i have a friend with the miserable 6.2 chebby, and the usual problem of garbage glow plugs that don't last. i did a little research (not much) and found that both the 6.2 and the ford 6.9 have the same thread size for the glowplugs (10x1.0mm), so this got me thinking, is there any significant difference in size that would prevent someone from installing a motorcraft ZD9 into his 6.2 heads?? i'm not worried about wiring, connectors are easy, i'm more concerned about whether it'll fit in his heads before i buy parts and commit to it. i assume the controller for those is decent?
on another note, he's having an issue with air intrusion causing hard starting (wears 2 optimas down to dead before it comes to life after sitting overnight), i pointed him to return lines like we have on the IDI, his logic doesn't see a possibility of getting air far enough up the system to kill it with just a return line problem, but my 6.9 experience (and research here for my 6.9) says it does. to troubleshoot, he changed his fuel filter, and found that when having the issue he does get air when loosening injector lines (high pressure), so air intrusion is definitely the issue here. anybody have experience on this system or just good advice that applies across the board?

 

You will have to research more than the thread size on the glowplugs as the "reach" may be different.
As for air intrusion, that does sound like his problem. Before trying to start it in the morning tell him to remove the filter and see if it is full to the brim with fuel, if not then there is air intrusion and the return lines would be a prime suspect.

 

Been awhile since I beat on a 6.2. Decent little motors for what they are. As old as that motor is, I'd bet a silver dollar it's the injector return lines, specifically, a busted spring clamp on one of the injectors.

 

he found a broken line near the tank, repaired that, and that solved the issue. he thought it was on the supply line, but i think he judged that wrong and it was on the return line, as i don't believe it would run at all when sucking that much (or any) air through the fuel supply lines. but its alive again, so problem solved. thanks guys

 

yes 6.9 glowplugs will fit. I used to have a 6.2 and i used the old gp's from the shop trucks. from the pressure seal to the element tip they are exactly the same length. i used a HD push button and did away with the controller completely. 10-15 seconds and she'll fire right up. as long as you let them warm up some before you lay the boots to it, they can go a long time. keep the load half way reasonable and a 6.2 will pull an amazingly heavy trailer. acceleration may not be so much but it will get it up to speed and chug along. especially in a half ton no other engine has ever got anywhere near the fuel economy of a 6.2 auto overdrive. air intrusion is the biggest issue with both the 6.9 and 6.2 and one of the easiest to fix

 

Been awhile since I beat on a 6.2. Decent little motors for what they are. As old as that motor is, I'd bet a silver dollar it's the injector return lines, specifically, a busted spring clamp on one of the injectors.
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