Engine Gaskets? Glow Plugs?

What do you guys make your engine gaskets out of???

I have tried several materials some are much easier to make gaskets with than others. They all seem to be working fine so far. I have tried .010" roofing aluminum and .010" roofing copper they both work fine for head gaskets. It is a little bit hard to cut the holes in the aluminum and copper but the outside can be cut easy. I also tried automotive gasket material which seems to work the best even for head gaskets. Automotive gasket materical comes in 3 thickness I have been using the thin material. It cuts easy with a razor knife and takes only a few miniutes to cut a new gasket. A very tiny gasketleak can make a huge difference in the way these small model engines run, a new gasket makes a world of difference.

I test ran a McCoy 35 with an 8x6 APC prop. The engine screams with that prop I didn't know that engine was capable of turning that many RPM's.

I rounded up all my glow plugs in one spot and discovered I have 31 glow plugs. I tested them all and discovered that some glow plugs will NOT run in a certain engine but it WILL run fine in a different engine. That must have something to do with the compression of the engine??? Some glow plugs will not start an engine on 1.5 volts but if I turn the voltage up a little the engine starts and runs fine. Some glow plugs the first turn on the coil will not glow but the rest of the coil glows fine and the plug seems to start and run the engine fine.

I found this article to be extremely helpful in understanding glow plug.

http://www.iroquois.free-online.co.uk/gloplug.htm

Gary,

If you have an inexpensive micrometer, or better, vernier caliper, that reads to 0.001", you can find many pieces of scrap soft aluminum between one and five thousandths thick. 0.010 is pretty thick stuff.

Examples: Aluminum peel-off tops on cans like Gatorade powder or similar, disposable aluminum foil roasting pans, even the very thin sides of pop-top soda cans.

For thicker metal, I scribe the required inner and outer diameters, punch several 1/4" holes and finish to the inner line with a small red point on a Dremel. Deburr that edge...

I use automotive type gasket paper for backplates, etc. A useful trick: you should be able to find a 1/8" pliers type paper punch in a stationery store or section. This simplifies cutting clean holes for the bolts. Then the bolts can hold the gasket material to the casting, or whatever. This makes cutting the inside diameter simple, moreso when the casting's shell thickness is small -- less tearing. For paper gaskets, a #11 X-Acto is as quick and sure as long as the blade is fresh and sharp. I prefer to cut a gasket to match the full outside form of the 'casting.' E.g., Fox 35s usually use a narrow paper ring: the backplate 'ears' can deform.

Old Playing cards. The Joker, because it isn't used much.

Used to be Fortune mag covers, when they were a manly monthly, not the weenie thing it is now.

EZ way to cut 'em.

1. Draw inside circle.

2. Draw outside circle.

3. Holding the entire card or sheet or whatever, cut out the inner circle, using a fresh X-acto. This allows an easy grip.

4. Now, use scissors to cut the outer circle. It is easier than a X-acto.

5. Stick on engine. If there is any excess, trim it off, right on the motor, with the Xacto.

Lou,
Good points as to the gasket making.
Have you ever used a compass with two metal points? The one that sets the center point I leave alone, the one that scribes the circle diameter I sharpen to a "knife edge" like a #11. Spinning around with a light touch will cut great head shims out of drink cans.
I do the punch, attach, cut method of yours on crankcase gaskets.
Bill <><

I use a Paper hole punch to make the inside circle works great for .005 brass and aluninimmmm

beverage cans work great. I believe they measure around 0.004" thick, and seem fairly consistent.

Manilla folder stock is great for cover gaskets.

