The replacement head for my 85 300D just arrived. I'll have to admit, I didnt know what exactly to expect, and didnt ask all possibe questions, so of course there are a couple of surprises... The replacement head consists only of 1) bare iron head, 2) new valves, seals, guides, springs, and adjustment nuts, and 3) positioning pins. It has no prechambers, no studs to attach the manifold nuts, and no threaded brass parts on the side opposite the manifold into which the coolant temp. sensors, knock sensor screw into. Therefore, I will need to either obtain new stuff, or take from old head.

1) Regarding prechambers, I will need a puller/installer tool, which I can rent from Performance. How do I know what size spacer ring since I dont know how much may have been removed from resurfacing of head-gasket mating surface. How difficult is it to remove prechambers from old head...could they be damaged requiring new ones...should I just get new ones??

2) Regarding manifold studs...should I get new ones or should I remove old ones from old head?...do they come out readily?

3) Regarding "brass parts" for the coolant and knock sensors..will these readily come off old head...should I get new seals/gaskets for these??

As usual, the job becomes ever more complex since I havnt done this before and dont know what to expect. Thanks in advance for help.

Mark

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

markm
First was this a recon head or new? If new just need new head gasket. If recon ask if it was milled. as far as the parts need reuse as much off the old head as is in good condition. Look at prechambers if no pitting in them or cracks they would be ok to reuse. I would replace any gaskets with new one this should be in a top end rebuild gasket kit. You can get stud remover which makes getting out studs out of the old head easy. Then useing same to reinstall.
Bill

__________________
94 dodge cummings,86 ford 6.9,75 mbz 240d[ sold], 82 mbz 300sd,83 mbz 300sd

The head is reconditioned. I talked to the supplier who said that the head was "surfaced" but not "milled" to the extent that I would have to use upsized spacer for pre-chambers..he said to use all original spec. spacers, gaskets etc. The problem I have is that I dont have very detailed specs on the work done to ensure that this recommendation is correct. The normal spacer for the pre-chambers is 2.0 mm, the 1st upsize is 2.3. I will read through MBZ manual on this topic and figure out how to determine exactly before I do the work.

What exactly is a stud remover?? Can it be purchased as any auto parts store? or is it a special tool.

thanks

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

Mark - to come up with the required spacer thickness - install the pre-chambers with the original spacers first. Torque to spec, turn the head over and measure how far into the combustion chamber the pre-chamber is going to stick. The manual shows a diagram and specs for how far in there it should protrude. If it is too far into the combustion chamber then go to the next thickness spacer until you get to the proper spec.

__________________
Jim

ah yes! that makes sense! I should buy both sizes of spacers to have them on hand, very inexpensive (about $1 each). I assume I can do this on one pre-chamber, and whatever the results, go with that for all of them.

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

Mark, I'm in the middle of replacing the head on my OM603 engine right now and had similar questions myself. Here's my $0.02:


1- You can buy the slide hammer and adapter to pull the prechambers from Baum Tools for $75. I did that instead of renting it. The prechambers are very pricey, ~$75 each I think. You'll want to reuse them unless they're damaged (cracked or otherwise messed up).

2- New studs are cheap - about 50 cents each from online suppliers. I also got new nuts, on the OM603 the exhaust manifold nuts are the "compression" locking type. Same price as the studs. I don't think it would hurt anything to reuse the studs though.

3- You can reuse the brass stuff, preferably with new seals. I *think* the new seals come with the head gasket kit, at least they did for my OM603 kit. I put in a new temp gauge sensor too - it was only $10 and I always wondered how accurate it was after 15 years...


Good luck,

__________________
Dave
Boise, ID
Check out my website photos, documents, and movies!

markm
You can get a stud remover from snap-on or sears or any parts house. You use it with a socket set it grips the stud on the part of the stud that has no threads. Using it will let you tighten the studs into the head so when you have to remove the nuts they will remove instead of the studs.
Bill

__________________
94 dodge cummings,86 ford 6.9,75 mbz 240d[ sold], 82 mbz 300sd,83 mbz 300sd

MarkM:

Who did you buy the head from and how much did it cost?

Thanks,
Tom

__________________
America: Land of the Free!

1977 300D: 300,000+ miles

American Honda: Factory Trained Technician & Honor Grad.
Formerly:
Shop Foreman;
Technical Advisor to Am. Honda;
Supervisor of Maintenance largest tree care co. in US for offices in Tex.

I bought the head from Cylinder Heads International in Grand Prairie, Texas (www.headsonly.com) and it cost $350. No up front core charge. Head includes new valves, guides, seals, springs. Pressure tested, magnafluxed, resurfaces etc.

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