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-   -   M104 AMG Engine - Timing set-up procedure (http://www.peachparts.com/shopforum/mercedes-benz-performance-paddock/274297-m104-amg-engine-timing-set-up-procedure.html)

OzC36 03-26-2010 11:00 PM

M104 AMG Engine - Timing set-up procedure
 
The timing set-up procedure for the M104 basic engine is shown in many threads and documents, for example, in the following link:

http://www.ps2cho.net/downloads/MB%20CD/W124/w124CD1/Program/Engine/104/05-2230.pdf

As noted, in the above link, the procedure for the AMG version of this engine is different.

In error, I set my engine as per the basic procedure above. My AMG engine runs fine above 1000RPM, but the idle is lumpy like a rottweiler dog pulling at a chain at idle.

Relevant differences I have noted during research indicate:

1. Different inlet cam and valve lift.
2. Different valve overlap.
3. Inlet valve opens 28 deg ATDC on AMG (34 deg ATDC C280).
4. Exhaust valve closes 16.5 deg BTDC AMG (14 deg BTDC C280).
5. Variable valve timing is 26 deg AMG (20 deg C280).

My question is...Does anyone know, or have a link to the procedure for setting the camshaft valve and timing chain for the M104 AMG engine?

MAG58 03-26-2010 11:10 PM

The cam size shouldn't affect timing unless they change the LCA. That said, did you make sure the cam was in the retarded position when you put the chain on?

OzC36 03-27-2010 12:08 AM

Yes I did ensure that I retarded the cam adjuster.

The cams are set on the 280 version as per the dowel holes drilled into the back of the cam gear sprocket wheels. However, the AMG valve openings are advanced by 6 deg for the inlet and 2.5 deg for the exhaust.

That advance could be achieved by a new cam profile for the inlet camshaft (it is an AMG specific cam part number). It could also be achieved by advancing the sprocket gear one or two teeth.

But how do they achieve 2.5 deg advance for the exhaust for the exhaust cam which is identical to the 280 engine? Could that be achieved by the higher compression (shaved) head alone, or shaved head and advance one tooth?

JayRash 03-27-2010 03:44 AM

1 Attachment(s)
Quote:

Originally Posted by OzC36 (Post 2435199)
Yes I did ensure that I retarded the cam adjuster.

The cams are set on the 280 version as per the dowel holes drilled into the back of the cam gear sprocket wheels. However, the AMG valve openings are advanced by 6 deg for the inlet and 2.5 deg for the exhaust.

That advance could be achieved by a new cam profile for the inlet camshaft (it is an AMG specific cam part number). It could also be achieved by advancing the sprocket gear one or two teeth.

But how do they achieve 2.5 deg advance for the exhaust for the exhaust cam which is identical to the 280 engine? Could that be achieved by the higher compression (shaved) head alone, or shaved head and advance one tooth?

Its done as follows
Attachment 78988

OzC36 03-27-2010 05:27 AM

Thanks for that jem of information Jay. That makes a lot of sense to advance the cam shaft by moving the dowel locating pin. That helps me a lot in making sense of what I saw earlier today.

I pulled the valve cover a few hours ago and check the marks and timing of the valves. The exhaust is pretty much spot on. But the intake valves are opening about 25 deg early...oh! oh!...looks like I must have assembled the timing with the camshaft adjuster in the fully advanced setting as opposed to the fully retarded position.

Photo shows inlet sprocket 4mm timing hole advanced due to AMG modified dowel location (3.5mm drill bit inserted after sprocket positioned to illustrate new AMG position).

Question: Can anyone confirm that if I set-up the timing for my M104 AMG as illustrated in the photos, but, correct the VVT to full retard, that this will be the correct procedure for the M104 AMG?

http://img697.imageshack.us/img697/3579/032sp.th.jpg

General view.

http://img707.imageshack.us/img707/8461/031dt.th.jpg

Exhaust sprocket 4mm timing hole spot on.

http://img707.imageshack.us/img707/8452/030xs.th.jpg

Settings were at TDC.

http://img697.imageshack.us/img697/9048/023ya.th.jpg

OzC36 04-09-2010 09:04 AM

I pulled the timing cover today and I found everything on the intake side was normal...I had reinstalled the VVT cam adjuster and set it correctly in the fully retarded position.

