Valve adjustment OM615, 616, 617 FYI. - Page 6 - PeachParts Mercedes-Benz Forum

boneheaddoctor · #76 01-24-2005, 04:03 PM

Quote:

Originally Posted by Old300D

Well, on my Nissan L28ET, an inline 6 with 12 valves, I can adjust all the valves with 4 or 5 stops during the 720 degree crank rotation. Sue me, I'm lazy. I do have the capacity to learn still, though.

any 4 stroke engine you can do valves in 720 degrees rotation of crank.

Assuming you are organised enough to take each valve as its lobe hits the sweet spot for adjustment.

Brian Carlton · #77 01-24-2005, 04:24 PM

Quote:

Originally Posted by leathermang

"I was thinking it correctly and worded it wrong. Each cylinder fires every 180 degrees of crank rotation."

Well, if you keep this up I will start to question whether or not you know this stuff...

Each cylinder fires every 720 degrees of crankshaft rotation. It is a four stroke system and each stroke is 180 degrees... four times 180 equals 720...

Grrrrrrrrrrrrrrrr.....

A cylinder fires every 180 degrees of crank rotation.

There. happy now?

Pete Burton · #78 01-24-2005, 04:27 PM

careful Brian, that will only encourage him

billrei · #79 01-24-2005, 04:58 PM

My $0.02:

I bought 2 used long handle Snap-On 14mm wrenches from ebay for $25 including shipping. I bent one that I used for the lower nut so the wrench face goes in parallel with the spring retainer. A straight wrench works fine for the upper nut. I found all I needed to do is use a finger to keep the valve from spinning. I use the power steering nut to turn the engine over that way I can watch the movement of the cam. I like to make sure that nose of the cam is pointed away for the rocker pad as shown in the manual. You are only dealing with .004" on the intake so why introduce runout from the lobe by having the angle off. If I am going to spend time doing this I like to do it right. I agree about greasing the linkage. I clean them first with carb spray to make sure I don't get dirt in the joint. I also brought the car to the local car wash and power washed around the valve cover so reassembly would go easier.

leathermang · #80 01-24-2005, 05:05 PM

"A cylinder fires every 180 degrees of crank rotation."

You mean ONE cylinder in an engine ... only if it is a four cylinder engine...

Any Particular cylinder fires every 720 degrees of crank rotation.

Brian Carlton · #81 01-24-2005, 05:11 PM

Quote:

Originally Posted by leathermang

"A cylinder fires every 180 degrees of crank rotation."

You mean ONE cylinder in an engine ... only if it is a four cylinder engine...

Any Particular cylinder fires every 720 degrees of crank rotation.

We were talking about your 616. A cylinder fires every 180 degrees of crank rotation. OK, now?

BTW, one of these days you ought to use the technology and press that "quote" button in the lower right hand corner.

Old300D · #82 01-24-2005, 05:57 PM

Quote:

Originally Posted by boneheaddoctor

any 4 stroke engine you can do valves in 720 degrees rotation of crank.

Assuming you are organised enough to take each valve as its lobe hits the sweet spot for adjustment.

You missed my point. With my inline 6, with 12 valves, I can adjust them all with 5 or 6 stops during the crankshaft rotation. That means I adjust 2-3 valves at a time, and this is possible because the camshaft on the Nissan engine uses a constant radius for the base circle, so it is not critical whether the lobe is directly opposite the rocker arm.

Apparently the Benz camshaft is designed differently, and does not have a constant radius base circle, so it is critical to get the lobe directly opposite the rocker pad when adjusting the clearance. It also means I have to turn and stop the crank 10 times during the adjustment process, not 5 or 6 times like I'm used to.

boneheaddoctor · #83 01-24-2005, 06:32 PM

Quote:

Originally Posted by Old300D

You missed my point. With my inline 6, with 12 valves, I can adjust them all with 5 or 6 stops during the crankshaft rotation. That means I adjust 2-3 valves at a time, and this is possible because the camshaft on the Nissan engine uses a constant radius for the base circle, so it is not critical whether the lobe is directly opposite the rocker arm.

Apparently the Benz camshaft is designed differently, and does not have a constant radius base circle, so it is critical to get the lobe directly opposite the rocker pad when adjusting the clearance. It also means I have to turn and stop the crank 10 times during the adjustment process, not 5 or 6 times like I'm used to.

It should have a constant radius base circle..............I never noticed the problem you had............or should I say mine appears to have a constant radias bace circle.

How many stops it took to do mine? I never really paid attention to it.....

Old300D · #84 01-24-2005, 06:53 PM

Quote:

Originally Posted by boneheaddoctor

It should have a constant radius base circle..............I never noticed the problem you had............or should I say mine appears to have a constant radias bace circle.

How many stops it took to do mine? I never really paid attention to it.....

I ended up doing my valves one at a time, starting from the front. When I started checking them as the lobes came up the second time, that's when I noticed they seemed off. I started re-adjusting them, then realized it mattered where the lobe was.

And I have been checking clearance with the proper feeler, and then making sure the next size up will not fit.

#85 01-24-2005, 07:30 PM

Quote:

Originally Posted by leathermang

"The cam peak must be perpendicular to rocker arm"

I have always understood that as "Up and to the right" or "Lobe pointing to the oil tube on the towers."

leathermang · #86 01-24-2005, 07:47 PM

Much of the " English" in the shop manuals is iffy... very hard to understand by itself... Fortunately there is a picture right next to that phrase and it is exactly as you describe it.

leathermang · #87 01-25-2005, 08:56 PM

http://www.mikesteinberg.com/my_story.htm

and

http://not2fast.wryday.com/patent/p2877752.pdf

by implication ... if you have two lobes it has to turn at one quarter the crank speed.

Hit Man X · #88 08-06-2005, 11:18 PM

I did mine last night.

Motor starts easier, turns off smoother, runs better, it's almost silly sounding but true. Once the turbo is really spooled up around 2800rpm on up... it runs much better.

One valve required no adjustment, seven were VERY tight, and two needed a some help. Took about three hours start to finish as I got hungry and had to stop to eat. Also changed the fuel filters too, primary had some stuff in it that had me somewhat worried...

JamesDean · #89 08-07-2005, 02:02 AM

i did mine last night as well..took about 2 hours...about 4 of the valves were in good shape...did a test run @ 2am...had my fogs on with my headlights...got picked up by a cop...lol...overall the performance increase very noticeable...I also adjusted the bowden cable on the tranny..that helped too.

Kris

#90 08-07-2005, 06:04 AM

I would change it from the valves need to be "adjusted" every 15k to they need to be "checked" every 15k and adjusted as needed.
Mine are doing just dandy at 15k so I am waiting until 30k (or winter)