pushed in cylinder sleeve, how long till another blown head gasket? - Page 4 - PeachParts Mercedes-Benz Forum

Stretch · #46 09-09-2010, 07:57 AM

Thanks for the tips folks (and sorry to thread jack - but it seems like the "owner" is AWOL). I have the engine in bits at the moment and I'm unsure about some vertical scratches on the bores... I'll ask the chap at the machine shop to see what he thinks.

Yeah here's a link for a cylinder sleeve on Fastlane for a OM617

http://catalog.peachparts.com/ShopByVehicle.epc?q=1981-Mercedes--Benz-300d-Engine--Mechanical&yearid=1981%40%401981&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6188%3AED|10000132%3AMBC|1503%40%40300D&catid=240154%40%40Engine+Mechanical&subcatid=240180@@Cylinder+Sleeve&mode=PD Just under $43 a piece...

layback40 · #47 09-09-2010, 08:25 AM

Army,
The key to it is to have good pistons to put in them. The piston diameters will vary as they are used. The liners need to be bored to suit each piston. Its not a good idea to try & hone each liner after fitting to the right diameter, you should get it bored.

layback40 · #48 09-09-2010, 08:56 AM

ivy and oxbridge, I dont think so, maybe in your dreams.

winmutt · #49 09-09-2010, 09:07 AM

FWIW Larry Perkins and his Percedes had this same problem I believe. 350head on a 300 block. You should ask him if his gasket is still holding up.

t walgamuth · #50 09-09-2010, 09:10 AM

Quote:

Originally Posted by layback40

Army,
The key to it is to have good pistons to put in them. The piston diameters will vary as they are used. The liners need to be bored to suit each piston. Its not a good idea to try & hone each liner after fitting to the right diameter, you should get it bored.

My machinist bores the new sleeve to nearly the right size and then hones for the final fitting.

layback40 · #51 09-09-2010, 09:22 AM

Tom,
You are having it done exactly correct. The thou or 2 difference from 1 cylinder to the next is insignificant to the "balance" of the motor. In a previous thread some one was suggesting that the sleeve could be replaced with the motor in the car & the sleeve could be honed out to the correct bore for the piston. It is not possible to maintain trueness honing that amount. i cant recall the exact amount, think its of the order of 50 thou to be removed.

When you press the old sleeve out, I take it you press it up from the crank side of the block?

On old massy tractor motors, I have seen a bead of weld run up the bore to shrink the sleeve before pressing it out, makes it just about fall out. I am waiting for some one to try it on a 61x before I would have it done on a motor of mine. Any one with a dead 61x want to try ?

t walgamuth · #52 09-09-2010, 09:32 AM

Correct, pressed from bottom. The block is placed upside down on the press and the pressure is down. The placing of the rings on the sleeve is an exacting thing since they need to place the force on the sleeve and it is not that big.

Stretch · #53 09-09-2010, 10:48 AM

Thanks for the information folks - I'm new to the engine building game. I was kind of hoping that should it be necessary it would be cheaper to replace liners and get the size right instead of replacing pistons - which I believe are very very expensive.

t walgamuth · #54 09-09-2010, 11:18 AM

Quote:

Originally Posted by Army

Thanks for the information folks - I'm new to the engine building game. I was kind of hoping that should it be necessary it would be cheaper to replace liners and get the size right instead of replacing pistons - which I believe are very very expensive.

This is exactly what I have done in most cases. I believe only once out of a half dozen or so benz engines we have done did I need pistons, and I found some good used ones.

mplafleur · #55 09-09-2010, 12:20 PM

jsap is correct. Either get the top of the sleeve up flush with the deck somehow (replace, shave, or shim from the bottom), or use no gasket (not an option).

More gasket is in the wrong direction.

jsap · #56 09-09-2010, 01:41 PM

Quote:

Originally Posted by layback40

ivy and oxbridge, I dont think so, maybe in your dreams.

