Sneakyboy: In comparing the photos in replies 6471 and 6473 it appears that the headbolt bosses of the original configuration are isolated from the surrounding materials whereas in the “new” configuration everything, including the outer perifery, appears to be coplanar.
What’s going on there?
Are we losing preload to the water jacket and other areas?
In a word, YES. That is the situation as it stands at this moment.
Although the block has been comprehensively "re-machined" in certain areas, certain other areas were left "untouched" because of the inability of the facility to deal with sizes much smaller than what is "normal" in USA racing.
So the net result of all this is that once the block returns to Beerhaven, some inspection is going to be necessary to evaluate just where the situation is at. The block and sleeves assembly is now in what I would consider to be in "semi-finished" form. I expect that with the modifications performed, and the upgraded lower "ladder" combined with the ARP stud kit, that the crank axis will be "distorted" enough to require align honing. This was an operation that the block facility could not perform. Some of the machine work (such as the final surfacing) may have been performed "out of order", due to this inability to service small sizes. But, this is the nature of racing an "oddball", 2 steps forward, 1 step back, if you will.
One of the "evaluations" is going to be considering the differential in expansion between the alloy block and the iron sleeves. Based on my prior experience, at this point I am "uncomfortable" with the idea of reduced "pre-load". I need to calculate how much growth "differential" there might be. If this number is small enough, say .001" or .002" max, I could be convinced into thinking that the increased fastener pre-load will overcome the differential in thermal expansion. That, in a nutshell, is the position of the block machinist. I'm waiting to do the numbers before I commit, one way or another. Of course if the numbers are "unfavorable" resurfacing the head gasket interface to add "pre-load" always remains an option.
And something else to consider is that if there are any problems with water jacket leakage while dyno testing, the head gasket interface may need to be re-evaluated. What this might require, I can't say at this point, other than to speculate that the engine may require the use of some sort of MLS type head gasket to resolve any problems. In any event, I'm confident that any problems can be resolved in an orderly and timely fashion.
Like so many other racing engines based on production parts, this one is also going to be: A triumph of development over design.
So to add a personal insight that probably isn't necessary, I'm far more comfortable making decisions based on reviewing numbers that I, or others, calculate. Even if it "elongates" the development timeline.
As opposed to say, the "speedier" methods of guessing, throwing darts or rolling dice. I'm perfectly happy to let others use those decision making methodologies . . . . . . and reap the benefits thereof.
Slideruleboy
Topic: Milwaukee Midget (Read 3576687 times)