You are on the right track. Cleaning and thoroughly inspecting the pistons is manadatory. The pistons in a diesel live a really tough life. There are those here who feel good about resleeving and reusing original pistons. Since I have seen ring land failure twice on these engines, I am leary about reusing them. If you plan on reusing them though, you are really right on in doing a thorough inspection.

Best of luck,

I have rebuilt several of these diesel engines over the years... I always put new liners in them even if I should use old pistons.. and have the liners bored to fit the piston.. New liners and boring is always a good idea... I have seen a lot of engines honed and new rigs.. but they never seem to hold up as well.. I always figure.. As long as its apart, give it the best job you can.. and if I can afford new pistons I always go for them..

Ken

Thanks everyone for all the advice. I checked the ring lands and there was a lot of wear on the bottom of the 2nd ring grooves - working the aluminum out - new pistons it is. Has anyone tried Deves rings with the 4 piece oil rings?

Ken,

You're missing a choice in your explanation. If you use the old pistons with worn cylinders the ONLY choice you have is to use liners and fit to old pistons.

The choice you left out was boring the original liners to fit oversize pistons. I don't remember seeing anyone propose honing the original holes and reusing the pistons in what is typically referred to as a rering job.

It comes down to two basic choices because reringing is rarely a choice unless the cylinders are in good shape because the engine was disassembled for other reasons.

Choice one; reuse the original pistons, replace the liners and bore/hone to fit original pistons.

Choice two; buy oversized pistons and bore/hone to fit the new pistons.

The choice you do not directly propose is buying new pistons of standard size, replacing liners and bore/hone to fit new pistons. This choice involves unnecessary expense. The pistons are the expensive component here, so if you replace them, you save the cost of the liners and their removal installation and have brand new and fitted piston/cylinder set.

Have a great day,

Sorry.. Should have made my self more clear... I have used, used pistions.. Some that came from engines with just a few miles that lost rods or had a hole in the oil pan or other problems.. I have never had any luck with a hone as far as trying to hone new liners.. or trying to hone to the next size hole for a pistion.. On cars or motorcycles or any thing else.. and have spent lots of money on Great hones hoping to be able to do it my self.. There always ends up being some type of taper in the cyl... and over time it gets you... I always have the engine bored.. unless just dressing it up for new rings.. Trying to hone worn cyl to the next size always has ended up just being a waste of time and money in my experience.. and on the mercedes engine you must remove the engine to get to the rear rod bearings any way.. So its out on the floor.. apart.. and trying to save a couple bucks by buying good hones has no point as a good hone and mic set will cost far more than just sending it to the shop and having it done right in the first place.... Now redoing an old American engine with one bad cyl while still in the car or pickup is some thing I have done lots.. Never works well but gets it running again.. but the local shop will bring the old portable boring bar out and do it in about half the time and the Cyl will be right.. So still a no win unless you are just going to dump the car or pickup any way..

Ken

Ken offers words of wisdom. A boring bar will make a new, cylindrically shaped hole. Using a hone on a worn hole will, for the most part, follow the hole. If the hole is tapered before the hone, it will in all likelihood still be tapered after the hone.

I think, however, leathermang was referring to honing a new sleeve. I don't know how close a new sleeve is to actual bore diameter. If it is only a few thou, then the hone MIGHT work since the new sleeve should be cylindrical.

Have a great day,

I think that even the new sleeves and new pistons are supposed to be honed to size, if one is following the MB manual... they expect you to do this and make them a size which will allow you to take out what you need to make everything fit....
My mental image of the process caused me to use the word 'boring' above because I was referring to a four stone fixed and adjustable aparatus which can be held to fine measurements.... NOT ONE WHICH IS FOLLOWING THE CONTOUR OF THE CYLINDER WALL IN WHICH YOU INSERT IT...
Perhaps I should have used "hone" only for the spring loaded item with three stones held in the center of each stone,,,and able to follow the contour of the wall.. well, not " able".. but which can ONLY follow it....
Thus the four fixed stone tool , while not able to be aligned to a crank can do more to correct wear patterns than the ' hone'...It is more like a stone boring tool... than a hone..
Technically boring would usually have one adjustable cutter and would leave concentric cut patterns... which would be taken out by crosshatching...
So , on honing a new sleeve... I don't think there is a choice...but I was certainly referring to the drill powered , spring operated device as ONLY appropriate for NEW SLEEVES.... this is what is shown in the Haynes manual picture...
Given the low relative cost of sleeves I would not trust trying to clean up an old sleeve...

