Building Chevy 4.3 liter V6 - 1994 with balance shaft
(→MACHINING AND PORTING) |
|||
| Line 321: | Line 321: | ||
=== PISTONS - ZERO DECK === | === PISTONS - ZERO DECK === | ||
| − | It turns out to be the major problem of this build and to solve it I'll have to do a complete test-assembly including camshaft and rockers with valves. JE Pistons states that 1.585 CD (compression distance/height) pistons are a "zero deck" application | + | It turns out to be the major problem of this build and to solve it I'll have to do a complete test-assembly including camshaft and rockers with valves. JE Pistons states that 1.585 CD (compression distance/height) pistons are a "zero deck" application. As my block is 9.025" deck height and I do not intend to machine .050" off that block. As I'm getting really close to the head now and using just the gasket to form the squish distance of some 0.030" - 0.040" (0.85 - 0.95 mm) in order to get good results, I will assemble it with the heads and valves and at the same time determine clearances. The pistons will need valve pockets to accommodate the greater valve lift. |
| − | Next will be a test assembly to figure the correct dimensions for valves, beehive springs, retainers (maybe titanium), locks and finally the pushrods once I have the geometry defined. | + | Next will be a test assembly to figure the correct dimensions for valves, beehive springs, retainers (maybe titanium - decided against as the beehive retainers are already smaller in diameter and lighter.), locks and finally the pushrods once I have the geometry defined. |
| − | + | ||
| + | == TEST ASSEMBLY == | ||
| + | It took quite a while to get it together for a test assembly. Mid of March 2017 it was the opportunity to put the block together with the crank I wish to use, one of the new EAGLE H-Beam rods and an OEM piston in order to come up with the compression distance (compression height) of the piston we want to use to get zero deck clearance. | ||
| + | |||
| + | The final result is a CD of 1.575" to reach zero deck. The pockets need not be very deep. Despite the higher lift of around 0.555" with a 1.6:1 ratio rocker arm with this lame camshaft it looks as not being a big issue. We'll see what comes from it once I have the new pistons where we end up. | ||
| + | |||
| + | === CAMSHAFT DEGREEING === | ||
| + | At the same time I had all the parts together I had the cam degreed. Turns out that the COMP CAMS grind is exactly on the advertised durations. The overlap is minimal, all in all a very mild cam which could work with the stock TBI without a new chip. Finally we'll see it on the dyno how it works out. | ||
| + | |||
| + | The large COMPCAMS degree wheel was a perfect assistant. The only thing I have to change is insert two thin plastic washers between the nut and the wheel in order to tighten the nut without turning the wheel again. A small pointer was quickly fabricated with a 1/2" wide strip of stainless steel sheetmetal. Makes a nice pointer and I can put the heads on without touching the pointer. | ||
Your Privacy Choices