avoided at all cost..

There must be a formula engine manufacturers use, knowing the minimum requirements and maximum limitations (max performance/stress level of internal components) of THAT particular engine, to determine the optimal SIZE/SHAPE (surface area) or thermal efficiency of the cooling head. They simply dont design an engine cooling head to look cool, no phun intended.

Force engines, given there low cost, are good ECONOMICAL engines which deliver decent performance. But personally, Id apply the cost of any aftermarket cooling head directly to the future purchase of a much better HIPO engine.
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andreas_h92



Joined: 16 Feb 2009
Posts: 63

PostPosted: Wed Mar 04, 2009 9:13 am    Post subject: Reply with quote

thanks for the fast replies and good information!
I would put here another one question.
My Force .32 sometimes reaches at 300F - 315F. As MotionMachine999 said, is normal that force engines reaches the 300 sometimes but i still worry. I want to reduce the temp a little. I am using a 25% fuel and an O.S #8 glow plug and the high needle setting is set to 3 turns and 3/4 of circle from closed. My Low speed needle is still in the factory setting. Any suggestions on how to reduce the temp without adding an aftermarket cooling head?

thanks again :)
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Eggbert



Joined: 27 Jan 2006
Posts: 331
Location: Nova Scotia, Canada

PostPosted: Wed Mar 04, 2009 10:06 am    Post subject: Reply with quote

MM has just explained why one should not tune by temps. You can tune too lean if you are only looking for a certain temp, and those glowplug temps will change a bit depending on the heatsink.

As far as it goes......I really think the Force 26 heatsink was inadequate. Engineers make mistakes. Sometimes it's not the engineer. The engineer may have specified a heatsink witha sufficient "X" number of fins, or sufficient "Y" surface area, but neglected to mention that this was for pure aluminum, of which billet is the closest and cast is very far away. With cast, you need more fins/surface area.

I did make a post somewhere about how much larger the 28 heatsink is compared to the 26, even though the engines are close in size. Somthing got mixed up when they spec'd the 26 I think.

I agree with MM....make due with what you have and put your money towards a better quality engine when your Force finally dies. But that's for you to decide. I bought the larger head, but I don't mind as I learned a lot with it.
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MotionMachine999



Joined: 20 Oct 2005
Posts: 1721
Location: Land of Oz

PostPosted: Wed Mar 04, 2009 11:53 am    Post subject: Reply with quote

andreas_h92 wrote:
thanks for the fast replies and good information!
I would put here another one question.
My Force .32 sometimes reaches at 300F - 315F. As MotionMachine999 said, is normal that force engines reaches the 300 sometimes but i still worry. I want to reduce the temp a little. I am using a 25% fuel and an O.S #8 glow plug and the high needle setting is set to 3 turns and 3/4 of circle from closed. My Low speed needle is still in the factory setting. Any suggestions on how to reduce the temp without adding an aftermarket cooling head?

thanks again :)


Wow, anything over 300 is not good...
First, get rid of the OS plug, I suggest McCoy #8 myself. Sounds like you may have the tune AFU and make sure you have no air leaks...
You most likely have the LSN tuned via an excessively lean HSN, a very common mistake.
When tuning an engine initially, dont worry about the idle speed, or having a crisp throttle responce, none of that until the HSN is nearly set. The HSN has 2 functions, 1- main fuel supply at the higher RPM's and 2- supply fuel to the LSN, thus its very easy to inadvertantly tune the LSN via the HSN. Not to say you cant adjust the LSN or idle as needed to keep the engine running while you do high speed passes to get the HSN somewhat set.
A properly tuned engine will not idle all day, so dont worry about that. Just get into the habit of blipping the throttle every few seconds to prevent it from loading up on ya.. Show me an engine that idles all day and still has a crisp throttle responce, and I'll show you an engine that will quickly overheat when ran hard for extended periods.
If your wanting exceptional performance (for a Force engine) without the excessive temps, bump up to 30% nitro and tune it ever so slightly rich. If you want to wring it out, install a McCoy #9 GP.
In the mean time, you might fatten the HSN a tad to reel in the temp, then lean the LSN as required..
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andreas_h92



Joined: 16 Feb 2009
Posts: 63

PostPosted: Fri Mar 06, 2009 5:11 am    Post subject: Reply with quote

Can air leaks cause overheat?? And by the way does the glow plug effects the temp of the engine?? I run my engine today rich, a lot of smoke was taking over the pipe but when i checked the max temp that the engine reached while it was running, i saw 310F. dang it
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MotionMachine999



Joined: 20 Oct 2005
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Location: Land of Oz

PostPosted: Fri Mar 06, 2009 11:48 am    Post subject: Reply with quote

andreas_h92 wrote:
Can air leaks cause overheat?? And by the way does the glow plug effects the temp of the engine?? I run my engine today rich, a lot of smoke was taking over the pipe but when i checked the max temp that the engine reached while it was running, i saw 310F. dang it


Yes, an air leak can cause overheating even though there is a thick exhaust trail (rich tune). An air leak in effect, leans out the air/fuel mixture..

Glow plugs are often misunderstood... Here is a decent article explaining the subject of glowplugs.
In a nutshell, the heat range of a glow plug, typically referred to by a #, controls engine ignition timing much like a distributor on a car... Cold plugs retard ignition timing, while hot plugs advance ignition timing..

Although diagnosing nitro engines on line is primarily a guessing game, sounds like you have an airleak...
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andreas_h92



Joined: 16 Feb 2009
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PostPosted: Sun Mar 08, 2009 3:44 am    Post subject: Reply with quote

WOW i didn't know these information for plugs. Great link MM. Thanks
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andreas_h92



Joined: 16 Feb 2009
Posts: 63

PostPosted: Tue Mar 10, 2009 9:18 am    Post subject: Reply with quote

MotionMachine999 wrote:
andreas_h92 wrote:
Can air leaks cause overheat?? And by the way does the glow plug effects the temp of the engine?? I run my engine today rich, a lot of smoke was taking over the pipe but when i checked the max temp that the engine reached while it was running, i saw 310F. dang it


Yes, an air leak can cause overheating even though there is a thick exhaust trail (rich tune). An air leak in effect, leans out the air/fuel mixture..

Glow plugs are often misunderstood... Here is a decent article explaining the subject of glowplugs.
In a nutshell, the heat range of a glow plug, typically referred to by a #, controls engine ignition timing much like a distributor on a car... Cold plugs retard ignition timing, while hot plugs advance ignition timing..

Although diagnosing nitro engines on line is primarily a guessing game, sounds like you have an airleak...


What if there is an airleak in the fuel tank??

Also there is an airleak between the throttle barrel and the Carb. I don't know if it's natural or not because throttle barrel goes in and out so it's sounds normal to me for an air leak to occur there. Please tell me about this because i don't know

Also i found an airleak in the screw that tights the carb on the crankcase
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twisted_metal



Joined: 20 Aug 2009
Posts: 6
Location: Los Angeles

PostPosted: Thu Aug 20, 2009 9:02 pm    Post subject: Reply with quote

I usually tune my engines by sound kinda like how a muscian would tune his instruments. I do however use temp readings and smell to help also. I guess its due to the 9 years of me being in the hobby ... I was considering buying one of those heatsinks though ..

FYI a properly tuned engine will not idle all day but it will idle the full tank if you know what you are doing ...
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