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Leaky spark plugs...


LeRoy
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I had a weird finding today on my d24. I was flushing the radiator and when I started the engine to circulate the new coolant I noticed some water in the spark plug depressions bubbling. So I ran a little water in all 6 depressions and 3 of the 6 we're leaking, one was leaking to the point it blew most of the water out of the depression. When I checked the plugs they were all pretty tight. I could get maybe 1/16th of a turn on the ones that were leaking. There is just a very small amount of bubbling on 1 after retorquing. I guess when they advise to use a new gasket each time there's a reason why....

Edited by LeRoy
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LeRoy: Yes it is advised to replace the copper gasket compression ring everytime you remove and replace the sparkplug.  Most owners do not replace the metal gasket. Also some people over tighten the gasket and it gets crushed. There isa set ft pounds to torque the plugs but I do not have that information right now.  Also make sure that you have the correct metal gasket for you specific manufacturer.

 

 

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Rich Hartung

desoto1939@aol.com

 

Edited by desoto1939
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I don't think I've ever seen spark plug gaskets for sale anywhere. The washers on these new plugs are white metal, I suspect aluminum or steel. A quick search on Amazon shows some copper washer sets but they don't look much like a spark plug gaskets to me, more like oil pan or carb gaskets.

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11 minutes ago, LeRoy said:

I don't think I've ever seen spark plug gaskets for sale anywhere. The washers on these new plugs are white metal, I suspect aluminum or steel. A quick search on Amazon shows some copper washer sets but they don't look much like a spark plug gaskets to me, more like oil pan or carb gaskets.

You can buy them from Summit Racing, 1000 at a time, lol

 

https://www.summitracing.com/parts/cpn-n678

 

One at a time from Amazon, hint a new plug is cheaper

 

https://www.amazon.com/ACDelco-GS14MM-Professional-Spark-Gasket/dp/B0016HNPMQ

 

From Aircraft Spruce (copper ones)

 

https://www.aircraftspruce.com/catalog/eppages/spgaskets.php

 

That said, I will tell exactly how many times I put a new gasket on an old plug, zero.  I either reuse them as is, or buy new plugs.

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Ive always heard you should use new gaskets but in 60 years I've never done it. Then again I've never had the situation where there was water in a plug hole to expose a leak.

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I have purchased the 14 mm copper sparkplug gasket for my Autolite sparkplugs on Ebay. If you have an older style car that has the butterfly hood style that has the center hood hinge then you have a good possibility when it rains that run off water will run between the two halves of the hood at the hinge and then the water will fall into the holes in the head where the spark plug screw into the head.  This is why they made the special metal cup and the rubber boot to seal up the sparkplug.

 

I have had this happen on my 39 Desoto

 

Rich Hartung

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I've never checked for leaking spark plug gaskets - Great - now I have to worry about that.  Maybe not.  😄

 

I have a solution for rain water in the spark plug wells on the 47 P15.  I try to not drive it in the rain.  Everything leaks.  Windows, doors, floor, hood.  Got most of the oil leaks fixed so now it's time to work on the water leaks.  This could take a while.

 

I can fix that - I think

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I've had water collect in the spark plug wells of both the Plymouth and truck. Started the engine and saw the bubbles... figured it was just from the water boiling from the heat of the head.  Leaking spark plug washers makes me wonder why they would hold water in the first place.  If they were leaking, seems the water would leak past the washer and into the cylinder.  As far as reusing them, if the spark plug was good enough to reuse, then I reuse the washer.  Only time washers were replaced was when they came with a new spark plug.  Regards to all.

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Ok, I have an old Autolite Mechanics Training Manual that was used back in 1938. The training class is what a dealership would send their Head Mechanic to the Autolite Headquaters to be certified with the Autolite electrical systems. This was prior to the new ASE certification that our current mechanics should have.

 

I have copied the section from the Autolite Spark Plug educations and traing in regards to the use of a new gasket when a spark plug is being installed. As per the copy of the training manual it clearly state on the second sentence: Use a new gasket each time a plug is installed.

 

So with my understanding the copper gasket gets compressed and this also helps with the transfer of heat and cooling of the plug. each gasket compresses when the spark plug is tightened down to the cylinder head.

