Spark Plug Thread Lubrication?

JoePorting · Post by **JoePorting** » Thu Jul 29, 2010 5:55 pm

I would think a thread lubricate as a conductor or insulator would be irrelevant. As long as you torque the plug in around 20 lbs, the threads would be contacting each other metal to metal, and the head, washer, plug would also be contacting each other, so heat and electrical energy should be able to conduct without any resistance. I would think the only objective of the lubricant is to keep the plug from fusing itself to the head. Hand torquing or not torquing sparkplugs should be a disaster since the heat and electrical energy wouldn't be able to conduct, or would conduct at a much reduced rate which would explain why the above sparkplug melted.

brian · Post by **brian** » Fri Jul 30, 2010 12:57 pm

Im surprised no one has mentioned Champion Spark Plug lubricant. It's an aviation product that is used extensively and is designed specifically for spark plug threads. You can buy it at an aviation supply house or airport. I have used it in VW race engines for many years with great success. The use of engine oil can backfire if things get hot and the oil hardens.

Post by **Schurkey** » Fri Jul 30, 2010 2:05 pm

brian wrote:Im surprised no one has mentioned Champion Spark Plug lubricant. It's an aviation product that is used extensively and is designed specifically for spark plug threads. You can buy it at an aviation supply house or airport. I have used it in VW race engines for many years with great success. The use of engine oil can backfire if things get hot and the oil hardens.

http://www.championaerospace.com/produc ... lubricant/

http://www.skygeek.com/spplthlu4ozb.html

razor66 · Post by **razor66** » Fri Jul 30, 2010 8:32 pm

brian wrote:Im surprised no one has mentioned Champion Spark Plug lubricant. It's an aviation product that is used extensively and is designed specifically for spark plug threads. You can buy it at an aviation supply house or airport. I have used it in VW race engines for many years with great success. The use of engine oil can backfire if things get hot and the oil hardens.

I actually had mentioned the Champion Spark Plug lubricant in one of my previous posts, but never received any responses about it until your post. I had just taken it that it likely doesn't work that well or more people would have commented that they were using it.

Re: Spark Plug Thread Lubrication?
by razor66 » Fri Jun 18, 2010 7:45 am

Alan Roehrich wrote:
Years ago, I attended a performance and driveability seminar hosted by Delco. Their testing showed that on average, even the correct application of anti-seize on spark plug threads increased the heat range of the plug by two numbers, and could cause detonation and/or retarded timing (in the case of computer controlled ignition timing). Delco went so far as to put a coating on the threads of any spark plug they had designed to be used in an aluminum head, so that anti-seize wasn't necessary. There were several tech bulletins issued, one of which dealt with the need for techs to wash their hands after handling those plugs to prevent coating related illness.

I usually use a drop or two of good motor oil. This being a BBS called "speed talk", most people would be thinking of performance engines when reading a post here, and wouldn't be likely to think anyone was asking about an application where the spark plug would be left in for 100K miles or 10 years.

I am the OP of this topic and the application that I was personally referring to with this question is street driven somewhere between 3,0000 and 5,0000 miles per year along with some open tracking road course events as well as a couple of autocross events thrown in. My plugs are extremely difficult to access for replacement, so unless I have an issue that is or that I think could be related to the plugs then I usually only change then perhaps every couple of years or so.

As with a lot of things it looks like there are multiple methods of which have their own pros & cons and perhaps no clear cut best practice for all applications. With all the information so far, I think for my particular application I would be inclined to continue to use a small amount of carefully placed anti-seize on the threads as a conservative approach to not having issues with the threads in the heads. I have seen where Champion Aerospace makes a spark thread lubricant (no. 2612) containing graphite that they recommend using, but it might just be for use in aviation turbine engines. I am definitely open to further suggestions and input as I do want to utilize the method that will best prevent all related issues from a mechanical and performance standpoint. Thanks for all the input so far.

williamsmotowerx · Post by **williamsmotowerx** » Sat Jul 31, 2010 3:52 am

How about some teflon tape?

tonyg64 · Post by **tonyg64** » Sat Jul 31, 2010 4:08 pm

Interesting thread this. In all my 30 yrs as a mechanic ive never had a plug sieze in an aluminium head.All the recent euro and jap engines we work with seem to have good heat treated heads so maybe this helps?

Ironically the only engine i would Not want to take the plugs from was a Ford fiesta engine circa 84 with the spanish version of the Kent engine which had iron heads with taper seats. I have seen plenty of those snapped in the head, maybe taper seats cause more problems than washer?

BTW i never use lube on plugs but only use NGK normally unless customers want oem stuff.

Tony

Barry_R · Post by **Barry_R** » Sat Jul 31, 2010 5:34 pm

I've been using a small amount of copper anti-seize. I might try the nickel stuff.

My dyno guy uses the mik of magnesia on his O2 sensors and it seems to work quite well - right RW?

Good to see you there the other day. That was a pretty cool one I had running, but the Cammer that followed was way sexier...

wjnielsen · Post by **wjnielsen** » Sat Jul 31, 2010 5:40 pm

williamsmotowerx wrote:How about some teflon tape?

