Anyone familiar with the OM314? - PeachParts Mercedes-Benz Forum

Biosmell · #1 11-04-2004, 07:07 PM

Sorry about the crossposting, but I am trying to see if there are any gear heads here who are familiar with the Om314 engine. It is the stock 4 cylinder bus/truck engine and it is in my 1975 O309D. The engine itself is running well, but there is some type of explosion/ backfire at the engine when put under load. More later.

Many Thanks!
Jeff
AKA: El Jefe de Biosmell

#2 11-04-2004, 07:20 PM

Humm, I've never seen an OM314. A picture would be priceless.

The only non OM61x or OM60x I've enver been in contact with is an OM352.

First, has any work been done to it lately?
Second, I'd check is the injection timing.
Third, Have the injectors pop tested/spray pattern checked. That seems to be a very common bringer of Doom.

R Leo · #3 11-04-2004, 07:27 PM

Seek, and ye shall find....

It's a DI engine:

Motordaten OM 314
Dezember 1965
Dieselmotor 4 Zylinder 4-Takt-80 PS bei 2800 U/min 3780 cm³

Manufacturer and type Daimler Benz /OM 314
Injecting procedure Direkteinspritzung
Combustion chamber Piston hollow
Highest torque 23 mkg with 1600 U/min
Largest available power 80 HP with 2800 U/min
Capacity achievement 21.16 PS/L Mittl.
Operating pressure 7,6 kg/cm² Mittl.
Piston speed 11.95 m/s
Compression ratio 17:1
Crank relationship 3,59
Situation in the vehicle in front
Suspension 4-Punkt in rubber gel.
Lubrication system Pressure circulation
Cooling Water
Weight 300 kg drying
Lowest fuel consumption 12.1 L
Number of cylinders 4
Cylinder arrangement being located in row
Cylinder mold alloyed special cast iron
Cylinder material Grey cast iron/alloyed
Zylinderbohrung 97 mm
Piston stroke 128 mm
Gesamthubraum 3780 cm³
Cylinder head 1

R Leo · #4 11-04-2004, 07:36 PM

Almost sounds to me like it could be a bent valve not seating fully or one (probably an intake) with insufficient clearance...pull the valve cover and roll the engine through by hand. Make sure all the valves are closing fully. Check the valve clearances too.

Have you been running boidiesel or WVO in this engine? There might be some coking going on inside...

#5 11-04-2004, 07:46 PM

A DI Mercedes Diesel that "old?"

So they do exist....

Biosmell · #6 11-04-2004, 08:21 PM

Yes they do exist, but are somewhat hard to find. Nice picture looks just like the one in the factory manual I have. I found it in Maine and picked it up this summer to drive it back to California after a couple weeks of wrenching on it. I have only put one tank (30gallons) of BioD through it that I was making on the road ( actually at an organic farm in NH after building some BioD EQ for them) and using PetroD in the other tank. It actually happened on the road and I had her opened up to 62mph for about 5 hours straight when she suddenly popped. She is in my driveway now but I have yet to dig in. My best friend's father is an old German trained Mercedes Mechanic and he used to wrench on these alot back in the day, but I haven't gotten him over to listen yet. I was just trying see if any of you guys had any first hand knowlege.

Apparently they are mostly up in Alaska now running pipeline crews and used in the parks where they are never shut off. They came into California as metro busses only to be deemed too slow for the hills except places like Fresno where it is flat. And they were shipped up to the North Slope (where it is also flat).

El Jefe de Biosmell at your service

83 300TBD-T 300,000+, 2+years on B100
75 O309BD 76,000 original miles

ZackaryMac · #7 11-04-2004, 09:05 PM

Looks very similar to the OM318. There is one sitting in a barn near me, with a 5 spd tranny with it. It was taken out of a bus, and used in a small saw mill. It didn't have enough power for the mill so they took it out and is sitting in a barn a few miles away. I could have had it for $350. I'm not sure if it is still there. I would have bought it to put it in a 1/2 ton truck, but it is so tall (36"), clearance is a problem. So is oil pan configuration.

