Barry, you mention i should not touch the primary pump timing. Why exactly is this? You think i should get my readings closer before i attempt this.

Sam, there was an earlier thread where I basically speculated on potential as a valid service tool.
Plus helped or tried to on two people with trouble.
The first gentleman had an obvious well advanced element.
I did not like the ideal of doing it by ear at my suggestion but it worked.
That started me thinking.

The second gentleman did it by ear and voltage comparison but discounted it as he said he thought the result was no better than by ear but that was wrong as he went back and forth till he got identical voltage.
His engine than ran very well.

Although I also fully agree with a hunting meter it would be very hard and hardly seem worth the effort to verify.
He also did not report the hunting meter as well and I was unaware of that effect until I saw it myself and the recent gentleman mentioned it.
Yes all the glow plugs linked or in parallel will provide an engine average.
I personally would like to read them all individually to ascertain that a problem did not exist that would tilt the average excessively prior to linking them all up though.

Say a glow plug was found in the group that was substantially lower or higher than the other four.
That should be investigated as why that cylinder is generating less or more heat.
If it was found say you had one cylinder of low compression and could not rectify it then I would use the other four plugs alone to establish an average.
Could be as easy as a tight valve for example though.
As for the components used with the voltmeter.
No they are not critical at all I believe other than I would want to see the condenser above 2500 microfarad and the resistor at probably 1k or better.

No harm to experiment but I got rock solid last digit readings with my values.
The addition of this is really important.
If you find the peak voltage has a plateau with a little width I would stay at the leading edge of it when you enter it.
That is primarily as we have no indication of how many degrees one tenth of a Milli volt represents yet.
If it turns out to be one or less it will replace all other systems.

As refinements are made we may have to move to a meter that reads 100ths of a Milli volt at some point in the future but at present 10ths of a Milli volt are OK.
I do not have at present and in past a therapist but who can tell the future?
I was speculating about the future perhaps as there is far more to be investigated with this procedure than meets the eye.

We have not even scratched the surface yet and to be hung up a little with so far to go is frustrating of course.
There will have to be a complete guidance manual written at some point as I visualize the uses as possibly extensive.
The last gentleman for instance may have had a really hard time as there is no general guide in existence yet.
Of course to try to expand the applications at this point would only result in bad feedback if not applied properly by a user.
It will have to move pretty slowly so this does not occur.

I do not have the time right now to really do this thing justice or disprove it.
It deserves better.

.

Jman300sd, you have already performed a very difficult task probably well with that hunting meter.

As soon as you get the components to build a voltage stabilizing device it will change everything.
The best pump timing is going to depend on that stability as well.

Your first statement about making sure they are all pretty well exactly the same still carries a lot of weight.
Of course any slight variance on 3,4,and five as individuals will have to be left alone if it exists.

There will have to be a set of protocols worked out at some point.
When you get your meter stabilized I would like to know the reading of voltage on each one of them individually.

At present it is starting to look like you advance your pump to the leading edge of the highest value obtained when reading the voltage.
As I have stated there is no risk if you pin punch mark the pump prior to adjusting as you can always then go back to your mark.

Also am waiting to see who can make or design a pump holder/ adjuster jig to simplify adjustment of the pump with engine running.
Am also starting to concentrate on how much advance is too much.
The last thing I want is pumps over advanced.
This is going to take some thought.

A gentleman set his by piezo electric pulse sensor a full eight degrees over factory setting the other day.
My suspicion is he may be too far advanced.
I am looking for a positive system to indicate that simply.
The old standards of less pre detonation may be flawed.
I now suspect top possible mpg for the type might be the test standard.

If you are too advanced mileage will be less than optimum.
There is a lot of work to do here.
It will take time.

.

I think for now what I have done will suffice in the operation of my car for a while. At some point though I would like to put new injector nozzles and at that point these mV adjustments might be even more relevant. But, I got a long list of things to do before then. I will provide fuel efficiency info as soon as I can.

