Angle Torquing M103 Head Bolts - PeachParts Mercedes-Benz Forum

long-gone · #1 08-12-2009, 02:59 AM

I'm putting the head back on my 91 300E 2.6 M103 tomorrow and was just wondering what methods people here use for angle torqueing.

I bought a KD angle torque gauge, which is a round plastic dial mounted on a short 1/2" extension. You turn the lens, which has a indicator printed on it, to set it to zero. There is a angled rod which can be set to anchor against a convenient part of the car (or hand held I suppose) and which holds the body of the gauge still while the breaker bar is being turned. The friction fitted lens moves with the bar as you turn it and you stop when the required degree is encountered.
Well, I tried a few dry runs and it was really a crappy tool. It would hang up and stick or stutter 90% of the time. No way would I trust it on my head. I took it apart and put a touch of grease on the contact points of the wavy spring where it contacts the lens. That's where it needs to slip in order to work correctly. It works MUCH better but I'm still leery of it. Also, it won't fit to do the bolts against the firewall unless I add a 6 inch extension which I'm not keen to do either.

So, what tools methods do you guys use? I'm considering aligning the breaker perpendicular to the head and just turn until it's parallel to the head. It seems I could accurate enough results like that, particularly if my motion is smooth and complete.

museikm4tt · #2 08-12-2009, 03:46 AM

im no expert on this subject but i think i can help you out.

http://www.griotsgarage.com/product/tools/specialty+tools/digital+torque+wrench,+1-2"+drive.do

i buy all my car care stuff from griots and they make quality stuff. so i would recommend looking at that.

i have never personally used that torque wrench but griots garage is a pretty reputable place. hope that helps!

long-gone · #3 08-12-2009, 05:05 AM

Hi Museikm4tt, Thanks for the suggestion. The digital torque wrench however still only shows traditional torque. Angle torquing is when you turn a fastener (particularly a fastener specially designed to stretch or "torque to yield") a specific number of degrees with no measurement of actual torque.

I believe I've seen angle torquing attachments or devises that were digital and somehow detect the movement of your breaker/wrench in degrees. But they were pricey. I would have to imagine that there's a digital torque wrench that does both torque and angle measurements. maybe I'll look around that site for one, but I bet it'd be expensive!

BTW I don't think I'd recommend angle torquing with a regular torque wrench as the unknown torque generated may exceed the rating of the torque wrench and throw it out of calibration.

t walgamuth · #4 08-12-2009, 06:31 AM

This is the first I have heard of it.

#5 08-12-2009, 07:55 AM

You don't need ANY fancy tool for what is known as angle torquing. What you DO need is about a half hour of uninterrupted time and good physical condition.

Once you have done the initial torque in sequence with a torque wrench, use a breaker bar and a cheater pipe if you need it. Start in the beginning of the sequence and turn each bolt 1/4 turn in sequence. THEN start through the sequence again and turn each bolt an additional 1/4 turn. This 1/4 turn does not have to be EXACTLY 90 degrees! Just turn it as close as you can to 90 degrees. This is a right angle and is very easy to visualize.

While you are involved in this procedure don't allow yourself to be distracted and DO NOT leave or abandon the process unless the building catches fire or an equal emergency. If the phone rings, ignore it. If the wife tells you it's time for dinner, tell her to keep it warm. DO NOT lose your place in the sequence.

It's okay to pause long enough to catch your breath and unless you are in Triathlon training or equivalent you WILL have to catch your breath. Pausing to catch your breath is okay. Walking away from a head that is not completely finished in the torquing process is definitely NOT okay.

mbdoc · #6 08-12-2009, 08:14 AM

A good method that costs very little & works well is white touch-up paint.

