617 weird behavior diagnoses - Page 3 - PeachParts Mercedes-Benz Forum

barry12345 · #31 11-02-2014, 01:26 AM

Quote:

Originally Posted by OM617YOTA

Funola, I was going to test all five injectors, just connected in turn to one delivery pipe that I could swivel out of the way. Otherwise some major bending of the hard lines would be necessary to do all five at once, and I wasn't in a huge hurry to do that.

As it turned out, I need to eat some crow. I apparently was pretty unsuccessful at drip timing, as it was way off. I retimed it using a different method and it sure runs better. The miss when first started is gone - in fact it restarted without glow plugs with the temperature gauge under 100F. I didn't have time to test drive it, but the rattle at idle when cold was gone. I suspect I still have it fairly advanced, it sounds a lot more like a Cummins than I think it should. At least the rare 617 powered vehicle I come across doesn't sound like that. Mach4's 617 powered SL sure didn't. I may have it timed by a pro, and ask him how much more he'd charge me to teach me how to do it.

Kind of an anticlimactic end, but one I'm thankful for. Nothing special after all.

No reason you should feel the need to eat crow.

Actually it is just a matter of properly doing the drip test with a friend perhaps pumping the lift pump to supply constant pressure. Proper directions should appear in the archives.

You can do it as well as a forty year professional mechanic can but just slower. You can also fashion a proper drip tube from an injector line off of a wreck. I am not totally sure you are out of the woods yet but certainly closer overall if not.

At least the suspect possibility of why the glow plugs helped is they may have induced ignition partially back in the prechambers somehow either delaying or reducing the fuel burn in the cylinders. They were doing something is certain. What exactly I have not fixated on as yet. Unfortunatly a dog with a bone has nothing on me when I get really interested. I suspect the same effect may not be there with normal timing or it is not noticeable.

Others will have better guesses. Items like this tend to take time to gell in my mind as I revise my thoughts over and over until they feel right. The main reason not to run these engines advanced much. Is I feel the shock loading may loosen the harmonic balancer over time and damage the crank end. Of course the normal issues of running too advanced as well are there to consider as well.

leathermang · #32 11-02-2014, 07:16 AM

Quote:

Originally Posted by barry12345

...... Unfortunatly a dog with a bone has nothing on me when I get really interested. ......

What is wrong with that ? I say it is necessary to figure out some of the problems we encounter around here.... certainly not the first time an OP has given ' problematic' original information... which is why others should not be insulted when we grill them on HOW they did something they have already done...

Stretch · #33 11-03-2014, 04:50 AM

Quote:

Originally Posted by leathermang

Stretch totally skips over the amount of work created by the fact that the timing chain is attached to the head...

In the context of the probably worn valve stems it seems like it might have to go that way anyway.

Quote:

Originally Posted by leathermang

Yes, I have suggested that people with problems with power they can not figure out .... once every****** 20 years*******....pull and clean their precombustion chambers...

I have a lot of running vehicles... most of which have AC.... I live in the middle of Texas.... My 240 gets driven once a week up to the mailbox... about 800 feet...and to town to get it inspected....8 miles total per year.... and I drove it to Houston twice in one week... so I have put about two thousand miles on it in the ten years I have owned it... so I have not pulled the precombustion chambers on it.... and it starts every time... even the
32 degree morning a few winters ago that I got up and went out to test it... normal glow.. started right up... no block heater or anything..

So have you ever done the job yourself?

Stretch · #34 11-03-2014, 04:53 AM

Quote:

Originally Posted by OM617YOTA

...

As it turned out, I need to eat some crow. I apparently was pretty unsuccessful at drip timing, as it was way off. I retimed it using a different method and it sure runs better. The miss when first started is gone - in fact it restarted without glow plugs with the temperature gauge under 100F. I didn't have time to test drive it, but the rattle at idle when cold was gone. I suspect I still have it fairly advanced, it sounds a lot more like a Cummins than I think it should. At least the rare 617 powered vehicle I come across doesn't sound like that. Mach4's 617 powered SL sure didn't. I may have it timed by a pro, and ask him how much more he'd charge me to teach me how to do it.

Kind of an anticlimactic end, but one I'm thankful for. Nothing special after all.

You still have clouds of smoke at start up though - don't you?

Are you planning on fitting new steam seals or trying a wiggle test with the head on?

leathermang · #35 11-03-2014, 06:16 AM

Quote:

Originally Posted by Stretch

......So have you ever done the job yourself?