Jman300d, good ideal as it also provides a chance to reflect on things.
You are right as a term of driving plus indicated mileage etc will give you some indication if all is well.

A little time will add refinements to procedures and that may help as well. Just keep following this thread.
Pretty soon I am going to start doing Mercedes diesel pump to engine timing.
System worked out well so far on Volkswagens. :)

.

OK I'm a late comer, but...
 

OK guys I'm a late comer to this intriguing little project Barry has hooked us on... but what can I do to help this experiment along some?

I do have access to my 1980 model 240D[na], my son’s 1980 300D[na], and my father-n-law’s 1985 300SD [turbo]… and propose that I get my “banana plug” connector test rig put together and initially collect precise readings for each of the glow plugs on these vintage M-B(s).

From that point on I will be need to know what additional steps I might take to help this project along.

I have recently talked my local independent M-B shop owner into investing in a new diesel pulse sensor [piezo technology] accessory that enables him to more readily check the timing on these cars using his timing light… so I guess I could get some data on what the present timing shows up as using this electronic equipment... what do ya think??

The thought just occurred to me that after a car has been peek tuned using this simplified "thermocouple" method... wouldn't it be interesting to have a local diesel injection shop [one with the top-of-the-line "dynamic" bench test equipment]... wouldn't be interesting to see what they might conclude from examining the CAR and/or the IP?

Regards,
Sam Ross

Sam, sounds like an excellent ideal.
Your car with the poorest overall mileage and performance might be selected for the test.

I would set the timing by the piezo method.
Mark the pump and see if it coincides with the highest leading edge of the Milli volt method.
I would not be shocked if it was not a few degrees advanced over the piezo method either with the Milli volt method.

Allowing for aging characteristics or modern fuel perhaps.
This is exactly the kind of information we need.
Can see no reason the two methods cannot be used simultaneously when doing the timing to compare.
As there is no interference between the two systems during application.

.

Barry... see Brian's post at
 

Barry - Thanks for getting back to me so promptly.
See Brian Carlton's post at:
http://www.peachparts.com/shopforum/diesel-discussion/150134-need-help-low-power-80-300d-%5Bna%5D-post1137442.html#poststop
and you will see that the pulse timing light method has to have a fudge factor that luckily Brian has already worked on. He wrote: "With the SD [his 1985 300SD] set perfectly at 15ATDC via the M/B RIV timing, the pulse timer registered 13.5° BTDC. So, I would presume that the n/a 300D [my 1980 300D(na)] should be close to this value."
Which I interpret to mean:
(1) The basic primary timing spec is 24 DegBTDC
(2) which=(s) ~15 DegATDC on the IP using M-B's "RIV" method
(3) which=(s) ~13.5 DegBTDC by timing light equipped with piezo pulse accessory.

Personally I get befuddeled [<-sp?] when I think about the several factors here that have potential to keep these three from being more absolute relative to one another, at least in my muddled brain.

Doesn't:"
(a) age of vehicle [ e.g. stretched timing chain],
(b) condition of glow plugs,
(c) condition of the injector nozzles,
(d) condition of the heat shields protecting the nozzles,
(e) how well the valves are adjusted, and
(f) how well the individual IP "elements" are set-up/timed relative to one another...

doesn't one or more of these [if any] keep us from establishing a precise comparison between the three numbered timing methods above?

If you guys can get my mind straight about these factors and timing methods I think I would be of some help going forward... what affects or changes what aspect of IP timing?

Regards,
Sam

Sam, you have just hit the highlight of the Milli volt timing function on the head.

It does automatically compensate for many factors present as you list them.
All other methods but the ear just basically refer to the factory recommendations from years ago.

Basically #1 injection point in reference to crank marking.
That I expect may be crude in comparison to reading the flame front.
Todays fuels alone are of less quality as well.

It may turn out perhaps on Mercedes that the peak Milli volt reading is perhaps a little too far advanced.
Even if so we will learn to set them a little before the peak.
What gives me hope that the factory recommendations are wrong for a large percentage of cars is the few cars that give substantially better fuel mileage than the majority.

