617 turbo valve adjustment lobe position - PeachParts Mercedes-Benz Forum

Bob300DSD · #1 11-15-2007, 12:47 PM

I adjusted the valves last night on my 83 300D. I reviewed old ShopForum threads as well as threads all over the web.

I have two questions:

1.When I position the lobe at "1 o'clock" does the tip of the lobe point to the driver's side or passenger side of the car?

My MB service manual says: "positioning the camshaft so that the tip of the cam is vertical relative to the rocker arm." but the picture in the manual does not show the tip or lobe on on the camshaft in the diagram.

Diesel Giant says: "To your eye this will look like the lobe is in about the 1 o'clock position" but the tip of the camshaft lobe in his picture looks to me like it is pointing toward the passenger side of the vehicle, (the engine he is working on is a 617 non-turbo).

2.Can I lube the linkage with regular wheel bearing grease after I clean them?

Thanks for the help. I have two more valve adjustments to go.

Bob

Shawn D. · #2 11-15-2007, 12:53 PM

Quote:

Originally Posted by Bob300DSD

1.When I position the lobe at "1 o'clock" does the tip of the lobe point to the driver's side or passenger side of the car?

My MB service manual says: "positioning the camshaft so that the tip of the cam is vertical relative to the rocker arm." but the picture in the manual does not show the tip or lobe on on the camshaft in the diagram.

Diesel Giant says: "To your eye this will look like the lobe is in about the 1 o'clock position" but the tip of the camshaft lobe in his picture looks to me like it is pointing toward the passenger side of the vehicle, (the engine he is working on is a 617 non-turbo).

Just position the lobe so the lobe is pointed 180 degrees away from the rocker. That way, the cam will certainly be on the base circle.

guage · #3 11-15-2007, 12:59 PM

I stood on the drivers side using a bump starter and positioned the lobe as pictured here, which would be also pointing to the drivers side

I used trans fluid to lube the linkage

Bob300DSD · #4 11-15-2007, 01:12 PM

Quote:

Originally Posted by Shawn D.

Just position the lobe so the lobe is pointed 180 degrees away from the rocker. That way, the cam will certainly be on the base circle.

When I look closely at the rocker it is not easy for me to discern the curve in the arm as displayed in the manual's diagram. Hence I am tempted to position the lobe straight up or positioned at 12 o'clock. When I turned the camshaft and checked clearance it seemed to me that the rockers had the most clearance at little past straight up at about 1 o'clock on the drivers' side. However the difference was so minimal it is hard for me to be sure there was actually any difference.

Bob

Brian Carlton · #5 11-15-2007, 01:31 PM

Quote:

Originally Posted by Bob300DSD

When I look closely at the rocker it is not easy for me to discern the curve in the arm as displayed in the manual's diagram. Hence I am tempted to position the lobe straight up or positioned at 12 o'clock. When I turned the camshaft and checked clearance it seemed to me that the rockers had the most clearance at little past straight up at about 1 o'clock on the drivers' side. However the difference was so minimal it is hard for me to be sure there was actually any difference.

Bob

We've had this discussion in the past and the opinions were varied. The question is whether the base circle of the camshaft is constant. If it is, then the slight difference between 12:00 and 1:00 is meaningless. Most folks conclude that it is not significant.

However, there were a couple of members who noted a difference in readings when the cam was moved from 12:00 to 1:00...........so, YMMV.

As Gauge mentioned, if you use the 1:00 position, it's toward the driver's side.

Bob300DSD · #6 11-15-2007, 01:32 PM

Quote:

Originally Posted by guage

I stood on the drivers side using a bump starter and positioned the lobe as pictured here, which would be also pointing to the drivers side

I used trans fluid to lube the linkage

Thanks for the feedback Guage, I interpreted things just as you.

Bob300DSD · #7 11-15-2007, 01:38 PM

Quote:

Originally Posted by Brian Carlton

We've had this discussion in the past and the opinions were varied. The question is whether the base circle of the camshaft is constant. If it is, then the slight difference between 12:00 and 1:00 is meaningless. Most folks conclude that it is not significant.

However, there were a couple of members who noted a difference in readings when the cam was moved from 12:00 to 1:00...........so, YMMV.

