I'm making final plans to do head replacement on my 85 300td...thanks for help in previous thread. I have a few more very general questions, as dissassembly of head, manifolds, etc. is a first for me:

1. When removing head, has anyone encountered problems with stripping one or more head bolts and not being able to remove them (I have the proper 12 point Hazet tool)?

2. Similar question regarding removal of turbo and manifolds.....any problems stripping nuts or removing a stud from the head along with the nut. Should I plan on replacing all nuts, or should I have a few extra nuts and studs on hand?

3. Related to above questions...I dont have an impact wrench, so I plan on using my standard 1/2" and 3/8" rachets with proper 6- or 12- point sockets, either standard or deep sockets...I would think that this is standard procedure for this job, and that an impact wrench is not needed or recommended...is this correct??

4. What is standard procedure after job is complete regarding break-in...I would think that I would initially adjust timing and valve clearances according to spec., then run for 500 miles, driving easily...no high speeds, then checking/re-adjusting valve clearances. After re-adjusting valve clearances, i will check compression. Is this correct??

Thanks again for all the help.

Mark

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1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

If you use an impact wrench on bolts you increase the chance of breaking it off... not any fun when you do .... Greg

It’s really quite straightforward. You are on the right path – no impact tools are needed nor advisable.

The headbolts are ostensibly reusable if they are not stretched beyond spec, and many people do reuse them. I had several that were showing signs of corrosion – this definitely weakens them by creating a stress riser. Others may disagree, but I think that replacement of the headbolts is good insurance against having to do the job again, or worse yet, having one snap on reinstallation.

Chasing the headbolt holes in the block is a good idea; do it carefully & properly. Make sure to get all the crud out of the bottom. I used some WD-40 to ‘flush’ the resulting particulates down the threads, then used vacuum to suck all the junk out from the bottom. If you blow the holes out, you will redeposit crud on the threads, making for a ‘crunchy’ torque-down. Crunchy may be good for breakfast cereals, but not for threaded assemblies. Use the heaviest weight oil you can get for lubricating the threads on reassembly. I obtained some 70 weight (!) motor oil for this (used for dragsters) – but don’t overdo it; you don’t want to create a hydraulic lock at the bottom of the holes.

RTH

Chasing the threads is necessary to get accurate torque readings... all the manuals list torque figures for Clean holes,lightly lubricated bolts....if the holes are not smooth then you reach the torque figure without getting the hold down power of the bolt... increasing the chance of cracking,warping heads or blowing a gasket....
If you put some wax (or heavy grease,like wheel bearing weight) into the hole before running the tap down into it it will push the crud out of the hole as you do it.... experiment with how much...

I was outside working on one of the cars (what else?) when I thought about what I wrote earlier.

-*DO NOT*- use an electrically driven vacuum source, i.e., a shop vacuum, for sucking the crud out of the bolt holes. If you used a solvent such as WD-40, (or worse – like carb cleaner) the vapors may ignite, causing an explosion! I used a hand powered vacuum pump (the one I use for testing diaphragms & bleeding the brakes) as a vacuum source. I have a bottle that I place under vacuum which collects the liquids via a suction hose/tube.

RTH

RTH, GOOD SAVE, VERY TRUE....

I've never heard of breaking a head bolt off while dissasembling a recently running engine. Old rusty antiques, well, that is a different story!

If you have a cast iron head, you won't have any siezing problems. The aluminum heads are soft (6060 "alloy" probably) and stripped holes are common -- but the head blots go into the cast iron block and don't stick.

Drive any way you'd like -- just check the valve clearance at 500 miles. You are not seating rings, the valves, if done correctly, probably have been lapped in anyway, and have already been seated.

Good luck!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!