I have suspected that knowledgeable mechanics may have set the pumps a little ahead by experience.
The 240d is a classic example of a possibility as some seem to deliver 15% better mileage than other examples in generally good condition as well.
Plus some of the same owners report much better power than average.
Also we can stand the additional power as well if it is available to us without over stressing the engine.

I am almost certain if the mpg are higher after the adjustment the car is not too far advanced.
If mpg are the same or less than it is probably over advanced.
That is the flaw in setting the pump by ear to some extent.
Too much trial and error.
You might luck into the right spot but chances are you will not.
We will see.

I also would do a fast preliminary check to see that the engine is in pretty good general condition.
Timing adjustments will not mask serious flaws.
But will help compensate for minor ones.
That is okay as these engines are not babies.

A good quick check of your engine is to just read each glow plug voltage separately.
If one has noticeably higher or lower glow plug voltage find out why. Swap the glow plug with it's neighbor first.
If no improvement perhaps swap the injector next.
I assume the valves have been checked at reasonable intervals before this.
Next might be a compression check of that cylinder if fault has not been isolated.
If that is good then you might want to start evaluation of the pump.

I did say evaluation not moving things until you are really sure.
Always remember two glow plugs beside each other that are reading low indicate a possible head gasket problem.
Great verification process of a suspicion.
This method has great potential if we can get past the preliminaries.
Remember it is also the method of choice already for some diesel engine builders to set their pumps to engines during the manufacturing process.

.

Some basic data... mv glow plug readings:
 

1980 240D: [ has 3 relatively new Bosch GPs and 1 Monarch GP ]
1980 300D: [GP's are a Non-Bosch mix ]
mv Readings:
"Composite" readings taken with all GP's connected in parallel !
240D... #1=9.9,..#2=10.3,. #3=9.9,. #4=8.6.................Composite=9.5
300D... #1=10.8, #2=11.6, #3=10.3, #4=7.9, #5=6.6... Composite=9.0
*As I understand it, the absolute accuracy of these mv readings is not really important so my cheap digital meter should suffice.... what's important here will be to eventually dynamically adjust these to peak/balanced mv readings, right?

The 1985 300SD data will have to come later.

Again the 240D and 300D are both geting about the same 22-24 mpg. I expect the 300SD is getting the best highway mileage. Things might improve for the 300D soon by virtue of infusion of a new/rebuilt tranny from Peter Schmid [Redwood City, CA] next week.

The 300D is currently the smoothest/quietest running engine and the 240D is the noisyest and roughest running. If nothing else I hope to get the 240D to settle down by fine-tuning the IP elements and IP-to-Engine timing.

Now I need information on how to proceed from this point. The IP-to-Engine timing I understand and I think my independent M-B shop owner is "on-board" with me on the notion of building a heavy, long-bar, tool that will clamp onto the front of the IP to facilitate this dynamic adjustment. So now I need input and/or will have to educate myself on the fine-tuning of element-to-element timing... something I do not want to jump into helter-skelter!!

Note- I picked up sone "Banana" type plugs at Radio Shack that make it a breez to connect to the GP Relay's connector to take the mv readings... individual one as well and the composite. I can supply further info on this if anyone wants.

I'm still working closely with my local M-B shopowner to try and come up with a workable piezo-electric pulse sensor timing light to quickly, dynamically check the engine/IP timing on the many diesels he sees.

Regards,
Sam Ross

I highly suggest you dont mess with the IP elements just yet. Do your primary Timing and then do take the mV readings and let us know what you find.

JMan300sd - Trust me I read your past posts...
 

and I fully appreciate the difficulty you had in trying to restore the timing of two of your your IP's elements that had accidently been changed. And I do not intend to make that mistake. I'm proceeding slowly with this matter! Thanks for the appropriate warning.

By the way I failed to say that in taking these readings I did NOT experience any appreciable "floating" or "drifting" readings using my cheap digital VOM and I did NOT use a R-C circuit to dampen the meter readings. The meter only infrequently changed by 0.1mv. Maybe my $40 VOM was designed by a genius!

