Timing adjustment methods - Page 3 - PeachParts Mercedes-Benz Forum

Stretch · #1 01-05-2011, 04:28 AM

Quote:

Originally Posted by MS Fowler

Another. non FSM, method I have read about on the Ford/ International IDI forum involves reading the voltage generated by the glow plugs on a running engine. From what I've read, it is simple to do. Proponents speak highly of it.

Does anyone here have any experience in using this method on MB?

So you are saying you get a reciprocal effect from the glow plugs? Instead of putting a voltage / current in and getting heat - you are putting heat in and getting voltage / current out?

If I've understood that correctly it would be nice and I'm sure I can find a way of calibrating glow plugs as transducers - I'm just a bit wary of the response time...

Diesel911 · #2 01-05-2011, 12:57 PM

Quote:

Originally Posted by MS Fowler

Another. non FSM, method I have read about on the Ford/ International IDI forum involves reading the voltage generated by the glow plugs on a running engine. From what I've read, it is simple to do. Proponents speak highly of it.

Does anyone here have any experience in using this method on MB?

It has been talked about on the Forum. Do a search for the milivolt method.
The Glow Plug is being used as if it was a Thermocouple.

fdanielson · #3 01-05-2011, 02:19 PM

At the risk of throwing more fuel on the fire here I'm going to try and point out that there are two timing methods that use the word 'Bubble' in the name and this leads to some confusion. First is the "Bubble Up" method that involves no drip or injector tube and has the person looking for fuel to bubble up from the port on the injection pump. Second is the bubble method described in previous posts in this thread that, if you read it carefully, is the same as the drip method except that that you are dripping air instead of fuel.

Personally I don't have much confidence in the Bubble Up method but have never tested it. The bubble method that uses compressed air instead of fuel pressure to find start of delivery seems to add some convenience if you don't have enough hands to pump the primer and fiddle with the pump and/or motor position while watching a drip tube. There is probably a good argument to be made for the difference between the injection pump moving air instead of fuel but I would be willing to guess that it is not a large difference which leads to the previously stated opinion that the method is accurate enough.

funola · #4 01-05-2011, 02:27 PM

I find the FSM IP timing instructions very confusing. It gives no explnations of why and what's happening for each step. And why are there so many methods given?

Here's a list of the different methods I found in an online FSM

07_1-108 Checking injection timing (begin of delivery) with digital tester (RIV method)

07_1-110 Checking injection timing (begin of delivery) (flow pressure method)

07_1-111 Checking injection timing (begin of delivery) (position indicator RIV method)

07_1-114 Checking injection timing (begin of delivery) with digital tester (RIV method) - following checkup

07_1-115 Checking injection timing (begin of delivery) (high pressure method) - following checkup

07_1-116 Checking injection timing (begin of delivery) (position indicator RIV method) - following checkup

Stevo · #5 01-05-2011, 03:33 PM

Quote:

Originally Posted by fdanielson

At the risk of throwing more fuel on the fire here I'm going to try and point out that there are two timing methods that use the word 'Bubble' in the name and this leads to some confusion. First is the "Bubble Up" method that involves no drip or injector tube and has the person looking for fuel to bubble up from the port on the injection pump. Second is the bubble method described in previous posts in this thread that, if you read it carefully, is the same as the drip method except that that you are dripping air instead of fuel.

Personally I don't have much confidence in the Bubble Up method but have never tested it. The bubble method that uses compressed air instead of fuel pressure to find start of delivery seems to add some convenience if you don't have enough hands to pump the primer and fiddle with the pump and/or motor position while watching a drip tube. There is probably a good argument to be made for the difference between the injection pump moving air instead of fuel but I would be willing to guess that it is not a large difference which leads to the previously stated opinion that the method is accurate enough.

Oh Yes, the bubble "UP" method, I'm not trying to peddle that

The bubble method is nice because your not dealing with fuel to spill or pumps to pump and if you gently blow through the upper hose (remembering not to inhale

) you wont taste any diesel, while you slowly turn the engine(by hand) till the bubbles stop coming from the hose in the container of water.

4thesporty · #6 01-05-2011, 03:44 PM

Aren't one of these bubble tests also called the "well up method"?

ForcedInduction · #7 01-05-2011, 07:10 PM

Quote:

Originally Posted by Stevo

if you gently blow through the upper hose

What CFM and pressure is the standard for "gently blow"?

leathermang · #8 01-15-2011, 02:35 AM

Quote:

Originally Posted by fdanielson

Second is the bubble method described in previous posts in this thread that, if you read it carefully, is the same as the drip method except that that you are dripping air instead of fuel.

The bubble method that uses compressed air instead of fuel pressure to find start of delivery seems to add some convenience if you don't have enough hands to pump the primer and fiddle with the pump and/or motor position while watching a drip tube. There is probably a good argument to be made for the difference between the injection pump moving air instead of fuel but I would be willing to guess that it is not a large difference which leads to the previously stated opinion that the method is accurate enough.

You have missed the most important point. That is that DRIPS are pretty much standard in size... so when they call for one drip per second... that is something one can time and adjust TO...

Please explain how AIR is DRIPPED ..... ?????

You are just making stuff up when you say there is probably a good argument because there is no easy way to standardize the amount of air coming out... as compared to the very easy standard of ' drop per second'..

You are willing to guess... that is exactly what you will be doing if you deal with air in these processes...

