Today started with a couple hour project of building a sidemount flathead adaptor for my engine stand...then on with the teardown. This is what I measured. Not sure I've had the aha moment that said this is it!
Quote:
Originally Posted by chuck stevens
Tim, When you take out the cam I would be interested in what it mic's out to. You can hold the valves open with a small pieces of wood, turn the engine upside down
so the liftters drop down. Check the size of the inside of the bearings with the outside of the cam. It's alot to go though but now is the time to find out. Chuck S.
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I measured the cam journals at both the front and rear of the groove cut into each journal. The cam journals mic'd at:
1.7994" (front side of front journal), 1.7991" (rear side of front journal)
1.7997" (front side of mid journal), 1.7993" (rear side of mid journal), 1.7996" (front side of rear journal), 1.7992" (rear side of rear journal)
Cam bearing clearances measured at:
.0038" (front side of front journal), .0042" (rear side of front journal)
.0047" (front side of mid journal), .0045" (rear side of mid journal), .0039" (front side of rear journal), .0035" (rear side of rear journal)
(higher than the .002" limit)
Main bearing clearances measured at:
.0021" front cap
.0015" mid cap
.0019" rear cap
(within spec of .000-.003")
Con rod clearance measured at:
#1 .0013"
#2 .0001"
#3 .0017"
#4 .0034"
#5 .0015"
#6 .0011"
#7 .0015"
#8 .0018
#'s 1,2, 5, 6, & 7 (especially #2!) have clearances tighter than the acceptable range of .0017"-.0036"
With the engine out and the flywheel removed, I can confirm that the rear oil gallery plug is also in place. It seems to me that low oil pressure is still quite drastic relative to the oversize of .002"-.003" of the cam bearings...and the too tight con rods which would cause heat but not necessarily oil pressure loss (or am I missing something?).
I'm taking my pile of parts to a machine shop that does a lot of flathead work tomorrow.