I just love to work with slant sixes. They are so simple!! Long block is completed now and waiting for the head to drop on. And maybe some paint. I have some light gray alkyd paint left, so maybe it will be gray. The firs engine I build I painted in orange (yes, that orange,the orange), but from ever since they have been flat black. Except the one in my daily driver. It should have been flat black, but for some reason it turned into semi-gloss dark grey. I can live with it.
When assembling the motor I found out two interesting things. One is deck height and another is timing marks. When I took this engine to machine shop I told to the machinist to mill off one millimeter from the head gasket surface, so that I would not have to mill so much material off from the cylinder head to get the compression ratio I wanted. Something in the 9-9,5:1 range would do just fine. When I instelled one piston I realized that the top of the piston was about 3,6mm below deck surface when at top dead center. That is about the number found in stock 225's! Yes, no material were milled off from the deck surface...The surface is machined, yes. It's very nice and smooth, but still at stock height. I guess I just have to mill the head some more. But I'm lucky because I didn't took the head to be machined at the same time with the block. Now I have a chance to fix this problem without any extra work. When the head goes to machine shop I just tell them to mill it a bit more than I planned to in the first place. The reason why I wanted the block to be "lowered" too, is because it has more material to work with than the head. If milling the head too much there is a small change that you will end up with head gasket sealing problems. Simply said, it is safer way to mill some of both than more from just either one.
Another interesting thing that I mentioned before is timing marks. They are needed when tuning the engine, especially when adjusting ignition timing. There is one mark on timing cover (or elsewhere) and another on the crankshaft. When these two marks match it indicates that cylinder number one is at top dead center. When assembling an engine it is very easy to check that timing marks are telling the truth. There are many reason why they are possibly lying and I'm not going to explain it all here, but when talking about slant sixes the most common reason is harmonic balancer failure. It is a part mounted to the front end of crankshaft and it's duty is to "dump" crankshafts harmonic vibrations .(they are dangerous and can be even lethal to the crank). It consists of two basic element, the inner part "the center" that is attached to the crankshaft and outer part "the ring" that is mounted around the center part using thin layer of rubber and vulcanization method. In slant sixes, the crankshaft timing mark is machined to the outer ring of harmonic balancer. If vulcanization fails, the outer ring may start to "slip" on the center part. If that happens (happens) the timing mark is no longer showing actual top dead center, when the timing marks match, it can be just about any number of degrees to/from top dead center to cylinder number one. The nasty thing here is that you maybe not see the failure, but end up with wildly inaccurate tuning. However, it is pretty easy to check that timing marks are where they should be.
I had already installed the harmonic balancer to the crankshaft and wanted to check and double check that they were showing the actual TDC. They were not. There was seven degrees "off set" between the reading from marks and real TDC. The problem turned out to be the balancer. It looks good, and there seems to be no visible problem with it, but obviously it is a useless piece. I found another one (many, actually) and it has the timing mark right where it belongs:) See the pics, crankshaft it at cylinder number one TDC, note the difference in timing mark position...