How are big rig Diesels so easy to start? - PeachParts Mercedes-Benz Forum

coldwar · #1 01-04-2006, 03:16 PM

It baffles me why I have to glow and crank the hell out of my OM617 when the temperature goes a bit below freezing, while the guy up the street from me with his new Sterling (not sure what engine is in it) just has to hit the key for a couple of cranks, and it roars to life. Although I must admit, I've seen lots of big rigs starting hard, with enough white smoke belching out the stacks to make you think there's a forest fire. Is this just a case of the new Diesel technology?

Red Pike · #2 01-04-2006, 03:31 PM

I don't know about the big rigs, but we start them with air on ships...they might do the same, since they must have an air supply for their air brakes.

#3 01-04-2006, 04:04 PM

I guess it depends what you mean by "bit below freezing." Both my 616 and 617 start without any additional effort down to about 10-15F, than they require some additional glow time and maybe a few seconds of extra cranking. A well tuned 616/617 shouldn't have any real problems just because the temperature is below freezing. I assume big trucks use diesel technology similar to modern diesel auto engines.

lietuviai · #4 01-04-2006, 04:11 PM

AFAIK, the big rigs have no glow plugs at least none of the old Cummins 6 cyl engines I saw 20 years ago. They started easily, since they have huge batteries and a starter the size of a small engine.

Oilbrnr · #5 01-04-2006, 04:28 PM

Quote:

Originally Posted by lietuviai

AFAIK, the big rigs have no glow plugs at least none of the old Cummins 6 cyl engines I saw 20 years ago. They started easily, since they have huge batteries and a starter the size of a small engine.

Didn't they have heating grids?

Uriah · #6 01-04-2006, 04:54 PM

I used to drive the old 70s Kenworths which happened to have a built in canister of ether with a little button on the dash for those really cold mornings. Somehow, I don't think they do that anymore.

Most of the big Cummins/Cats, ect... start pretty good in cold weather, up to a point. It really depends on how old the engine is, ect... but if it's in fairly good shape, it'll start OK.

When I lived in Maine and it got REALLY cold, the Macks I was driving, we would simply leave running 24/7 as they were a real bear to start in a -40 cold snap. Even at that, you had to take it really easy until the trans and rears got warmed up.

phidauex · #7 01-04-2006, 05:33 PM

The big International engine in my friend's bus has no glow plugs, no pre-heating system of any kind, just tons of raw compression, and a freakishly powerful starter. Cold morning he just gets in, cranks it for a few seconds, and it lights up with a roar and a cloud of black smoke. No problems though!

peace,
sam

Hatterasguy · #8 01-04-2006, 05:52 PM

It depends on the condition of the engine really. My 603 with nice light synthetic oil would spin right over like a gas engine. Starting just wasn't an issue after the glow plug light turned off, turn the key and your good to go.

With a diesel compression is everything. If its old with low compression it will be a pita to start, thats why they have block heaters use them!
Oil makes a surprising difference. This winter I am running 15w-40 dino in the SD and you really can feel the difference in the teens. With 5w-40 or 0w-40 temp really isn't an issue.

Condition of the battery is another issue, diesels need a strong healthy battery if its old replace it.

Starter condition is important as well, if your starter is pretty old a rebuilt one will probably crank faster.

Their are a bunch of other little things to check but basicaly if a diesel is in good shape it will start to just as cold a temp as any gas car.

Modern diesels are also much better in the cold, I imagin CDI's probably glow for a couple seconds and light right off.

One of the boats I work on has a pair of somewhat tired 6v92TIB's. They smoke like crazy if you don't plug the box heaters in. Even if the water is 70! Gota love old Detroits, loud stinky sobs.

whunter · #9 01-04-2006, 06:18 PM

http://www.zafr.com/trucktcom/starters.htm

http://www.auxiliarypowerdynamics.com/product_details/

Meta6981 · #10 01-04-2006, 06:19 PM

Well i don't really know how my car would handle snowey conditions because i live in california where it was like 60-70 degrees today. But my car really does not like sitting for more than a day. It is a pain to start once the sun goes down after sitting for a day. likes to start then stall out, then start again and idle till i go to shift from reverse to drive. But on the 82' foot cutter. that was a pain in the arse to light off. It would take about half a can of ether to light off. then it would smoke for about 20 minates if idleing less if we left immidiatly. but once they fired it was the wake up call for the boat man. Dual V-12 cummins. Ahh good times, good times

R Leo · #11 01-04-2006, 07:32 PM

Most industrial engines (Cat, DD, Cummins etc) are direct injection. DI engines are significantly lower compression (16:1 or 17:1) than the 61X and 60X engines we know and love. The lower compression means they spin fast and make enough heat where it is needed. In addition, the fuel getting injected directly into the combustion chamber generally means nothing else is needed for starting. In severe situations, a shot of manufacturer-approved starting fluid is typically enough to get them going.

My JD2040 (1978 Mannheim-built, 40hp, 3cyl, DI) cranks and fires off as easy at 20°F as it does at 100°F. In addition, the battery looks like one you'd find in a Camry...there's not enough room for anything bigger. For the really cold days, this tractor has a special port just below the steering wheel that is used to squirt starting fluid into the intake tract from a proprietary Deere container. I've neve neede this and, if it is that cold, I'm either going to stay inside or go borrow my neighbor's tractor that has a cab.

The ancient 4-35 Jimmy that powered our bay shrimper had no glow plugs either. In cold weather (40° or so was the coldest we hever went out in) you simply hit the switch and cranked until it started...sometimes it would take 30-60 seconds if slow grind to finally burp to life, belching huge clouds of blue smoke out the stack until it warmed up.

boneheaddoctor · #12 01-04-2006, 09:17 PM

My W123 hits instantly with never more than a 30 second glow....and that being sometimes in below freezing temps.....if it takes a lot of effort you need to find out why....either have a glow plug or more bad or maladjusted valves or low compression......

And example is my parts car that I got off DCulkin last winter started on jumper cables (battery would not hold a charge at all) in 10 degree F temps on the third revolution after a single glow cycle...This car was dragged out of a field the previous day where it sat in mud up to it rocker panels for the previous two years....it ran smooth and didn't even smoke....(had two year old diesel in it.)

Matt L · #13 01-04-2006, 09:35 PM

I'd check the glow plugs first, then the valves. That rules out the easiest and most likely things. Assuming, of course, that the starter turns the engine just fine.

JimmyL · #14 01-04-2006, 09:50 PM

It's funny. All this talk of compression, and I can't get my starter to move in cold weather. I think somebody mentioned sticky solenoid, possibly from cold grease, but I haven't investigated at this point.....
I can't imagine the cold would have anything to do with electrical connections....

kerry · #15 01-04-2006, 10:13 PM

Quote:

Originally Posted by JimmyL

It's funny. All this talk of compression, and I can't get my starter to move in cold weather. I think somebody mentioned sticky solenoid, possibly from cold grease, but I haven't investigated at this point.....
I can't imagine the cold would have anything to do with electrical connections....

Mine used to do the same thing. Procrastination paid off. The problem has completely gone away of its own accord.