I have only owned two diesel MB's... both had great engines... why would I do that with no complaint about how the engine ran ?

Stretch · #36 11-03-2014, 07:21 AM

Quote:

Originally Posted by leathermang

I have only owned two diesel MB's... both had great engines... why would I do that with no complaint about how the engine ran ?

Well I don't know. I'm not passionate about removing pre-chambers at all. I saw how much trouble a machine shop had removing the ones on my OM617's head...

...heck I enjoy taking things to bits! But after seeing the grief they had I was glad I asked them to do the job. I'm firmly in the camp of "if a pre-chamber ain't broke then don't fix it" - and again that is unusual for me as I do like to see random groups of component parts on my garage floor.

leathermang · #37 11-03-2014, 08:37 AM

Since there is NO WAY to inspect the precombustion chamber without removing it....

and

it will be necessary to remove them in the event of doing a valve job with the head off...

seems reasonable to remove them , inspect, clean them.... first...

I am of the opinion that ' if the head is not broke ' it should not be taken off the engine'... of course it could be good...and one need to resleeve and do rings and stuff...
but yall know what I am saying....

Many people have taken the precombustion chambers out and not reported nightmare results of the process...

OM617YOTA · #38 11-03-2014, 09:17 AM

I'll be checking on valve stem seals but as long as it goes down the road right now during firewood season, that's a relatively low priority. I am unlikely to yank the head any time soon, to the point where I may just run it and start looking for a motor in much better shape to swap in.

mach4 · #39 11-03-2014, 09:40 AM

Quote:

Originally Posted by OM617YOTA

I'll be checking on valve stem seals but as long as it goes down the road right now during firewood season, that's a relatively low priority. I am unlikely to yank the head any time soon, to the point where I may just run it and start looking for a motor in much better shape to swap in.

Smart move. Sourcing a new engine and swapping it in is probably less work and money and hassle than working on the head. Engines are still reasonably plentiful and you'll have a boatload of extra parts hanging around as needed from the old engine. Swapping the engine should be no more than a couple of days, or maybe just one long one. You'll also have a chance to re-do any of the conversion mods you weren't happy with and get the engine all detailed and looking pretty if you're into that.

Simpler=Better · #40 11-03-2014, 11:05 AM

Quote:

Originally Posted by OM617YOTA

I'll be checking on valve stem seals but as long as it goes down the road right now during firewood season, that's a relatively low priority. I am unlikely to yank the head any time soon, to the point where I may just run it and start looking for a motor in much better shape to swap in.

I wouldn't worry about it. The engine should have a distinct ignition sound(much clearer than a gasser) but shouldn't sound violent or like metal-on-metal. Most old diesels are out of tune and sound like a blub-blub-blub. You want yours to sound more like a newer car.

Are you looking for perfection or a decent car? My [gas]DD knocks like crazy on one cylinder until it's up to temp. My solution is to let it idle for 5 minutes instead of rebuilding the engine.

Valve stem seals can be done from the top, but if the guides are worn then they're only a bandaid. I'm not telling you don't do it, but just a heads-up.

If you do yank the head, expect to spend $400-$500 on bits-n-bobs

OM617YOTA · #41 11-03-2014, 03:48 PM

Thank you gents.

Quote:

Originally Posted by mach4

Smart move. Sourcing a new engine and swapping it in is probably less work and money and hassle than working on the head. Engines are still reasonably plentiful and you'll have a boatload of extra parts hanging around as needed from the old engine. Swapping the engine should be no more than a couple of days, or maybe just one long one. You'll also have a chance to re-do any of the conversion mods you weren't happy with and get the engine all detailed and looking pretty if you're into that.

Yessir, those are my thoughts as well.

Quote:

Originally Posted by Simpler=Better

I wouldn't worry about it. The engine should have a distinct ignition sound(much clearer than a gasser) but shouldn't sound violent or like metal-on-metal. Most old diesels are out of tune and sound like a blub-blub-blub. You want yours to sound more like a newer car.

Are you looking for perfection or a decent car? My [gas]DD knocks like crazy on one cylinder until it's up to temp. My solution is to let it idle for 5 minutes instead of rebuilding the engine.

Valve stem seals can be done from the top, but if the guides are worn then they're only a bandaid. I'm not telling you don't do it, but just a heads-up.