So as I understand things at this moment, my next step should be to accurately check and if necessary correct the IP-to-Engine timing.? It might be a while before I get around to that.
We are presently trying to obtain and satisfy ourselves with a piezo-electric pulse accessory that will allow us to use a timing light to dynamically check and set the car's IP-to-Engine timing.

What do you say Barry about my next step?

In the mean time, I'll work on getting more mv data on the '85 300SD [W126] M-B.

Sam

I just wanted to note that I'm following this thread eagerly... I'm facinated by 'test in place' methods, and this seems like a great example. For those who asked, or are confused still, I wanted to note the reason for the voltage...

It was noted at one point by an Estonian scientist that any metal, subjected to a heat gradient, would show an electrical potential across the piece of metal. The amount of the potential depended on the type of metal, and the difference in heat between the two parts. Of course, to read the voltage, you have to connect another piece of metal, which is, itself, now subject to a heat gradient, and is now producing a voltage of its own. The difference between these two potentials is what we can measure.

So any time you have two dissimilar metals together (as in the internals of glowplug), you have a thermocouple. The difference in voltage can be measured, and will increase with temperature.

If you were crazy, you could fashion a fake glowplug with a calibrated thermocouple on the end, like a K or J type thermocouple. Then the mV reading could be compared to a chart, and correlated directly to a temperature, and you could measure the cylinder temperature directly.

Instead of doing that, we just use the glowplug. They aren't calibrated though, so different brands and ages of glowplugs will show different voltages, even at the same temperature. If you had the right test rig, you could 'calibrate' a scale to your glowplug, create your own conversion scale, and read an actual temperature of the cylinder. 14.5mV = 1200F or whatever.

But since the actual temperature isn't crucial at the moment, thats not worth the time and energy. It makes more sense to just look for the max temperature, or in our case, the max voltage.

The 'hunting' described is probably a combination effect... The cylinder isn't one temperature, its heating up, and cooling down, through the cycles. This pulsing up and down heats and cools the glowplug irregularly, causing a variation in the voltage, corresponding to a laggy variation in the cylinder temp.

One thing to note is that in the 'millivolt world', everything creates potential. Try wiggling the test leads around while they aren't connected to anything. You'll see a little voltage from their inductive interactions. When making a reading under the hood, make sure your test leads are as still as possible, to eliminate that fluctuation.

Anyway, thanks for working on this method, folks! I'm very curious to see how it all turns out, and will be trying it once there is more data (I've never timed a pump before, so I want to make sure I know enough to do it right the first time!). I'll see about taking some mV data on my 300TD soon, just to add to the pool of data we are building.

peace,
sam

PS more about thermocouples: http://en.wikipedia.org/wiki/Thermocouple

Adjusting Rod
 

Gentlemen- I think I've got it. A facsimile of the special tool required to move the IP (see pic).

It's part of a door closer assembly. The left end would clamp to the fuel line bolts on top of the IP, while the right end will slip over the engine cam-cover stud and fasten down securely with the nut.

To finish it, I need to do three things-
- drive that pin out that goes across the left end so the piece that goes in there can be extracted
- cut the aluminum tube shorter so it will fit in between the IP and cam-cover stud
- re-insert the removed piece, but instead of staking it with the pin, I've got to somehow weld a retainer on the end of the tube where I cut it, to hold the piece in and allow it to rotate within the tube, thus pushing and pulling the threaded part while turning the tube with a vice grip or wrench.

Problem- I always get stymied on the physical execution of things. First, I tried driving that little pin out with a punch and hammer, but couldn't get it to budge. It does look like it would come out though. Second, I cannot weld- especially aluminum, er- especially nothing- I just can't weld.:rolleyes:

Barry- if I can bring this over some time this week, and if you can bring this to completion- it's yours man! I know the idea will work.

