560SEL engine rebuild or spruce up - PeachParts Mercedes-Benz Forum

merchauser · #1 12-08-2010, 11:06 AM

i have a 560SEL motor with 140k. seems to run strong, immediate start up, no smoke. since it is out of the car i am thinking i should change the mains, rods, rings and oil pump. an MB mechanic friend of mine disagrees and says all i should do is chain, tensioner, rails and POSSIBLY head gaskets. one of this thoughts is that he would rather keep the car factory assembled because of better build quality.

in my ignorant mind, i am thinking of polishing the crank, honing the walls, and throwing in some std. bearing and rings (providing that the journals and cylinders are not out of whack

i just don't want to pull the engine again; so if i have to bite the bullet and antie up, then allright

Stretch · #2 12-08-2010, 11:12 AM

My advice would be to do the work your friend suggests - there may come a time when you will need to do the work you want - but by the sounds of it, it isn't now. Oh and leave the head gaskets alone if they don't need doing.

If you are itching to build an engine - why not buy a spare and do what you want to that?

rocky raccoon · #3 12-08-2010, 03:14 PM

are almost diesel strong and seldom need work unless of course they have been badly abused.

The dual row chain itself is very robust and if the engine was still in the car I would say measure stretch and if it is spot on, change plastic gtuides and runners and leave the chain alone.

Since the engine is out, I would say inspect closely and change ALL plastic guides incuding the lower one which is seldom changed since it is not failure-prone and is a pain in the ass to get to with engine-in-car. If the chain is good AND it is the factory endless chain I would leave it in there. Replacement chains use a master link and that is the weak point.

Be sure to replace the camshaft oiler fittings also.

tinypanzer · #4 12-08-2010, 07:02 PM

My recommendation:

1) Timing chain and plastic guides
2) Head gaskets if any oil leakage at the back of the motor is evident
3) Valve stem seals
4) Oiler tubes (cheap insurance against a destroyed cam)

Save the rest of your budget for fixing all the vacuum leaks that are in your future. The intake plenum rubber, the injector cups and seals, the donut seals for the intake manifold, etc....

My indie mechanic says he's been working on M117 for 25+ years and he's never even SEEN the bottom end of an M117 motor. They're nearly bullet proof.

As to the cylinder walls, you are likely to see the FACTORY honing marks still perfectly intact should you take a peek in there. They hard-faced the surface of the cylinder walls with silicon to make them almost wear-proof. If you hone the cylinders, you will lose this.

cth350 · #5 12-10-2010, 07:54 AM

left out from the above advice is a description of the pain involved in doing the head gaskets. The block is an alloy that will need threaded inserts for the cylinder head bolts on reassembly. To drill out the holes, you need a special fixture to get the angles right.

My machinist no longer has that fixture. He regrets lending it to somebody and never getting it back.

-CTH
PS. If anybody has a spare fixture setup or plans for building one, I'd take it.

tinypanzer · #6 12-10-2010, 08:23 PM

I did leave that bit out. I guess that's because I had it done by my indie and didn't directly experience the issue.

At any rate, when those gaskets go, the oil likes to leak out onto the exhaust manifold and then smoke gets sucked into the car through the vents. It can get so nasty you don't even want to drive the car. It would suck to have that issue a few thousand miles after putting the motor back in the car, which was my only point.

My indie has a 560SEL that was abandoned at their shop because it had that problem. The owner didn't want to pony up for the head gasket job, and the smoke was too awful to tolerate. I've been salivating on that car, since other than the color of the seats, it matches mine perfectly and would make an excellent donor car. I'm waiting for that phone call that they've finally liened it...

jhodg5ck · #7 12-10-2010, 08:56 PM

If the engine is out, I'd @ the VERY get the engine on a stand, drop the lower pan and pull a main and rod bearing or two.. Depending on how the engine has been treated you may be surprised by what you find.. If the bearings are showing signs now is the time! A new oil pump is likely un-neccesary, but it does buy piece of mind.

Unless the bearings are Toast and the journals a mess installing a set of standards isn't going to be a big deal. If you use plastigauge properly you can get accurate results, just so many people screw it up when doing so.
Clean, clean, clean and assemble with thought and care. 3X check your torque, mark each fastener when completed. You'll be spot on just as the factory was.

If the engine needs time-serting, I have the jig and tools required.

Jonathan

V1nny · #8 09-16-2016, 10:51 AM

Hi All. I know its an old topic! My father has an 1987 MB 560SEL and its sitting in our drive way for the past couple of years in Putnam County, NY. Hard to believe that after all these years and harsh winters that there is hardly if not any rust on this vehicle!! Would love to get it back on the road and its not starting. My father tells me the 1987 560 SEL burns a lot of oil. My friend recommended that I either rebuilt the Carburetor or the engine.

If anyone has any valid recommendations would appreciate and thank you in advance.

cth350 · #9 09-16-2016, 10:58 AM

you'll want to start a new thread about dad's car and what is a good thing to do to get it started.

In that thread, you'll discover that it's got a fuel injected engine (no carb) and that its fuel injection system get gummy from sitting for years and needs cleaning most likely.

Burning oil is a relative concept too. A quart of oil over 1,000 miles is within "acceptable limits". It has 8 quarts in the pan, but don't let 3 of those quarts burn away or you're looking for real trouble.

-CTH

nulu · #10 09-17-2016, 05:18 PM

Ive rebuilt several of those 560 and 420 sels,you will need to do a valve job at your mileage new guides and possibly exhaust valves , new timing chain, replace all plastic rails, the bottom end unless not maintained can be left alone,my brothers 420 has 500,000 on original bottom end,all the others went to about 280,000 miles or more

97 SL320 · #11 09-17-2016, 07:52 PM

Given the car is based in chilly NY rather than sunny LA, it's engine life will be reduced. A 20*F start with cold oil bypasses the filter and it will take a bit for oil pressure to build. And, it will take a bit longer for oil to make it's way to the valve train.

Add in a longer amount of time for warm up ( rich mixtures ) and even longer for the oil to get hot, oil contamination is a real issue.

I remember the Toyota ads that touted vehicles with 200 K miles, it seemed that all were from sunny states and none from salty cold areas.