Some specs I also found for the 314:

ENGINE : OM 314
Number of cylinders : 4 in line
Displacement (cm3) : 3782
Performance (ps/rpm) : 85 /2800
Compression ratio : 17 : 1
Maximum torque (nm / rpm) : 235 / 1800
Cooling system : Water
Gear box : S5 - 24 / 3 - 7.13
Gear ratios :

I1=7.13

I2=4.05

I3=2.41

I4=1.59

I5=1

IR=6.55
Fuel consumption (lit / 100 km) : 24.5
Starter motor : 24 V / 4 HP

Biosmell · #8 11-04-2004, 10:34 PM

Thanks! I actually have all the tech info and shop manuals. Including an entire factory body/interior/trim catalog in 6 languages. I also have an entire book of Mercedes truck and bus service centers for the US and Canada, but I doubt any are still open since Merdedes' foray into the industrial vehicle market flopped here. I was just questing for kindred souls who are as nuts as I obviously have to be to aquire an 20' bus powered by a 4 cylinder engine. Hmm...I wonder if it will fit into a VW (48hpwr at work!)? The engines are known to be underpowered but will run forever. Top speed I got on the flats with a radar sign was 62mph. The biggest problem was that the lazy Americans insisted on an automatic transmission instead of the orignal 6 speed and my friend's father, Leo, said the first auto trany burned up on the short drive from the Oakland loading docks to the SF Benz dealership so they replaced them with what they could get over here, the big ol Alison bus tranys (which can take up to 490? horse power rather than the OM314's 85). This was a weighty overkill and basically killed their chances in SF. Leo claims in his thick Bavarian accent, "They couldn't make it up Lombard street fast enough with 19 passengers and all their luggage and the airconditioning units (more about this later), so they tried it in reverse gear and they still had problems". He also uttered my favorite quote, " Oh! You can drive it too the moon and back as long as you don't go uphill"!. I didn't choose it for speed but for style. I just have a thang for those Mercedes diesels. But let me tell ya, a top speed of 60/40(uphill) when your trying to get from the Maine peninsulas to the SF Bay area can cause you to realign your patience! Especially after setting cruise control to 85 and running at night in the wagon.

Oh, so the other problem they had was the airconditioning units installed by a South SF company who used insufficient plates/washers to mount them, therefore causing them to peel back the roof and drag behind the busses by their wires. Quite an exciting time for a tourist running to the wine country for the day (this was before universal studios). All this with a top speed of 60mph! And so the American modifications doomed the Mercedes truck market in California. Now there were also national politics at play in decimating the foreign truck market, but I will not delve into that now.

R Leo · #9 11-05-2004, 05:42 AM

Quote:

Originally Posted by Biosmell

He also uttered my favorite quote, " Oh! You can drive it too the moon and back as long as you don't go uphill"!

ROFLMAO!! Of course! 480,000 miles is really not all that far for one of these engines. I too am infatuated by those MBZ vans; I'd sure like to get a closer look at one someday.

I'll bet you are up against the governor at 60-62 mph...you might get a little more top-end with a manual tranny but finding one could be a real challenge.

One of the members here that goes by the handle 'kerry edwards' has a 409D and used own a similar model (a 307 methinks) in England a couple of years ago as well. He occasionally hints at having parts sources; you should contact him. FWIW, I believe that Kerry's 409 has a OM616 installed instead of a 314; could that be because his is an 85 model?

He never makes any speed claims but he doesn't complain much about the slowness either and a 616 only makes 67-70 hp. It seems that the 80hp 314 should be even better than a 616...surely the auto tranny isn't soaking up that much HP? Maybe

Anyway, back to this 'popping' problem....is it continuous? Intermittent? Could it be associated to your power (or lack thereof)? What about partialy clogged fuel filters?

Keep us filled in!

tenknots · #10 11-05-2004, 01:17 PM

I nearly bought an MB camper (dualie with a cab-over sleeper) a few years ago - had the 4 cylinder engine. The guy had driven it from NY to Argentina and back. Must be one tough chassis.