You've been pissing on your dream since yesterday. You must be so far away from my world, that such accomplishments must seem unattainable. Judging from the way you parade around this PE license like it was the crown jewel, I suspect that you've overcome the great adversity against great odds. Congratulations, and keep it up.

jsap · #57 09-09-2010, 01:48 PM

Quote:

Originally Posted by Army

Thanks for the information folks - I'm new to the engine building game. I was kind of hoping that should it be necessary it would be cheaper to replace liners and get the size right instead of replacing pistons - which I believe are very very expensive.

Yes, if you have slipped liners, but the piston rings have not come up over the liner, then you shouldn't need new pistons.

For whatever reason, diesel liners seem to be a plenty. So that good.

If you pull the short block out and transport it to a machinist, and will be marrying the block with the bay yourself, then you've saved $2000 (my area going rate). If you are pulling and reinstalling our own head, you've saved another $2000. For me, the total job would be about $5000-8000, depending on parts. For you, it could be 1/4 of that.

jsap · #58 09-09-2010, 02:09 PM

Quote:

Originally Posted by mplafleur

jsap is correct. Either get the top of the sleeve up flush with the deck somehow (replace, shave, or shim from the bottom), or use no gasket (not an option).

More gasket is in the wrong direction.

Yup. Another option would be to convert this to a closed deck, but I believe the cylinders are also made of alu-sil (the same expensive material as the cylinder liners), so welding aluminum to it would be experimental and not a sure bet.

I've been getting conflicting reports on the liner stop, however. One machinist who works on diesels says they exist on MB engines, and another who's done this on a gasser before says the sleeve will continue to drop.

However, I was looking for the simplest and cheapest repair option. Just replacing the head gasket, it'll probably leak again. Adding a shim at the top would be great, but no one around here is willing to do that. With a liner that's dropped about 2mm, a 2mm shim becomes a compression ring free floating on top of the liner. Can anyone think of a shim design that would work?

jsap · #59 09-10-2010, 03:19 AM

Btw, this is how Mercedes should have designed the cylinder liners in the first place. They have flanges on top to keep them from slipping, and they call em top hats. (This is from a Land Rover article; attached.)

There's lots of stories of engines being replaced before heads are pulled, because the owner knows that replacing the engine is more cost effective than an extensive tear down inspection. I wonder how many of these cases are caused by slipped liners. My guess is that when the engine recycling/rebuilding specialists get hold of these engines, they routinely replace these liners.

layback40 · #60 09-10-2010, 05:40 AM

This thread appears to be going off at a tangent.

Cylinder liner slip is very uncommon on OM617's. The 2 examples mentioned on this forum have no history as to how they occurred, though both have knowledge of prior major motor work. It could be that incorrect assembly has occurred and not operational slip.

It is common on V8 petrol landrovers and has been reported on petrol Subaru's as well.

OM617's do not have alloy blocks with pressed in liners like has been mentioned as a possible cause of liner slipping.

The reason OM617's have liners replaced is that its much cheaper than re-boring and using over-sized pistons. According to the FSM the liner is to be replaced if it cannot be retrieved by re-boring & fitting over-sized pistons. They are designed to be re-bored.

The liners in an diesel OM617 are fitted with an appropriate interference fit so that they dont under normal operating conditions slip.

The liners are sufficiently thick so that they can be re-bored, unlike some other motors that have very thin liners and are prone to slip like the V8 landrover petrol motors mentioned.

It has been reported that the slipping in the landrover V8 petrol motor may have been contributed to by the motor suffering from severe "pinging". Diesel motors like an OM 617 dont "ping".

The lip top style of liners are common especially in some diesel motors that are designed to have liners replaced when motors are rebuilt instead of re-boring. This is not the case with the OM617. In some cases it is not appropriate to place shims under the lip as has been suggested as some of the motors with these removable liners require the liner to be fully down in the bore for other sealing & alignment reasons. There are stationary engines that have shim washers fitted to the top of the liner to insure flat and smooth block surface.

Unlike the landrover V8 petrol motor, the OM617 is not a motor that has come from the increased bore size of an earlier motor. There has been no reduction in liner thickness and so the original design has not been compromised by a significant reduction in liner thickness.

For some one to be making a "beat up" about poor design when they do not appear to even own a diesel Mercedes and are negative towards such ownership is a little inappropriate.

Maybe time to go back to a gasser or landrover forum.