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When replacing piston rings, what other moving parts should be replaced at that time? What is usually included in a general lower-block rebuild?
I got a price quote of $145 for a valve/head rebuild, but the shop wouldnt even quote me a rough estimate on the lower block...said it could be $1000 to $5000... honestly, i wouldnt want to put a huge sum into a 2.4litre NON TURBO.
Anyway, the car starts right up, but runs a little rough at idle. There was oil around the injector when i pulled one to look at it. What is the best option to determine the extent of piston ring and or valve wear? Compression was 350 on all cylinders, and it got there by jumping up in stages, should compression read high on the first crank?
 
G

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Hi Greg.

Before thinking about a rebuild first
explore a few other possibilties.

1)Injectors: Over time they don't
perform as they used to and this
may account for the ruff idle at
start up.
Buy some diesel purge(link to follow)
and run two cans pure thru the engine.
This should take care of the problem.
If not then a professional cleaning
might be needed.
In the worst case a complete rebuild.

2)The idle: the rack damper bolt might
need adjustment since this controls the
idle.
In the worst case a new one might be needed.

3)Primer pump(if equipped): if this is still
the old type and it leaks when priming the
fuel system you might have small amounts of
air entering the fuel system.
As the engine warms the leak could stop
or greatly be reduced.

4)Fuel lines: see #3

5)Fuel filters: VERY IMPORTANT and should
actually be #1.
If they are dirty you can have this sort of
problem.

6)Air filter: Often overlooked but important
non the less for a diesel engine to run correct.


As to oil around the injectors that can be
from several sources, but most often it is
just from the valve cover gasket.
It tends to leak and the oil can end up
around the injector.
If the gasket hasn't been replaced since
you had the car then it might be a good
idea to do so.
Once that is done and doesn't leak, clean
the top of the engine and see if the oil
returns.
My guess is that it will not.

As to the compression, since I'm in no way
an expert I will just say that 350 is very
good, because when new the compression should
have been around 400.
And I do believe that that number won't
be reached after the first compression
stroke.
But if you are still concerned then a
leakdown test needs to be done.
This test will tell you alot more.

Just incase you deside to go for a rebuild
any way I'm including a link for that too.


Link for diesel purge:
http://www.etyproducts.com/LM%20product%20catalog%20with%20pictures.htm

This link has it too but costs more.
You can order a free catalog, somewhere inside
it explains the diesel purge procedure.
http://www.performanceproducts.com/

Link to rebuild engines:
http://www.remanufactured.com/Mercedes_Engines.htm

Louis.
 
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