He didn't know much about MB's though - he had a vacuum leak and couldn't get the engine to turn off, so he justt popped the clutch in 1st gear to kill it. Did that for 2 years.

ZackaryMac · #11 11-05-2004, 09:34 PM

Quote:

Originally Posted by tenknots

I nearly bought an MB camper (dualie with a cab-over sleeper) a few years ago - had the 4 cylinder engine. The guy had driven it from NY to Argentina and back. Must be one tough chassis.

He didn't know much about MB's though - he had a vacuum leak and couldn't get the engine to turn off, so he justt popped the clutch in 1st gear to kill it. Did that for 2 years.

Goes to show you how tough these cranks must be to take that shock over and over.

Biosmell · #12 11-08-2004, 01:35 PM

Here is a picture of her. I found her in the coastal backwoods of Maine where she had been sitting awhile. It took me more than a week just to get her going and on the road.

Wt-3610kg(7942lbs)
WB-3500mm(138")
length-5990mm(19.7')
width-2120mm(7')
ht-2555mm(8.3')

R Leo · #13 11-08-2004, 02:01 PM

Über kühl!

Biosmell · #14 11-08-2004, 10:43 PM

TROUBLE DIAGNOSIS DIESEL ENGINE:

Engine vibrating and running out-of-true, coupled with sharply sounding noise and considerable smoke development

1. injection nozzle stuck
2. injection pump check valve

SERVICE MANUAL
Bus O 309-US Version
pg.00-9
-----------------------------
I would almost hope it is that simple, keep your fingers crossed. There is some background history that could possibly attribute to that. I am going to pull the cover off tonight and look for any glaring mechanical irregularities.

It was sitting for 2+ years with petro diesel.

I did use up the petro and refill with unwashed Biodiesel which I made in NH at a farm I visited. I only use unwashed when I am traveling time vs. distance and don't have time to hang out (visit post on plugged filters).

I was in triage the entire time.

I did have an injector line leak and found the line where it attached to the nipple on the IP side was sheared at the head of said nipple.

I did get spare injector lines delivered by a friend of the Farm (and now mine) out of a 300D from a local junk yard.

Although the lines inner diameter from the 300D was slightly smaller, my friend's father Leo (who I frantically called while trying to drill out and silver solder the old nipple onto the existing pipe) said that the pressure was delivered by the pump and that the lines just held a volume of fuel until required and the difference in diameter would not matter as long as it was not radically different.

My attempts to drill out the nipple and resolder the line was becoming more apparent as a lost cause (I have been told since that they are a rolled edge, but it sure looked like the injection line brazed in, and yet it sure didn't unbraze and come out hence the drill attempt. I was waiting for the doner injection lines so I had to try something!).

With the new lines I had a good nipple attached to a 300 line and a sheared end of a 314 line but I still had to connect the two. How?

I went down to the local hardware to look for small hobby parts or anything possibly handy. I was thinking I either had to silver solder some custom coupling hoping it would hold with the pressure or find... something? Hobby section anyone? One of the possibly useful items I picked out was a 1/4" brass compression fitting, even though the injector lines were by no means SAE.

Now the nominal pressure rating for brass is below that of the injection lines but as Leo said the lines held a volume of fuel and the pump supplied pressure while they were open. I ended up emory clothing the fuel line tips to fit into the compression fitting and she started right up, this time without the copious amounts of diesel fuel spaying the inside of the cowling.

I continued on, the simple hardware store compression fitting working like a champ. Running unwashed B100.

I did have fuel filter clogging/cleaning odyssies (and others) on the road in the rain, in the middle of the night.

At this point in my life I have to say I have a distaste for Pennsylvania, but I have only had limited experience there. No offence intended.

Anyway, just some background info.

And stalling pulling the cover off. The plus side is I have an on board workshop.

Talk to ya'll later!

Biosmell · #15 11-10-2004, 01:47 AM

I hate it when it does that!