Dave

I hope your guys N. of the border have something, but...
 

this aluminum door closer cylinder idea seems a bit "flimsy" to me and I canNOT really follow Dave's explanation of how it would work!?

My independent M-B mechanic has an idea that appeals to me for hit would literally clamp onto the front of the IP just forward of the individual elements where the IP's body is clear/clean and the top and bottom surfaces of the IP body are square. As a quick-N-easy way I could see a "giant" crescent wrench [ metric of course :D ]... or even vicegrip-like tool [how big do they make them?] connected to this squared off front the IP might give us the leverage needed to dynamically adjust the IP-to-Engine timing.

My M-B mechanic friend is inclined to make a tool from scratch that would have a strong clamp, heavier and longer arm thus providing greater leverage and greater accuracy. However this will have to wait until we get our diesel IP timing light working. The timing light will allow us to readily confirm what timing results from using the dynamic IP [ miliVolt fine-tuning ] method that we think has potential.

Chou,
Sam

dynamic adjustment control rig...
 

I like the door opener concept as it allows very small adj. during the dynamic movement....like a turnbuckle type adjuster....I may make one out of heavier gauge fine-threaded rod and large fine thread spacer nuts...also more force and finer adjustment available with the screw mechanisim.....I see the square area on the IP you are talking about.....this is good info...maybe combine these two clever designs....A nice rig could even be left in place like the adjusters on the belt driven stuff....keep on thinking guys!....kevin

" Dynamic " is the operative word here...
 

and " DNAMIC " means we are looking to change the IP's timing while the engine is running which means that the heavy fuel lines snaking their way between the IP and injectors act like one big strong spring resisting our effort to twist the IP's body and change it's timing. In a way I like the "turnbuckle" idea especially if a secure enough place on the engine can be found to anchor the other end. Early stage testing for such a tool would most likely tell us whether or not we need such a precise "hold-fast" feature as the turnbuckle. I still think that the inherent strength gained from as much long-arm leverage as practicable will be important in such a tool.

From our prospective here, keep in mind we are thinking of a tool for a profit making mechanic/repair garage trying to check and then easily change the IP's timing, not something that would be left on the engine. Also such "fine-tuning" of IP timing is not likely to be needed that often... should it?

Sam

turnbuckle and lever
 

I was thinking of a tool left in place just for our own test vehicles...so as to quickly change the pump timing for optimum starting and running...the lever you speak of could be used to help rotate the pump/turnbuckle fixture if a slot or tube was attached to the turnbuckle device that you could slide the bar or arm into....kind of like the old bumper jacks have.... so as to be removable for driving test so you close the hood....the injector lines are very strong and this extra leverage will probably be needed to help move the contraption....of course several designs are possible....I just want to move my pump to see how these voltages track performance....I hope this glow plug thing works out...I hate the drip tube...this is a great site!....kevin

Customer-make IP timing some have spoken of…?
 

I was rummaging around under the hood of my 240D and notices for the first time some marks that have been made on both the engine and IP sides of the IP mounting flange. See photo below [ I hope was able to upload it].

If this is what others have spoken of, what do you make of these marks that obviously indicate that the IP is no longer set the same as the marks… but in this case I think I know why this might be. This M-B dealer imported rebuilt engine only has ~20,000 mi on and no doubt when installed it was matched up with a used/rebuilt IP from another source.

So if I wanted to have MY reverence, I would have to put a new set of marks using a small chisel across this engine/IPP flange line? Your thoughts please so I'll know I'm on track:confused:?
Sam

Nothing wrong with putting a new set of marks so that you have a starting reference for your adjustments.

However, I'm curious about your original marks. If correct, the timing is quite late. Have you checked the timing to see if it's near the specification?

IP tool....
 

Sam...
Baum Tools already makes a fixture like we were discussing.....but no lever...part number 617-0721...They did not have a price...looks expensive ...will call for pricing tomorrow...kevin

Brian / yellit... thanks for the posts... this is it for tonight!
 

