Spark Ignition Nitro Engine

[Jeff Lutz]

We've run a lot of nitro and gasoline engines on a variety of fuels with both glow and spark ignitions. We have not tried glow ignition with gasoline, but that testing was done a long time ago by Sir Harry Ricardo to investigate preignition. The only time I've used my fire extinguisher was with a gasoline fueled boat running spark ignition. Methanol based fuels are a lot safer reguardless of how you ignite the fuel. The only reason the nitro guys don't want to run with spark ignition engines that I can see is that they would need to learn some new things.

Lohring Miller

I think most diehard nitro guys will run what ever is legal and fastest. Clearly there are people on here that just don't know how fuels burn, and thats why they don't realize nitro/methanol is safer than gasoline. Spark ignition has been tried before with nitro in our model engines. Let alone cars,full-size boats,etc…Spark could be more efficient burn, but burning the fuel is not the only problem modelers face. I know we have to load are engines on glow to burn fuel, but on spark it still will not help someone that has an engine going lean on the top end. And people will still have problems with blowing/burning spark plugs. You cannot forget that is how the idea for the glow plug came about in our model engines. Maybe with todays ignition systems it will be better.

 

[dwilfong]

What I see is with a ignition system that is programmable you will have good control over the timing.

Not like the hope you get it right with a glow plug.

In a larger eng say a 27cc you will not need as much nitro to make good power.

Parts are much cheaper for this type of eng. with a ringed eng you will not be a slave to the fit and pricy P/L sets.

with the new engs like the Tiger King there are many options.

So you burn a $30 piston and ring? then you can hone the cyl and not worry about that chrome and pesky tapper.

When I ran my Cagive 125 I went threw many pistons. had a custom big boar sleeve made by LA sleeve and ran cheaper ProX KX125 pistons.

Chased the tune for some time with that Delorto carb. Thy would not release the needle jet needed to keep it rich on the top end.

The factory did not want any one competing with there drivers.

This is not rocket science just a toy boat eng.

 

[Jeff Lutz]

What I see is with a ignition system that is programmable you will have good control over the timing.

Not like the hope you get it right with a glow plug.

In a larger eng say a 27cc you will not need as much nitro to make good power.

Parts are much cheaper for this type of eng. with a ringed eng you will not be a slave to the fit and pricy P/L sets.

with the new engs like the Tiger King there are many options.

So you burn a $30 piston and ring? then you can hone the cyl and not worry about that chrome and pesky tapper.

When I ran my Cagive 125 I went threw many pistons. had a custom big boar sleeve made by LA sleeve and ran cheapler ProX KX125 pistons.

Chased the tune for some time with that Delorto carb. Thy would not release the needle jet needed to keep it rich on the top end.

The factory did not want any one competing with there drivers.

This is not rocket science just a toy boat eng.

. Glad this will fit your budget better.

 

[dwilfong]

What I see is with a ignition system that is programmable you will have good control over the timing.

Not like the hope you get it right with a glow plug.

In a larger eng say a 27cc you will not need as much nitro to make good power.

Parts are much cheaper for this type of eng. with a ringed eng you will not be a slave to the fit and pricy P/L sets.

with the new engs like the Tiger King there are many options.

So you burn a $30 piston and ring? then you can hone the cyl and not worry about that chrome and pesky tapper.

When I ran my Cagive 125 I went threw many pistons. had a custom big boar sleeve made by LA sleeve and ran cheapler ProX KX125 pistons.

Chased the tune for some time with that Delorto carb. Thy would not release the needle jet needed to keep it rich on the top end.

The factory did not want any one competing with there drivers.

This is not rocket science just a toy boat eng.

. Glad this will fit your budget better.

Have to save some cash to build the merk V6 for the Vector.

 

[Andy Brown]

Found an interesting book title. Maybe someone can find a source for the actual book.

Improved Nitromethane Utilization in Spark-ignition Engines

By, K.C. Bush

Brigham Young University. Department of Mechanical Engineering., 1985

http://books.google.com/books/about/Improved_Nitromethane_Utilization_in_Spa.html?id=Y3cwHAAACAAJ

FOUND IT!

Here on the SAE site.

http://papers.sae.org/852130/

 

[BobBonahoom]

I studied all this work about 15 years ago. I was contemplating starting a business blending and selling racing fuel. I even went so far as to try to license patents related to this work and I corresponded with Angus Chemical Co. about the matter.

The main idea was to study fuel blends that might reduce pre-ignition and detonation when using nitromethane and alcohol. The work was sponsored by Angus Chemical and it was phd thesis, (now a book I guess).

What they found, was that if you substituted a particular isomer of nitro-propane (I think it was 3-nitro propane) you still got some power gains. Not as much as nitromethane, but there was almost no knock in the engines. I thought this was so interesting that I bought some nitropropane and did some testing. I sort of ignored the safety issues with 3- nitro-propane while I did the work, thinking that parhaps I could use 2-nitro-propane instead. In the end, I gave up on the whole idea because 3-nitro-propane is a carcinogen and I did not feel it was safe. I could not get the 2-nitro-propane to work as well. Who would have thought back then that boaters would be using gasoline today, which contains several potent carcinogens.

