What is the right glow plug for your engine?

Many years ago, when we were running the Veco 19, K&B 6.5, and OPS 40 and 60 marine engines, the choices for glow plugs were limited. I ran the K&B 1-L in just about everything. If my engine was taking plugs, I'd add a head shim.

Then there were the McCoy glow plugs, OPS glow plugs, K&B HP glow plugs and several others. Again, we'd add or take away head shims to get the best engine performance and reliability.

We were adjusting the engine to fit the glow plug we used.

Since then, engines have become more powerful. This was due to improved design, better materials, and better parts fit. Larger marine engines are now available.

At the same time, some glow plugs were no longer available. Other glow plugs became available.

Things change over time.

Glow plugs not only ignite the fuel, they establish the ignition timing in our model engines. That is why there are cold glow plugs, colder glow plugs and much colder glow plugs. An extremely cold glow plug will work in a 21 size engine, it just won't work well. Plugs that work well in a 21 size engine will not last long in a large engine.

Most model boaters are not serious racers. They like to go out and run their boats with friends on the weekends, but they don't travel to big races. They want a dependable glow plug they can run in their different engines. One glow plug for a few engines. They are getting convenience, not peak pervformance.

The serious racers, the people that travel, sometimes hundreds of miles, to compete in a prestigious event, want peak engine performance. Head space, head volume, and port timing can be changed to improve power and rpm. Many people change their engines to work better with a certain glow plug. That is a lot of work and testing to adjust your engine for a certain glow plug.

With the number of glow plugs available today, it is much simpler, and cheaper, to test your engine with different glow plugs. Instead of chasing what engine mod helps the glow plug, you can test different glow plugs to see what glow plug gives the best performance out of each of your engines.

Glow plugs have become expensive. This is because the wire alloys and gone up in price, the other materials used in glow plug manufacture have gone up in price, and the technicians operating the machines are no longer working for $4.00 per hour.

It is cheaper to find the bestt glow plug for each of your engines, than to replace engine parts and/or burn out a glow plug every time you run your boat.

I run these. same one for a year now.

Well written al, thank you

Dave Gilles said:

I run these. same one for a year now.

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In what engine?
Fuel used?

FloridaScaleBoater said:

In what engine?
Fuel used?

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I was gifted a 3.5cc outboard nitro boat and a gallon of 15 year old 30% byrons car fuel. lol. but ive also since purchased 60%.

Dave Gilles said:

I was gifted a 3.5cc outboard nitro boat and a gallon of 15 year old 30% byrons car fuel. lol. but ive also since purchased 60%.

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Curious how the plugs will hold up with 60% fuel.
Keep us posted.

buy some and see. im sure you know 100x more about nitro stuff than I do.

Thanks Al, Good read.

I found the oil we use in our fuel make a huge difference in plug life too.

But.. that ship has sailed.. LOL

In general I have found one wants to (for me) use the hottest plug possible that survives your setup.


Grim

Grim
Care to share what oil you use.

dave roach said:

Grim
Care to share what oil you use.

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I heard “virgin oil” it’s very rare nowadays.

Dave, I was not the one who developed the oil.. I would like to keep that to them.

All I did was test and qualify the oil to our fuel mixture.

Thanks for asking.

(Sorry its not a great answer)

Grim

John Beardslee said:

I heard “virgin oil” it’s very rare nowadays.

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'Virgin' anything is hard to find nowadays, John!........

Grimracer said:

Dave, I was not the one who developed the oil.. I would like to keep that to them.

All I did was test and qualify the oil to our fuel mixture.

Thanks for asking.

(Sorry its not a great answer)

Grim

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Latest gen synthetics outperform castor across the board....cleaner, from every perspective.

Klotz Lite Techniplate KL-198 and Redline at 18%-20% does the job very well, with added performance. The lube engineers at Klotz and Redline are right.

Klotz KL-198 Lite Techniplate-

• 100% Pure Synthetic Lubricant lightweight formula
• Identifiable Klotz red color and racy scent
• Increases swept volume fuel charge for stronger performance
• Improves throttle response and provides enhanced flowability
• Clean burn technology
• Provides easier needle adjustment and smoother transition from low to high speed
• Increases fuel economy, Less Drag - More Power!
• Extreme film strength protecting all engine parts

Timbo Whalen said:

Latest gen synthetics outperform castor across the board....cleaner, from every perspective.

Klotz Lite Techniplate KL-198 and Redline at 18%-20% does the job very well, with added performance. The lube engineers at Klotz and Redline are right.

Klotz KL-198 Lite Techniplate-

• 100% Pure Synthetic Lubricant lightweight formula
• Identifiable Klotz red color and racy scent
• Increases swept volume fuel charge for stronger performance
• Improves throttle response and provides enhanced flowability
• Clean burn technology
• Provides easier needle adjustment and smoother transition from low to high speed
• Increases fuel economy, Less Drag - More Power!
• Extreme film strength protecting all engine parts

Click to expand...

Tim, where do the water soluble Ucon oils fall now days? Ron Logghe worked with them quite a bit. Many of the SAW customers back then used them but not the everyday racers. I’m wondering if a water soluble oil might not attack/contaminate the wires like others may.
John

Timbo is dead on.. the days of needing Castor are no longer...

