Engine Rebuild

[bloeff]

Hi everybody,

I'm a new member and look forward to picking all your brains! I'm rebuilding a 78 Mercedes 300D engine and have spent a lot of time on the internet looking for a complete engine and camshaft/valve rebuild kit but haven't come up with much! Could anyone direct me to a web site that might be helpful?

Thanks,
bloeff

[Moppie]

have you looked for parts for the Nissan 3.0 Diesel from the the mid 80s?
It was used in a number of large RWD Nissans, and is basically the Merc engine made under license.

[bloeff]

Hi,

Thanks for your quick response! My search has led me to a local machine shop that comes highly recommended. I gave them a call and they have access to a company that can provide me with all the kits I need. My days in this phase of the rebuild seem to be over!! Thanks again and I look forward to hearing from you again if you have any other advise to give me. This is my first rebuild!!

Thanks,
bloeff

[bloeff]

Right now I'm relying on the machine shop to hot tank the block and head, check for cracks, bore, and look over the crankshaft. I'm planning on rebuilding the valve train myself with all new parts. Chilton goes into great detail with valves. I'm just a beginner , but it seems to me that all new parts will give me the longest engine life. I'm also applying this logic to the block and planning a bore and oversized pistons. I know this will cost me a lot more , but again I'm looking for long engine life. This Mercedes has one solid body and there's no sign of rust. I believe it can keep up with the engine. But I'm open to being talked out of this if someone has had a good experience with resleeving, a good valve job, and reusing as many parts as possible. Let me know what you think!
Thanks again.

[KiwiBacon]

My Isuzu engine uses hard chrome sleeves (Chromard). They're dry (no coolant contact) and slot in basically size for size.

It's a fantasticly easy way to get a perfect bore. Of course you may never find some the right size for your merc block.

[bloeff]

Hi everybody,
Let me throw a few things out there and see what you guys think. I've spoken to several professionals and they have talked me out of a bore and oversized pistons. I'll have the machine shop look over all the parts and make recommendations. Would resleeving create longer engine life, even if the cylinders show no appreciable wear? What do you think of hard chrome sleeves? Some mechanics have told me that a properly reconditioned valve will actually outlast a new valve? Is this true, or is it self-serving? If its true, then I'll get a valve job. If not, then I'll rebuild the head myself with all new parts. Let me know what you think. In either case, if the head is rebuilt first, what is its "shelf life" and how should I store it? What about the block and the rest of the car? The car is sitting under my car port. The previous owner did an amateur restoration. I've owned the car for more than a year and there are no visible signs of rust. Do you recommend a car cover?
Thanks,
bloeff

[Moppie]

Oiled metal will keep for ever.
The trick is to keep air off its surface, which is what causes it to rust.
Iv used parts that were kept in a light oil for over 30 years, and still worked perfectly.

So no problems with storing the head.
The block isn't an issue either, just as long the cylinder bores, any bearing surfaces and the deck are kept clean and lightly oiled.
Any corrision on those surfaces and its another trip to the machine shop, or a new block

the rest of the car should be fine except for the brakes, and clutch if it has one.
The clutch can corrode onto the fly wheel, easily fixed by just working it every now and then.
The brakes can also rust up. There is little you can do to prevent that, so I would recommend a rebuild just before you re-commission the car, especially if its a botched restore done by someone else, and the car has already been sitting for some time.


Iv reused plenty of valves when rebuilding old motors.
As long as you number them when they come out, will have no trouble putting them back in. There is very, very little wear that occurs on the valve itself. Its the guides that wear out.
If you do get new valves (and Iv re-valved a motor with other second hand valves) just make sure you get them lapped into the seats properly.
Like wise the rest of the valve train is going to be in pretty good order, although the machine shop should check for wear on lifters and rockers etc. If its a very high millage engine it might be worth replacing them all just as a matter of course, something you need to do if you replace the cam anyway.



If there is no wear on the bore then there is no need to machine it, or re-sleeve it. Just give it a hone, and put new rings on the pistons.
I can't imagine the machine shops are turning away work unless there is genuinely no need for it. Also shows they are honest shops.

[bloeff]

Originally Posted by Moppie

Oiled metal will keep for ever.
The trick is to keep air off its surface, which is what causes it to rust.
Iv used parts that were kept in a light oil for over 30 years, and still worked perfectly.

So no problems with storing the head.
The block isn't an issue either, just as long the cylinder bores, any bearing surfaces and the deck are kept clean and lightly oiled.
Any corrision on those surfaces and its another trip to the machine shop, or a new block

the rest of the car should be fine except for the brakes, and clutch if it has one.
The clutch can corrode onto the fly wheel, easily fixed by just working it every now and then.
The brakes can also rust up. There is little you can do to prevent that, so I would recommend a rebuild just before you re-commission the car, especially if its a botched restore done by someone else, and the car has already been sitting for some time.


Iv reused plenty of valves when rebuilding old motors.
As long as you number them when they come out, will have no trouble putting them back in. There is very, very little wear that occurs on the valve itself. Its the guides that wear out.
If you do get new valves (and Iv re-valved a motor with other second hand valves) just make sure you get them lapped into the seats properly.
Like wise the rest of the valve train is going to be in pretty good order, although the machine shop should check for wear on lifters and rockers etc. If its a very high millage engine it might be worth replacing them all just as a matter of course, something you need to do if you replace the cam anyway.



If there is no wear on the bore then there is no need to machine it, or re-sleeve it. Just give it a hone, and put new rings on the pistons.
I can't imagine the machine shops are turning away work unless there is genuinely no need for it. Also shows they are honest shops.

Thanks loads for all the info!! I'll keep you updated on my progress.