Checking Timing Question/Help - PeachParts Mercedes-Benz Forum

tobybul · #1 03-18-2007, 07:38 AM

I recently did some tune up work on my 85D - valve adj, ALDA adj and diesel purge. The valve and ALDA work were most beneficial in my case. The ALDA adj gave it more power but engine seems to be running just a bit rough. No smoke. Best noticeable side effect is smoother tranny shifting.

Now, I just want to make sure that the timing is correct. How do you check it in the 617? Is it like a gasser where there are timing marks at the crankshaft that can be lined up? Is a tool like a timing light necessary?

Thanks in advance for your help.

WINGAS · #2 03-18-2007, 07:59 AM

Dude, I havent set it yet, but its not like a gasser, there are no electric timing connections, ie. wires to use a light on. Timing is mechanical and govered by the injector pump. I need to get a red/green two bulb gizmo to check it. I'm not sure about your vintage. There must be a D-I_Y link here somewhere. NOT HAVING DONE IT YET,it seems as simple as getting the engine to 15 degrees BTDC and checking the IP.

tobybul · #3 03-18-2007, 08:07 AM

Thanks, 427L88. I kinda knew that its not done like a gasser but I thought I'd mention it anyway as a comparison.

I mentioned earlier that the engine is a bit rough but I think its more like a bit louder. It does accellerate more like a gasser now though. The car actually responds when you hit the gas pedal

.

Brian Carlton · #4 03-18-2007, 09:14 AM

Which timing are you interested in checking?

IP timing........or camshaft timing?

tobybul · #5 03-18-2007, 09:47 AM

Quote:

Originally Posted by Brian Carlton

Which timing are you interested in checking?

IP timing........or camshaft timing?

Well, I don't know, Brian, since I don't know what each one affects.

I was just reading my Haynes manual and finally found discussion on what must be IP timing adjustment. It talked about and showed using a drip tube tool, lining up the timing mark at TDC (23-25 deg), loosening screw at filter to relieve any air in fuel line by pumping hand pump, turning camshaft, watch drip tube at rate of one drip/sec. I don't know where to get the drip tube tool but seems easy enough to duplicate using copper pipe and a brass fitting. Just need to know the npt thread type and size of the tool.

I have not come across camshaft timing discussion yet.

Either way, I am just trying to make sure that the engine is running the way it should especially after the Alda adjustment I made.

barry123400 · #6 03-18-2007, 10:26 AM

Before actually resetting the timing read the archives. Find out how to determine how much chain stretch you have if any and what is allowable. Also if you have allowable stretch read about using a correction key for the camshaft if the need is indicated. They are quite cheap if required.
Again into the archives as some people have posted extensive instructions over the years on both items. Them set the injector pump timing.
You are good to go for quite awhile then with maximum efficiency.
After the first time at this it will be like rolling off a log the second or subsequent times. Thats if they occur of course.
Also read up about checking the chain guides as it seems they are usually the reason the chain lets go with disasterous results normally . A little knowledge in this area is a good thing.
To ignore it can be folly with our average high milage cars that perhaps have not been checked for many, many years. They just where driven as long as they ran. Some past owners thought no service was required as it is a diesel after all.. Overall this area is pretty inexpensive to work around in. The posted knowledge and experience is very extensively documented as well.
Love to tinker covers it well.

Brian Carlton · #7 03-18-2007, 10:30 AM

Quote:

Originally Posted by tobybul

Well, I don't know, Brian, since I don't know what each one affects.

I was just reading my Haynes manual and finally found discussion on what must be IP timing adjustment. It talked about and showed using a drip tube tool, lining up the timing mark at TDC (23-25 deg), loosening screw at filter to relieve any air in fuel line by pumping hand pump, turning camshaft, watch drip tube at rate of one drip/sec. I don't know where to get the drip tube tool but seems easy enough to duplicate using copper pipe and a brass fitting. Just need to know the npt thread type and size of the tool.

I have not come across camshaft timing discussion yet.

Either way, I am just trying to make sure that the engine is running the way it should especially after the Alda adjustment I made.

The drip tool is a PITA and it probably won't give you accurate results due to inexperience and variable pressure affecting the outcome.

