Hi

I didn't find any pics of aluminum block honing in this forum,
so here are some.

Honing this blocks is a 4 stage process.
this are the stones used for the first 3 stages.



Left to right:
Course stone (first stage)
medium stone (second stage)
polishing stone (third stage)



This are the felts for the 4th stage
Sorry, i don't have any new ones on hand right now.



The silicone paste used in the 4th stage.



A pic of the block in the honing machine.



A cylinder just after starting the honing process.
Notice the wear ridge from the first piston ring, also faintly visible the one from the second ring.





Cylinder after the first stage.
Most of the material is removed at this point.
0.08 to 0.1 mm remains in the cylinder.





After the second stage.
About 0.02 mm left.





After the third stage (polishing).
Notice the reflections in the cylinder.
Hone marks are still visible.
Cylinder is at final size.





After the 4th stage.
Cylinder is finished.
Reflections and hone marks are gone.
The surface is dull gray and featureless.



4 cylinders in 4 stages of machining.

__________________

76 240 D. Bought in 1998 for $25.
85 300D. Got it for free with a bad engine. ( Sold )
60 Unimog 404. What was left of it, was given to me. Now powerd by 617A.
88 560 SEL. Bought without engine and trans. Now powerd by 617A.
67 250 SE. Cuope. For resto or sale.
64 220SE. For resto.

That is cool, thanks.

I always believed you wanted the crosshatching per your stage 1 photos.

__________________
'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)

On cast iron cylinders you shoot for about stage 2, but not on this aluminum ones.

__________________

76 240 D. Bought in 1998 for $25.
85 300D. Got it for free with a bad engine. ( Sold )
60 Unimog 404. What was left of it, was given to me. Now powerd by 617A.
88 560 SEL. Bought without engine and trans. Now powerd by 617A.
67 250 SE. Cuope. For resto or sale.
64 220SE. For resto.

Great photos! Thanks a bunch for posting.
I really did not know the repair process for the aluminum cylinders. The photos really show the patterns with good detail.Are you a tech at a dealer, indy, or?

__________________
Providing a home for these cars:
1951 Buick Special De Luxe
1977 Rolls-Royce Silver Wraith II
1970 Rolls-Royce Silver Shadow
1986 Mercedes-Benz 420 SEL
2005 Mercedes-Benz E 320 CDI
2012 GMC Sierra 1500 4X4
1927 Pierce-Arrow Series 80
1931 Pierce-Arrow Series 43
1926 Ford Model T coupe

I did some engine rebuild mani years ago when I lived in California,
but I still have the equipment.
Got hold of a damaged 560 block, that I could mess up for this thread.

__________________

76 240 D. Bought in 1998 for $25.
85 300D. Got it for free with a bad engine. ( Sold )
60 Unimog 404. What was left of it, was given to me. Now powerd by 617A.
88 560 SEL. Bought without engine and trans. Now powerd by 617A.
67 250 SE. Cuope. For resto or sale.
64 220SE. For resto.

Do you intend to rebuild this engine? I ask because MB has a special process for their aluminum bores. While I don't understand all of the nuances it is my understanding that the castings have a high silicon content. For the surface finish the aluminum is chemicaly etched leaving a predominately silicon surface for the rings to wear against. That is how Mercedes gets such an unusually long service life from such a soft material.

FWIW, when BMW first tried to build its aluminum V8, it failed miserably. I've seen those with 10K mi and completely worn out bores.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
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3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
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90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
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PCS TCM2000, built 722.6
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