Pulled out my engine today

[Nick DV]

There is actually quite a bit of meat at the top of the one that's now sheared, I can't see any reason to not grind off a good chunk and have another go at welding on another nut.

Why not, you've nothing to lose

 

[RaceDiagnostics]

Yes, I just need a bit of patience, I made a small retainer with dum dum and filled it with "plus gas" penetrant, I'll keep it topped up for a week then have a another look at it.

 

[Jay1st]

The header is in aluminium, you can dissolve the rusted bolt without affecting the header.

 

[RaceDiagnostics]

More table space set up.

Removed the rocker arms.

This was a good investment.

Next I decided to get the dip stick tube out of the way.

It came out easier than expected.

Then the tensioner.....

...and manifold.

Using a strong magnet to ensure the chain circlips don't go missing.

Releasing the cam shaft bolts.

Removing the chain guides, these ones are ten years old.

Not much wear.

Refreshing my memory before taking the heads off.

First head, cylinders 5 to 8.

Other head, cylinders 1 to 4, you can see cylinder 1 which had the valve guide problem has the most build up and is oily.

Surprisingly, it also has the cleanest piston???

The bores all look in reasonable condition with the cross hatching still visible to some degree.

Curved guide removed.

That's it for today.

I did try to remove the front cover, all the bolts are out but it didn't want to come off so I will investigate more tomorrow. Perhaps the oil pan needs to come off first.

 

[jsf55]

Still got hone marks on the bores, a good sign

 

[RaceDiagnostics]

Sump off first thing today.

There were a few plastic bits in the cruddy oil at the bottom of the sump.

Bits of chain guide rail.

It is what it is.

Oil pump off.

I couldn't get the front cover off till I spotted this bolt.

The lower chain guides which have never been changed in 41 years.

The oil pump chain looks to be in good condition, all the links are tight so I wont replace unless there is good advice to.

Timing cover with the idler wheel at the top and distributer cog on the left.

Lucky I bought a new idler wheel, two broken teeth.

Oil pump chain tensioner also 41 years old and worn.

Measuring the big end end axial float and then crank axial end float.

Crank was 0.21mm vs limit of 0.3mm

Big ends were 0.29 to 0.33mm vs limit of 0.5mm

Pulling off the crankshaft sprocket.

Seven of the pistons were 91.99mm.

Just one was 92.05mm, which is at the large end of the standard sized pistons.

The last thing I did was remove the first big end bearing cap nuts, but the cap didn't want to come off. I gave the studs a light taps but it didn't break free. Any suggestions on how to free it off without damage?

 

[roofman]

A few taps on the flat face of the rods with a copper hammer should break the caps free...did you spot what appears to be a crack on the tensioner? and where did you buy that bridge puller from? looks a handy item to own that. great thread btw

 

[RaceDiagnostics]

Well spotted, I have a closer look at that tomorrow. Here is one of the uppers that broke ten years ago, bit more than a crack.

One morning there was a loud clack on start up.

The puller came from ebay from memory, Sealey do a few different sizes.

https://www.sealey.co.uk/search?q=Twin+Leg+Puller

 

[roofman]

Well spotted, I have a closer look at that tomorrow. Here is one of the uppers that broke ten years ago, bit more than a crack.

One morning there was a loud clack on start up.

The puller came from ebay from memory, Sealey do a few different sizes.

https://www.sealey.co.uk/search?q=Twin+Leg+Puller

cheers bud for the link and ouch on that upper

 

[RaceDiagnostics]

I removed the pistons first today, the caps are held on tightly even once the nuts are removed, an interference fit between the cap and the lower portion of the studs. It took a bit of courage to separate the first one.

There is some slight scoring on the top side of the pistons, I was surprised that the underside was clear. Left bank viewed from the front of car.

Right side.

Main bearing sizes, only four shown but there are five bearings?

Before removing the caps I made this video.

Crankshaft lifted out.

After I measure the main bearings and piston bores I plan to send the block out to be cleaned at a machine shop, should I remove the pressure release valves or is it ok to leave them in place?

These two are the main over pressure release valve and the oil cooler over pressure valve.

This one is the oil filer pressure relief valve.

 

[roofman]

i would take the valves out as you might have some crud getting lodged in them in the cleaning process

 

[RaceDiagnostics]

I found a picture of one of them, should just screw out, the other two look like the need a very big flat blade screwdriver.

 

[Wallace]

Are new valves available from Mercedes and are you replacing the oil pump?

 

[RaceDiagnostics]

No, I'll reuse the old ones, a new oil pump is £1,700 and the pressure relief valves are about £160 each.

 

[Wallace]

Crikey, I thought dry sumping was expensive!

 

[Nick DV]

No, I'll reuse the old ones, a new oil pump is £1,700 and the pressure relief valves are about £160 each.

I appreciate it's an older vehicle, but how is that price justified!

 

[Melvyn Best]

I appreciate it's an older vehicle, but how is that price justified!

I rebuilt a 3.5 lt version of this engine around 1987 , the bill for parts and machining was something like £1600 but that did include reborn, pistons , valve guides , timing gear etc

 

[Nick DV]

I rebuilt a 3.5 lt version of this engine around 1987 , the bill for parts and machining was something like £1600 but that did include reborn, pistons , valve guides , timing gear etc

That would have been expensive for the time!

 

[RaceDiagnostics]

I appreciate it's an older vehicle, but how is that price justified!

Mercedes don't give a flying feck about the owners of its old cars, they try to screw you at every turn and keep cranking up the prices, a set of big end bearings, £600. They assume that for old classic owners money is no object and so try to milk them dry without worrying about whether or not it is justified.

 

[jpmillermatic]

what a great thread. love the work you are doing. I am not "geared" this way so your attention to detail and methodology are very educating.

keep at it!

JP