Advantage is a more accurate torque than the OEM TTY bolts to me. Those TTY are pains in the ass, even with a good angle meter. Yes, reuseable since the M103 likes to eat gaskets.

I will try to find the pictures from the install. Still a leak free headgasket! Damned valve cover is weeping up front some, but has only lost and consumed half a quart in about four months of driving. Not bad for the ol' 325,000 M103 in this car. ...that also included a 120mph run about six weeks back.

Head was off about 70k ago I guess now and car runs well. Catalyst has been gutted which was decently clogged. I think it needs a rebuilt fuel distributor after speaking with CIS Flowtech for a while.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

The above isn't true.

Bolt torque is an ,often inaccurate, inference of clamping force because thread / bolt head friction affects torque readings. TTY bolts were invented to remove this variable and they do a very good job at this.

Think of TTY bolts as fixed weight holding the cylinder head down where regular bolts are a variable weight. TTY bolts are tightened as tight as they can go then stretch to limit clamping force, think of them as a spring. A regular bolt will increase clamping force until it breaks off, more clamping force than desired can crush out gaskets.

The initial torque on a TTY is just to get a starting point and settle the head. Two or three angular sequences are to evenly load the cylinder head. During the last sequence, one can feel the torque rise then level off before the final angle is reached. This is the yield part of the system.

Once the torque levels off, clamping force will not increase even it you tighten the bolt more. I don't get fussy with finding the super exact angle, on the last step I tighten until torque levels off + maybe 5*.
At this point I'm still under the factory angle but turning further won't increase clamping force. The factory angle has a safety margin built in to assure yield occurs as telling someone to tighten until torque levels off would be too variable.

Now, if one wants to increase clamping force beyond the design of TTY bolts, studs or regular bolts are needed.

Good to know.

I will never use OE style fasteners on an M103 ever again.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]