http://www.mercedesengines.net/
I had an opportunity to spend some time with Mike, the owner of Metric Motors today (link above) A few months ago I asked him to call me if he ever was simultaneously rebuilding the engines from the 320 and 32 so I could take a look at the engine blocks and the internals to compare them for future mod. projects and educate myself some more...
When I arrived today, he had the entire re-furbished engine blocks, heads, intakes and internals ready for assembly for both the 320 and the 32... The re-furbished parts were blocks, heads, intakes, cams, balancing shafts and many other odd-and-ends, including re-sleeved cylinders on both engines... All of these re-furbished parts looked like they just came off the factory floor...
Mike also had all new factory pistons, valves, springs, connecting rods and the works for each of the engines... Most of the parts were still boxed, but I briefly pulled them out to compare the appearance between each engine...
I wish I had my digital camera with me at the time, because it would have made for some interesting/educational photos... But, I didn't want to take too much of his time since this is a pretty small shop with few employees and a HUGE workload... So I kept my visit brief, but my enthusiasm over the top...
Here's what I can report to the forum...
Engine Blocks:
Each of the two engine blocks have a stamped serial / part numbers that are different, but both begin with 112... and are followed by a dozen other numbers +/- (I will explain this difference in a later post) The blocks are really quite small and very light (Surprisingly, maybe 45 lbs)... and the cylinder diameter is tiny compared to a 350 block that was sitting nearby...Everything else appears to be exactly the same spec sizes, bolt locations, cylinder bore, exhaust, valve guides, intake, etc... I paid special attention to the shape, design and bolt patterns of the location that bolts-up to the transmission bell housing, every aspect appears to be exact, which means the manual transmission could bolt directly to the AMG engine...The exhaust ports contain the typical casting roughness and would benefit from the port/polish process (not nearly as bad as some of the old chevy and ford engines i've seen)...
Pistons:
I had to pull the (new) pistons out of boxes to look at them...My first impression was "these things are tiny"... Noticed that rings were already installed... Asked Mike what his cost was on each piston ($230 for either 320 or 32)... Piston heads are dished on both, but appears the 32 pistons are dished a bit deeper than the 320 (to lower the compression ?)
Gotta finish this later... But it looks like we can do this engine swap from NA to SC, providing we have the electronics to match...