So I have to go by the Autolite Schooling Technical Manual information.  This manual is approx 6 inch thick and is very intensive training that the mechanic had to pass to be an Autolite Certified mechanic.l

 

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25 minutes ago, PareosWC said:

Ain't nothing wrong with introducing a little water in your cylinders. The steam clean will do your old vehicle some good.

 When your intake is lower than the valve the opportunity exists for the water to pool in the intake until is accumulates enough to get sucked into the combustion chamber hydraulicing it and bending a rod, BTDT on a Neon.  So you have to make sure that doesn't happen.

 

Don't think any new production plugs come with copper gaskets.  Video for ASE prep on this issue.  Things changed since 1938. 

 

https://www.tomorrowstechnician.com/video-crush-gaskets/

Edited by Sniper
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I do not that when you had carbon buildup the old school mechanics would get the car running and pull the acceleraltor rod to race the engine and then pour a small stream of water down the cab to cleanout the carbon.

 

Also plese read the posting that I just did about replaceing the gasket after a sparkplug has been removed. This was taken from the Autolite maintenance school for all certified mechanics. The statement is two posting above this posting.

 

Rich Hartung

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Sniper: Yes I did read the article from Autolite, but I disagree with the not changing the crush washer after removing a plug and then installing the same plug. Here is my thinking, the copper or steel washer is a crush washer and has space between the two halves of the lips upper and lower. So this is called a crush washer to make a secure seal on the flat part of the spark plug hole on the head and then also on the flat of the bottom of the plug.  So you torque down the plug and the gasket not crushes to make the seal as is it designed.  When you remove the plug that was under pressure the old gasket had been crushed to make a good seal and I doubt that the gasket will return to its original size and opening when first installed. So therefore the old crushed washer is not performing the required duty to make a good seal at the treads.

 

I know techniques have changed but we are still dealing with old technology with these flat head engines so I feel that we should put new gaskets on every time you pull a plug.  You can get the copper gaskets on Ebay.

 

Just my 2 cents on the topic.

Rich Hartung

desoto1939@aol.com

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Hey all

I looked around a little more after I dropped this stink bomb of a topic here and have a little news / learnings you may find interesting, or not. As has been discussed here it's recommended to use new gasket every time you install a used plug, I never have. I run 306s which have  14mm thread and a tightening spec of half a turn after its finger tight (quarter of a turn if you reuse old gaskets). If you're using a torque wrench tighten to 16-29 ft lbs (reduce by 30% if you use anti-seize, I do use anti-seize). 

I haven't used a torque wrench in the past, I've always put a very light coating of anti-seize on the threads (and the seat if it's a tapered plug) and tightened till it feels right. I backed my plugs out with a torque wrench the other day and I had retightened them to about 35 to get them to stop bubbling (as I mentioned above number 4 still had an occasional bubble at that torque). When I reinstalled them I added new gaskets and tightened 1/2 a turn.  When I ran the engine I put water in the plug wells to give it the check, no bubbles.

In the future I'll add new gaskets when I reinstall if I have some on hand or maybe just give them a little extra snug and know they may seep a little.

Good day all

Andy

 

 

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I forgot to mention, when I asked the guy behind the counter at the ancient little NAPA store in my neighborhood he laughed and said he couldn't remember the last time he sold a spark plug gasket. He dug around until he found an old box and gave me a handful for free.

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1 hour ago, LeRoy said:

stink bomb of a topic

 

Well, I hadn't intended to turn it into one.  Just kicking out options and reasons why things are done.  If you want to run new gaskets every time you pull the plugs, have at it.  I've never done it and I don't know that I ever had a problem going that route.  But I never checked.  I also don't run 70 year old plugs so what's applicable to them may not apply to me.

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I certainly didn't mean for it to stir anyone up but I guess if you ask 8 or 10 people you will get about that many different opinions. I appreciate the banter and different thinking as much as I do the facts. When I started fooling around with these old cars I would have given anything to have this group of people to bounce things off of.

 

I'm still a little shocked I found it in the first place.

 

Good day all.

Andy

Edited by LeRoy
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I have enjoyed this forum for years.  It's been a great help and source of knowledge, and every once in a while I get to contribute my small sliver of knowledge. 

 

And then there's the banter and occasional smoke bomb.  (Haven't had a knock-down, drag out fight for several years, thanks to the monitors.)  We  all have to consider that the printed word can be taken differently from the writer's intent, especially when the opinions get a little heated. 

 

And thanks to the administrator and monitors for keeping us on track. 

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