Well, here’s a topic that’s been beat around a few times. I’ve read what I can search out, but would like to knock it around one more time if you don‘t mind.

At 290+K miles, and a chimney of blow-by, I think I’ll be doing an engine overhaul before too much longer.
I’ve rebuilt plenty of gas burners and a few diesels as well, but never an MB diesel. I’ve looked through and studied a few manuals got my hands on, and have only one real issue with the whole job. Pistons and cylinder sleeves. I know I’ll be buying a complete set of new pistons. The question comes with the sleeves in mind. New sleeves? Or bore the sleeves? (I know - that was two questions. sorry.)

I’m asking for your opinions on the following: 1. I’ve read enough posts and spec sheets to know the tolerances are pretty tight. Lately, I’ve seen posts where some machine shops are calling those tolerances ridiculous. So, it kind of scares me to think I might not find a shop that will do my bores the way they should be to match the new pistons. 2. Performance products says the sleeves (liners) they sell are matched to the pistons. No boring necessary. Well, if that’s true then cool, for less that 200.00 I can go that route and not worry about the precise boring requirements. 3. I’ve got a shop that claims they can pull and replace my sleeves. Cool. But what about them being corroded to the block? I’ve had that problem with a couple of our Case tractors and it’s “New block time” when it happens. Has this ever been an issue with the MB blocks? (Not that I would ever actually compare the two, mind you)

Call me crazy, but I’d like to keep this car (well…) basically forever, and have the same block # that’s on the build sheets. So, with that said, what do you guys think? Bore first over and put in new pistons hoping the shop was as accurate as MB was when they built it? Take a shot that Performance really has matched/bored sleeves and go that route? I’m figuring about 2500.00 for the parts on a complete rebuild with darn near new everything that wears in the motor; plus new hoses, belts, exhaust system, etc. I think that’s pretty cheap compared to a new car, so money’s not the issue here. It’s putting a motor back in the car that will last another 24+ years. Thanks for any input.

First I would pull the head and see what is going on. After inspection, If you need to rebuild lower end Then, I would order the new sleeves..after the block has been checked out by the machine shop...

__________________
2000 Ford 7.3 Powerstroke 4x4
2006 Mazda Tribute
1983 Black 300 D (donated to charity)
1993 Teal 300 D (160K) Sold
"I love the smell of burnt diesel fuel in the morning, it smells like ....VICTORY"

Semper Fidelis
USMC 1973-1976

Bore first over and put in new pistons.
DDH

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

Also, a good machine shop can bore the sleeve till it is thin enough to be easily removed and the new sleeve pressed in. I would suggest finding a reputable machine shop to do the work and give them the specs you want the engine built to.

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Jim

Since you are buying new pistons anyway, there is no need to resleeve, just bore to the oversize. I think this is the best way to go, due to the fact that diesel pistons are so highly stressed.

The only reason to resleeve is if you want to go back to original bore so you can reuse the pistons.

Good luck,

1. Not having the motor apart yet how do you know you really need new pistons?
2. If you don't need new pistons resleeve and go.
3. In the interest of less blow by and oil contamination I would highly recomend Total Seal rings.

Just some thoughts to ponder. Definately check out Total seal rings.

http://www.totalseal.com/totalseal3.html

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87 300SDL 220K
85 300SD 218K
82 diesel Chevette 440K
85 subaru 4WD turbo
83 4.1L buick powered cutlass THE TOY

Those total seal rings look very promising.
I have a question as well regarding the stock pistons.
I recently had my motor apart and the tops said "90.86" but whenever I look at standard size pistons and rings they all say 90.90. Am I missing something?
Thanks for your help.
Adam

First, this should not be done without getting a copy of the 617.952 Factory shop manual.... that will clear up a lot of these questions where you get different opinions...

Adam.... Pistons are ' available' in three groups... the size you mention is in the middle of group 2 in terms of size... I assume they do this the way they do front sprongs... they make them... then measure them and place them into categories according to the size they happen to be... and make a chart which tells you which size sleeve to buy to go with it ( but all sleeves require honing for the specific PISTON going into THAT HOLE...

