Glow plug conversion

[Arcan]

I learned from the 6.2/6.5 Diesel Troubleshooting & Repair Guide that AC9G glow plugs should be replaced as soon as possible because of the possibility of distortion and potential problems if the plugs can't be extracted in one piece. I checked my 1984 G2500 van camper and found AC9G glow plugs installed! The 6.2/6.5 Diesel Troubleshooting & Repair Guide article said to upgrade AC9G's with AC60G's but I've read several references elsewhere on the internet that alude to starting problems with the AC60G's because the glow plug controller doesn't keep them on long enough. There were some references to the need to modify the glow plug circuit by installing a 10 ohm resistor somewhere to lengthen the on time.

On the Kennedy web page I see they make a reference to starting problems with AC60G's and sell an "instant" glow plug that's claimed to work better and not distort. There isn't any reference to glow plug controller modifications.

Does anyone have any experience with cold starting problems with AC60G plugs or any comment on controller modifications?

[DmaxMaverick]

Good idea to address the 9G's now, rather than later. Once they swell, life isn't over, but it gets a little more complicated.

You have 4 options with your '84 (in no specific order):

1. Install KD Quick Heats, and they'll work fine with your current GP controller (if it's working correctly).

2. Install 60G's and modify your controller for longer glow cycle.

3. Install 60G's and upgrade to a 85+ controller, and modify it for the longer glow cycle. The 85+ controller is much less expensive than your current OEM setup, and better in many ways. You will likely have to replace your current controller at some point in the near future in any case. The upgrade is simple, with no additional parts needed, other than the new controller.

4. Install either new GP's, and also install a manual GP system. This is the least expensive method (no controller to purchase), and also the most reliable (fingers rarely fail). If you consider pushing a button or flipping a switch for 10-15 seconds on cold starts too much of an inconvenience, or several different people operate your vehicle, it may not be a practical option. A manual system involves obtaining a Ford type starter relay (cheap), some wiring to the dash, and installation of a momentary toggle or button switch. Most of the existing wiring is used.

In any case, consider upgrading your controller to 85+, if you keep a controller. They are more reliable, less complicated (all-in-one unit, about the size of a baseball), and about 1/2 the cost of the OEM 84 controller timer and relay.

[Robyn]

If you run into plugs that are swollen and breakage becomes an issue you are not in real trouble.

The secret is to stop before the plug breaks off.
You remove the injector on the hole in question and then stuff a nice piece of old flanel shirt into the bottom of the precup. Now go ahead and break the plug off and drive the tip back into the cup with a hammer and punch.

The BIG THING is to be sure your little piece of flanel shirt is laying nicely over the oulet port of the precup to prevent any pieces from getting out into the cylinder.

Lightly oiling the piece of flanel will help it stay in the bottom of the cup.
Once the offending piece has been driven back in to the cup a magnet or suitable tools can be used to retrieve the junk.

OHHHH BTW dont forget,with all the fanfare of getting the nasty broken plug out and be sure and remove the piece of flanel shirt. :eek:

This is a task that although tedious is not all that tough and if taken carefully will allow the issue to be resolved easily.

With the Injector removed one can see easily into the precup with a flashlight.

best

Robyn

[Arcan]

Thanks to DmaxMaverick and Robyn for the advice! I'm relieved to say that I got all the AC9G Glow plugs out without breaking any of them off! A few were pretty hard to extract but I just patiently turned them while gently pulling on them and that eventually worked.

I decided to replace them with the Kennedy Quick Heats for now because they cost about $10 each compared to ~$30 for AC60G's (from both GM and Partsource).

Thanks again

[muddymess]

as to removal of stubborn ones, starting it up worked slick to pop mine out.