Larry, you said " The pistons are the expensive component here, so if you
replace them, you save the cost of the liners and their removal installation and
have brand new and fitted piston/cylinder set. "
This I really don't agree with.... The pistons are so expensive that I can not understand why one would not put the NEW sleeves in there to match them... as an investment knowing that everything will be straight... and all the machine shop has to do is get the hole the right size...Why have a thin sleeve from boring out when you can have a brand new one relatively cheap ?

The reason I prefer boring and using new pistons is because the piston is so highly stressed in these engines. I have seen piston failure twice, so I'm not anxious to reuse pistons. I know that there are folks here that have reused pistons with success and I'm happy for them.

Boring these holes is no different than boring any other block. The first oversize is only about .020", that is only .010" sleeve thickness removed. This is no big deal. Even going to the second oversize is no problem. These are not wet sleeves, if they were, the engine would be more expensive and so would the sleeve. It would also make much more sense.

I've always been kind of puzzled why they use these dry sleeves anyway. They're nothing special, and they were not designed to be replaced at overhaul time as in a wet sleeve industrial or truck engine. I think people have gotten into replacing sleeves instead of boring the block just because they are available. There is nothing magic about these liners. All sorts of blocks are repaired with similar liners all the time. As a matter of fact, there's absolutely no need to buy liners from MB or an OEM supplier. Your machine shop can buy a dry sleeve, bore the block to fit, put the liner in place, top it and bore it and have EXACTLY the same result. In fact if you dropped off a block at most machine shops, without supplying liners or telling them where to get them, that's what they would do. They wouldn't so much as lift a finger to buy liners (dry sleeves) from Germany.

My point about the pistons being the most expensive component and replacing them to save money is probably confusing the point I'm trying to make.

The point I was making in response to the original post in this thread is: The pistons were determined to be bad. Since the pistons must be replaced anyway, you can simply bore the original cylinder to the oversize and save the cost of the liners since you have to buy pistons anyway.

If the pistons are deemed okay for reuse, then you have a different situation, and if you are okay with reusing them, then of course it would be less expensive to resleeve and fit the bore to the original pistons using your hone method.

Again, I'm not one for reusing pistons in these engines, but if you do, resleeving is the most economical approach. If you are replacing the pistons in an engine that has not previously been rebored, then boring the original liners to .020" is clearly the most economical and best new piston approach. A caution here is to ensure that the cylinders clean up at .020"(or exactly whatever it is) before buying the pistons. If they don't clean up, then you can get the second oversize.

In reading leathermangs post again, it sounds like I need to explain some more. It sounds like leathermang is saying that even if you buy new pistons you need to replace the liners. IF, I repeat IF, your machine shop is using a Rottler boring bar and a Sunnen Cylinder King, then there is absolutely no advantage to replacing the liners. If you don't have these proper machines to do the job, then you may have a better chance of having cylinders perpindicular to the crankshaft centerline by replacing the liners and honing to fit. If it were me though, I would find a properly equipped and competent machine shop before I would bother with the trouble and expense of the liners, unless of course I were reusing the old pistons.

The issue is not having a nice fresh liner with new steel. The issue is having a ROUND cylinder that is PERPINDICULAR to the crankshaft centerline, and of course having proper piston/cylinder clearance. In addition, you should have the proper finish and cross hatch of course.

I apologize for not being articulate enough to have previously made all this clear. Maybe I still have not made myself clear.

