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I built an engine for a W111 280SE3.5 coupe

Started by s class, 27 June 2016, 06:00 AM

s class

All the hardware was stripped, disassembled, categorised and recorded using charts like this :







The parts went in for cleaning and zinc plating. Once it all comes back the fun starts to re-sort the hardware  ;)



Aluminium castings.  All completely stripped of hardware, gaskets, bushings, fittings etc .  Went off for chemical cleaning :



hardware back from plating, the tedious process of re-sorting gets under way...



some of the aluminium components back from cleaning :

Now that they are clean, its easy to see how badly corroded some of the water fittings are.  They will now go the specialist aluminium welder for repair.



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

#1
Block ready to go off for inspection at the engineers.



Its clear that there were some issues with this engine.  Obvious heat-seizure marks, plus the expected pitting in the bores from corrosion :



Had a meeting at the engineers to inspect the block.  Its had its initial acid bath and descaling, plus the pressure test. 

The bearing caps have cleaned up nicely :



THe waterways have also cleared out well :





A pair of heads was carefully selected after critical examination, and assessment of head thickness.

THe red numerals indicate the thickness of the heads at the bolt towers.  When new, they were 60.0mm.  Limit of machining is 59.6mm.



Hardware stripped off the heads :



New valves :



Each new valve was critically examined before acceptance :



The whole lot is at engineering for machining and new valve guides.

A set of good pistons and rods from a W109 300SEL3.5 was procured from a contact in the U.S.  The 300SEL3.5 uses the same pistons as the W111 3.5.

New pistons are not available from any source for this engine, which is why we were forced to look around for used ones.









[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

#2
Block as received back from engineering :





A whole day was spent :
- cleaning out remaining scale in waterways
- washing out oil galleries
- general cleaning of surfaces
- preparation for paint
- painting of external surfaces
- checking of dimensionalities



Masked and etch-primed :



Painted :





Some nicely machined parts :





[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

mounting the crankshaft :



Bearing caps aligned and torqued :



Crank in, seen from above looking through bores :



Measuring end-float of rotating assembly :



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

Resized rods, and cleaned pistons being weighted to match-balance the engine .

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Ring gaps being filed for proper clearance :



Pistons and rods assembled, new rings installed :



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

Heads with new valves and guides, and intake valve seats :



Valve sealing checked with mechanics blue :



Assembled head :



With new valve springs :



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

Timing chain and related equipment installed :



Enging rotated right-side up, heads and cams being mounted :



Setting up valve timing with woodruff keys :



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

Timing cover installed :



Oil pump in :



Sump on :



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

Preparing for inlet manifold :



Resurfaced flywheel :



Reconditioned clutch :



[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

s class

WHile we were at it, I painted the engine bay, which obviously involved the standard issue rust repairs...





After extensive surface cleaning and flatting :

Etch primer applied where required :



Standox 2K-HS-Pro primer/surfacer applied :





Customer insisted on painting without stripping all the wiring and piping, which certainly didn't make my life easy. 







[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

Zaxxon

Love your attention to detail! great job! This will be a stunning car when finished! What differences did you see in rods and pistons? More than +/- 5g?

Congratulations on awesome work!

--Zax
---
Mercedes: '99 CL500, '86 500SEC, '96 SL500, '06 R500, '02 ML320, '78 450SEL
Porsche: '80 928S 5-Speed, '86.5 928S RogerBox '86.5 928S 5-Speed, '83 944
Others: '84 Callaway Alfa Romeo GTV6, '83 Tiara, '87 FZ

s class

Yes, the variation in piston weights was about 2 grams, but the rods varied by up to 6 grams if I recall.  The rod/piston combos are now all within 1 gram.


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

Zaxxon

Quote from: s class on 27 June 2016, 08:35 AM
Yes, the variation in piston weights was about 2 grams, but the rods varied by up to 6 grams if I recall.  The rod/piston combos are now all within 1 gram.

That's great! I doubt they were matched that close even from the factory!
---
Mercedes: '99 CL500, '86 500SEC, '96 SL500, '06 R500, '02 ML320, '78 450SEL
Porsche: '80 928S 5-Speed, '86.5 928S RogerBox '86.5 928S 5-Speed, '83 944
Others: '84 Callaway Alfa Romeo GTV6, '83 Tiara, '87 FZ

Harv

3.5 Coupes are bringing big dollars now in the US. Really nice job.
1980 300SD
1983 240D
2000 E55 AMG
2002 G500