Building Chevy 4.3 liter V6 - 1994 with balance shaft
(→TECH STUFF ABOUT THE 1994 4.3l V6) |
(→SEARCHING FOR PARTS) |
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Looks like the heads will have the pressed studs removed and replaced with screw in studs and the valvespring pockets will be machined as well as the stud bosses to get good seating for springs and studs. The seat height at the moment is nice. The difference measured over the valves tips is less than 0.01" (0,1 mm). Exhaust valves protrude a lot more into the combustion chamber due to thicker material which adds to compression. The decisions about the seat cutting can be done only after I have the proper geometry figured out. To get some basic figures I have to put a head onto the block and use clay to see what valve clearance is based on the OEM camshaft. | Looks like the heads will have the pressed studs removed and replaced with screw in studs and the valvespring pockets will be machined as well as the stud bosses to get good seating for springs and studs. The seat height at the moment is nice. The difference measured over the valves tips is less than 0.01" (0,1 mm). Exhaust valves protrude a lot more into the combustion chamber due to thicker material which adds to compression. The decisions about the seat cutting can be done only after I have the proper geometry figured out. To get some basic figures I have to put a head onto the block and use clay to see what valve clearance is based on the OEM camshaft. | ||
| − | == | + | == THE PARTS == |
One of the downsides of this engine is the fact that nobody ever took care of serious builds on this base. Although this engine has seen a myriad of applications and has been produced in millions it has never been seriously considered for racing or builds. It shares a great deal of common parts with the SBC V8 so a lot of parts can be sourced from there. The hot-rod magazine has probably built the ultimate 4.3l V6 showing the potential. | One of the downsides of this engine is the fact that nobody ever took care of serious builds on this base. Although this engine has seen a myriad of applications and has been produced in millions it has never been seriously considered for racing or builds. It shares a great deal of common parts with the SBC V8 so a lot of parts can be sourced from there. The hot-rod magazine has probably built the ultimate 4.3l V6 showing the potential. | ||
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The 1.94 Intake and 1.50 Exhaust valves should have acceptable flow at low lifts which would be a nice thing for a daily drive and low to mid rpm power band modifications. At the same time this will keep the cost way down. Modifications for screw in studs and decent roller rockers should deliver more power and a sturdy valvetrain. | The 1.94 Intake and 1.50 Exhaust valves should have acceptable flow at low lifts which would be a nice thing for a daily drive and low to mid rpm power band modifications. At the same time this will keep the cost way down. Modifications for screw in studs and decent roller rockers should deliver more power and a sturdy valvetrain. | ||
| + | As of 2016-04-21 I got my order from Summit with the majority of parts for the build. I'll gibe a short brief on the parts and the reasons for ordering them. | ||
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| + | '''CRANKSHAFT''' | ||
| + | Got one from a guy close by who does marine engines. The crank is nearly brand new. As it may only need some polishing I'll go for this one. I consider this an option also for a build when simply buying a new crank OEM casting. It is a huge step up to a billet crank and I would consider that only if building an all out racing engine or a serious hot rod build. | ||
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| + | '''CONNECTING RODS''' | ||
| + | Ordered EAGLE rods CRS570063D which is an H-beam rod. Careful when building the V6 - the big end bore is 2.225" not the V8's 2.125". As for my research this holds true for all the even fire engines in the 4.3l V6 series. The odd fire may have the 2.125" big end bores. Even at summit they list rods with the wrong big end bore for this application. (The solution is - measure - measure again - order) | ||
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| + | '''PISTONS''' | ||
| + | Will be a custom order JE forged pistons as pointed out below. As soon as I get them I'll list the item here. | ||
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| + | '''CAMSHAFT''' | ||
| + | COMPCams mildest grind will be used to be compatible with the stock TBI and computer and still be within emissions limitations. It is a 260/266 degree duration cam. Lobe separation 112 deg and durations of 206/210 deg at 0.050" lift. For the V6 with balance shaft. | ||
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| + | '''TIMING SET''' | ||
| + | Part number is: 56-440-8 (CV6B) 260AH-R12 | ||
=== MACHINING AND PORTING === | === MACHINING AND PORTING === | ||
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