>I rounded up all my glow plugs in one spot and discovered I
>have 31 glow plugs. I tested them all and discovered that
>some glow plugs will NOT run in a certain engine but it WILL
>run fine in a different engine. That must have something to
>do with the compression of the engine??? Some glow plugs
>will not start an engine on 1.5 volts but if I turn the
>voltage up a little the engine starts and runs fine. Some
>glow plugs the first turn on the coil will not glow but the
>rest of the coil glows fine and the plug seems to start and
>run the engine fine.
>
>Gary Weaver [email protected]

Nobody's answered on the glow plug part. There are hot plugs and there are cold plugs and there are in between plugs. Hot plugs are usually better for engines running rich, such as in stunt. Cold plugs are better on some speed applications. And in between, well, you get the idea. There are also 2 volt plugs which may be why you have to turn up the voltage on these. Some also draw more current and need a boost. Some plugs will run the engine ok on the test stand, but won't do so good in the air, especially if the engine is running rich. If you are cheap, you can test run the plugs one at a time in your planes, and mark the ones that work the best or not at all. However, you may also find that by being cheap you experience a flame out at just the wrong time that could be quite expensive. Also, plugs do go bad over a period of time (running). Just because they light or fire up the engine doesn't mean they are a good plug for flying. So, unless you are really cheap and don't care, you may be better off using a plug of known quality rather than relying on scrap box plugs.

Leonard,

Please pardon my ignorance on the subject of glow plugs, but how do you determine heat ranges when buying glow plugs? Are they numbered, or do you just have to know which ones are hot --- cold --- medium --- etc.?

>Leonard,
>
>Please pardon my ignorance on the subject of glow plugs, but
>how do you determine heat ranges when buying glow plugs? Are
>they numbered, or do you just have to know which ones are
>hot --- cold --- medium --- etc.?

I wish there were a heat range chart that manufacturers could go by and all would agree to rate their plugs accordingly. Unfortunately, that is not the case and it is mostly knowledge passed on from modeler to modeler. However, I have some Kavan glow plugs that I got once that come in a neat little hard plastic container with a colored end on it.
Red is hot,
Yellow is medium,
Blue is cool,
Green is super, and
Black is speed.

Now, that was one manufacturer that at least made an attempt to let people in on what they were attempting to do. Unfortunately their hot and somebody else's hot may still not be the same. And what "Super" is supposed to mean, I really don't know. But basically we try out plugs and see what works for our application and go from there. It is a good idea, however, to use short reach plugs only in heads calling for short plugs and long reach plugs for all other engines. From there on in check with others to see what they are using and recommending. But getting the most expensive plugs does not always mean you are getting the best, and the once inexpensive Thunderbolt plug seems to be going up in price faster than the number of Kerry's campaign promises.

I don't know anything about glow plug I just thought it was about time to learn. Over the past several years I have always bought the OS #3 short glow plug the guy at the hobby shop tells me I need. He says there is a hotter plug but don't buy it. I have a lot of these OS #3 plugs they seem to work fine most of the time. I have several glow plugs that came in engines that I bought on ebay I have no idea what heat range or voltage the plugs are. The OS #3 works great in the OS 25 engine on my F2D combat airplanes with an 8x6 prop but not so well in the same engine on a stunt airplane with a different prop. I should have taken Glow Plug 101 in college SIU Carbondale.

A friend has a Fox 35 stunt engine that he bought brand new then mailed it someplace to be reworked. I am not sure what was done to the engine inside but the head was replaced. The head has 2 glow plugs. Whats the deal with 2 glow plugs???

>
>A friend has a Fox 35 stunt engine that he bought brand new >then mailed it someplace to be reworked. I am not sure what
>was done to the engine inside but the head was replaced.
>The head has 2 glow plugs. Whats the deal with 2 glow
>plugs???
-------------------------------------------------------

Theoretically? Better Combustion.

Actually? To attract attention.

I have one of those myself. Lew Woolard did the modification.

I got two of those heads, one I made myself and the other I got fron a guy in Dallas. Neither runs any better than the stock head.

Bigiron

Made it back from VSC by the skin of my teeth.

Hi

Taipan plugs also come in varying heat ranges.

