Ok everybody,

Here is my situation:

I bought a 1983 300D at Thanksgiving time last year to do a diesel conversion on a Ford Ranger. I wanted to get a truck with much higher fuel economy for my business as I am on the highway a lot.

The car ran well and I drove it home. The engine was caked with oil, dirt, and sand from the front and rear crank seals being shot. I removed the engine, scrubbed it clean, disassembled as far as necessary to install the new seals. Installed new head gaskets, valve seals, polished the valves and seats.

Mated it to a Jeep 5 speed AX-15 transmission using an adapter kit from Nathan Koch. Installed a supposedly good starter, and now it will not start.

I have it all installed in the truck, have fuel to the injectors, all the air is purged out, but it just won't turn over very fast.

I had the starter checked out at the local parts store, and they said it checks out, but that it's pulling more amps than normal.

The engine will fire, and I get a lot of smoke from the exhaust but it will not run.

Last night I pulled the first two glow plugs and hooked up my new compression tester. I only had time to do the first two so far, but my compression is 225 psi on #1, and only 170 on #2.

This engine, while in the car, fired right up every time immediately after the glow plugs turned off. About the glow plugs: I wired a manual glow plug circuit and have tested it. They work fine now. Still will not start.

I know the compression is very low for a diesel. I believe it should be 350-400 psi IIRC.

I think my problem is the Jeep starter, but I do not want to go throwing money at it if it is not the problem.

Will a slow turning starter cause the compression to be this low if it is not cranking fast enough?

I don't know what the compression was before I started doing the work on it. I bought one later. I did not remove the pistons from the cylinders when I replace the crank seals. The cylinder walls were in excellent condition when I pulled the head off though.

I will check the compression on the remaining cylinders later today, but I expect similar results.

Thanks for any advice.
Rick

Yes it is concievable and reasonable that the jeep starter may not have enough torque. Simple things first though. Verify you really do have a properly working glow plug circuit. Second you had the head off so make sure the first cylinder cam lobes are pointing upwards when the injection pump timing is checked.

It is possiblle to get the injection pump on the wrong stroke whenever a head is removed and cam and valves removed from it.. Both the low compresion readings and the non start could be caused by the very slow rolling over. The compression check especially if you did not open up cylinders 3,4,&5 as well to do it.

I would also put a piece of reflective tape on the crank pulley and establish the rpm of the engine with the starter turning the engine. Either using a reflective tachometer or physically counting. Just growling over will not start it. . Once you have the rpm information you should be able to compare it to what is normal. I can imagine at this point you are pretty frustrated after all the work.

I am not sure what you mean by polishing the valves and seats. Just cleaning them up might actually reduce the sealing ability. Most these engines have fairly high accumulated milage. I doubt if even attempting lapping the valves in would be very much help if they were marginal and well worn. Lapping of course was very common way back when engine compression even new was very low .

The engine must turn over at a min of 100 rpm. I think maybe the jeep starter isn't getting the job done.

__________________
1977 300D Lost coolant while someone else was driving
1983 300D Can't run without oil
1985 300SD (gone but not forgotten)
1990 300TE 4matic Sold
1991 Yamaha Venture
1975 Kawsaki 250 triple
1974 Honda 200CL
1951 8N Ford
2008 Wildfire 650C

You're trying to turn over an engine with 21-to-1 compression, with a starter made for an engine with only 8-to-1 compression? Yeah, it might not have enough torque to do the job properly. It'll draw way more amps than it's designed to, and turn slower, because it's turning a heavier load than it was ever designed for. The glow plugs help ignite the fuel when it is injected while starting, but the starter still needs to turn it over fast enough.

If the compression is really that low, it'll be harder to start, even with the proper starter. Like Barry said, you'll never start it if it just growls over TDC.

Also like Barry said.. check the timing on the injection pump. If that's not right, it won't run no matter what you do.

You didn't make any obvious mistakes, like plumbing the vacuum shutoff directly into the vacuum system, did you? You didn't mention how you intend to control the vacuum to that device in this retrofit.

__________________
'83 300DTurbo http://badges.fuelly.com/images/smallsig-us/318559.png

Broadband: more lies faster.

I pulled the last 3 glow plugs and have tested the compression in cylinder #3 and #4. 230 psi and 200 psi respectively. #5 is impossible to get my tester in the glow plug hole due to the oil filter being too close to allow the quick connect fitting to connect on the adapter in the hole. Will have to pull the injector and do it from the top.

I meant to mention that in the process of replacing the valve seals, and polishing the valve faces and seats, I also did a valve adjustment to spec before putting it back together, so I'm sure I don't have any issues there.

Have a great Memorial Day.

Thank you to all of our Veterans. Those still with us, those who gave the ultimate sacrifice in serving us, and their families. May God bless you.

Rick

Timing is all checked out and correct.

I'm not the first person to put an OM617 into a different vehicle, by far, and I am using ta kit made specifically for the MB to AX-15 tranny, which calls for using the Jeep starter from a 4.0L in-line 6. There are many successful conversions before me, and I am trying to follow in their footsteps.

I am really thinking it is the starter. I will now try to find out the rpms on this when it cranks. I don't think it is anywhere near 100 rpms as mentioned above.

Thanks everyone!