If you want to set timing in 10 minutes, rent the RIV lights from M.B. Doc and do the job properly. You've got the port on the '85 and the lights allow you to set timing accurately to 1 degree without any question of the result.

Note that the tool is costly and he'll need a hefty deposit for it.

Danny wrote up an excellent DIY article for the camshaft timing. Check out the DIY list at the top of the page.

Scott98 · #8 03-18-2007, 10:35 AM

How to check timing chain stretch:

http://www.peachparts.com/Wikka/OM617TimingChainStretch

How to check injection pump timing:

http://www.peachparts.com/Wikka/OM615OM616InjPumpTiming

Remember, if you correct your timing chain stretch, you have to reset your injection pump timing.

Scott

tobybul · #9 03-19-2007, 01:56 PM

I was able to loosen the idle screw nut with no problem. Followed Brian's advise to soak with WD40.

Brian, a question on the TDC position vs the No 1 cam lobe position. If the timing mark is set on 24 deg, is the No 1 cylinder lobe (2nd Lobe) suppose to be at the one o'clock position (or is it the 11 o'clock position)?

Brian Carlton · #10 03-19-2007, 02:35 PM

Quote:

Originally Posted by tobybul

Brian, a question on the TDC position vs the No 1 cam lobe position. If the timing mark is set on 24 deg, is the No 1 cylinder lobe (2nd Lobe) suppose to be at the one o'clock position (or is it the 11 o'clock position)?

If the #1 lobes are pointed upwards (11:00 or 1:00.......doesn't matter), the piston is on the compression stroke and not on the exhaust stroke. If you can't see the lobes (pointed down and opening the valves), it's on the exhaust stroke and you've got to go around again.

tobybul · #11 03-19-2007, 03:54 PM

Quote:

Originally Posted by Brian Carlton

If the #1 lobes are pointed upwards (11:00 or 1:00.......doesn't matter), the piston is on the compression stroke and not on the exhaust stroke. If you can't see the lobes (pointed down and opening the valves), it's on the exhaust stroke and you've got to go around again.

So, I guess the cam timing is ok when they #1 cylinder lobe (2nd lobe) is at 11 o'clock and timing mark is at 24 deg?

DeliveryValve · #12 03-20-2007, 03:39 AM

Sorry for being blunt, but you should remove your valve cover and use the markings on the cam tower and grear shown here

http://www.peachparts.com/Wikka/OM617TimingChainStretch have an accurate picture.

I posted this link on your previous thread. Accelleration and speed

Once you know your timing is accurate (both chain and IP) then you can go on to other things.

tobybul · #13 03-20-2007, 09:32 AM

Thanks for the reply, Pare....

I'll read the link you sent. I didn't know there were timing marks inside the valve cover. Also, is it the No 1 Cylinder or the 1st lobe that you line up (I don't recall anymore if the 1st lobe is the No 1 cyl or the 2nd lobe).

Does positioning the lobe in that manner (about the 3 o'clock position) mean that the TDC is also suppose to be at 24 deg? Or is it just the lobe position that matters? Does this question make any sense?

winmutt · #14 03-20-2007, 09:41 AM

The only real way to accurately get timing is the 2mm lift method.

DeliveryValve · #15 03-20-2007, 11:25 AM

Quote:

Originally Posted by winmutt

The only real way to accurately get timing is the 2mm lift method.

Yes this is the best method to know for sure. But you can use the timing marks in a pinch and can be accurate if your marks are correct (you wouldn't know until you use the 2mm lift method).

Quote:

Originally Posted by tobybul

Thanks for the reply, Pare....

I'll read the link you sent. I didn't know there were timing marks inside the valve cover. Also, is it the No 1 Cylinder or the 1st lobe that you line up (I don't recall anymore if the 1st lobe is the No 1 cyl or the 2nd lobe).

Does positioning the lobe in that manner (about the 3 o'clock position) mean that the TDC is also suppose to be at 24 deg? Or is it just the lobe position that matters? Does this question make any sense?

What matters with the cam lobes is that they are both pointing up. It doesn't matter where they are positioned. 24 degrees is either before top dead center or after top dead center. It is not TDC. 0 degrees is TDC.

24 degrees BTDC about when the number one injector should spray. You woud set your IP to that spec.

Check out the links to timing stretch and IP drip method stated earlier and we'll help you through this!