The turbo makes zero difference to starting.

 

Just got a call. Need to go out of town for work for a few days. Will try again when I get back.

Rick

 

Ok, came back home and started working on sorting this thing out.

I have checked the timing and everything checks out with that.

Pulled the glow plugs to check compression and have only 170 to 230 psi in each cylinder.

I really think it is the starter that is not cranking fast enough. I will try a new starter this week. Even with a fully charged battery and the glowplugs out it just seems way too slow to crank over, even though the local parts store says it is good. They did say it seems to draw more amps than a new one, but did not tell me how many it did draw when bench tested.

Are you guys aware of a different model starter that would bolt up to this conversion that might be stronger than the one for a 4.0L Jeep? Someone over on one of the MB forums suggested that there is no way the one made for a gasser 8:1 compression ratio could hold up to a 21:1 compression of the OM617. Any thoughts?

Thanks
Rick

 

Ok,
I took the starter to a mechanic that i know and trust today and he checked it over inside and out. Literally. Says he can see no indications of any shorts, bearings/ bushings and brushes are in excellent shape. He gave it a clean bill if health. Just said some starters turn slower than others, and this one may not turn fast enough to start this MB engine.

Later I ran into a guy who had replaced several Ford starters on his boss' 7.3L that did not hold up. He finally installed a Nippon-Denso starter and never had to replace it and said it cranked that Ford over faster than any starter he had ever seen.

Do any of you guys have any experience with the Nippon-Denso products? He has only used them now for the last several years and won't use anything else.

Thanks for your thoughts and experiences.

Rick

 

LOL! Tell that to my 84 300 CD Turbo. I've unplugged the GPs when several of them went out and gave it a little whiff to start it up MANY, MANY times. It has over a quarter million miles on it and still starts and runs great. Never blew out any prechamber tips either. The key is to only give it a little whiff. Have someone else crank it and give it about a 1/4 of a second spray into the intake snorkle. Crank a few seconds and repeat if needed.

Rolson, it sounds to me like your compression is more than just a little on the low side on some cylinders. 170 PSI is more the kind of compression numbers you'd expect for a gasser. Cranking it dead cold with the starter you'd like to see around +/- 250 PSI or so on all cylinders. Really good compression is more in the +/- 350 PSI range.

So are your GPs working now? Have you cracked loose the injector line nuts at the injector end and cranked it over to purge the air out of the lines and make sure you have fuel all the way to the injectors?

 

The problem is that diesel need a quicker starter than a gasser.
Gas engines need around 100 to 120rpm to start.
Diesels are different they need around 150rpm minimum. Second to that they have overcome the higher compression.
Excerpt taken from the Bosch tech handbook.

 

CheaperJeeper,

Thanks for the response.

Yes I have purged the air from all injectors and have fuel to all cylinders. In fact, when I pulled the glow plugs, they were wet because of all the cranking and very little firing from the slow starter. I get a lot of smoke from the exhaust which proves I am getting fuel, but it just won't turn over fast enough to run.

Do any of you guys who have put this OM617 into your Jeep's have any experience with the Nippon-Denso starter? I talked with a guy last night who swears by them. I looked them up on google, and ebay last night and they are in the $200-$350 range. I will pay the money if I need to, but I want to hear from someone else that has done this swap about their experience first.

Diesel Stink3r,

I agree completely that the diesel needs a faster starter, and understand the difference between the rpm range. I am having trouble finding actual specs from manufacturers about the starter I need. I am hoping to find on DieselBombers others who have put this engine in their Jeep with an ax-15 transmission and what actual make and model of starter they are using.

Thanks everyone.

Rick

 

I have looked all over the net, and talked to a few people I know and here is what I found:

Denso starters, according to some, are they best they have ever used, and will use nothing else, ever. I looked on ebay and found many available from $125 to over $350, reman'ed and new.

I was also referred to the "mean green" starter from MG Industries and I called them. After explaining my application, the rep told me that their starter motor for the OM617 engine, and the Jeep 4.0L are the same motor. Only the head is different for the bolt up. Price-$349

Do any of you have either of these brands on your rigs?

On my dad's farm we have more John Deere diesel equipment than I care to list, along with some Case, and Case IH tractors. From 50 to 400 HP. Every one of those cranks and fires up immediately, even in cold weather, without glow plugs,(although we do have a couple we use block heaters on when it gets below 20 degrees F). 15W40 is pretty stiff when it is that cold.

I want to crank this OM617 like it did with the original starter on it, or like these tractors do. The stock Mitsu starter I have from the Jeep just can't cut it. Of the options listed above, which should I go with, and why do you believe that way?

All input is gratefully received.

Thanks
Rick

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I just received an email from Tech support at Denso. Steve tells me that he does not have much technical information to give me from when I inquired yesterday. He told me they do not make their starters. They are supplied from Mitsubishi.

Of the two models 280-4114, and 280-4178 that are listed for the Jeep 4.0L, the 4114 has a 1.4kw motor, and the 4178 is a 1.2kw motor. Given my application he recommends the 4114 to start my diesel.

What I learned from my local parts store is that the factory Jeep starter is made by Mitsubishi. I would have gained nothing by spending the money on the Denso.

He also told me that it is too bad I can't use the starter from a Ram 2500 which uses a 2.7kw motor, but uses a completely different head and bolt pattern.

Guess the Mean Green starter from MG Industries looks like the strongest option.

Rick

 

They have a poor reliability reputation and a worse one for service/support.

 

Another option is to wet a t-shirt type rag with gasoline and hold it over the intake opening. I just started my Cherokee with the 4.3 V6 Olds today for the first time in several months, and that's what I ended up doing. Its a lot less violent than ether, jst takes a little more effort.