However, I found out how the AMG factory achieved the change in timing (from the C280 engine) on the exhaust cam. AMG reworked the cam sprocket. They elongated the holes for the three retention bolts and also drilled a new locating dowel hole.

If you have two holes available, you just know that someone is going to use the wrong hole. Yep, that's what happened...I should have use the new hole marked with a "U".

This is what I found (exhaust cam sprocket)...

http://img683.imageshack.us/img683/6433/033hr.th.jpg

I still don't know the basic timing setup for AMG M104 and how it varies from the C280 M104 setup. Any takers on this one?

At the moment I am turning the crankshaft over after trying different chain sprocket positions and trying by trial and error to achieve the AMG spec settings of:

1. Inlet valve opens 28 deg after TDC; and
2. Exhaust valve closes 16.5 deg before TDC.

I have the exhaust setting spot on.

But the 4mm drilled hole on the inlet sprocket will be way off when I set the cam to achieve the 28 deg event.

Appreciate any input guys!

OzC36 04-10-2010 11:51 AM

I really should acknowledge JayRash for his link on the exhaust valve timing as that was the precise source of my timing problem there (assembled using the wrong dowel hole). I didn't quite understand or appreciate the significance of the information in the link on the first read. Thanks JayRash!

There must be some guru here that knows or has access to the timing setup procedure for the M104 AMG engine?

I really would appreciate any help or advice or direction from any kind soul on this situation before I button it up and take my chances.

JayRash 04-10-2010 12:08 PM

Thnz Oz,
ill try and pry that info from my mechanin on monday afternoon, but i wont promise u much for he is a bit tough to deal with in this respect.

OzC36 04-10-2010 12:13 PM

Thanks JayRash, any information would be much appreciated. I have worn my fingers out searching Google and the Tech books I have access to. I am just thrashing around in the dark at the moment!

JayRash 04-10-2010 12:58 PM

droped M.B.DOC a PM he might have that info.

JAY

mbdoc 04-12-2010 09:05 AM

ALL M104's set the basic cam timing that way.

If you remove the valve cover & rotate thae engine ONLY clock-wise to TDC, both pins should go into the camshafts w/o moving anything else!

OzC36 04-12-2010 09:27 AM

Quote:

Originally Posted by M.B.DOC (Post 2446366)
ALL M104's set the basic cam timing that way.

If you remove the valve cover & rotate thae engine ONLY clock-wise to TDC, both pins should go into the camshafts w/o moving anything else!

Hi M.B.DOC,

Many thanks for your personal attention and expertise!

As I understand the AMG engine, the exhaust cam is stock standard with the C280. But AMG has slotted the three attachment bolt holes of the exhaust cam drive sprocket to advance the exhaust timing about 5 deg. They also drilled an additional dowel locating hole which is marked with a "U". I think this causes the timing mark to be about 3-6 mm above the top of the head with the 4 mm drill inserted.

AMG also installed an AMG-unique reprofiled inlet valve cam. Also they changed the variable valve timing (VVT). So exactly where the 4 mm dowel should be on the timing setup for inlet valve cam for the AMG is a mystery to me. I can present cases to support the dowel hole to be above the head or below the head for line-up of the 4mm drill bit.

If you can shed any light on this dilemma, I would be extremely appreciative!

JayRash 04-12-2010 09:32 AM

OZ,
Was the exhaust cam advanced or retaded 5deg?

OzC36 04-12-2010 09:40 AM

Hi JayRash,

The exhaust cam sprocket has a slotted modification for the attachment bolts. With the cam set on the dowel AMG modified hole marked "U", it is rotated clockwise compared to standard.

So I would say it is advanced from standard?

http://img683.imageshack.us/img683/6433/033hr.th.jpg

JayRash 04-12-2010 02:37 PM

ok since it rotated clock wise, come assembly time dont u rest the sprocket to the correct mark? Wouldnt that mean the cam now is retarded to get the correct set up at TDC?
Just asking for its been some 11 years since i played around with cam gears.


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