PB Blaster on plugs before change out

[jryan]

Hey All, I'm getting ready to do my annual maintenance (took the boat out last week and it was missing at higher RPM's under load). Seems like it needs a plug change.
I've never done this and am very nervous about breaking the plugs off. I have a few questions.

1. Would there be any harm in putting some PB Blaster on it a few days before I change them out? (Wasn't sure if the residual of it would cause any issues).
2. Does everyone put Anti-Seize on the plugs when re-installing?
3. Is there a torque settings that's recommended when re-installing?

Thanks so much!

 

[rbarthur21]

There are a couple guys on YouTube that have great videos on this. They are pretty easy to find.

 

[AZMark]

1. Shouldn’t hurt anything, just don’t spray too much. You might try them first and see how stuck they are. The plug torque is high on the 1.8 engines. When I took mine out it required a decent amount of force before each plug broke loose but not excessive, maybe 25-30 ft lbs.
2. I did a very light coat because my old plug threads had some rust on them
3. It’s 18.4 ft-lbs/25nm on my 2018 212 which has the same engines

 

[jryan]

1. Shouldn’t hurt anything, just don’t spray too much. You might try them first and see how stuck they are. The plug torque is high on the 1.8 engines. When I took mine out it required a decent amount of force before each plug broke loose but not excessive, maybe 25-30 ft lbs.
2. I did a very light coat because my old plug threads had some rust on them
3. It’s 18.4 ft-lbs/25nm on my 2018 212 which has the same engines

Thank you so much, exactly the info I needed!

 

[AZMark]

Thank you so much, exactly the info I needed!

There is not consensus on the anti seize. Some people say it will make you overtorque the plugs. I actually dialed down the torque a few ft lbs to compensate.

 

[Zizzou 192]

There is not consensus on the anti seize. Some people say it will make you overtorque the plugs. I actually dialed down the torque a few ft lbs to compensate.

Manual says no anti seize. It also says to spray the whole engine with silicone spray after each use. Manual is a guideline. Use your judgement.

I did this experiment a couple of years ago. Put anti seize on plugs. Torqued them to 18.4 with the torque wrench. Waited two years. Yes, there was performance loss on year 2 even with the iridium plugs. When I removed them with the torque wrench they read 25, 24, 12, and 32 foot lbs to remove. There are a lot of variables involved here.

Who even puts in spark plugs in with a tourque wrench?

How many marinas even put the right oil in the engine let alone the right amount?

Does fogging oil mess with the plugs?

Definitely staying with the anti seize.

 

[johhnyboat]

I use dialectic grease on the threads. Always and never any issues.

 

[jryan]

Got the plugs done this weekend, way easier than I thought it was going to be. Mine didn't need any PB blaster and came loose very easily.

 

[2kwik4u]

There is not consensus on the anti seize. Some people say it will make you overtorque the plugs. I actually dialed down the torque a few ft lbs to compensate.

In general (spark plugs or not), clamp load is what you are after when talking about torque values. Since the force (at a distance) required to turn the thread (torque) is directly related to friction, any lubrication will result in MORE clamp load per given unit of torque. Remember, a thread is nothing more than an inclined plane wrapped around an axis. So you are overcoming the friction required to move the object further up the plane when you are tightening. The normal force (or clamp load) is directly proportional to that. The clamp load you need here is directly correlated to cylinder pressure as well. There are some more details involved, but that's the basics..........in theory.

The problem with that very theoretical approach is that friction coefficient is always a guess. It can vary from 0 to 1, and is always a judgement call. Plug manufacturers will often test and empirically decide on torque values based on application. Same with engine builders. Often times it might be more "black art" than science, and the manufacturer is basing the values given on experience alone.

Moral of the story here, backing it off a few clicks is likely a fine choice, and is well founded. How many clicks is a much bigger question. I'll be happy to go through the math if anyone is interested. For me......I use anti-seize on the threads to prevent galvanic corrosion in a notoriously damp environment, then torque to about a 4 on the TFAR scale, or until my elbow pops using a Craftsman 3/8in drive ratchet. It's 100% feel for me, and I'm comfortable with that after decades of plug changes on damn near anything that that has an engine (no airplanes or snowmachines yet though).

As always YMMV

 

[Bryan Halsey]

I change my plugs every year after dewinterizing (burning off the fogging oil) and apply dielectric grease on the threads. No problems yet on my 08 SX210 with plugs getting stuck, and I’ve rarely used the torque wrench while installing just hand tighten with the ratchet extension and then a little turn with the ratchet until I feel resistance.