As I get older I trust people doing things like this for making their living even less than I used to since they may have other jobs pressing them or be distracted by day to day life... ... I assume this is a labor of love and you plan on keeping the car as long as it will last..... so....

Don't order parts until you have taken the engine apart and done your measureing.

That post about the ridiculous tolerances was a misstatement .... they are tight but not to the extent that the first post stated due to them reading the wrong chart...

IF in fact you are putting in new pistons... which are the major cost... there is no way I would not have new sleeves installed...

It is a very different thing to bore out something which is variably worn compared to taking a straight hole (new sleeve) and making it evenly bigger to fit a particular piston..... false economy not installing the new sleeves..... the former requires expert machinists or big machines... the latter you can do with a hone.
I would not worry at all about the sleeves being so corroded they mess up your block....

If you have the engine out.... be sure you read the shop manual concerning cleaning the block... including taking out the steel balls at the rear to be sure your main oil passage starts off clean with these new parts in it....

It IS cheap compared to a new car.... and much more satisfying also....

ask Phil ( at fastlane here on this site) about the same pistons/matched sleeves which Performance quoted for you....

edit: I added" big machines , and Hone" in response to Larry...

Leathermang,

There are two basic types of boring bars, the old type that you simply set in place over the top of the cylinder, and the newer machines such as the Rottler that is a large machine that indexes off of the main bearing saddles. The old style will follow the existing hole. This hole made by these old machines is very dependent on the hole that you start with. In the case of using one of these machines, what you say is true.

In the case of a competent machinist using a Rottler type machine, the hole is NOT dependent on the condition or position of the original hole.

If I had to depend on even the best machinist with an old type boring bar, I would follow your advice to the letter. In the case, however, of a competent machinist with a Rottler machine, I would feel confident that if I brought him the new oversize pistons after he told me which oversize to buy, that I would get a result just as good as a matched sleeve and piston.

The reason I say that I would buy the oversize he specified is that he will take the block and bore most of the way to see that the bore will clean up at the first oversize. If it doesn't he will know that he must go to the second oversize. Once he gets the new pistions, he will then finish the bore to fit to the pistons.

All that said, if I did NOT have a machinist that I was very familiar and comfortable with and that had a Rottler or eqivalent machine I would follow what you said exactly.

Have a great day,

Larry, my inclination is usually to try to minimize the number of things which are possible to mess up which are in other people's hands.. and since he has indicated that he is not restricted to the point he can not afford the new sleeves... I was trying to describe a situation where he himself could count on getting a pretty much perfect job done without big expensive machining tools or the ability to run them...
Thus, I figured with new sleeves and pistons matched before they arrive at his place... that a simple , but sturdy, hone, then a good crosshatch 'brush' would allow him to get what he wanted...

And remember that even Jay Leno has bemoaned the loss of competant machinists these days.... he wrote an article for some major magazine... I think Popular Mechanics...

EDIT: Here is the url for that article....
http://www.antique-engine.com/leno/jayleno.htm

But I want to mention again... that reading the Factory Shop Manual , particularly with regard to the sleeves , is very important in this situation...( Bailey, in the ' Case' comparison.. you may have been comparing wet vs. dry sleeves....)

What you said about the very good piston design is true enough that I would have no problem recommending that a careful inspection of the current pistons may suggest that they are fine to reuse... and thus would require sleeves to bring the bore back into agreement with the pistons...

I cant speak definitively for Diesels but I wouldnt go with a sleeve unless the cylinder is really worn over. Obviously make sure you have confidence in the shop doing the boring as their jigs will make all the difference in the world regarding a straight and accurate reboring.

Have rebuilt several gas engines and have never needed sleeves to date?

__________________
1996 E300 D
1929 Model A Roadster
1929 Model A Fordor
1985 500 SEL (donated to charity)
1980 300 SD (Traded in for an Ugh minivan)

jdlow, These MB diesels are not built like the gas engines you are familiar with.. if you will get a copy of the engine shop manual you will realize that they planned this from the start... this is the way in which you replace the friction parts in a diesel and start over new...