Finish your initial torque & then put a drop of paint on each bolt head facing the intake.
USE a breaker bar!
Then turn each bolt 1/4 turn & all paint dots will face forward.
Then turn each bolt 1/4 turn again & all paint dots will point to the exhaust.
That works well with cars that require a 90deg angle of rotation.

hanno · #7 08-12-2009, 11:19 AM

First time I had to use the angle method after torquing I thought the bolt would snap before reaching 90 deg. A very uneasy feeling that was unfounded.

long-gone · #8 08-12-2009, 12:18 PM

Thanks for the comments and advise!
I think I'm more concerned about the tool breaking than the bolt.

QUOTE: "... It's okay to pause long enough to catch your breath and unless you are in Triathlon training or equivalent you WILL have to catch your breath. Pausing to catch your breath is okay. Walking away from a head that is not completely finished in the torquing process is definitely NOT okay."

So what happens if the breaker bar tool breaks? Would it be okay to leave it for an hour or so while I hunt down another tool, as long as I don't lose my place? Or should I loosen all the bolts and start again when I get retooled if the bolts are still in spec (still within the acceptable length)? Is the head gasket ruined?

workerunit · #9 08-12-2009, 12:49 PM

Another method that I use to torque "Stretch" bolts is to do the initial torquing of the bolts in the proper pattern and then I use either a prick punch or a engraving pin to mark all the bolt heads at say 6 0' clock and then do the remainder of the torquing, that way when I am done I can view all of my markings to make sure that I did not miss a bolt. also a little grease on the underside of the bolt head helps with the final torqueing.

babymog · #10 08-12-2009, 12:58 PM

IF this happens, it is a bad day. It will be easy to find out where you stopped though, because the sheared end of the bit will be permanently lodged in the last bolt head you attempted to tighten, preventing you from properly torquing or removing this bolt (BTDT).

Buy a quality tool.

Quote:

Originally Posted by long-gone

Thanks for the comments and advise!
I think I'm more concerned about the tool breaking than the bolt.

QUOTE: "... It's okay to pause long enough to catch your breath and unless you are in Triathlon training or equivalent you WILL have to catch your breath. Pausing to catch your breath is okay. Walking away from a head that is not completely finished in the torquing process is definitely NOT okay."

So what happens if the breaker bar tool breaks? Would it be okay to leave it for an hour or so while I hunt down another tool, as long as I don't lose my place? Or should I loosen all the bolts and start again when I get retooled if the bolts are still in spec (still within the acceptable length)? Is the head gasket ruined?

long-gone · #11 08-12-2009, 01:10 PM

Oh, that's it Babymog, feed my anxiety!
I got my 12pt allen socket on-line, not sure who made it. It just has an "ST" in an oval. It held up okay for removing the old bolts.

I think I'll see if I can catch the Snap-On truck down at the dealerships!

#12 08-12-2009, 01:44 PM

No your tool will probably work okay. I don't caution about walking away due to a time consideration. I said not to walk away for fear that you would lose your place. If you are worried, then marking each bolt after the torque wrench step is a good idea. I have marked them before and I have just gone through the sequence before. For me, it's just not worth the time to mark them. I just go through the sequence and don't allow myself to be interrupted.

If you ARE interrupted with an emergency, in case there is anything to work with after the fire burns itself out, just leave the wrench on the next one to be angled. That means you will have to finish the one you are angling while the flames are licking at your back side, but oh well.

babymog · #13 08-12-2009, 02:16 PM

... now did I leave the wrench in the last one I torqued, or the first one I didn't, ...

t walgamuth · #14 08-12-2009, 05:49 PM

Oh, now that I see the rest of the story, I have seen it and done it before.

long-gone · #15 08-12-2009, 07:15 PM

Thanks for all the tips, info and input! I'll have to do it tomorrow, been raining all day. I think I'm just going to eye it up, the gauge actually seems like it might be distracting trying to keep it still and all. Maybe I'll try it on the first round to see what it's like. I think I'll also try the set mark or paint dots on the bolt heads, seems quick enough to set up and real handy reference-wise.