Trying something new on my 07 Honda van

[k9sar]

So anyone who knows me on facebook knows what I'm up against but here's the story. I'm posting here because my Odyssey forum is much less active and this may be of help for my pathy peeps.

 

My wife's van was getting a P0305 code which is a misfire on cylinder 5. It would periodically clear itself so I didn't rush to get to it. Several days ago, I decided to determine if the problem was with the #5 coil or the spark-plug. The Odyssey has individual coils for each cylinder. I planned to clear the codes and swap the coils between #5 and #6. This would tell me if it were a bad coil or a faulty plug. #6 came out nice and easy but #5 would not budge. I eventually had to rip the coil head off and try to get some PB Blaster down the sides to release the rest from the deep well it was in. Within a couple of hours of digging, twisting, swearing, pulling etc, I eventually had the coil parts removed. As I was cleaning out the sparkplug well, I noticed that the sparkplug itself rattled a bit in the hole. Not good. I pulled it out and this is what I had:

 

Here is a close-up of the sparkplug:

 

 

So after a few days researching options, I decided on tapping the spark-plug hole and putting in an insert for new threads. Heli-Coil makes a kit shown below (Thanks Adam)

 

 

As for the process, I did pull all other coils and plugs to make sure this was the only problematic one and did a fairly good cleaning on the well for #5 such that a new coil will slip in easily. There was a lot of gunk buildup in there. I plan to do the following steps for the repair:

1. Set cylinder #5 at mid-stroke. I want to minimize the void but need to be far enough down so it doesn't interfere.

2. Using a straw, fill the cylinder with cheap-sh!t foam shaving cream (isn't this use where it got it's name?)

3. Fill the grooves of the tap with a thick grease

4. Slowly tap the sparkplug hole, taking care not to go too fast and to frequently remove it, clean it of shavings and then re-grease it

5. Once tapped, remove the tool and reach in with forceps to grab any visible shavings that escaped the grease

6. a shop-vac and a piece of tubing to suck as much shaving cream out of the cylinder as I can, along with any suspended shavings

7. use an air-gun with an extension down into the cylinder to blow out the remaining shaving cream/shavings

8. Clean everything well with carb or brake cleaner, using air or cranking engine to blow any crud out

9. Make sure new threads are clean and dry

10. Thread insert, knurled end first, onto a new sparkplug and coat the outside with high-temp RTV or thread-lock(red)

11. thread assembly into the newly cut hole. The sparkplug lip should keep from running the insert any further than flush with the head

12. Carefully remove the sparkplug and pray that the insert does not come back with it. If it does, I have a plan using a back-tap

13. insert the set-tool and smack it good with a hammer to spread the knurled part into the aluminum to hold it in place

14. One final cleaning then install the new sparkplug and coil

15. If using RTV, let it sit overnight to cure, preferably 24 hours. If using thread-lock, run the engine to temp to cure the thermoset plastic

 

In theory.... this should all work. I'll update the post if there are any changes

[fleurys]

whoh... This is major delicate surgery... Good luck...

[Slartibartfast]

I've never seen a spark plug do that. Hopefully there's enough of the head left for the insert to seal.

[LittleFR]

You may be better off tapping a size larger and using a different plug... I don't trust the heli-coils. They can work, I've seen a ball of thread tape hold in a plug but it just makes you nervous for the remainder of ownership.

[adamzan]

 

This guy's videos are really helpful. It's where I got the idea to do it on my friends car. It is still holding up fine.

[RIPB.88]

Had to do that on a Chevy S10 I had, and its held up extremely well. Easy process, but very unnerving.

[k9sar]

As promised, here are some pictures. I removed the engine cover as well as the plastic shield over the radiator. This allowed easy access to the sparkplug holes.

Here you can see the damage to the sparkplug hole

Using a drinking straw stuck on the end of the shaving cream can, I filled the cylinder with foam.

[k9sar]

Grease the tap and start cutting, approximately 2 to 3 threads at a time, cleaning and regreasing after each set.

Once you get completely through, us a small, long screwdriver to remove any excess grease in the hole. Use a piece of tubing attached to a shop vac and suck out as much foam as possible. Shavings will come with it. Use compressed air to blast out the remaining foam. Clean the hole with brake cleaner (will break-down grease and soap foam) and use more compressed air to cleanout the hole.

[k9sar]

Thread the insert onto an old sparkplug (with a crushed washer), knurled side furthest closest to the washer, smear some hi-temp RTV around the insert and carefully thread it into the hole. Now for the tricky part.. As soon as you hit resistance from the washer coming in contact with the seat, STOP. If you tighten any more, you will probably remove the insert with the sparkplug. With a quick twist, start the removal of the sparkplug. This tool a few tries and a little bit of intentional buggering of the threads on the insert so it would bind to the head better but if all goes well, your insert should remain in the hole and be flush with the plug seat. Verify with a probe, screwdriver, borescope, whatever. Tape an extension to the punch tool (I just used a steel axel from a lawnmower) and carefully insert the flaring tool into the insert. Smack it a couple of times to spread the first couple of threads and driver the knurls into the aluminum. Wipe (don't spray) any residual RTV from the sparkplug seat.

You can now either wait several hours for the RTV to set or carefully thread in a new (uncrushed washer) sparkplug until it's snug. SLOWLY torque to 15 ft-lbs. This was the most nerve wracking part. Replace the coil and reinstall the guards/shields. Let the RTV cure overnight and it should be good to go in the morning.

 

NOTE: It is important that you use a new sparkplug when you do this as the crush-washer will conform to any variation in the seat introduced by the insert and knurls.

 

[fleurys]

[dupersc]

Wow! Hope things work fine afterward. I had the shop retap the sparkplug thread on my 84 prelude back in the day and while it ran, it was never smooth. Always misfired of some sort.

 

I also have a 06 Odyssey and recently did the plugs and front rotors. I also installed the VCM hack to disable VCM too.

[Charlie_Brown]

This is why I love this thread

[k9sar]

Van is running great. Gonna pull the coils and plugs and do a compression test before winter but I hesitate to even try to pull the 5 plug and risk the insert coming out.