Brian – I immediately figured a new set of reference marks might be in order. As to why the current set are off… after close examination, I believe the two marks there now were made at different times. Remember the engine was replaced so it’s entirely plausible that these marks were made when the engine & IP were NOT mated together. If I’m wrong about this, then you could be correct that my 240D’s IP is likely to be out of time a little and that might explain the extra “vibes” at idle !

Mississippi [yellit] – I found the WebSite for Baum Tools and their graphic for p/n 617-0721… I’m attaching it. The tool looks interesting and might give us another approach for a DIY tool if there is gold plated.

Sam

I agree with this Sam. The IP pump end of my door closer (left end of my photo) just happens to mate perfectly with that flat area. It's possible that it could be clamped directly on there, provided the clamping mechanism fits in the very confined space around the front of the IP. (Too bad MB didn't oblige us with two threaded studs protruding up from that flat area- my door closer would bolt right on if that were so!)

However, it is not shown in my picture, but I was thinking more along the lines of another metal plate held on the left end with ordinary screws and nuts that would clamp it over one of the five heavy nuts that secure the lines to the pump.

I can't say whether or not the door closer would be too flimsey. The threaded part certainly isn't, and the two end brackets and threaded tube, although aluminum, seem to be very robust and not easily bent.

My biggest problem is that if this were bolted down at both ends, the tube is not free to turn because that pin that goes through it on the left has it staked to the short collar piece that goes into it. The pin has to be removed, and something like a split flat washer has to be welded over the end of the tube to hold the collar in place while the tube is turned. I'm thinking that if this were to break, it would be at that weld, unless I can get someone who can make a very strong weld with aluminum. On that point, I suppose the "split washer" would have to be aluminum too wouldn't it? Don't know for sure, but you normally can't weld steel to aluminum, can you?

Dave

IP adjusting fixture...Baum Tools
 

Sam and fellow Dieselers...... Looks like there is still a need because Baum does not have this infernal contraption any longer....both of the tool suppliers that baum uses do not have it either...Baum said they did not sell enough of them to make it worthwhile...they were priced at $612.00 each when they were trying to sell them...The Baum guy said he does not think they even sold one??!!....
Time to get out the brazing torch and silver solder...I can at least see how the thing is supposed to look...Cheers!...kevin

Dave – did you see my last post ?..............
 

I don't understand how this Forum's software performs the branching on such long threads... but if not check it out at: http://www.peachparts.com/shopforum/diesel-discussion/152389-setting-pump-primary-timing-milli-volt-method-post1174009.html#post1174009
as it includes a graphic of a tool by “Baum Tools” that is apparently made specifically for “DYNAMIC” timing adjustments on IP(s). If you click on and blow up the graphic, it appears the lower part of this tool is designed to clamp onto the front of the IP where we are talking about and the upper part attaches somewhere onto the engine… and in between these 2 attachments there appears to be a heavy adjustable part that no doubt has fine threads. On our M-B(s) we could do the same thing and the engine attachment could use the valve cover bolts. I'm try to attach the small graphic file again to this post below.

Today I will have to do some measuring and picture taking and possibly do a “hybrid” drawing [ that’s a drawing done on a photo] to see if I can come up with something that I can send via e-mail attachment to anyone interested.
Mississippi [ yellit ] is going to see what Baum wants for their tool and whether its useable on our M-B(s).
Regards,
Sam

Tool
 

Sam...I found the price and info...see my previous post from today....kevin

Yep- I saw this picture before- a couple of weeks ago by doing a search under the "special tools" tab. This is what I'm trying to replicate with "found objects", except this "official" tool has a major drawback that you have to remove two cylinder head bolts which are in turn used to hold the tool down. I would want it to be long enough to reach the cam cover stud instead- much less risky.

Dave

IP Tool..
 

Hello Dave...My thinking exactly....I do not want to go unbolting old settled in headgaskets....Did you see the price they wanted for that thing!?...$612.00.....The rocker cover stud should work...might even run another support to something else..I have some metal working equip. so I have been digging through my scrap pile for some good steel...I am going to braze up something crude but functional...not a large range of movement needed anyway...will keep everyone posted....kevin

I think the tool's idea has some merit...
 

but I agree, you should not loosen any head bolts.

