Spark Plug Gaskets

[desoto1939]

Ok here is a question for the Mechanics in the group.

I run Autolite A9 plugs in my 39 Desoto.  Each plug has a copper crushable gasket at the base of the body when it it treaded into the head to make a tight seal.

These are 14 MM gaskets and I have read that when you take out a Sparkplug you should always put on a new copper gasket and I agree.

 

I see copper gasket made for AC, Champion and other plug companies that were copper and also some other metal type and non copper. So if they are a crushable non copper gasket can they be used to make the seal or not or should I stay with the Autolite Brand.

 

I can not find any data to support that you need to use the original gaskets that came with you sparkplug manufacturer or if you can use the flat copper gasket.

 

Also i see flat style copper and non copper gaskets for 14MM plugs can they were used instead or should I not use they since they are not crushable like the Old style Autolite sparkplug gasket?

 

Trying to get more knowledge on this subject. What are every-ones thoughts. I know this is a small items but using  the wrong style gasket could cause compression issues.

 

 

These below ae non copper:

rich Hartung

desoto1939@aol.com

[Sniper]

Just spitballing here so take it with a grain of salt.  Copper is a real good conductor of both heat and electricity.  Which is probably why they were first copper gaskets.  But as time moved on and costs became more important they found that the later style plated gaskets worked.

 

I don;t think it matters which manufacturer or material you use.  But if the price to you is ok go with what makes you comfortable.  Myself?  I just buy new plugs so that's where I am coming from.

[Sam Buchanan]

May be poor practice but during the course of fine tuning fuel mixture by reading plugs I have reused the same gasket several times and never had a problem.

Edited March 28, 2021 by Sam Buchanan

[kencombs]

1 hour ago, Sam Buchanan said:

May be poor practice but during the course of fine tuning fuel mixture by reading plugs I have reused the same gasket several times and never had a problem.

You and every other DIYer ever.  At the race tracks that happens hundreds of times a day

[desoto1939]

The other reason that I am asking the question on the gaskets is that I an a 1938 Autolite Mechanics school training course Manual that was taught by the Autolite Compnay and this was a way that Chrylser Dealership could get their mechanics Certified prior to the AEA  that is used to certify the mechanics today.

 

Part of the lecture series and the class material it was taught that when ever you removed a plug you should never reuse the original gasket bu should replace it with a new gasket to make sure that you have a good seal at the head.

 

I know most everyone and me included have the practice of just putting the sparkplug back into the top of the head and resue the old crushed gasket. Never had any issues with that process.

 

But any opinion on that if its a 14mm gasket, copper, aluminum or from a different sparkplug manufacturer is there any issue with using a gasket that is not from the same manufacturer as the brand of sparkplug such as Autolite versus and Ac gasket so long as they are both 14 mm gaskets.?

 

rich Hartung 

[Plymouthy Adams]

never in my life have I ever seen these gaskets carded and hanging on any parts counter wall...never were they part of the Autolite or AC tune up cabinets as stocked by jobbers at the shops I worked as a youth...as stated by many people, they get used many times over...and as Greg stated...how many racers worry of this and these guys are usually very picky on parts and practices...and if you worried and they are copper...just soften them for reuse.....

[Dan Hiebert]

My answer to your question is, no, there will not be any issues using gaskets from a different manufacturer than the plugs you are using.  More than likely, the sparkplug manufacturer did not make the gaskets that are included with their plugs anyway, subbed out with the company's specs.  I've bought packaged sets with two different kinds of gaskets a few times.  My learning about sparkplug gaskets is simply that if the plug comes with a gasket, a gasket should be used, not that you have to use a particular one.  As long as your previously used gasket(s) can still seal the plug with a good ground, you'll be OK.  The folks I've noticed that have issues with their plug gaskets are the ones that gorilla-torque their plugs.      

[greg g]

Shop mechanics as part of their training process are encouraged to upsell parts.  The set of plugs in my car have about 45000 miles on them.  I pulled them two years ago to regap them before our road trip to Detroit.  Reused the washers. So they have been in there about 7k miles since the check and regap.  Zero issues

 

Haven't thought this much about plug washers since the getting ready for the Plymouth trouble shooting contest in 65.

 

Edited March 29, 2021 by greg g

[chrysler1941]

I can only add that my other non Mopar car uses AC flat copper gaskets. Flat coppers gaskets is also used around bolt/screw heads for oil sealing. 

Copper is soft and will seal when squeezed.  

[JBNeal]

I have never replaced a spark plug gasket...if anything, the plug seals to the head with a layer of carbon, and from my observations, the gasket appears to keep the plug from digging into the head when torqued.

[desoto1939]

According to the Autolite school class the use of the copper crush washer is to help with the transfer of the heat from the tip to the porcelain. The crush washer also makes a seal.  The copper was used because it has a greater heat transfer rate then steel.  All of this was learned by reading an Autolite Mechanics course that was presented back in 1938.  i have the complete 5 inch thick training manual that the Autolite trained mechanics had to pass to be certified.

 

I just putting info out to the group for educational purposes.

 

Rich Hartung

Desoto1939@aol.com

[Sam Buchanan]

I think this is one instance where I prefer to be uneducated.......   ?

 

On our aircraft engines we use solid copper plug washers but we are dealing with BIG bore air-cooled engines with aluminum heads running constantly at ~75% rated power, and heat transfer is important. I suspect our over-built and under-stressed old Mopar flatties would be content with washers made out of.....whatever.

Edited March 29, 2021 by Sam Buchanan

[Frank Elder]

Sometimes a piles of bricks is just a pile of bricks, I just can’t see why you are worried about teeny tiny minutiae like that .....thread your plugs in and just let it go.

[Plymouthy Adams]

twist them in, crank them down and let the big dog eat............!!!!!!!!

[RNR1957NYer]

For what it’s worth, the steel spark plug tubes serve as the gaskets in my NYer’s 392.

[Tom Skinner]

Ahhhh, the can of worms is open now. How about using Champion Plugs for years and taking them out to clean them each year and re-installing them?

I never had any problem doing this with anything but great results. LOL. Sooooo me thinks Autolite just likes (or whoever) to sell them expensive washers/gaskets.

Of course I am just a retired know nothing and some young wipper snapper will jump in here now and remind me of that fact with all kinds of numbered facts and figures and such. Oh how smart they are, I wish I was that smart. Of course Grandpa always said: "Some people are so smart - they are stupid".

[Tom Skinner]

By the Way Happy Birthday Walter Percy Chrysler!!!!! Born April 2, 1875. If it weren't for him, we wouldn't be on this site today.

I am going to get a Cake and celebrate with my mechanic buddies today after supper. Great FUN!