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For those that wished.....well here is Zak's information and lesson on BRF
Wayne Baldwin's ZAK crankshaft report is not just historical and even personal to racer's that have them they are so immediately instructional, so why not store this webpage section to your computer as a download for posterity and even re-print it for your personal notebooks.
On the instructional side it shows that a racer having 2 mounted centers on a simple jig along with a magnetic or fixed repositional dial guage can use the ZAK diagram to check forged or cast crankshafts and even help build or reset multi piece crankshafts. Harry Zak's simple instructions not written but implied and are really in that diagram and "point out" report. You can use this same checking setup be it a one cylinder or 6 or more cylinder crankshaft. The end result, what ever you do when it comes time to set the crankshaft in its main bearing sets through out a Merc, OMC or what ever 2, 4 or 6 cylinder crankshaft engine which means the end caps on, reed blocks without the pistons and rods assemblies, crankcase then tightened and torqued down to secure all critical bearings with their torque hold down pressures, simply slowly then rotating the crankshaft in situ like this will measure your results of your crankshaft work.
That is through out any degree of crankshaft rotation with a inch pound torque or in case foot pound wench on the end of the crankshaft there should be no difference in inch or foot pound torque right around the 360 degree in situ rotation of the crankshaft. Should you find any stiffness or binding in rotation at any degree in that rotation it shows up too on the torque wrench and close visual inspection of the slow rotations should pick up the binding point problem identifying it for possible addressing or change repair. Doing this adding on to crankshaft assemblies with rods, pins but no rings and going through this torque wrench turning process can diagnose any further binding on any further pre-piston ring installing phase and finally with rings loaded and engine assembled, set up and torqued using a torque wrench in final rotation with rings checked for breakage through inspection ports, the measured rotation with the wrench can pickup any final prior to actual start up and run binding conditions through the full rotation of the crankshaft. Find any unusual binding in these phases or rotations of the crankshafts in these phases of engine preparation means you have a problem to diagnose and fix.
These tips are of course are given and dependent that all block preps are done so that the crankshaft will lay straight and true in an aligned block ready to accept a straight crankshaft or identify a crankshaft with out of wack measurement problems for what ever the reason. This may be a lot to digest but getting into it a little taking some interest makes it all the easier, satisfying and knowing what you are eventually going to put in the engine and together carefully will be very good assembly with good results.
For those just looking for straight crankshafts to get some stock to work with later, it is as easy as taking an inch pound or ft pound torque wrench to a salvage block, lubricating with block innards through plug holes etc. if long time storage making it all internally dry and then rotating the crankshaft in situ to check for the binding and at would degree of rotation to find if the crankshaft or some other part of the assembly creates a problem like crankshaft bend, hydralic bend problems elsewhere and so on. Makes for a great negotiating strategy when your buying used motor powerheads assemblies for parts because you would know about inner rotational problems with some simple tips and tricks.
For Merc 4 enthusiasts with 2, 3, and 6 cylinder engines most of the same applies as all the others. There is one other difference though if the powerhead is apart and your looking for straight crankshafts is to look at the aluminum or brass non roller bearing carrying reed blocks. It is simply examining the flat or in case ribbed labrinth seal machining that surrounds the crankshaft at that point for wear. No contact and non scratched reed block surfaces combined with the crankshaft missing the same wear elements where the reed block surrounds is an extra indicator including all the others that would tell you the crankshaft is relatively straight to even dead straight. If there is damage on one side (the reed blocks, crankshaft side and usually both) there has to be a crankshaft or closeby related problem that translates into the crankshaft and its rotation. Also look at the inner block side reed block locating pins. If they are in tight and there is no wobble or looseness in any direction that would indicate a stable crankshaft at work as the reed blocks contacted by the crank would loosen the reed block locating pins. Reed block locating pins found very loose, ovalled or fracturing their surrounding aluminum even to the point of cracking and breaking the nearby cast iron or other ferros type cylinder liners would indicate severe vibrations of a bent crank. Similarly these reed block locating pins breaking through surrounding metal could indicate excessive crankshaft end play from bad bearings, or wrong setup in assembly etc. where the crank is physically bouncing up, down vibrating horribly and damaging the engine in which case you could have a damaged engine block between cylinder pairs, damaged crankshaft, reed blocks and related assemblies.
All these are good tips and tricks as any crankshaft rotational binding using these simple tricks or tips lead to finding a good rotating crankshaft that will not cause performance difficulties in any engine. Similarly these same elements are used to check, build or repair piece together crankshafts.
We all know and recognize there are those that can and will use this information and others where this all presents varying problems that may be too hard to address or there is no want to address and would sooner pay others to do competently. Coupled to this there are crankshaft specialty places that with some economies of scale and pricing systems for work needed and or done specialize here like Pete Nydahl's crankshaft services in the USA's midwest or an outfit called Associated Crankshafts up in this neck of the woods. Some outfits also can not only do this but find a slightly bent crankshaft have the capability to straighten them too but again many things outboard racers deal with can be expensive to the economical so doing what ever but be cheaper just purchasing another new or good used product for less than the cost of fixing the bad part you have. It all needs examination.
Wayne: Your picture is a great way to get information out that is very technical for everyone else in the technical section found elsewhere on BRF but it also applies so very much here in British Anzani or its cousin the Harrison (HRP) racing engines threads webpages. Thank you for giving this subject matter a good nudge into gear!
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