Grid Heater - Long

The short of it:

Has anyone ever started an IDI in the cold weather strictly by using a grid heater or hair dryer? That means not plugging it in or using any glow plugs.

The long of it:

I have heard stories of people getting in a bind and using a hair dryer to start a diesel in the dead of winter. The jist of what I'm wondering is can you effectively start an IDI using a grid heater? It seems to me if it was a viable option it would have been done. My concern is that it seems like you only find grid heaters on engines where this hot air stream would contact the fuel at some point during or prior to ignition...Primarily DI engines. But you also find grid heaters on the old style IDI engines found in farm tractors. On the farm tractors the precup is opposite the injector (at least on the engines I am familiar with) and so the fuel would come into contact with this hot blast of air prior to hitting the precup.

By saying all of the above I'm assuming that this hot blast of air would take some time to effectively warm up the precup on a 6.9/7.3, causing long cranking times...or possibly not allowing it to start at all.

Flame suit on...

I have not had good luck with glow plugs. It seems like everytime I hold my mouth wrong I'm replacing plugs. A fella can preventive maintenance himself until he's blue in the face, but what it boils down to is if a few trivial items fail and you shut your rig down in the sticks...your walking. I know people that have run them for the life of the vehicle and not had one problem starting them up while there rig sits on the ice over night while ice fishing in -30 Deg F temps. To me the guy that said..."Hey I've got an idea. Why don't we take a hair dryer coil, surround it in fragile ceramic and tin foil and put it in the combustion chamber."...needs to have his head examined. There's two types of engineering...practical and theoretical...and that old boy left the practical mother ship long ago.

My idea is to get the heater out of harms way.

Sorry about the length here, I'm just wondering if I can get some feed back from you fellas.

Thanks,

Paul

Possibly someone who has Cummins and IDI experience could comment.... I know the Cummins supposedly uses a grid heater. I don't see why it couldn't work. That said however, your experience aside, glow plugs work great and it shouldn't be that hard to keep a set forever. I don't think a hair dryer is going to produce enough CFM.

Yes the cummins use a grid heater but some never use it or just disconnect it, it seems like it just discharges the system too quickly, specially for short runs. Now for IDI's that would extend the cranking time.

The grid heater would work great down to -20 but other wise the block is just to cold. In the great IDI's the heat needed to fire is really high compared to Cummins so I don't really know how well it would work. If any thing the IDI in industrial series come with ether systems. Without glow plugs a little ether is plenty safe and works great.

I have used a hair dryer to start my 240D Mercedes. But 2.4 liters is NOT 6.9 liters. On the Mercedes, the hairdryer fit the hose to the air cleaner perfectly.
Have you considered switching to 12 volt glowplugs and a manual push button? I made that conversion years ago, and have not had a problem since.

A good set of Beru glow plugs will start down to about -30 so I'm told here. Yes, the temp diesel needs to lite off is high about 950 degrees and that heat is from compressing the air charge and the glow plugs. The faster you can turn over the motor the faster it will start either way. Bad connections, weak batteries will turn the motor slower and slower till you can't start it. The last thing you want is to grind on the starter. It has only so many starts in it. Then you find a way to "let the smoke out of it" and thats the end of that starter.

Now having owned both (IDI and Cummins) I would say that the IDI might be able to use one (Grid heater) but I would expect a much longer cranking time when the temps get low less than 30 degrees. I know on my Cummins the grid heater electrical connections rotted off quite a while ago from battery terminal corrosion so they haven't been in use for the last two winters - she still fires up just fine even on the coldest of mornings here in NE Indiana. The Enterprise would never be able to pull that off and I believe it's because of the fact that the injector is buried in a pre-cup so it does not get a direct feel for the warmed air that would be entering the combustion chamber. What vintage of IDI do you have? If it's a 6.9 with the rube goldberg system I can see why you have some complaints but the solid state controller that was found on the later generations is actually pretty rock solid and we need to troubleshoot the actual problem instead of trying to band-aid it or work around it.

Some of the most common problems associated with glow plug failure is timing. If the timing is advanced it will shorten the life of the glow plugs. Advanced timing can come from either someone moved the injection pump at one point in time or you have some injectors that are weak / worn out and are popping off early.

My problems have run the gamut. Started out with IP timing. Then had a bad connection with the temp sensor that disables the cold advance. I do have the dinasaur. It actually has been working well...knock on wood. I just don't like the idea of my wife taking the pickup for the weekend and the cold idle system going berzerk causing her to have problems. I understand that if it runs with the cold advance engaged or for some reason the fuel system advances for a long period of time I will have bigger problems. I just have faith in the 6.9 that if it does do these things it will get my wife (and kids...someday...knock on wood) home.

I've got most of the parts to make a grid heater system for my rig. I've done a little research and it seems like the cummins heating intervals are very similar to the glow plug intervals for the IDI. I'm just wondering how the two separate coils work with the grid heater. Does the cummins system energize one coil prior to startup, then energize the other intermittently after startup?

Thanks for feedback fellas.

Paul

There are those that will argue this point; but, from my own experiences and observations, the GRID-HEATERS, in the Cummins engines, do absolutely nothing in aiding a cold engine to start.

The sole purpose of the inclusion of grid-heaters is to pre-heat COLD ENGINE intake air, in an attempt to clear up emmissions in a cold engine.

They are too far away from the combustion chambers and produce too little heat to be of any benefit.

