450SEL developments

[TJ 450]

It certainly was a fun day, making all that mess under the carport.

I do find it odd that there is a large gap around the pistons in the original engine (1mm plus), seeing as the test piston fitted with a minimal amount of clearance (formed vacuum without rings). The gap around the original pistons was also very even, but large.

Those Euro pistons are very attractive, I must say. I haven't made the decision yet though.

Tim

[Big_Richard]

Unbelievable!   

[TJ 450]

What I will do is rebuild the heads and when I have those "on the shelf", I will consider the bottom end.

I may find at the end of that period that I'm willing to remove the engine and do the bottom end.

As I'm sure you're aware, I don't have anywhere to put yet another block/crankshaft/pistons at this stage.

Do you realise that I have 46 pistons in total in my posession. Hahaha

Tim

[Big_Richard]

that's tapped

Whats more of a worry is this fictitious shelf everyone keeps talking about, it must be busting at the seams these days with the amount of stuff its expected to hold on it

[s class]

So, did you find anything related to the suspected oil circulation problems?

[TJ 450]

Surprisingly, there wasn't any evidence of that at all. I can only imagine that it was relating to the camshafts themselves and surprisingly, the rockers were in good shape. It's possible that the oilers came loose and were repaired, but the camshafts were re-used. That's all I can think of, anyway.

PB, I know you desperately want to see that engine removed and the subsequent forking out of funds.

As for the shelf, well, it resides in my bedroom and it is indeed choc-a-bloc!

Tim

[Big_Richard]

its all been very educational regardless.

I'll never be afraid of MB engine internals now, rebuilding any of these v8's would be fun and definitely not considered to be rocket science in the slightest. 

[TJ 450]

Yep, the most difficult part is procrastinating and removing the engine from the car, it seems.

I just completed cleaning up the mess from the day's work. I'll try and take some photos of the pistons we removed as well as the pitted camshafts later on today.

It was the height of productivity yesterday, I must say (it is in fact after 12am).

It would be interesting to know if there is a way of cleaning out the water jacket silt without running the block through a cleaning solution. The garbage in the bottom of these blocks is astonishing to say the least.

I will say that the 6.9's block design seems to be superior in this regard, as the two main coolant passages are at the lowest point. This means that they can be cleaned out by removing the water pump and I was able to drain the system on the 6.9 by simply removing the plugs with no blockages.

When I removed the drain plugs on these M117s, nothing came out because the sediment was absolutely solid and at least an inch thick. It required punching through with a screwdriver and hammer, that's how solid it was.

Tim

[TJ 450]

The only progress over the last few evenings has been some cleaning of piston tops and inspection. So far, I have cleaned #1 and #2. The gap in the upper compression rings PB spoke of is just over 1mm (slightly out of spec) and I'm impressed with the condition of the bores considering the 350,000km mileage.

I'm fairly certain that this bottom end will remain untouched for a while yet, unless I change my mind at the last minute.

All piston tops are soaked in CRC to soften the carbon. I used a scouring pad with CRC and some rags to clean and slightly polish the tops of the two pistons I have cleaned so far. The lips hardly catch my fingernail.

Cleaned #1:




One of the pitted camshafts from the Euro engine:

[s class]

Ah those cam lobes are nasty.  The bearing journal isn't a lot happier either. 

[TJ 450]

Yes, both of the camshafts are pretty bad. The main and big end bearings had a few scuff marks and a bit of light pitting, but nothing to indicate a severe lack of lubrication. The crankshaft showed some minor scuffing. Nothing like those cam bearing journals, though.

Despite the initial "good appearance" of the bores in the Euro, the lip at the top was quite a lot more pronounced than on the 350,000km engine where it is hardly noticeable.

Tim

[Big_Richard]

you change your mind more often than a woman when it comes to this 450

[s class]

I'll support TJ in this.  It sounds like he's taking a proper considered approach to the decision.  Scuffing on the crank does indicate some lubrication problems.  Sounds like the original plan to retain the Aus block is going to be the way to go. 

[Big_Richard]

I was simply suggesting to use the high compression euro pistons in his AUS block, but it looks like he dosent even want to do that 

[s class]

That does sound appealing, but one would need to measure very carefully, as it amounts to fitting worn pistons from one engine into a different engine with worn bores/crank etc.