The oils we used in our Grimracer fuel were pure SYN and I have to say.. the best I have ever used. The stuff LOVED needle bearings as well as bushings.. Bearings lasted LONG TIME.. no splaying or slipping..

Never any burn pattern on the piston or anyplace in the motor.

IT HOWEVER could making reading a plug a challenge.. you had to read the wire.. (thats best anyway)

Grim

John Beardslee said:

Tim, where do the water soluble Ucon oils fall now days? Ron Logghe worked with them quite a bit. Many of the SAW customers back then used them but not the everyday racers. I’m wondering if a water soluble oil might not attack/contaminate the wires like others may.
John

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Not sure, John....you worked with Ron on those Pro Power fuels, seems to me.
Ron told me one Saturday morning at Tom and Matt's shop that, at that time ('84-'85ish) he was using UCON LB-625 at 15% with 2% castor for total of 17% lube.

About 6 yrs ago, Mike Betke picked up a load of fuel at Toledo from Ritch's Brew out of Texas....had 15% LB-625 w/2% castor. Seems to me that was the mix Mike liked at the time.....still have half gallon, with flakes floating around in it from being in storage in TC for couple of years.... guessing castor doesn't like sub freezing....however, coffee filter should cure that.

Ron Logghe's Pro Power probably best fuel I remember, at super excellent price point, and buy locally. Hmmm, sure miss those days, John.

Hope all's well with you, John.

Thanks-
Tim

You miss those days, I didn’t have to buy fuel or fuel components until 1996 when I started flying helis, ugh!!! We tested the 625 down to 9% with a few of the SAW guys. Plus every kind of oil or additive that was out there we had samples. It was a time of never ending experimentation for fuel, hull design, engines, pipes and propellers.
Anout your fuel that some of the castor came out of suspension, you can filter it out for sure and use it. It probably won’t be noticeable as long as it been sealed. Truex left some of his “hot lemonade” in his aircraft up in Minnesota at the Superbowl after he won the Cup Championship in 17. It had big globs like I never saw before. Indicates a high percentage of castor that Technology Fuel provided him to his specs I’m sure.

John Beardslee said:

You miss those days, I didn’t have to buy fuel or fuel components until 1996 when I started flying helis, ugh!!! We tested the 625 down to 9% with a few of the SAW guys. Plus every kind of oil or additive that was out there we had samples. It was a time of never ending experimentation for fuel, hull design, engines, pipes and propellers.
Anout your fuel that some of the castor came out of suspension, you can filter it out for sure and use it. It probably won’t be noticeable as long as it been sealed. Truex left some of his “hot lemonade” in his aircraft up in Minnesota at the Superbowl after he won the Cup Championship in 17. It had big globs like I never saw before. Indicates a high percentage of castor that Technology Fuel provided him to his specs I’m sure.

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All of John’s fuel has some castor so you can bet all of Truex records were set with it in it. I’m sure John led him in that direction long before his knowledge had him wanting to change those oils in different amounts .I still prefer a little castor myself. I’ve tested both and a little castor does best for me. I’m only mentioning this in case someone reading this is mixing their own fuel they can hear different experiences. With the records set with castor it’s something for anyone to test both ways, Jeff Lutz

Jeff Lutz said:

All of John’s fuel has some castor so you can bet all of Truex records were set with it in it. I’m sure John led him in that direction long before his knowledge had him wanting to change those oils in different amounts .I still prefer a little castor myself. I’ve tested both and a little castor does best for me. I’m only mentioning this in case someone reading this is mixing their own fuel they can hear different experiences. With the records set with castor it’s something for anyone to test both ways, Jeff Lutz

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I just bought fuel from him and he mentioned the truex mix was 14 percent oil and he uses 2 oz per gal of castor. that was on the 65 percent nitro mix. I really would like to get away from castor myself . I know it seeks heat but even all the way back to the pylon race days it gums and slows the engine down when hot and causes power loss. Today we were looking at a old webra 90 and that thing was so gummed up from all the years of castor. in the old days the guys would scrub the castor off the piston with comet to get the speed back when they started slowing .

Jeff Lutz said:

All of John’s fuel has some castor so you can bet all of Truex records were set with it in it. I’m sure John led him in that direction long before his knowledge had him wanting to change those oils in different amounts .I still prefer a little castor myself. I’ve tested both and a little castor does best for me. I’m only mentioning this in case someone reading this is mixing their own fuel they can hear different experiences. With the records set with castor it’s something for anyone to test both ways, Jeff Lutz

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A couple of tribologists once told me recently latest gen pure synthetics outperform other lube options. Maybe so, albeit in broad context....our engines and fuel considerations are unique, IMO.

Like you, Jeff ('a little castor'), I prefer 2% of the gallons lube package to include castor. From my perspective, it's good insurance in case of a missed needle setting- especially on the lean side. Factor in that nitro performs better in higher combustion temps due to its unique adiabatic process under compression.

Back to plug temps, the hotter plug, used with nitro, will build higher cylinder pressures, and initiate sooner going to TDC as well as burn the charge more completely....another tuning consideration, along with coolant flow.

Holding to the 2% mentioned above, it seems the reason to increase the synthetic base lube percentage would be when going up in engine displacement and power output.

All food for thought.