Right now I'm working on what to use this design and anchor the tool to one of the valve cover bolts instead. I'll probably soon have a hybrid picture/ sketch to show you guys to see what you think. As I do this I automatically do so with the notion of using off-the-shelf hardware store parts... and minimal welding/fabrication.

Send me your E-mail address via the Forum's e-mail feature if you want receive a copy of my graphics workup. You should know that the 65K file size limit on the Forum prevents me from posting what I'm working on.

Sam

IP timing tool... graphic 2; part 1
 

This 1st graphic is a basic block style front crossectional view of the engine/head/valve cover and IP. Don't worry about reading the small numbers here as they will be easier to read in graphic 2; part 2.

Note #1 -the ample lever that starts out as angle-iron and then changes to a better handle to grip [pipe].

Note #2 - the clamp bar/plate across the top of the IP... again there will be better detail on the next graphic.

Note #3 - please give me your thoughts as to the material you think will be needed [ thicknesses / dia etc.] .

On to graphic 2 in the next post!:silly:

Sam

oops... here is graphic #2; part 1
 

oops... here is graphic #2; part 1... this silly Forum software forces you to write something here!!!
Sam

Graphic 2; part 2
 

OK, this time I loaded the graphic first so I don't forget!

Hopefully this will give you clarity where it is needed.
Here I'm showing dimensions [in metric] for my 240D. I have not checked these against the 300D yet. I’m thinking that if warranted to give the mechanic more control, we can somehow fashion a long fine machine thread bolt [all thread] between the valve cover bolt and the base of the angle iron lever that comes up from the outside of the IP.

Give me your thoughts!
Sam

Tool
 

Nice drawing Sam....We are thinking the same......I am thinking of a 5/8 threaded rod firmly attached to the rocker cover stud.....going through a hole or U shape slot in the tool you have drawn...this rod will have a nut on each side of the fixtures vertical vane for adjustment and locking in either direction...I am making a sort of pocket or hat that will go over the squared end of the IP that the handle and screw assy can be attached to.......this thing may have to be made in pieces because there is not any room in my 300D compared to my 240D...I will take some digital pics when I start....I hope the rocker stud will have enough meat to support all this pushing and pulling....kevin

Sam, have been away and otherwise occupied so have unfortunately missed a lot.

Quite impressive to see you people moving along.
There are a lot of tests to preform to even establish if you have say an element off but from past posters your general glow plug voltages seem to have quite a spread.
Could be caused by individual glow plugs.
So one would have to move them to different cylinders to verify.
Valve settings, compression, injectors, injectors are my own biggest thought for your readings at this moment from your description but again one would verify just by moving an injector to a different cylinder.

Others will have other suggestions as well.
Only after everything else is eliminated does the pump become suspect.
And even if suspect we do not yet know how many degrees 0.1 mv indicates.
In other words still very early in the game.

At present and probably always one might say with the simple Milli volt method until we have eliminated all other causes the situation of running it down to the pump before adjusting elements will of course take priority.

One should already be prepared to shop the pump if indicated before trying to tune the sequential portion or elements if it proves to be a requirement.
I suspect at some point hopefully that will not have to be a consideration.
Again still very early in this area but perhaps not that far away.
Thanks and good information all. :)

.

Sam, I just reread your post.
Did you get all your different glow plug readings while still hooked in parallel?
Suspect when relay off they are still wired but isolated from each other if so.
If they were still wired up I will have to think about this a bit.

Also for everyones thought I have an ideal that we can make a comparator with four, five and even six piezo connectors so we will eventually just clip them all to all of the injection lines and will be able to read out the exact spacing in degrees of each element while engine is running.

This I feel will not be rocket science either but still we have to see a lot of present though change and continue to make steady progress on the start.