As Gauge mentioned, if you use the 1:00 position, it's toward the driver's side.

Thanks Brian:

I think I have read every thread on ShopForum and the rest of the net and understood there was some varied opinions. I intentionally did this on my junker 300D before working on two cars with good engines. I was a little disappointed after I finished the job because the car still has really poor compression and wanted to make sure I did the procedure correctly. The valves on the car had no clearance prior to adjustment so I was hoping for the best.

Bob

Brian Carlton · #8 11-15-2007, 02:07 PM

Quote:

Originally Posted by Bob300DSD

Thanks Brian:

I think I have read every thread on ShopForum and the rest of the net and understood there was some varied opinions. I intentionally did this on my junker 300D before working on two cars with good engines. I was a little disappointed after I finished the job because the car still has really poor compression and wanted to make sure I did the procedure correctly. The valves on the car had no clearance prior to adjustment so I was hoping for the best.

Bob

Once the valves get down to zero clearance.........there's a chance that they don't fully close. If this happens, the seats are usually damaged from the heat.

..........there goes the compression.........

guage · #9 11-15-2007, 03:01 PM

Just to muddy the waters a little, this is the conversation I had on another fourm.

Quote:

Originally Posted by HenrySchuman

Diesel Giant has some really nice pictorials ,unfortunately some are wrong and the valve adj is one of them in respect to you should measure between the Rocker and the Top Nut of the Valve (not the cam and the rocker ) use a 4 thousadnds and a 5 on the intake and 16 and a 17 on the exhaust and only adjust them when the engine is cold , 4 goes 5 don't and 16 goes and 17 don't . Start with number one and rotate engine Clockwise to get the cam lobe straight up from the valve and do your measurement if you should go past a point go around do Not rotate the engine backwards . I wish you did not have to remove the injectors to do this but if you don't have the proper tools then it may be neccessary .

Quote:

Originally Posted by Guage

How about the angle of the lobe?
Should it then be pointed 180 degrees from the valve?
Measure at the new red arrow?

Quote:

Originally Posted by HenrySchuman

Put the lobe as close to a 90 degree angle as you can to the the top of the valve and measure where I stated for a proper measurement .

Brian Carlton · #10 11-15-2007, 03:09 PM

Quote:

Originally Posted by guage

Just to muddy the waters a little, this is the conversation I had on another fourm.

I don't believe any of those statements are accurate. The proper measurement is between the rocker and the cam, AFAIK, and the proper angle for the camshaft when measuring is such that the lobe is 180 degrees from the contact point of the rocker...........definitely not straight up.

............mechanics..........

BIGRED · #11 11-15-2007, 03:16 PM

Had I known... while mine was apart.....I would have used a dial indicator to read the base of the lobe to see if there is a difference and if so...where the "sweet spot" is.

pawoSD · #12 11-15-2007, 03:19 PM

Wouldn't all of the cam lobe have to be equal except for the point with the lobe? If it was not all equal it would slightly open the valve during its travel, which would not be good. So I bet having it at 12 o'clock or 1 o'clock etc....doesn't matter. I usually do it with it at 180 degrees all the same though, its easiest.

Brian Carlton · #13 11-15-2007, 03:22 PM

Quote:

Originally Posted by pawoSD

Wouldn't all of the cam lobe have to be equal except for the point with the lobe? If it was not all equal it would slightly open the valve during its travel, which would not be good. So I bet having it at 12 o'clock or 1 o'clock etc....doesn't matter. I usually do it with it at 180 degrees all the same though, its easiest.

I believe you are correct. However, the FSM shows a perfect 180 degree position away from the rocker.........which shouldn't be necessary if the cam had a constant base circle.

MattBelliveau · #14 11-15-2007, 03:24 PM

Quote:

Originally Posted by pawoSD

Wouldn't all of the cam lobe have to be equal except for the point with the lobe? If it was not all equal it would slightly open the valve during its travel, which would not be good. So I bet having it at 12 o'clock or 1 o'clock etc....doesn't matter. I usually do it with it at 180 degrees all the same though, its easiest.

I agree. I Can't see how there would be THAT much variance (what maybe a couple 1/1000?).