Spark plug gaskets

[huntin dawg]

I didn't know where else to post this so here goes...

Is there any place to find replacement spark plug gaskets? I know once a new plug is installed the gasket is crushed. Can they be replaced so the plugs can be reused. Is it necessary?

HD

 

[achris]

Re: Spark plug gaskets

HD,

The gasket is usually made of a material soft enough for it to be reused, many times.

Chris.......

 

[Rocky_Road]

Re: Spark plug gaskets

I didn't know where else to post this so here goes...

Is there any place to find replacement spark plug gaskets? I know once a new plug is installed the gasket is crushed. Can they be replaced so the plugs can be reused. Is it necessary?

HD

You are totally correct in that these 'crush' style gaskets are only good for the first torque down...and they are not replaceable. When they collapse the first time, they contort to the unique characteristics of the spark plug head shoulder they are placed in. This guarantees the best possible seal....

Most people just ignore this, and reuse them...but I don't. If my plug comes out, for any reason, there will be a fresh plug going into its place!

Happy boating!

 

[achris]

Re: Spark plug gaskets

... If my plug comes out, for any reason, there will be a fresh plug going into its place!

Ouch... That could get expensive, real fast....

Chris.........

 

[Rocky_Road]

Re: Spark plug gaskets

Ouch... That could get expensive, real fast....

Chris.........

LOL!

I've only got half the cylinders that you have, and I am not anal about replacing them every year. In fact...my current set of 4 have 3 seasons on them, and the engine fires off in seconds (hot or cold) and idles like a kitten.

I can't even recall the last time I replaced the plugs in either the truck, or Vette. Today's plugs (or more correct, today's ignition systems) don't seem to chew up plugs like granola...and the thrill I used to get with changing plugs as a teenager has long faded!

Happy boating!

Correction: I do change the plugs in the PWC annually, since I pull them at the end of the season to fog the chambers. The old plug goes back in finger tight, until the new season when the new plug gets its turn!

Take care!

 

[j_martin]

Re: Spark plug gaskets

3 reasons plugs last a long time now.
1. Plugs are better
2. No lead in the gas, thus no lead fouling.
3. High energy ignition systems that will fire a wide or partly fouled plug.

 

[Silvertip]

Re: Spark plug gaskets

Rocky, although GM specifies 100,000 miles on plug changes I can assure you going that long is a recipe for issues. First is the constant heat/cool cycles can cause plug seizure in the the head. Second, is an equally troublesome problem. I've seen the rounded seal area of the plug (that area where the top of the metal plug shell meets the porcelain) weakened to the point where the entire electrode and porcelain blows out of the plug. The next issue is when trying to remove seized plugs is that the thread area of the plug breaks off the hex part of the shell. It happens a lot and not just on GM cars. While the plugs look great at 100,000 miles, operating conditions and the plug construction may not be up to the task.

 

[huntin dawg]

Re: Spark plug gaskets

Rocky, although GM specifies 100,000 miles on plug changes I can assure you going that long is a recipe for issues. First is the constant heat/cool cycles can cause plug seizure in the the head. Second, is an equally troublesome problem. I've seen the rounded seal area of the plug (that area where the top of the metal plug shell meets the porcelain) weakened to the point where the entire electrode and porcelain blows out of the plug. The next issue is when trying to remove seized plugs is that the thread area of the plug breaks off the hex part of the shell. It happens a lot and not just on GM cars. While the plugs look great at 100,000 miles, operating conditions and the plug construction may not be up to the task.

I agree with everything you said. One small preventive measure that can save a lot of hassle down the road is to put some anti-seize on the plug threads before installing. At least that way, a year down the road they may come out easier.

HD

 

[Rocky_Road]

Re: Spark plug gaskets

Rocky, although GM specifies 100,000 miles on plug changes I can assure you going that long is a recipe for issues. First is the constant heat/cool cycles can cause plug seizure in the the head. Second, is an equally troublesome problem. I've seen the rounded seal area of the plug (that area where the top of the metal plug shell meets the porcelain) weakened to the point where the entire electrode and porcelain blows out of the plug. The next issue is when trying to remove seized plugs is that the thread area of the plug breaks off the hex part of the shell. It happens a lot and not just on GM cars. While the plugs look great at 100,000 miles, operating conditions and the plug construction may not be up to the task.

Hi Silvertip!

I am well acquainted with plugs seizing in heads...used to pull wrenches on Mercury when we called them 'Kiekhaefers', and they only had a 90 day warranty. Actually, there is an amusing story about the short warranty period...tells you volumes about how Carl Kiekhaefer felt he had the superior product.

I treat the threads on my plugs, and actually use a torque wrench to install them. I will never be posting here about 'my plug has broken off, and what can I do now???'

I have no problem with those that change their plugs annually, and for many that may be the safest thing to do. I was addressing the question about the crush washers that the OP referred to...and I stand by the 'fact' that they are designed for one time use only. I also went on to say that most don't worry about that fact, and that seems to be the prevailing thought. My plugs don't get reused if pulled (my 454SS truck is an exception, since I am pretty sure that they have tapered seat plugs).

In short: I agree that the average boater might be better off replacing their plugs every several years...if only to prevent plug seizure. But I also say that the average boater probably doesn't pay any attention to treating the threads...using a torque wrench...and not reusing the crush washers.

I do...and I suspect that you do also!

Happy boating!