Only precondition to using it I can think of would be to make sure all injectors were adjusted to the same pop pressure values.
Great tool to have available in our loaner program someday.
This is another reason it is important to move cautiously and progressively.
We want to benefit everyone that has one of these old diesels if possible.

Any electronic heads have any thoughts about above.
Think there is enough isolation to dampen interaction if any with simple sensitivity adjustments.
Package should be rugged enough to survive fairly rough handling in postal service without affecting reliability..

Also think circuit not a good ideal but some kind of liquid crystal display perhaps with different overlays for the different spacings of various amounts of cylinders or just directly readout in degrees.
Any thoughts?

I know some of you younger generation are out there.
How about a patch cable to average home computer for readout with simple software program?
Are cheap piezo crystals adequate?
Perhaps we could even use piezo tweezers elements clamped to each line?
Cheap, cheap, cheap, then would we ever be able to adjust sequential timing very accurately if required.
Should be workable I think gentlemen.

Have no knowledge of anyone doing this before and wonder why not?
As I stated Sam it's still hopefully very early in this re timing of elements in pumps. :)
I am not trying to start another completely different discussion running but rather trying to show we might go a very long ways yet before we are finished.
First things first I guess.

.

Barry and others:

So you think it's individual timing and not amount of fuel?
I will ask an electronic to use an oscilloscope with 5 piezo inputs but just to verify how accurate the mV-method is. Further he is overthinking an assembly of 5 (analog=slow) mV-displays probably with signal amplifier to deal with all values at the same time for better adjusting the elements.

Tom

Welcome back Barry, honest I was only borrowing YOUR THREAD...
 

for a while. Your idea of using piezo-electric pulse technology to concurrently monitor all of the elements of these mechanical Bosch IPs in our vintage M-B is brilliant... but as I see it, a next best step forward is for us to get more people who read this THREAD to at least progress to where they fine-tune their IP-to-Engine timing using this mv technique.

If only we [ me and my M-B mechanic friend ] can get a piezo-electric timing light accessory to work reliably for us, then this would let us more easily check what the existing timing is. We don't have a
M-B "R.I.V" instrument. The Ferret brand sensor accessory has not worked out for us, so we are now looking at a Snap-On model that I think sells for ~$350.00. We will hopefully learn something from our local Snap-On route man who makes his regular call on us tomorrow. The electronic [inductance] timing light we are using is one of the latest that Snap-On has so hopefully that will count for something in trying to get two instruments to work together!

Welcome back Barry!

Yellit - will get back to your post tomorrow!

Sam

let me throw this one at ya... before turning in here on the LEFT coast!
 

Here is a sketch depicting something I think our timing tool should have...
a protective layer of neoprene to protect the surfaces and s/n plate of
the IP.

Night-night,
Sam;)

IP tool
 

Tried the O-scope today to read the 6.9-7.0 millivolts that my 4 digital voltmeters were reading ....4 different brands of digital meters...a cheapie,Beckman,HP,and Fluke...one on each glow plug... $10.00 cheapie read as accurate as the $300.00 HP...glow plugs are new so all readings were close without parallel averaging hookup...The O-scope only went down to a 5 millivolt per vertical division resolition so I could not see the small changes in the dc trace....The meters were more easily read.....I noticed that after the +12 from the relay to the glowplugs shut off which was as soon as the engine started...the glow plug voltages are tracked down from about 15 millivolts to the stable 6.9 millivolts over a period of about 10-15 seconds...this would be the cool down from the glow cycle maybe ......I think the glow plugs are tied together in the relay so external jumpers may not be needed if you leave the relay plugged...I read them both ways...not much difference...did not try to adjust IP yet...still making tool similar to Sams design....kevin

Question- Basics of Diesel Timing
 

I want to ask a real simple question- does a Diesel engine's timing remain constant in terms of degrees throughout its RPM range, or does it change as RPM's increase and decrease?

I know that on a gas engine, the distributor timing angle advances with RPM as the timing plate is altered by centrifugal force and vacuum assist. Does the same principle hold true for Diesels?