Tell me why so many engines with this type injection system use the drip method....and why the FSM would specify it in the Shop Manual if there were easier methods ?

Stretch · #9 01-05-2011, 04:17 AM

Can someone post a link for the bubble method?

I'd like to try both and see what happens. I've almost finished my engine rebuild and I have to set the timing one way or another so I might as well turn it into a little high school experiment!

Stretch · #10 01-05-2011, 02:17 PM

Ah ha Milivolt method:-

Setting pump primary timing by milli volt method.

Diesel911 · #11 01-15-2011, 02:15 AM

In this thread there there is a pic of an IP with a Drip Tube on it and it has the fuel supplied to it by a Gravity Feed set up.

http://www.benzworld.org/forums/vintage-mercedes-benz/1494188-75-240d-injection-pump-oil-consumption.html

paddo · #12 01-15-2011, 12:09 PM

What are the symptoms of timng being out?
My motor sometimes has a "rattling tin can" sound which I think is a timing issue in a gas engine.

Also sometimes the engine has a "thump" when it first starts, but this is intermittent so probably not related to timing.

Diesel911 · #13 01-15-2011, 12:40 PM

Quote:

Originally Posted by paddo

What are the symptoms of timng being out?
My motor sometimes has a "rattling tin can" sound which I think is a timing issue in a gas engine.

Also sometimes the engine has a "thump" when it first starts, but this is intermittent so probably not related to timing.

The thumping is most likely being caused by the Motor Mounts and Transmission mounts and maybe the Engine Shocks (if you have them).
Have someone crank your Engine and see of the thumping is caused by your Engine Block being jerked to one side.
If the thumping is coming from the Air Filter housing there is some threads on how to deal with that.

There is more than one thing that can cause the Ratteling Sound.
If it rattles after starting and the ratteling goes away after the Engine ie warmed you could have a Glow Plug Issue. Easy to check them with an Ohm Meter
Things that you can do yourself without spending much money are a Valve Adjustment and the Timing.
After that it is an Injector or Compression issue and maybe Camshaft Timing late due to Timing Chain/Gear wear.

paddo · #14 01-17-2011, 05:09 PM

Quote:

Originally Posted by Diesel911

The thumping is most likely being caused by the Motor Mounts and Transmission mounts and maybe the Engine Shocks (if you have them).
Have someone crank your Engine and see of the thumping is caused by your Engine Block being jerked to one side.
If the thumping is coming from the Air Filter housing there is some threads on how to deal with that.

There is more than one thing that can cause the Ratteling Sound.
If it rattles after starting and the ratteling goes away after the Engine ie warmed you could have a Glow Plug Issue. Easy to check them with an Ohm Meter
Things that you can do yourself without spending much money are a Valve Adjustment and the Timing.
After that it is an Injector or Compression issue and maybe Camshaft Timing late due to Timing Chain/Gear wear.

I recently replaced a damaged motor mount and adjusted the valves, both of which made a huge difference. The thumping doesn't sound like mounts to me, and it sort of starts and stops randomly mainly when cold, so not sure what it is but it hasn't been happening lately (??).so I'm not too worried about it. I also replaced all faulty glows recently so at this stage I think the most likely candidate for the rattling is the timing.
the car is running fine lately, so really my only concern is if the timing is out enough to be a risk of causing engine damage. It would be good to have the engine running at absolute peak but I don't have time or money for that and I'm just happy if it is getting me from A to B reliably.

It just seems that adjusting the timing is a bit more tricky and involved than the other above jobs and the instructions I've read so far don't make it clear how to actually do it, I think they mostly assume prior knowledge of various components. I mean for example, where are the actual nuts or bolts that you actually turn and what do you move to adjust the timing, how do you measure the timing, what is this mysterious drip test etc etc. I guess when I have time I'll go over the posts, read manuals etc but at present it just seems too much of a hassle esp in NE winter. Also I'm worried about making it worse and actually causing damage, I destroyed a motor in my younger days doing just that (on an old merc gasser, I think it was a 220sb 1960's)

Diesel911 · #15 01-17-2011, 05:42 PM

Quote:

Originally Posted by paddo

I recently replaced a damaged motor mount and adjusted the valves, both of which made a huge difference. The thumping doesn't sound like mounts to me, and it sort of starts and stops randomly mainly when cold, so not sure what it is but it hasn't been happening lately (??).so I'm not too worried about it. I also replaced all faulty glows recently so at this stage I think the most likely candidate for the rattling is the timing.
the car is running fine lately, so really my only concern is if the timing is out enough to be a risk of causing engine damage. It would be good to have the engine running at absolute peak but I don't have time or money for that and I'm just happy if it is getting me from A to B reliably.

It just seems that adjusting the timing is a bit more tricky and involved than the other above jobs and the instructions I've read so far don't make it clear how to actually do it, I think they mostly assume prior knowledge of various components. I mean for example, where are the actual nuts or bolts that you actually turn and what do you move to adjust the timing, how do you measure the timing, what is this mysterious drip test etc etc. I guess when I have time I'll go over the posts, read manuals etc but at present it just seems too much of a hassle esp in NE winter. Also I'm worried about making it worse and actually causing damage, I destroyed a motor in my younger days doing just that (on an old merc gasser, I think it was a 220sb 1960's)

Maybe there is a Member in your area that would allow you to watch when he does the timing.