If you do yank the head, expect to spend $400-$500 on bits-n-bobs

My goal is a reliable runner, this truck will never be perfect. The engine sounds fine now with no metallic clatter, just much more like a Cummins with a fairly jarring ignition note. Mach4's beautiful car with the same engine was much more subdued. Mine sounds like a tractor. I don't mind the noise, but I don't imagine someone purchasing a luxury car accepting that, which leads me to believe my timing is still a bit off.

I've done valve stem seals on V8's plenty of times by pressurizing the cylinder with air through the spark plug hole to keep the valves closed, and I might do something similar here. Have to make sure the pistons are in the right spot when you do that.

$400-$500 for bits and bobs when yanking the head is the lion's share of what another motor costs. I only paid $600 for this one.

Thanks again.

leathermang · #42 11-03-2014, 04:05 PM

Quote:

Originally Posted by OM617YOTA

......I've done valve stem seals on V8's plenty of times by pressurizing the cylinder with air through the spark plug hole to keep the valves closed, and I might do something similar here. Have to make sure the pistons are in the right spot when you do that......

WARNING FOR OTHERS...

If you think about doing this research it VERY WELL...
there are threads in the archives talking about what can go wrong REALLY WRONG....
like having to take the head off.... if your valve is not seating PERFECTLY... IE.. the valve drops into the bore..
AND the danger of the engine turning over due to the huge air power pushing on the piston.... catching something like your finger when the belts or fan moved when you were not expecting them...

OM617YOTA · #43 11-12-2014, 12:39 PM

Well.......................

Reset the timing and it went away for a little while. The miss when cold is gone completely, but it's rattling again when cold, and when at part throttle all the time. I bumped the timing back a bit more and the engine sounds NICE, other than that dang part-throttle knock. Drove it to work today as we might get snow, but been kind of a binary driving style, accelerating or coasting down to avoid that part-throttle knock.

The local diesel guy will be back in town next week, and I have an appointment set up with him. Any ideas?

Thanks everyone. By now I owe you all dinner and a case of beer at least.

Lucas · #44 11-12-2014, 01:49 PM

Time for a novice opinion? Valve springs. If the motor sat for a while before you got it they sat compressed.

I have a cummins I put a bigger turbo on, larger injectors, and cranked it up. Valves rattled like crazy. Put on stiffer springs and it was smooth.

I've been told multiple times, springs and seals are cheap. And a cheap easy start.

I would avoid using air. But if you do, my motor turned over at 40 psi. I would only take the plow plug out only on the cylinder you are working on. I would also put in in gear or park and push the car against the stopping point so the motor can't turn. Question is, which way is it gonna turn? I believe mine went backwards with air... You could also stick something in the cam gear.

Someone (stretch?) said if you drop the valve you can fish it back into the head with a magnet through the precipitation chamber and turning the motor. That sounded fun.

I think you started with multiple problems, and need to reset your thinking to one problem you have now.

Correct me if I'm wrong, I don't want to give wrong advice.

Sent from my iPhone using Tapatalk

barry12345 · #45 11-12-2014, 01:52 PM

How much smoke now? Still the same? Will engines oil fill cap stay on if loose?

If so and not moving around. For the time it takes I might check for any indication of turbocharger seal leakage. Lots of smoke when accelerating away would make it a consideration for me. The leaking oil pools in the turbo and when velocity of air increases it gets sucked into play.

For some strange reason there are still many good used engines out there. In my opinion you have to examine them carefully before purchase. As by the same token there are many that are seriously worn.

Many engine sellers will not be able to tell the difference or will even lie in this area. It is just the way it is.

Personally I like really sound used engines from cars that are off the road or going off the road for other reasons. That way I can extensively evaluate them before purchase. There are just too many decent used engines of this type out there to get stuck with a questionable or problematic one.

The amount of available good used engines of the type used in 123 cars is now reducing with time as well though. I had a look at 123 diesel cars for sale on ebay the other day and the quantity of cars for sale seems to have really fallen off now. This compared to just a year ago. This may be just temporary but I suspect not. The BS to sell them is getting more intense as well. A guy on u tube was trying to push a 300k plus example off as having 128 K I also noticed.

For your engine it might be a good ideal to build a tester and check your injectors. Besides leaking down issues their pop pressures may be all over the place with age and wear. If you could manage this cheap enough it may be worth the effort. Usually a cheap injector tester is just a small bottle jack and pressure gauge and a few connectors.