Franko6
Vendor , w/Business number
In all the years of repairing stripped or stuck glow plugs, I think some improved method for installing properly is in order. Not to take away from what has been said previously for proper torque and use of an anti-seize, being careful to not cross-thread, we still see many gp's that ruined the threads in the cylinder head.
One of the things we think causes thread damage and stuck glow plugs is a poorly seated gp that has exhaust gas blowing soot up into the threads. Over years, the accumulation will cause the threads to deteriorate and the soot will pack into the threads making them very difficult to remove.
In order to properly seat the gp, first, we use a 10 x 1.0 tap to clean the threads of the gp bore. Then with a properly cut 11/32" drill bit RUN BACKWARD, We scrape the carbon from the seating area for the gp. Here is a picture of a modified drill we use.
And another picture showing the matching angle against the glow plug itself, which is a 55 degree angle.
Remember, the drill must be relieved aggressively and can ONLY BE RUN IN REVERSE or you will cut into the seat, damaging it.
When the seat is clean, you will see about an 1/8" circle shined up where the gp contacts. With the gp seat cleaned like that, there should be no leaks and no carbon build-up in the plugs.
As always, we recommend the use of an anti-seize. And we replace gp's when they stop working. We often see people replacing sets. My question is:
When you have a light bulb burn out in your house, do you replace all of the light bulbs? Why not? Because it would be expensive and foolish to replace them all, when you don't know how long they will last. So, what's the difference? Some gp's last 50k, some last 250k.
One of the things we think causes thread damage and stuck glow plugs is a poorly seated gp that has exhaust gas blowing soot up into the threads. Over years, the accumulation will cause the threads to deteriorate and the soot will pack into the threads making them very difficult to remove.
In order to properly seat the gp, first, we use a 10 x 1.0 tap to clean the threads of the gp bore. Then with a properly cut 11/32" drill bit RUN BACKWARD, We scrape the carbon from the seating area for the gp. Here is a picture of a modified drill we use.
And another picture showing the matching angle against the glow plug itself, which is a 55 degree angle.
Remember, the drill must be relieved aggressively and can ONLY BE RUN IN REVERSE or you will cut into the seat, damaging it.
When the seat is clean, you will see about an 1/8" circle shined up where the gp contacts. With the gp seat cleaned like that, there should be no leaks and no carbon build-up in the plugs.
As always, we recommend the use of an anti-seize. And we replace gp's when they stop working. We often see people replacing sets. My question is:
When you have a light bulb burn out in your house, do you replace all of the light bulbs? Why not? Because it would be expensive and foolish to replace them all, when you don't know how long they will last. So, what's the difference? Some gp's last 50k, some last 250k.
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