Have a great day,

The man looked at the MB manual, which shows a tool which a person can make to pull the liners themselves.... and he pulled his liners...
This caused me to assume he would like to do whatever stuff he could PROPERLY DO himself....
If he buys new pistons, he can , with minimum cost and a little care hone his own new sleeves and put the engine back together...because with new sleeves everything should be square,etc....
The new sleeves are relatively cheap... so the cost of a machine shop using the much higher tech equipment will be a big factor in the comparison here...the cost of the new sleeves and a low cost hone compared to useing the old sleeves and the machine shop taking it out to whatever size it needs to go to....
I think there is less left to chance if new pistons AND new sleeves are installed .
You said " boring these is no different " etc... very true.. but boring is very different from honing , which is all that is needed if new sleeves are used with new pistons...
You have been very specific about the name brands which you would insist that your machine shop use.... how often is the machine shop which a person trusts going to have exactly those machines ? Most people are at the mercy of one or two good shops in their area.... and may not want them mad at them... may need to use them for other stuff at some date in the future... I would be cautious about saying to them " if you don't have thus and so machines I don't trust you to do my MB block "....

Perhaps you were directing the part about new pistons to someone else.... I can't tell.... I think anyone that can afford new pistons and wants them should put them into their engine... that would be the best feeling in the world to have the stuff which takes the brunt of the force brand new...

In my first post in which I mentioned the Rottler and CK10, I indicated "or equivalent" or something like that. I used those brands to indicate what is necessary to do competent cylinder machining. In my last post I did not say "or equivalent" because I had said it before. I used those brands because I don't have a white board or sketch pad here to show you the difference between them and an old fashioned boring bar.

I expect that there are now many competing machines to these that are out there.

My point is that if you try to bore and hone a block with an old fashioned boring bar, you will not have a hole that is perpendicular to the crankshaft centerline. These machine types are quite common nowdays, so if your machine shop is still using an old fashioned boring bar, that merely sets on top of the cylinder, you are not getting a proper job. It is not only an MB block that I would require proper machinery, I would require it if I were rebuilding six cylinder Chevy. I would not let anyone use an old fashioned boring bar on anything that I am rebuilding. The shops charge about the same amount of money per hole, so why would you settle for less acceptable work?

Again, I AGREE, that if you replace the liners and they do not need much "meat" taken off of them, then the hand hone will probably give decent cylinder geometry.

Have a great day,

Not one in a million people could go into a machine shop... (and most are not going to be allowed into the work area anyway)...and be able to tell if they have " the equivalant " machinery.

And just determining that they 'HAVE' that equipment does not mean it is in good shape.... or more importantly , that the operator is 1. experienced 2. careful....

With a spring loaded three stone hone with a spring (or ujoint) between it and the drill it is pretty straight forward for anyone to open up the sleeves to the proper size...It is a selfaligning system...

Since we are talking new pistons and new sleeves I think the PROBABILITY of getting it right is much higher than your statement" the hand hone will probably give decent cylinder geometry. " implies... Especially since this is the method proscribed by the Factory Shop Manual....

The Rottler machines: look like this:


http://www.rottlermfg.com/machines/index.htm


I could not find a good picture of the Sunnen, but it is similar configuration. The block is held in place while the boring mechanism bores a hole in a precise position that is relative to crankshaft position and not loosely related to the cylinder deck

You can explain away all of these common machines if you wish. I have already said that I agree with you about your honing method used on a new liner.

With roughly 300 million people in the US, your math would come up with only 300 people nationwide that would recognize this equipment. That's a little pessimistic, especially since these machines have been constantly referred to in Hot Rod engine building magazines for the last 25 or 30 years. I expect that there are 300 in the hoaky little county that I live in that are aware of this equipment.

If you must go get boring work done at a machine shop, see that they use machines of this configuration. It should not be difficult since my look at the websites, such as Kwik Way, for the old fashioned equipment now only show equipment of the Rottler configuration.

This concludes my explanations and recommendations. You can lead a horse to water, but you can't make him drink.

Have a great day,

" This concludes my explanations and recommendations"

There is NO WAY you can resist responding to me posting on this thread.....

Because you have spent much time in machine shop settings you assume other people, just because they are ' DIY's' have also...

You are correct that all the people in the US which can recognize those machines live in the same county which you do.....

I am reminded of the Triumph Co of old... which had to close its doors when the old man who ran the boring machine died... no one else could hold the machine to close enough specs to put out a product....

Bet you can't keep from posting to this thead....

this should be good...:p

Pete, If Larry does not crumble TODAY... which I think he will... he will be SLEEPLESS until he does post......