Head bolt question - Page 2 - PeachParts Mercedes-Benz Forum

barry123400 · #16 07-04-2011, 12:26 PM

Quote:

Originally Posted by bgiovan

The cam towers and camshaft are brand new. I need to source some other bs parts, sound like I might need to add new rocker arms to the order. Sigh. But I understand the wear notion and hate to cheap out at the 5 yard line.

New cam may get away with decent looking rocker arms. You need the advice of an expert at this point. I am not one.

leathermang · #17 07-04-2011, 01:09 PM

You are this far in, 5 yard line...... you need new rockers to go with the new cam... this is SOP for machine longevity .......

JimSmith · #18 07-04-2011, 01:37 PM

As Greg noted, you should clean the tapped threads carefully before inserting any bolt in a tapped hole inside the engine. When I do this I typically use a lubricant, engine oil, on the tap, and do so pretty liberally. I clean the hole out as Greg suggested - rags and then compressed air. Then, it should also be common practice to run the fasteners into the holes by hand to verify the bolt and the tapped hole are clean and free running. Once clean it is not a bad practice to leave something in the hole to prevent junk from falling in - one of my fears whenever I am assembling a machine. I typically leave a clean bit of a rag in there until the gasket and head go down.

Once the head is on, I typically go through this again and have them seat on the bearing surface - usually the washer with the washer seated on the head. IF you think you may have oil in there preventing the bolt from seating, try this without the washer, by hand, and see if the bolt seats on the head. If the bolt is "hydro-locked" it feels different than seating, or actually bottoming in the tapped hole.

In any case, you would have noticed "hydro-locking" at assembly - it feels different than bottoming. Metal to metal is different than a viscous fluid being forced into the clearance between the male and female thread forms.

Good luck,

Jim

ROLLGUY · #19 07-04-2011, 01:59 PM

I have had the same "cow foot in mud" sound when pulling head bolts. I think engine oil may be getting between the bolt and the towers after many years/miles of running. The shank of the bolt is thinner than the threads, and any oil around the bolt and above the threads, will make that sound when the bolts are pulled out of the towers. The same sound would NOT be good if heard during re-assembly. As stated earlier, a small amount of oil on the threads (I would add on the top of the towers and head surfaces that are in contact with the bolt head as well) is needed, but not so much that it makes the "Sluuuuuuuurrrrrrrrrrpppppppffffffff" sound.

JimSmith · #20 07-04-2011, 02:26 PM

As one loosens the bolts on the head during the disassembly, it is not uncommon for pooling oil to seep into the bolt hole, leading to the the "sound." Not to worry then.

Jim

bgiovan · #21 07-04-2011, 08:19 PM

Thanks for the feedback all. I'm going to continue with the BS work until Roy gets back from vacation and I back from mine. Hopefully have it on the road by first week of August! Jeez, the head gasket project will only have taken 10 months by then.

bgiovan · #22 07-25-2011, 02:47 PM

By the grace of God I happen to live about 20 mins from Roy. Luckily he dedicated a chunk of his Sunday in my garage (with a trip back to his place for a gasket). Learned a ton. Thanks again!

He wanted me to snap some pics of the cam sprocket for the group. One from the car and one from the donor. Note the badly warn vs. clean sprocket. One had a bad timing chain and the other not so much. Can you guess which one?

leathermang · #23 07-25-2011, 02:54 PM

Roy is allowed to take vacations ?
You living there is like someone with auto trans problems living next to S Brotherton... can't get any luckier than that...

bgiovan · #24 07-25-2011, 03:36 PM

Actually bought the SD from a gent in Gainesville and trailered it back up to Michigan. Chances are great that is had Brotherton hands on it at some point.

bgiovan · #25 07-25-2011, 06:21 PM

Just checked the maintenance book and indeed this car was serviced regularly in the late '80's and early 90's at Continental Imports on Main in Gainesville and then later at Star Import Service with the last entry in the book being an oil change at Star on 12/18/96 with 130,109 on the clock. Has 153,169 on it today (assuming of course the odo hasn't been changed out.)

So yes indeed Mr. Brotherton's shop had their licks in on this one for at least half of the 1980's...