 

[BobBonahoom]

I forgot to mention, that the idea these guys settled on, was to eliminate the methanol, replacing it with the nitropropane. They were still using high percentages of nitromethane. I could not get this blend to work well with a glow plug and assumed spark ignition was needed, hence my interset back then in spark. (No problem in a fuel dragster of coursse).

Another issue was that nitropropane is expensive. A good thing if you are Angus! I did try putting some propylene oxide in to get it burning and that seem to work. Still not practical for comercial fuel though and also a powerful carcinogen.

 

[Andy Brown]

"Who would have thought back then that boaters would be using gasoline today, which contains several potent carcinogens."

"propylene oxide...... also a powerful carcinogen."

Bob, Are you saying that gasoline and propylene oxide are much more carcinogetic than methanol and nitromethane?

Can you place all four on a scale of 1 -10 as to their documented carcinogetic hazard potential?

Thanks for the information!

 

[BobBonahoom]

Nitromethane and methanol are not considered carcinogens.

Gasoline contains several known or suspected carcinogens. The most notorious carcinogen in gasoline is benzene. I am familiar with this because my first job at Dow Chemical company was measuring water in the benzene they were making. About that time (early 70s) the industry was just starting to learn about the carcinogenicity of these kinds of aromatic chemicals. Long story short, our data back then showed long term exposure to vapor concentrations, above 1 part per million, caused leukemia type cancers.

If you search the web you will see that gasoline usually has between 0.1 and 5 % benzene in it. Typical would probably be about 2 percent. I did the math and on a 75 degree day, if you open a can of fresh gasoline, the vapor coming off the top would contain anywhere from 120 to 6,000 parts per million benzene.

Here is a cut from an MSDS for Gasoline regarding their caution specifically because of the benzene in it:

CHRONIC EFFECTS and CARCINOGENICITY

Contains benzene, a regulated human carcinogen. Benzene has the potential to cause anemia and other blood diseases, including leukemia, after repeated and prolonged exposure.

Here is a link to the complete MSDS: http://www.evnut.com/docs/gasoline_msds.pdf

Here is some other warning info: http://www.who.int/ipcs/features/benzene.pdf

The health dangers associated with gasoline are significant. It is one thing to fill your gas tank with it once a week for 5 minutes, but quite another to breath it and spill it all over your hands all day at the boat pond. For me the danger is just too great. I use camp fuel in my gas boats for this reason.

Hope this helps.

 

[Andy Brown]

Thanks for that info Bob!

I have been testing a gas boat for the past couple of months on regular pump gas. I have been sitting on the fence on weather to start running 100LL or Coleman fuel.

You just helped me make up my mind! Camp fuel it is!

We are going to run methanol in the TK for break-in and some early test runs. Then I will swicth over to the Colemans and get the engine tuned for racing in the gas class.

 

[charles siler]

Andy 3 years ago I got bored with a gas boat that I got for my kids. It was a little slow and my friend Rod was running another gasser and was having problems needles to say I told him about running mixed nitro with our gassers to up the power. I added 1/3 of 55% to the fuel and came out 3 turns get it running tuned it down 11/4 launched and rocked the lake for 18 min. Came in checked the plug didn't harm it at all . Add some more gas rest and still running strong. I'm surprised you guys haven't done anything like this already on these sparky motors. Oh my buddy Rod just sat there shaking his head. Got the idea from spiking the methanol in my mud racer but something that expensive 10% was the most we ran. Pass ya later Charlie

 

[lohring]

Whatever the fuel, these plugs should light it. Would they qualify as glow plugs? I want a ruling.

LOL

Lohring Miller

 

[dwilfong]

O dam you really want to shut down the pond now don't you.

 

[Andy Brown]

Whatever the fuel, these plugs should light it. Would they qualify as glow plugs? I want a ruling.

LOL

Lohring Miller

tumblr_n0gymcBm3p1t968xzo1_500.jpg

Polonium spark plugs! .......by Firestone! Gotta Love it!!!!!

 

[John Beardslee]

Hey Lohring are those 18mm thread plugs? My first outboard a Champion Hot Rod used 18mm plugs and that Firestone looks very familiar!

Thanks, John

 

[lohring]

I have no clue. That picture is a result of what happens when you spend too much time on the internet and not eough actually doing something.

Lohring Miller

 

[LarryConrad]

Interesting thread.

 

[Sean Wills]

This is an interesting thread. Have you guys seen this sight before: http://www.rcexl.com/

Sean

 

[Ron Olson]

Sean, I've got one. The pickup bracket for Zen's, RCMK's and the like is missing. I'd order one but it appears that the service is lousy. From the instruction sheet it also looks like the unit is only good up to 10K RPM.

 

[Sean Wills]

That sucks about the service. It seems that every gas rc engine with electronic ignition uses there boxes. I dont know if they can run at nitro engine rpm but I think that they can run well beyond 10k rpm. Posted a video of some gas pylon racers running. Its an old video but shows how high the rpm's can go. Take a look and listen! At least it sounds like there running higher. I could be mistaken.

http://www.youtube.com/watch?v=zF1GOdpf45I#t=249