84' 300D

What length of head bolts do I need when replacing the head? Are they all the same or are they different lengths and in different quantities? If someone knows that information please post.

Also, what size 12-point Torx tool do I need to remove the head bolts?

Lastly, when removing the head is it easier to remove the cam sprocket and hold the chain or to simply disconnect the chain and keep it in place?

first it's not a torx bolt, it's a tripple square.
it's 12mm
yes there are different length bolts, I do not know the lengths. call Roy from the buy parts link above.
I've found it simplest to wire tie the chain to the cam gear, and remove the bolt, and drop the gear into the chasm in the head.

It is strongly suggested that you obtain an engine manual when doing this work.

there are a few different lengths of bolts in varying quantities. If you call Phil at the 1-800 number on this site, he will know all the sizes and quantities you need for your order.

the tool is NOT Torx! It is triple square, xzn, or double hexagon.... all the same. I think it is M12.

Assuming you are pulling the head,

-pull the pins and the guide rail.

-Pull the tensioner.

-you can either make marks on your chain to the sprocket and remove the sprocket and drop the chain... or you can tie the sprocket to the chain and drop them together in the cavity.

the head will come off without too much interference from the sprocket resting there.

the issue of timing becomes important when people remove the sprocket and do not realize there may be a bunch of loose chain in the cavity. Pull really hard on the injection pump side to remove the slack created by the vacuum pump.

do not break your chain unless you plan on replacing it.

It is very important that you do this... too many Important variables which must be followed to get it right ( meaning your head gasket seal for many miles ).

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Here is a cheap local alternative to the MB 10mm Triple Square head bolt tool.
Most generic auto part stores carry it..

Performance Tool# W1395.
4 pc serrated wrench set
12 pt. Triple Square




Have a great day.

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1985 300SD
1983 300D
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All this dropping of cam gear into the cavity spooks me. I tie the chain to the gear, then keep tension (a bungee cord) on the chain by pulling on the bungee (up) until the head is raised. Then keeping tension on the chain move it out from under the head and pull it to the side. Call me paranoid.

__________________
Cheers!
Scott McPhee

1987 300D

Torx/Triple Square clarified. i knew it wasn't a Torx b/c is has 12 points but didn't know the name so went forward to be corrected. And yes, any normal auto parts store will carry it.

-Issue, I hear 10mm and 12mm. Verification that it is in fact 12mm?
-For the bolts 12mm x 104-105mm
12mm x 119-120mm
12mm x 145-146mm (and I'll find the quantities for these)

Guide rail? Does this part have another name such as "tensioner rail?"

The process appears to be very strait forward, my remaining issues are-
- Is the head so heavy that 2 people cannot lift it peacefully?
- Is removing the hood in my best interest?
- I am definitely correct in thinking I should replace the head bolts?
- Definitely take the head to a machine shop?

Thanks for the help thus far. I believe I will wire the chain to the cam and mark it, then see what I am most comfortable with once the head is ready for removal.

And yes I will remove the head because, a knock after 30second-1 minute of driving and that when I get on the freeway the temp goes from 10 degrees to about 90 in half a mile. Still no water in the oil, and no oil in the coolant (though it is rather dirty) but it it never goes hotter than around 90 no matter how far or hard i drive.

m12

2 people can lift it easy... one can do it as well

unless you measure them very carefully, replace them

there is a tensioning rail... but not during the head removal. You are only looking at removing the upper guide rail

hood... totally unnecessary

it needs machine work if you know what to look for. If the valves wiggle in the guides its the biggest giveaway. I think most people who have done these heads will agree its not common for them to warp or crack.

Just a hint for removing the guide rails..... the pins are pressed into the head/block. MB says to use a slide hammer....this tool, at least I found here is pricey. My solution? I went to the local hardware store, grabbed a m6x1.0x 60 bolt, 5 or so fender washers and a nut. Thread the nut onto the bolt, place the fender washers below that, and then stick the bolt through a socked. I used a socket with a 1.5 to 2 inch depth. Thread the bolt into the guide rail pin and gently snug. Then using two wrenches, hold the head of the bolt in place while threading the nut towards the washers and socket. It will have resistance but will pull that pin right out. And all for a few dollars!

__________________
1982 300SD 180K, rebuilt engine
1973 450SLC Megasquirt
1990 Volvo 780 - 273k
1993 Volvo 240 Wagon - Scrap yard slumber

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Thanks for the guide pin help. The method seems similar to removing the rocker arm pins on older Ducatis