callmejavier said:
I had Napa on Lake City Way (Seattle) do the machine work the first time. The experience was terrible, starting similar to what you describe. And the work that came back was wrong or bad or not done.
Now the block is at an factory rebuilder. A friend who works there should be able to direct the machinist with my info.
How do you measure deck flatness laterally (perpendicular to the crank) without being thrown off by piston rock?
Thanks.
j
Parallelism to the crank is a whole other issue. When the factory machines the raw casting they start with the crank saddles and oil pan rail. The crank and pan rail are assumed by subsequent operations to form a plane in space that is accurate unto itself which will hold the casting in proper alignment for further operations. This assumption is used to set up the following machine operations of milling the timing case and bellhousing faces, the cam bore, lifter bores, head decks, and cylinder walls. So each operation assumes the first operation was completed properly and the casting there after is aligned for the next operation always off the crank bores and pan rail. Castings that fall outside acceptable tolerances are removed from the line to be repaired or scrapped.
Depending on the equipment, the corner machine shop can either in part or in whole duplicate the factory machine experience, or if not well equipped it starts with the assumption that the crank bores and head deck are essentially correct and machine cylinder walls, or even the deck based on the assumption that the decks are centered around the diameter of the crank bores and are parallel to it. In these shops, like NAPA on Lake City Way, cylinder boring is often indexed off the head deck, so if that's out of line to the crank, so are the resulting cylinder bores.
Now the data I gave you on flatness and waviness do not take into account the surfaces alignment to anything. All we're talking about is how flat the surface is compared to laying a straight edge on it and measuring deviations between the two objects with a feeler gauge.
Typically a large rebuilder shop like your friend has access to, has machines that can duplicate the factory experience. The down side from a race engine builder stand point is that they run hundreds, if not thousands, of blocks thru the shop and make some dimensional assumptions to which all blocks are subjected whether they need the fixes or not. But some shops will do custom work on the night shift or on weekends and with this equipment that can do some extraordinary work.
A lot of the work you're intrested in having corrected really falls into "blueprinting". This adds a lot of expense to an engine because each operation is measured back to a corrected crank position. This takes a lot of time to make measurements and adjust the machine setups when your not in the one size fits all mode.
Getting good work can be difficult, especailly at afforable prices. I'm not adverse to sending parts all over the west coast to get things done, but around home in Western Washington I hang with these shops a lot.
- Autosport in Seattle for general machine work
- Castle Automotive Machine in Longview (a bit of a drive from Seattle, or Portland, but worth it. On the surface old man Castle does big rigs, heavy equipment, and shipboard; but he's a chronic racer which you can take advantage of)
- Delta Camshafts in Tacoma (What can you say when you break a cam in an old MG during the Tacoma Gran Prix and the guy from Delta looks at it and says well there's nothing like that in the northwest, but it looks a lot like a Massey Ferguson tractor cam, I bet we can re-machine one and get you racing, and so he did)
- Heads Up in Auburn (these guys weld on cast iron or aluminum, have heat treat facilities, and offer full machine shop services, they've forgotten more about head construction than most of us ever knew)
Bogie