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Old 03-31-2006, 03:25 AM   #1
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Dynamite Compression Guage

I was going through some RC Nitro Web pages and stumbled upon a picture of a Dynamite Compression Guage. Is it worth getting? Have you used it before? Is there something better? If you're not using a guage, how can you tell that you are starting to lose compression?

The product page: http://www.dynamiterc.com/Products/D...ProdID=DYN2514

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Old 03-31-2006, 07:55 AM   #2
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That looks good. What reading should you be looking at for a .12 race engine shimmed to 0.4mm head clearance?

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Old 03-31-2006, 09:45 AM   #3
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You probably just baseline it and then keep an eye out for when it starts to decrease. This is what the article stated:

"When you buy a new engine, it will have lots of compression. Using a compression gauge, check its compression after it has been properly broken in. After every three or four tanks of fuel, check the compression. When you see a drastic drop, you'll know it is time to replace the piston and sleeve. When the engine loses compression, raw fuel is able to pass the piston and sleeve on the compression stroke, so there's less fuel to burn, and that means less power."
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Old 03-31-2006, 12:14 PM   #4
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That's cool! but I think it would be easier to count or note the amount of fuel that passes through your engine. like one racer here in my place, he knows that for this number of tanks he must replace his conrod and for this number of tanks he must place all internal parts. works pretty well...
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Old 03-31-2006, 01:20 PM   #5
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Counting is good and I will certainly take the other advice I was given regarding engine maintenance after going through the 1.5/2.0 gallons of fuel. The only thing I worry about, is losing compression prior to the normal maintenance cycle. In addition, I don't want to replace the piston and sleeve before I have to replace it. If I don't get any bad feedback on it and no one has a better recommendation for a compression guage, I'm probably just going to get it.
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Old 03-31-2006, 01:32 PM   #6
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Default Compression Gauge measurements.

On our motors compression changes when the motor is hot vs when it is cold. I don't think that this gauge will be a viable determining factor in changing anything. I have had some motors that flopped over extremely freely when hold or cold and they were rockets. They seemed to have almost no compression. I just think it would be difficult to get any kind of consistant gauge of when the motor is cold..... and when it is hot when compression matters most. Just my $0.02....
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Old 03-31-2006, 01:35 PM   #7
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I will be getting one.... I dont like the method of replacing parts after a given amount of fuel.... way too many variables. each engine is different as well as running conditions.. and I dont believe that every p/s set is gonna wear out the same.
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Old 04-01-2006, 06:30 AM   #8
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When the motor runs like a dog throw it away and get a new one... Simple system
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Old 04-01-2006, 11:19 AM   #9
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What?!! Throw it away?!!

The next time you want to throw out an engine, please let me know and I'll pay for the shipping for you to send it to me! Well, since you live in the UK, maybe not!

How long do your engines last before you throw them out? Are they damaged beyond repair? What is the condition of the crankcase, crankshaft and heads? Is crankcase metal fatigue (i.e. expansion/contraction)/damage the primary reason you throw out an engine?
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Old 04-01-2006, 12:17 PM   #10
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Something good to add to the tool box.
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Old 04-01-2006, 01:57 PM   #11
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Wow guys. Looks like some of you use different methods.

I have a compression gauge and it does work. You say cold and hot this and different motors have different compression. Yes thats true there will be different numbers.

But, ever hear of controlled tests. Do the test when the motor is always cold. That easy.

Next, there is a dry compression test and a wet compression test. I think its pretty obvious to what im referring to.You do the compression test with no oil (dry) then you add 1-2 drops of after-run and run the test again (wet).

Take your readings for that specific motor dry and wet, write them down. Check it every gallon or half gallon or every race if you feel. Just keep a method and watch for big drops. As well watch the motor power itself a motor might loose compression but will still run ok, another thing to watch is gas mileage. Cant complete a race or its running to hot or flaming out. Probably time for some replacements.

Another way to test is to pull the motor apart and try to pass the piston through the sleeve...see how far it can go. If it cant pass the sleeve your probably fine...if it goes well beyond...might be time for a new motor.

Next get a digital caliper , measure the parts new if there arent measurements readily available , check with manufacturers and see what tolerances they have. They normally have zones you shouldnt allow a part to go and thats when you replace it.

This is how you check a motors condition. Simple as that.
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Old 04-01-2006, 02:25 PM   #12
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I had one years back. Will this one work on turbo buttons?
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Old 04-01-2006, 03:25 PM   #13
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Quote:
Originally Posted by Artificial-I
This is how you check a motors condition. Simple as that.
Thanks Artificial-I! Really good info!
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