I got tired of flicking motors on dead batteries and the single cell NiCads seemed to suffer a shortened life at high drain so I made up a parallel 4 cell pack with an amp meter, whole thing cost me $18 Aus. Went through my plugs using a 1500 mAh 1.3V NiCad and discovered all the 1.5 V plugs draw around 3 Amps while the 2V plugs draw 1.5 Amps. All glow quite well on a single 1.3V cell though the 1.5V plugs glow brighter.

Seems to me the 1.5V and 2V plug thing is historic from the days we used Bell Telephone batteries to supply the amps required at 1.5 V or alternatively tap a 2V cell of a lead acid battery.

These days, a NiCad or pack of NiCads cells seem to glow both 1.5V and 2V plugs well enough to start a motor. The plugs test at almost no resistance and so present a short on the battery (cold). The amp meter flicks right over on connection but then as the glowplug element heats up, it's resistance increases and the meter drops back to 1.5 top 3 Amps. So what is happening here is, you get a ballance between heat and Current (amps). That is, provided the internal resistance of the power source is not limiting in the circuit. That is why both 1.5 and 2V plugs can be operated form 1.3 V NiCads.

In short, source voltage in not very important. It's ability to supply current is. At least that is how it seems to me.

At the moment I don't have a way to control current in my circut but that is probably a good idea to prevent the initial high current short upon connection at least.

> I got two of those heads, one I made myself and the other
>I got fron a guy in Dallas. Neither runs any better than
>the stock head.

Interesting thing is, you'd think that if you lit one plug, and the engine started running, the second plug would light by itself, right? Then I came across some article on the web about some dual plug head conversion for some RC helicopter motor (a .90, I think), and the guy claimed that the engine started fine with one plug lit, but picked up a goodly number of RPM when he touched off the second plug once the engine was running!

Mebbe one needs to do this on the Fox as well to get the benefit of the two plugs?

I'm just curious, what is it that happens to a plug? I just threw away 3 old plugs that lit fine but the motor (slightly into 2-stroke)dies without batt power. A new plug, runs fine. Don

I just threw away 3 old plugs that lit fine but the motor (slightly into 2-stroke)dies without batt power. A new plug, runs fine. Don

I have some plugs that do this and I discovered they work fine if I put a muffler on the engine. Without the muffler the engine won't run without the battery.

>I just threw away 3 old plugs that lit fine but the motor
>(slightly into 2-stroke)dies without batt power. A new plug,
>runs fine. Don
>
>
>I have some plugs that do this and I discovered they work
>fine if I put a muffler on the engine. Without the muffler
>the engine won't run without the battery.
>
>Gary Weaver [email protected]

All of this probably has to do with the heat range of the plug. And the heat range can change over time. The elements get disfigured (bad, throw them away) or they get coated with something that makes them less effective.

Silicone in the fuel is one of the great offenders. A drop or two per gallon can prevent foaming, and is small enough in quantity to not greatly affect the life of your plug. But plugs are finicky, and some will go hundreds of flights while others may only last a flight or two (Yes, it happens even to the best of them.)

I always suggest you have a tested plug on your glow plug wrench. Whenever you have a problem with your engine that you haven't figured out, or you simply want to test the effectiveness of your glow plug, switch to a new one. If it makes no difference, put the old one back on the engine and the new one on your wrench as a tested plug for future use. If the new one does make a difference, and I would suggest in Gary's case it would--even with the muffler--then throw away the old one if the element is distorted or save it for use in breaking in an engine.

Sometimes there will be a difference in a couple of hundred rpm in switching from an old to a new plug. You haven't noticed it because you adjusted the needle. But the engine did, and it is not running efficiently. That plug may work well for break in of a new motor on the bench later on.

If you do an extended break in of a new engine on the bench that plug is usually not up to par for flying afterwards anyway. This is a good place to use a functioning plug that just isn't up to par. The key word is "functioning". If the engine runs irregular or rough with the plug, it whould be discarded under any circumstances.