I currently have FOUR 5.9 Cummins powered trucks, and the grid-heaters are disconnected on all of them.

I have ZERO trouble starting these engines in sub-zero temperatures.

They will start when a lot of the gas-burners won't.

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Now, for my experience with IDI engine starting.

When I first bought my first IDI, many many years ago, nothing short of a squirt of ether would start it.

Knowing absolutely nothing about what I was doing, and dealing with a parts man that knew even less, I bought a set of eight A-C DELCO glow-plugs, screwed the old ones out, and screwed the new ones in, just like changing spark-plugs.

Still no start, so a new relay.

Still no start, so a new thermostat-something-or-other-thingie that cost near two-hundred bucks and screwed in under the back of the breather.

After all this new stuff, she never failed to start, regardless of temperature, for over twenty years.

I never touched any of that stuff again.

I don't see how, though; because, when I pulled the old 6.9, three of the eight glow-plugs had rotted away, flush at the head, with their wire-connectors just hanging.

It would start, as good as new, the day I pulled it in to remove the engine, as it did the day I got all this new stuff installed, over twenty years ago.

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All that being said, I have known numerous people to throw money at glow-plug systems, and replace everything twice, and still can't start.

If I were ever in that situation again, although I don't foresee it, I would remove and discard everything to do with the glow-plug system, and install a mechanical push-button ether system, off a big old International tractor, and go that route.

All this old-wive's-tales about an engine getting adicted to ether is just so much hog-wash; engines are made of metal, with no taste-buds, and no memory.

Paul,

I used to have the same problems keeping glow plugs working. I now run the plugs from a push button switch in the cab (see tech article write up) Plugs are still going strong since i've put the switch in!
The 6.9 is just as easy to wire but unfortunately i didnt do my 6.9 myself so i didnt include it in the tech article, but there are members who have done it and could provide guidance.

Midnight,

I have heard that very same thing...that the Dodge cummins grid heaters are for emissions reasons only. I know that most non automotive B series cummins don't use grid heaters for starting and like you say they have no problems starting in the cold. I have also heard that any new truck coming out with a DT466 will have a grid heater as well as the new Duramax trucks...all of this to help reduce emissions (smoke) on startup.

The one thing that makes me think this is still an option is that a grid heater really does aid the old farm tractors in starting in the cold weather. I'm trying to work out a way I can test this idea before I really install it. Once I get something figured out I'll post back.

Thanks for the help, Paul

Cowboy,

I've thought about this. I just may have to go this route.

Thanks,

Paul

engines are made of metal, with no taste-buds, and no memory.

Click to expand...

i like that!

Yeah, I used to go thru plugs every 6-8-10 months. (Probably because I tend to enjoy smoking the bicyclers out too much & got things set to destructive ) But whatever the cause there always were 2-3 plugs that were burnt off or didn't test out.
After I did my dash pushbutton setup I've made 2-2 1/2 years so far. Push the button &...."Blast-Off!!"

I've never had any experience with any diesels except my 6.9, BUT, my experience with the IDI has been almost identical to Midnight Rider's

When I got the truck, the relay didn't work so I replaced it. Still glow plugs no workie. Replaced the burned out glow plugs and still no good. Replaced the controller (which actually screws into the back end of the driver's side head), and VIOLA' its been working pretty much flawlessly for 6 months since then.

I did a slightly modified pushbutton mod on mine. The controller on the pre-87models has a couple of different failure modes. One of them is for the controller to start "short cycling" and only turning the plugs on for a couple of seconds at start up. The other failure mode is for the controller to start cycling the plugs on intermittently even after the engine is running - causing them to burn out prematurely. So, rather than installing a pushbutton between the control terminal of the relay and a 12 volt source, I installed my pushbutton in the signal wire from the controller to the control terminal of the relay.

If I hold down the button and turn the key to ON the controller sends its signal to the relay and energizes the plugs. If I'm not holding down the button, the signal doesn't get from the controller to the relay and the plugs aren't energized.

That way the controller still makes the decision on whether the plugs are needed or not - based on the conditions (engine temps, etc.) - and the plugs are still on a timer so I can't under use them (resulting in hard starting) or over use them (resulting in premature plug failure). BUT, if the controller fails and starts trying to cycle the plugs while the engine is running, the signal doesn't get past the pushbutton - which saves my plugs.

If the controller fails to where it starts "short cycling" the plugs I can either short cycle them repeatedly 4 or 5 times for a cold start OR disconnect the wire from the controller to the pushbutton and connect it directly to the battery to convert it over to full manual control.

I figure I'm getting the best of both worlds as long as the controller holds up, and if it fails, it won't fry my plugs and can be bypassed in about 5 minutes.

Oh, and BTW, IMHO, the ONLY plugs to use are the Motorcraft plugs that have the words "Beru - Made in Germany" on the ring just above the threads. I won't even take a chance with any Autolites or Champions or any of the other commonly available brands. They don't last and when they burn up they tend to swell up - increasing the potential for having a tip break off when you try to remove them. If the broken tips go down into the cylinder you can easily end up with a cracked piston or a valve with a chunk broken out of it.

I wouldn't trust the 6.9 system. You want to either go with a push button system preferably with 12V or constant duty plugs or go all the way and do a solid state conversion. As long as the solid state system works well it shouldn't let you burn out glow plugs. On the bad side, a solid state system will not work right if even one plug is out. The 6.9 system will usually start the truck as will a manual system if even a couple glow plugs are still working.