Rick

I haven't hooked up the vacuum line to the fuel shut off yet. Will likely use a manual valve for that once I get it running. I did not keep the one from the MB when I removed the engine.

Some of the guys over at DieselBombers have used a simple syringe in the cab running a line out to the shut off valve for their fuel stop.

I know I am getting fuel to the cylinders due to all the smoke that comes out of the exhaust. Just doesn't seem to turn over fast enough to start like it did with the MB starter before I removed it from the car.

Thanks.
Rick

The compression registered on a tester is proportional to crank speed.........to a degree. No set of rings will stop airflow past the combustion chamber to the crankcase. When you rotate the engine by hand, you can feel some compression and it quickly escapes. You might register 10 psi if you had a tester.

When running, the piston has less than .1 seconds to compress the air volume and there isn't enough time for the air to escape in a significant amount, and, hence, you'll get very high compression values.

During cranking, however, if you're cranking slowly and the piston takes .5 seconds to travel to the top of its stroke, there is plenty of time for the air to leak past the rings.

Crank speed is one of the most important criteria for starting a diesel, and, at 100 rpm, you don't have enough.

Thanks for the help.

Before I knew that you could just look down the oil cap at the cam lobes I actually pulled the rocker cover off to verify my timing marks at TDC. It's right. Then I set the IP timing marks and installed the pump per the manual.

I really think I have that part all correct, and am getting fuel on the correct stroke.

Knowing what I do now, I think I could have eliminated removing the IP and still accomplished the work. oh well. live and learn.

Thanks.

Rick

Thanks for the input. You and the other posters have confirmed what I was thinking the problem was.

I will get a new starter this week.

Thanks everyone!!!

Rick

A little history:

I pulled a good running engine from an 83 300D I bought last fall. I drove it home about 350 miles and ran great. The main seals were shot and the engine was caked with oil and dirt. I bought the seals, head gasket kit, valve stem seals, head bolts, etc from Phil. Stripped it down, cleaned and inspected everything, re-assembled with the new parts, torqued it down to specs, replaced the valve seals, adjusted the valves to specs, rebuilt the turbo, mated it to a Jeep AX-15 transmission, with a flywheel that was match-balanced to the MB one, and installed a new starter. Installed the assembled unit in my Ford Ranger, and now it won't start.

I have triple checked the timing, I have a slight variance from the 0 degree mark on the crank, to the timing mark on the camshaft, but it is the same as before I dis-assembled it. Have rechecked the IP timing. It's right. I have fuel to all the injectors and all air purged from the pump and lines. Installed new glow plugs as 3 of the old ones were no good.

When I crank it over it fires, I get lots of smoke, but will not start and stay running. I thought I finally had it once last night, let go of the key and it immediately died.

What am I missing? I am not a trained diesel mechanic though I have been around diesels most of my life. I have successfully rebuilt gassers, and am pretty confident in my skills, but very teachable. Any help and insight will be gratefully appreciated.

Thanks,
Rick

I have never ever messed with the pump on a diesel. And I don't know why your 300D just won't fire up. But from what I read in your post put with what I know to be the case from reading other posts here in the past, IF I was a betting man I would bet that your injection timing is off and could be by as much as 180 degrees. You had it all apart, better go by the factory manual and get it all set correctly. There is no quick fix for the problem, it is just a lot of grunt work.

__________________
Junqueyardjim
Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis



1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA

2003 Jaguar Type X, AWD. beautiful, good mileage,
Mom's car, but I won't let her drive it!

Have you adjusted the valves? Sounds like the IP timing is off.

__________________
daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
Cluster Needles Paint
New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

junqueyardjim,

Thanks for the input. I marked everything very explicitly before dis-assembly, re-assembled it just like I found it, and have verified it step by step with the Todd manual. I should put in an off-set Woodruff key on the cam to account for the chain stretch, but again, it is exactly where it was before I took it apart and it started every time. The only difference is the starter.

The MB starter is rated at 2.3-2.5KW according to the research I have done. The Jeep starter on the other hand is rated at 1.2, 1.4 or 1.7KW. I bought a new one rated at 1.7KW. It does not turn over as fast as it used to, but all the Jeep-Diesel guys that have done this swap have no trouble with their Jeep starters.

I don't know about if the IP is getting worn, or the injector nozzles are fouled. I had planned on doing a Diesel Purge on it as soon as I got it running to optimize how it ran, but can't get there yet. I'm obviously getting fuel to the cylinders because I get lots of smoke from the exhaust, but maybe it's not turning fast enough to create the compression to burn completely.

I bought new glow plugs, tested all of them before I installed them to make sure they all worked. They do. I have even tried to leave the glow plugs lit while cranking it over, but it noticeably slows down the starter if I do that so it is no help.

daw-two,
I have done the valve adjustment when I re-assembled the head according to the procedures and specs in the Todd manual.

As to the IP timing, again I had everything marked before dis-assembly, re-assembled exactly as I found it, and verified it to the Todd manual.

I'm stumped.

Thanks for the input fellas.

I will keep working at it. I am a very determined individual and do not give up. I will find a way over, under, around, or through this problem. I'm also willing to learn from others advice, and their experiences.

Thanks for reading and responding.

Rick

Since you have a manual transmission, how about push or pull starting it just to get it running. Once running, you'll be able to figure out what's wrong with it, if anything.