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I begin by grinding for clearance at the cam tunnel area.
This is the area I hope will give clearance going by past
experience. The type of I-beam connecting rod that I'm using
will always need additional clearance in this area.. An H-beam
will not require additional grinding.
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I decided to put the rear main cap oil galley plug in at this
time. I can always punch it out and install a new one if I end
up having to do more work on the block such as grinding and cleaning.
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The main bearings are the King MB577XP and the oil hole does not
line up with the block. I decided to clearance the bearing instead
of grinding the block.
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Main cap bearing clearance process begins. Here we have the
main thrust cap, (#5) at 0.0034"
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And the rest: All using standard size bearings top and
bottom. .0021 to .0034"
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Main thrust by feeler is .004"
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Main thrust after crank installed, (crank end-play) = .007"
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#1 Rod bearing clearance at .0026" (standard size King
bearings CR807XPN). All the rest were from .0026 to .0028"
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Time to see if the rods will clear the block.
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Right off the bat #1 rod shoulder bumps the inboard cylinder
bottom...(marked in yellow).
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Here is a close up. I will need to remove the crank/rods and
grind in that area. On purpose I did not install the cam
bearings for just this situation. After all the block grinding
is complete then I will install the cam bearings.
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It turns out that all other rods clear. It was only #1 that
does not. That's not all too bad. Next on the to-do list
is to disassemble and grind/clean and reassemble.
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More clearance grinding at the bottom of #1 bore.
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After a thorough cleaning of the block the camshaft bearings are
installed.
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Here is a reference photo of the cam numbers. This is a mild
street cam grind #62801-62702-112, 215/227/112, .546"/.565"
with 1.6 rockers.
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Camshaft installed. Oil galley plugs installed. These
have weep holes for oil cooling of the timing set.
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Ring gap: Top ring at .018", 2nd ring at .014",
(Street/Strip all natural)...as per Mahle suggestion.
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The ring gap is also checked with ring in the bore.
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Timing set on. This is so that I can check each piston/rod
combo one at a time for clearance with the camshaft.
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One final look at the rod/piston.
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All installed and no interference with cam or block.
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Rod side clearance is .020" to .022" Rod bolts at
70ft-lb
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Crank sprocket installed at "O" (zero).
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Intake centerline is dialing up at 106*. The cam card spec
is 108*.
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Trying the +4 sprocket setting gives 102* ICL
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Trying the -4 sprocket setting gives 110* ICL. I decided to
put it back to zero and go with 106* ICL.
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The heads are mostly bone stock genuine GM LT4. The owner
did a valve lap and new springs and seals. The non adjustable
rocker studs are shown in the photo. The pushrod length will
need to be established. In a nutshell the pushrod has to allow
for 1 turn past zero lifter pre-load.
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Turns out I have an adjustable pushrod and I set the pushrod
length that gave a tight rocker nut at 1 turn past zero
pre-load. That ended up being 7.310", (Stock is 7.200"
and so I'll order a set of 7.300" pushrods).
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I also want to check the valve spring height with various
keepers/locks. This shows 1.748" with the locks in the
Lunati spring kit.
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In the vice a 1.748 compressed spring gives 170psi. I like
it.
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Back to the bottom end. I have a re-supply of Milodon
windage studs and have them installed.
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The stock windage tray is massaged up and away from the rods.
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Melling M155 oil pump.
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Now with the oil pump pickup.
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Now the Corvette oil pan. Surprisingly it did not need to be
massaged for rod clearance.
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FelPro 1074 head gaskets. .039" - .003" =
.036" piston to head clearance.
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Heads on with ARP head bolts at 70ft-lb
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Back to the valve spring and making sure they are mostly all the
same spring height. Since there were no shims installed, (just
spring locators), I want to make sure all of the springs are similar
in height. Some valves are showing less tip than the others
indicating the spring would be installed higher, (1.760").
I checked all that were "off" and installed Crane locks
which brought all of the springs in the range of 7.740" give or
take .005"
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Here is a visual of the shorter valve tip.
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The one on the left is the 1.740" spring and the one on the
right is 1.760"
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Swapping valve locks.
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Back to the pushrods. Turns out the 7.300" pushrod was
too long. Thankfully I had a set of 7.250" by TREND.
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All rockers are from 3/4 to 1 turn after zero pre-load. The
preload is not adjustable. The 7.250" pushrod allows for
the 1 turn after zero pre-load (tight rocker nut bottomed out on the
rocker stud).
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