Guess it's probably going to discourage sticking.

Of course, it might not encourage the needed ground path for the plug. Probably get by because of the threads cutting thru it and touching, or making continuity thru the gasket.

But... Murphy is a pretty damned fine lawyer.

-Bill

enigma57 · Post by **enigma57** » Sun Aug 01, 2010 6:02 am

Interesting thread and a subject I have never given much thought. I have changed thousands of spark plugs over the years and have always used a couple of drops of WD-40 or light machine oil on the threads, screw them in by hand to ensure threads are lubricated and started well and tighten to 15 ft./lbs. or less. Iron or aluminum heads, hot or cold, tapered plug or crush seal, never had a problem.

Regarding teflon...... You can get it in tape and in liquid form as well. There are several types available, including an oil free type for oxygen and medical gas piping, one which has copper granules (anti-galling compound, not for thread sealing) and one which is impregnated with nickel granules (anti-galling and thread sealing).

Do not use teflon on spark plug threads. I spent many years working as a pipefitter, steamfitter and plumber and I can tell you for a fact that teflon has excellent dielectric properties and will affect the transfer of heat as well. Not what you want when installing spark plugs. It is good to around 400 degrees Fahrenheit, temperature wise.

Best regards,

Harry

Warp Speed · Post by **Warp Speed** » Mon Aug 02, 2010 10:13 am

robert1 wrote:Warpspeed, I have a question for you. On some of the SB2 stuff I've done the electrode breaks off of the plug at the base. I've talked to others that have seen the same thing. And no it's not detonation burning the electrode off, they just break off. I see the Cup guys are using X plugs, did they go this route because of this?

Robert, sorry I missed your question.

We never really had a big ground strap issue (as long as the tune wasn't out in left field! LOL), but the plugs that did have ground straps were pretty tough, race only plugs. Still, we only raced a surface gap, and would only run a strap type plug qualifying and in race practice as the surface gaps were all but impossible to read.

The SB2 head, with it's flat valve lay-out and plug location, does have a pretty efficient combustion chamber (most teams designs anyway), so they can be fairly sensitive to plug cooling (water flow and pressure is important) and timing/spark plug heat range. We really didn't start having many plug issues to speak of until about 800hp. It seemed right around this HP level they became less forgiving to heat range, especially on high duty cycle track were extended throttle times can create high combustion chamber temps. About this time is when we started getting aggressive on water flow and pressures (along with plug heat ranges).

One thing you can notice during cylinder pressure testing is intermittent pressure spikes. These happen very fast, and at first we thought it may just be noise in the data. This could cause a big enough shock wave to pop a ground strap (during a restart/high load situation ect) without it really showing up on bearings or piston tops. This can be aggravated by elevated water temps.

In our application we have never seen any advantage to a high heat range (or extended tip) plug. We always try to run about the coolest plug we can, and still keep from fouling during warm up and idling periods.

What plugs are you using, and does it seem to have a particular cylinder it picks on?

What is the combo and usage?

Post by **SchmidtMotorWorks** » Mon Aug 02, 2010 11:05 am

Here's what "finger-tight" does to stock heat range ACs in a 1989 Firebird 305 TPI after a few flat-out laps of the Atlanta road course. Note that not only have the center electrodes disappeared, the ceramic insulators have softened (melting point of aluminum oxide is 3600°F.) and slumped to one side, like The Tower of Pisa...

The first time I came across finger tightening I was working on Bryants Pro Stock car (this is back when heads were welded to shape) Dave Butner was the engine guy. I think he put them in finger tight to keep the index in the weld softened heads.

I was always troubled by the finger tight deal. If you ever had a two-stroke you know that spark plug that is not tight enough can cause a lot of problems.

MadBill · Post by **MadBill** » Mon Aug 02, 2010 11:20 am

SchmidtMotorWorks wrote:...I was always troubled by the finger tight deal. If you ever had a two-stroke you know that spark plug that is not tight enough can cause a lot of problems.

Back in the sixties, a pal of mine had an umpteen-to-one CR, 'built to the hilt' 125 cc BSA 2 stroke and used a hot plug on the street to avoid fouling. His favourite party trick was to get the engine hot and with it running at a fast idle, remove the plug wire, hand it to a bystander and then ride off...

RW TECH · Post by **RW TECH** » Mon Aug 02, 2010 6:48 pm

Barry_R wrote:I've been using a small amount of copper anti-seize. I might try the nickel stuff.

My dyno guy uses the mik of magnesia on his O2 sensors and it seems to work quite well - right RW?

Good to see you there the other day. That was a pretty cool one I had running, but the Cammer that followed was way sexier...

Hey Barry,

Good to see you there too. Glad those FE's worked out well for you & the customers. I know the guy with the 1st engine is going to be a very happy camper once he tromps on that loud pedal.

The milk of magnesia trick came from when he worked at Williams Aerospace and it does a good job on the O2 sensors. W/m·K for copper is ~410 vs. 90.7 for nickel so I'm not sure I'd recommend that change unless there's another compelling reason...