SD25 Manual Glow Plug Timing

[subwar2001]

Out of curiousity. For those people using a manual switch for their Glow plugs, how long do you energize your plugs for assuming you are using the original spec. plugs.

[rlaggren]

If you search here "glow plugs" or "glowplug" you'll find a number of posts.

The generic wisdom points to 12 secs as the maximum. If you know the brand and #, then look at the manufacturer's spec sheet for those plugs - can often be found on their website or that of large vendors. There are graphs of time verses final operating temp.

Cross reference lists usually provide a number of options for any application and often the after market dictates that one plug serve multiple installations sort of adequetly rather than having many plugs spec'd exactly to specific applications (more money for less inventory at the purchase point). Combine this with the differences between plugs and realize that if yours have ever been replaced, they may not be very close to OEM spec.

Also remember that everybody does the "one little alligator, two little..." count at different speeds, so don't cut it too close.

Anecdotal evidence points to the cheap Champions not heating up very quicklyr. But if you're going to a completely manual system, then any difference from the OEM spec doesn't really matter to you and cheap might be good if you burn them out regular.

Rufus

[Tom Young]

Out of curiousity. For those people using a manual switch for their Glow plugs, how long do you energize your plugs for assuming you are using the original spec. plugs.

I don't know if they're the same as the old SD22 glow plugs, but I burned mine for nearly a half an hour once. That's how long it took the solenoid switch to burn up after the push switch for the glow plugs stuck closed.

I know all this well because my SD22 is in my boat and once I got through the Cape Cod Canal and got to Provincetown on my way to Maine, I tried to start the engine. That's when I found the burned up solenoid below. (Awful smell)

I jumped the solenoid and counted to 20, and it fired right up. Since then, I've used those glow plugs for a whole season, pulled them, and see no problems. They were a replacment part a few years prior.

I believe there are others designed for short duration that will burn up if energized too long.

[exsimguy1]

Ditto on the early glow plugs.
My 83 SD25 came with the early slow plugs with a late timer. Never started well. With a spring loaded toggle, the original glow plugs will start at 0-10F by glowing for 30-45 seconds. The spring loaded toggle has been replaced twice, but the original 83 slow glow plugs are still in place. Approx. 150-160kMiles now and running great.

Terry

[Nissan_Ranger]

I've never had a timer on my SD22 since I put it into the Ranger. Winter time, I feed them for 30 - 45 seconds at -20F. Summertime, it gets about 10 - 15 seconds. Reason it starts at so low temps in the wintertime is the synthetic 10w30 I use. I use a pushbutton switch controlling a Ford type fender mounted solenoid to feed the glowplug circuit. The plugs are the 'old type' y'all have been referring to and they are the originals. Never had a problem. I've had more problems with the Ford end of the truck.

N_R

[asavage]

These numbers are a general guide:

SD22 (Type I) GPs can run for a minute without burning out.

SD25 (Type II) GPs can burn up in ~15 seconds.