What size bolt? - PeachParts Mercedes-Benz Forum

mplafleur · #1 04-10-2004, 09:39 PM

I have a 300SDL block I need to attach to my engine stand. I don't have any of the bolts. (I need longer ones anyway)

Does anyone know the thread size of these?

whunter · #2 04-10-2004, 10:11 PM

Quote:

Originally posted by mplafleur
I have a 300SDL block I need to attach to my engine stand. I don't have any of the bolts. (I need longer ones anyway)
Does anyone know the thread size of these?

Had I known.
I would have pulled the information Friday, when you stopped by the shop.
I will check Monday, if the nightmare Jaguare is completed.
I will e-mail the address of a local bolt supply company also.
Have a great day.

mplafleur · #3 04-10-2004, 10:38 PM

Roy,

How did I know you would answer this?

Local? Thanks, otherwise I'd have to go to Acme Nut & Bolt on Oakwood.

I actually had some that I got for my last rebuild but they are missplaced.

mplafleur · #4 04-12-2004, 11:06 AM

*bump*

gsxr · #5 01-01-2005, 05:05 PM

M10 x 1.5, length varies depending on your stand. Which brings me to the next question:

I just pulled the OM603 out of my 300D to replace the timing cover, and do some other assorted maintenance. I was going to bolt it up to my Harbor Freight engine stand, but then I noticed the bellhousing bolts are awfully small... M10! Is it safe to hang all the weight of a complete 603 from four M10 bolts? The last thing I need is to break off the back of the block or something...!

Am I just being paranoid?

Best regards,

Brian Carlton · #6 01-01-2005, 05:31 PM

Quote:

Originally Posted by gsxr

Is it safe to hang all the weight of a complete 603 from four M10 bolts? The last thing I need is to break off the back of the block or something...!

Am I just being paranoid?

Dave, each M10 can handle about 15,000 lb. at their ultimate tensile strength, using 150K psi hardware. Safe working load would be half this amount. So, at 7,500 lb. per fastener, I'm quite sure that you won't have any issues with the bolts. The block, being cast iron, should also have no issues with holding this load. Just make sure that you use at least five threads on the M10's.

mplafleur · #7 01-01-2005, 05:48 PM

My 603 has been hanging from those 4 bolts for 8 months now. It's the engine stand I worry about!

gsxr · #8 01-01-2005, 06:31 PM

Whew! I feel better now. I just bought the bolts at Home Depot, rated "8.8" on the head. I'll see how it goes. I'll feel better once the turbo & exhaust are removed (gotta be 75+ lbs there), and better yet when the head comes off. Oh yeah, that will be the next fun part - trying to crack the head bolts loose with the engine on a stand!

I'll probably brace it against something, as the force needed to loosen those suckers is surprising.

Thanks everyone!

mplafleur · #9 01-01-2005, 09:27 PM

8.8 (ISO R898)

Medial Steel
85,000 lb proof load
92,000 psi min yield strength
120,000 psi min tensile strength

The first number represents the ultimate tensile strength of the bolt, 400 Mpa, 800 Mpa or 1200 Mpa respectively. The second number represents the point at which the bolt will permanently stretch. (Officially, the 0.2% proof load stress). A 4.6 bolt permanently stretches at 60% of its ultimate, an 8.8 at 80% and a 12.9 at 90 %.

Grade 8.8 bolts are tightened by the part turn method, torque wrench, or by using load indicating washers. In the part turn method, the bolt is done up to snug tight, and then advanced one, two three flats of the hexagon, depending on the size, length etc. The torque wrench method is used commonly, often in the form of an air operated rattle gun. Special load indicating washers, such as Coronet washers can be used. These have dimples which indent the mating surface. A feeler gauge is used to determine the pre-load. Grade 8.8 Bolts are used in High Strength Friction Grip applications. If this is the case, the mating surfaces must not be painted or galvanised. For added security of the joint , use any one of the plethora of systems such as spring washers, shakeproof washers, Loctite, wired heads, split pins and castle nuts, locking tabs, lock nut or patented nut systems (Nyloc is common). For serious work, use castle nuts, either with split pins or wired together in groups. Also for serious work, do not re-use fully tensioned grade 8.8 bolts, Nylocs, split pins etc.

gsxr · #10 01-04-2005, 03:52 PM

Check out that downward slope - yikes!

Brian Carlton · #11 01-04-2005, 04:40 PM

with, or without, the jack on the front end?

Pete Burton · #12 01-04-2005, 04:50 PM

that is quite a bit of slope. I think a lot of that is due to the weldment. Look at the angle betwen the vertical and the sleeve welded to the top of it. My stand has the sleeve pointing UP slightly, so when I put my 617 on it it was nearly level. That doesn't look right to me.

gsxr · #13 01-04-2005, 05:01 PM

I think the weldment normally is pointed upwards, but the 603 is so long and heavy, it's bending it down a LOT! The jack up front is raising the front end about 1 inch, just taking a little load off the back side. I need to get some better reinforcements before I start yanking on the 27 (!) head bolts though.

Brian Carlton · #14 01-04-2005, 05:14 PM

Quote:

Originally Posted by gsxr

I think the weldment normally is pointed upwards, but the 603 is so long and heavy, it's bending it down a LOT!

I don't believe that it is possible for the weldment to bend at the welded junction between the round tube on top and the vertical rectangular tube. This is a very strong joint.

The bending must be occurring in the plate that bolts to the engine.

mplafleur · #15 01-04-2005, 08:35 PM

I just got back from the farm an hour ago and I took a quick peek in the garage at the 603. Apparently I used the come-along to pull up on the engine to take some of the weight off that stand. I must not have liked that droop either.