Building Chevy 4.3 liter V6 - 1994 with balance shaft
(→2016-JAN-22 - TEARDOWN, THE REST) |
(→MACHINE THE HEADS - VALVETRAIN) |
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I have removed all the studs and prepared for screw in studs. I'll go with 3/8" studs. The choice of rockers will also be decisive. Aiming at a nice steel roller rocker such as CompCams Magnum Pro Roller Rocker 1,6:1. The geometry defined I'll have the bosses machined for proper height of the studs then the centers bored according to proper alignment from the lifter bores to the valve stems. Most probably I will NOT need guide plates as the rocker arms have stem guides. | I have removed all the studs and prepared for screw in studs. I'll go with 3/8" studs. The choice of rockers will also be decisive. Aiming at a nice steel roller rocker such as CompCams Magnum Pro Roller Rocker 1,6:1. The geometry defined I'll have the bosses machined for proper height of the studs then the centers bored according to proper alignment from the lifter bores to the valve stems. Most probably I will NOT need guide plates as the rocker arms have stem guides. | ||
| − | '''CAUTION:''' | + | '''CAUTION: ROCKER ARM STUDS''' |
The replacement studs proposed for this exact engine will not work! SUMMIT proposes ARP studs which are shorter than the V8 parts and feature a M10x1.5 thread for the base thread. This means the outer diameter of the screw in part is 10 mm. The original bosses on my heads have a diameter of 9.4 mm which leaves us with 0.6 mm diameter to cut the tap which is 0.3 mm on each thread. This is a mere 0.012"! | The replacement studs proposed for this exact engine will not work! SUMMIT proposes ARP studs which are shorter than the V8 parts and feature a M10x1.5 thread for the base thread. This means the outer diameter of the screw in part is 10 mm. The original bosses on my heads have a diameter of 9.4 mm which leaves us with 0.6 mm diameter to cut the tap which is 0.3 mm on each thread. This is a mere 0.012"! | ||
The diameter of 9.4 mm is a perfect center bore for a 7/16"-14 thread. | The diameter of 9.4 mm is a perfect center bore for a 7/16"-14 thread. | ||
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Machine the valve spring pockets and the valve guide bosses for clearance to accomodate the new lift and oil seals as well as the new springs. | Machine the valve spring pockets and the valve guide bosses for clearance to accomodate the new lift and oil seals as well as the new springs. | ||
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| + | '''CAUTION: VALVE COVERS''' | ||
| + | Even when having machined the bosses I'll end up about 5 mm (1/4") above the height the original rockers had. This is even withouth the poly lock nuts which protrude an additional 5 - 8 mm. In order to clear the valvetrain I'm planning on machining a 20 - 25 mm thick aluminium plate to act as a spacer. The next step is to check on the installation if it will fit under the hood. | ||
=== PISTONS - ZERO DECK === | === PISTONS - ZERO DECK === | ||
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