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Old 12-22-2000, 05:47 AM
Posts: n/a

Do you have a manual to give you torque sequence and values? It sounds like you don't. Does this engine have star headbolts or hex(allen) headbolts? If you don't have a manual let us know and we will give you the information you need. The sequence will be difficult to verbalize here without a picture, but we can probably work through that.

Basically the torquing of star headbolts consists of this general procedure:

Clean threads on holes and bolts and oil bolt threads. Torque the head in sequence to the first setting, probably about 30 ft/lbs (I don't have my book with me) then torque to the second setting in sequence which I believe is about 52 ft/lbs. Let it sit for ten minutes and turn each bolt, in sequence, 90 degrees. Let it sit ten more minutes and turn each bolt again 90 degrees in sequence.

You will need a breakover bar for this, and be prepared to be very tired after this accomplishment. If you use a cheater pipe on the breakover bar, I promise not to tell anyone. The first time I did it, I went back to mercedesshop and called my friend the MB tech to see if these bolts were really supposed to be this tight.

The first one I did was my M103 engine. The bolt and hole threads were in great shape. I oiled the bolts before threading them in. On my daughters diesel, there was one bolt that was very stubborn coming out, so I got a tap and die, I believe the size was 12 x 1.75, but check yours to be sure. I ran the tap into every hole, and really messed around with the hole which gave trouble coming apart. I then stuffed a rag in each cylinder and blew out each bolt hole.

I chucked the die in the vise and ran every bolt in and out of the die. Since you're block is going to the machine shop, they should thoroughly clean the block after the machine work. It would be a good idea to chase the bolt hole threads before taking it to the machine shop, so all chips or crud that is loosened will be cleaned.

You can make a poor boy's thread chaser by taking a bolt the same size and thread, and file a couple of notches lengthwise through the threads with a three corner file. Make sure you clean the bolt before screwing it into the block.

Sorry for the long windedness, but you sound like a guy who is hungry for all the information you can get. I certainly relate to that. If I'm giving you more info. than you want, just tell me to pipe down.

If I were there and had plenty of time, I would enjoy helping you.

Good luck,
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