Building Chevy 4.3 liter V6 - 1994 with balance shaft
(→2016-JAN-22 - TEARDOWN, THE REST) |
(→THE PARTS) |
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'''PISTONS''' | '''PISTONS''' | ||
| − | 2016-03-30 Today ordered custom pistons at JE-Pistons. They will be forged flat top with two valve relief pockets for the V6 (means a set of 6). We're running the risk as we had to get the compression distance (CD) right in order to achieve the target 10:1 compression ratio (CR). The stock pistons sit so low below deck that the standard 1.5" CD did not work out. Even the available 1.565" is not even close enough to reach 9.7:1. At this time we're aiming at zero deck height with a 1 mm (0.04") gasket uncompressed so we get an ideal 0.85 mm (0.034"). It will be interesting enough to see what the squish will do once we get it right. The OEM stuff is a joke and will not produce any squish. I have nearly a 1/4" distance to the heads flat portion. | + | 2016-03-30 Today ordered custom pistons at JE-Pistons. Actually ordered them only on the 2016-06-20 as my machine shop forgot about them... They will be forged flat top with two valve relief pockets for the V6 (means a set of 6). We're running the risk as we had to get the compression distance (CD) right in order to achieve the target 10:1 compression ratio (CR). The stock pistons sit so low below deck that the standard 1.5" CD did not work out. Even the available shelf pistons with a CD of 1.565" is not even close enough to reach 9.7:1. At this time we're aiming at zero deck height with a 1 mm (0.04") gasket uncompressed so we get an ideal 0.85 mm (0.034"). It will be interesting enough to see what the squish will do once we get it right. The OEM stuff is a joke and will not produce any pronounced squish. I have nearly a 1/4" distance to the heads flat portion from the dish. |
| − | The piston pins will be full floating at 0.925" diameter to fit on standard rod's small ends. We will use wire locks as the dual spirolocks would be overkill on a street engine which I will hopefully not rebuild a second time. I hope to use the Blazer to haul parts around and not fix it again. Because of the rather tame target rpm we're not going crazy with the rings. Just ordered them as file fit's to define gaps when building it. | + | The new piston pins will be full floating at 0.925" diameter to fit on standard rod's small ends. We will use wire locks as the dual spirolocks would be overkill on a street engine which I will hopefully not rebuild a second time. I hope to use the Blazer to haul parts around and not fix it again. Because of the rather tame target rpm we're not going crazy with the rings. Just ordered them as file fit's to define gaps when building it. |
'''TIMING SET''' | '''TIMING SET''' | ||
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'''PUSHRODS''' | '''PUSHRODS''' | ||
| − | + | Once the geometry has been defined (after machining the heads) and a test assembly has been made with the test rocker arm I have ordered we'll go an measure for custom pushrods. I'll be using COMPCams lifter measuring kit. | |
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| + | '''ROCKER ARM STUD KIT and a bit of a warning''' | ||
| + | ARP 100-7201 (ARP-100-7201) Set of screw in rocker studs. If correct they will feature a 3/8 by 24 thread for the rocker arm to be compatible with the adjustable nuts. WARNING - I have ordered studs with M10x1.5 mm threads for the screw in portion. This metric thread is common at my place and will make machining easier but may cause confusion in the US. One review actually stated that the buyer found out he had no tap for this thread. So make sure you get the correct one for your application. | ||
'''ROCKER ARMS''' | '''ROCKER ARMS''' | ||
COMPCams 1618-1 (CCA-1618-1) Ultra Pro Magnum Rocker Arm at 1.6:1 ratio. I have ordered just a single one to be able to check the valvetrain geometry for the machining of the studs and check rocker arm height with the OEM valves. At the same time I want to make sure they do not interfere with the OEM plastic covers. With the new camshaft I should already have about .100" more lift at the camshaft. I'll see during a test assembly if it fits. The lifter I have been sent is a self adjusting featuring two lips left and right of the roller tip thus most probably eliminating the need for guide plates. | COMPCams 1618-1 (CCA-1618-1) Ultra Pro Magnum Rocker Arm at 1.6:1 ratio. I have ordered just a single one to be able to check the valvetrain geometry for the machining of the studs and check rocker arm height with the OEM valves. At the same time I want to make sure they do not interfere with the OEM plastic covers. With the new camshaft I should already have about .100" more lift at the camshaft. I'll see during a test assembly if it fits. The lifter I have been sent is a self adjusting featuring two lips left and right of the roller tip thus most probably eliminating the need for guide plates. | ||
| − | ''' | + | '''VALVE SPRINGS''' |
| − | + | I'll employ beehive valve springs. The seat pressure and open pressure will be determined once the heads are finished and test assembled. We'll have to open up the valve pocket on the heads and at the same time machine the guide bosses on the upper portion of the head for more lift and new seals. | |
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| + | '''VALVES''' | ||
| + | Most probably I'll end up with stainless steel valves in OEM sizes. These will be determined again with the test assembled heads and engine with pistons as we have also to define clearances with the piston. | ||
=== MACHINING AND PORTING === | === MACHINING AND PORTING === | ||
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'''HEADS - MACHINE''' | '''HEADS - MACHINE''' | ||
| − | 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. Came up some new information about valvetrain geometry which will be incorporated here. Most probably I will need guide plates as | + | 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. Came up some new information about valvetrain geometry which will be incorporated here. Most probably I will NOT need guide plates as the rocker arms have stem guides. |
Machine the valve spring pockets and the valve guide bosses for clearance to accomodate the new lift and oil seals. | Machine the valve spring pockets and the valve guide bosses for clearance to accomodate the new lift and oil seals. | ||
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