Anti seize on plugs yes or no

[SCSTWG]

Thanks for the numbers Mel. The forums do all that you mentioned and offer another way to enjoy the boating experience.....especially for those of us who only get to boat 3-4 months per year. On a daily basis it seems someone is getting help while stuck on the water or being saved from having their boat tied up at the dealership for weeks while summer flies by.....not to mention saving them a ton of money in repair costs. The other 95% are really missing out....and I assume most of them don't even know the forum exists.

 

[jawsf16]

I'm a former mr1 owner that still anti seizes in the 1.8l...

 

[txav8r]

We are constantly considering new ways to get the word out to Yamaha owners, well, all jetboat owners, that we are here, and that they are welcome. It is happening, and it seems slow, but considering we are approaching 700 members in just a few months,, we are really growing fast.

 

[-klb-]

Dry or lubricated absolutely makes a difference. It isn't the torque that engineers care about in nuts, bolts, or spark plugs, but the tension. It is the tension that holds the parts together, that holds the seals tight, and that results in failures in use, or from over tightening. Torque only causes failures if the threads are prevented from turning, by rust, improper threads, or other seizure.

But measuring tension is very difficult, and measuring torque is relatively easy. There are commercial tables where for a given grade of bolt, size and thread pitch, typical industry torque ranges are listed. They have separate columns for dry and lubricated, with lubricated numbers being lower.

If you think about it, you have two sources of resistance to the torque applied by the wrench. The first one is the pitch of the thread interacting with the tension in the bolt. It is similar to the work of pushing a car up a ramp. Except the result is increasing the stretch and tension in the fastener. The other is the friction that is generated between the thread surfaces under the tension of the fastener. These two factors add to generate the fastener torque. If you reduce this friction contribution with a lubricant, then to have the same total torque, you must be generating more torque from the interaction of tension and the pitch of the thread.

But the key item for the 1082 MR1 is that the Yamaha manual specifies anti seize. So if they wrote the manual correctly, the torque they provide should be for lubricated threads, and would be too loose if used on a dry thread.

 

[mmgg]

Put on a little anti-seize on but leave the last two threads dry by the electrode,, because it may drip and foul the electrode.
That's what I've been told.

 

[maboat]

Dry or lubricated absolutely makes a difference. It isn't the torque that engineers care about in nuts, bolts, or spark plugs, but the tension. It is the tension that holds the parts together, that holds the seals tight, and that results in failures in use, or from over tightening. Torque only causes failures if the threads are prevented from turning, by rust, improper threads, or other seizure.

But measuring tension is very difficult, and measuring torque is relatively easy. There are commercial tables where for a given grade of bolt, size and thread pitch, typical industry torque ranges are listed. They have separate columns for dry and lubricated, with lubricated numbers being lower.

If you think about it, you have two sources of resistance to the torque applied by the wrench. The first one is the pitch of the thread interacting with the tension in the bolt. It is similar to the work of pushing a car up a ramp. Except the result is increasing the stretch and tension in the fastener. The other is the friction that is generated between the thread surfaces under the tension of the fastener. These two factors add to generate the fastener torque. If you reduce this friction contribution with a lubricant, then to have the same total torque, you must be generating more torque from the interaction of tension and the pitch of the thread.

But the key item for the 1082 MR1 is that the Yamaha manual specifies anti seize. So if they wrote the manual correctly, the torque they provide should be for lubricated threads, and would be too loose if used on a dry thread.

I love reading your posts. My synapses are all tingly.

 

[txav8r]

I love reading your posts. My synapses are all tingly.

Would you guys get a room...LOL I like both of your posts, good stuff in them.

 

[biglar155]

I've been puttering around with small engines since I was in my teens. One thing I taught myself the hard way was to not use a torque wrench on spark plugs.

Dad had received a torque wrench as a gift - never had one before. That spring I decided to torque the plugs to spec in our 1965 Evinrude outboard. I stripped the thread out of the head on one of the spark plug holes. I subsequently learned about machine shops, heli-coils and head gaskets...

Point being, I like the 1/4 turn rule or even the "go by feel" rule. You don't need to "give 'er" when you install them. They're just spark plugs.

As far as re-using them after the gaskets are crushed... Well, "Bless Me for I have sinned" is all I can say there. Yes, technically you're supposed to only install spark plugs once. Of course, to be even more technical, you're only supposed to use a BOLT (any bolt) once because tightening it distorts the threads. Naturally, it's the bolt salesmen that remind you of this.

I've cleaned, gapped, and re-used plugs on every engine I've ever had (from lawnmowers to outboards to automobiles) with the exception of the Suburban (too much effort to remove them to not just change them). Even the Yami only gets new plugs every other year - I clean and gap on the "off" years - and even then I feel like I'm tossing money away. I know how sensitive these motors are to spark plugs so I concede to every other year. I personally have never encountered a problem due to re-installing spark plugs. Not saying it can't/wont happen at some point, but after 30 years I haven't seen an issue.