As we approach the beginning of Mitsubishi Astron engine rebuilding season, it is time for the first in a series of tools that can help get the job done. A quality step in transforming a salvaged engine block into a working short block is checking the deck for flatness. One might think they could lay any old reasonably straight thing across the deck and mark it good, but unblown head gaskets on boosted engines depend on a perfectly flat deck. Measuring this kind of flat requires not just any straight edge, but a super straight edge – machined super straight. There is little room for error. The standard value of deck flatness on the G54B Astron turbocharged engine is 0.0020 inches, with a limit of 0.0039 inches, or one tenth of one millimeter. Checking for flatness requires a super straight edge and the right thickness of feeler gauge. Run the super straight edge across the deck in as many X and H patterns as possible, and see if the feeler gauge goes under the edge at any point. Looking close for any cracks at this time is also a good idea. The super straight edge is also useful for measuring flatness of intake and exhaust manifold surfaces, oil pump gear clearances, and countless other things where flat must be wicked flat. While you might be able to get away with using a belt sander and a vice to get that old Alfa Romeo exhaust manifold surface flat, this same method is not advised for engine block decks. Support your local machine shop to fix warped decks. Listening to SS Decontrol or Minor Threat and using the super straight edge is OK, but using that old McMetrics conversion ruler you picked up from the McDonalds in 1973 as a super straight edge is not.
The Super Straight Edge shown here came from Proform Tools, who were instrumental in the production of this edition of Tool of the Week.
http://www.youtube.com/watch?v=1w5aML-dbno
LMAO. McMetrics.
You sure you want to go to all that trouble with a 4G5-? Feigned individuality aside, a 4G6- installation would be so much more reliable and have much more potential, don’t you think, Mike?
I can understand if you’re going for OEM condition and the super clean, super stock project, but if you’re looking to do things a little differently and want to stick with the Astron, consider going 4D5-. 😉
I would use a 351W if I were you, but then you would have to check two decks…. but that would take two straight edges, right? You might be better off with two of them there G54B motors. Oh wait, still two decks. This will never work… Unless you get two happy meals, then its all good.
McMetrics. The wave of the future!
http://ny-image2.etsy.com/il_fullxfull.126526138.jpg
I’ve got two G54B blocks and enough connecting rods and crankshafts to put together three. Besides, who doesn’t love turbocharged forklift engines with throttle body injection? Modern engine swaps are far down the road, and probably in another Starion.