NEW DIAMOND FORGINGS FOR ALL 454-502 CHEVROLET ENGINES
Sun, 2009-08-02 10:00
The Chevrolet 454 and GM Performance Parts 502 cubic inch engines are mainstays of the street machine, drag race, dirt track, 
marine, street rodder aftermarket.
Both the 454 and the 502, regardless of rating or application, have always been equipped with a forged rotating assembly: both of them with a 4.00-inch stroke crankshaft and 6.315-inch long connecting rods. The 454 came on line in the 1970 model year as a production engine; the 502 arrived in 1996 as an aftermarket unit that was never offered in a production vehicle. In 2000, however, it was initiated for marine applications by Mercruiser, but is no longer available.
Original equipment for both engines included Speed Pro pistons (PN 693CP). Though forged, a nominal compression ratio of 8.75:1 left much to be desired. Now, the original forgings are no longer available from Speed Pro. The Chevrolet 454 and GM Performance Parts 502 cubic inch engines are mainstays of the street machine, drag race, dirt track,marine, street rodder aftermarket.
Both the 454 and the 502, regardless of rating or application, have always been equipped with a forged rotating assembly: both of them with a 4.00-inch stroke crankshaft and 6.315-inch long connecting rods. The 454 came on line in the 1970 model year as a production engine; the 502 arrived in 1996 as an aftermarket unit that was never offered in a production vehicle. In 2000, however, it was initiated for marine applications by Mercruiser, but is no longer available.
Original equipment for both engines included Speed Pro pistons (PN 693CP). Though forged, a nominal compression ratio of 8.75:1 left much to be desired. Now, the original forgings are no longer available from Speed Pro.
Diamond Pistons acknowledged that as well as the need for a bit more compression and developed 4032 alloy replacement pistons for both cubic inch capacities. Using the 454 as an example and depending on combustion chamber volume (112, 118, or 124cc’s) and bore size (4.270, 4.280, or 4.310-inch), the Diamond forgings produce compression ratios of 10.4, 9.4, or 8.9:1, respectively. The compression ratios for both engines are calculated with the piston situated 0.005-to-0.020-inch below the deck surface.
Although the top ring land on both forgings is 0.300-inch down from the piston deck, the ring packs differ; the 454 manages 5/64-inch widths for the top and second rings, and a 3/16-inch oil scraper. The 502 uses 1/16, 1/16, and a 3/16-inch oil ring. Considering the use of 2.190-inch intake and 1.88-inch exhaust valves for both engines, valve pockets for the 454 are 0.270-inch on the intake and null for the exhaust valve. The 502 provides a 0.280-inch pocket for the intake and nothing for the exhaust.
Piston pins are Trend premium 8620 chrome-moly (case-hardened alloy steel); H-13 and 9310 endurance alloy pins are optional. The H-13 is through-hardened (same hardness throughout) and is ideal for drag race applications, especially in the presence of a power adder. A 9310 pin is chrome-moly steel made from aircraft-certified bar stock, however it is not recommended for power-adder engines.
454 bore size/part #: 4.270 PN12703
4.280 PN12704
4.310 PN12706
502 bore size/part #: 4.470 PN12701
4.500 PN12702
4.530 PN12703
For more information contact, visit www.DiamondRacing.net
marine, street rodder aftermarket.Both the 454 and the 502, regardless of rating or application, have always been equipped with a forged rotating assembly: both of them with a 4.00-inch stroke crankshaft and 6.315-inch long connecting rods. The 454 came on line in the 1970 model year as a production engine; the 502 arrived in 1996 as an aftermarket unit that was never offered in a production vehicle. In 2000, however, it was initiated for marine applications by Mercruiser, but is no longer available.
Original equipment for both engines included Speed Pro pistons (PN 693CP). Though forged, a nominal compression ratio of 8.75:1 left much to be desired. Now, the original forgings are no longer available from Speed Pro. The Chevrolet 454 and GM Performance Parts 502 cubic inch engines are mainstays of the street machine, drag race, dirt track,
marine, street rodder aftermarket.Both the 454 and the 502, regardless of rating or application, have always been equipped with a forged rotating assembly: both of them with a 4.00-inch stroke crankshaft and 6.315-inch long connecting rods. The 454 came on line in the 1970 model year as a production engine; the 502 arrived in 1996 as an aftermarket unit that was never offered in a production vehicle. In 2000, however, it was initiated for marine applications by Mercruiser, but is no longer available.
Original equipment for both engines included Speed Pro pistons (PN 693CP). Though forged, a nominal compression ratio of 8.75:1 left much to be desired. Now, the original forgings are no longer available from Speed Pro.
Diamond Pistons acknowledged that as well as the need for a bit more compression and developed 4032 alloy replacement pistons for both cubic inch capacities. Using the 454 as an example and depending on combustion chamber volume (112, 118, or 124cc’s) and bore size (4.270, 4.280, or 4.310-inch), the Diamond forgings produce compression ratios of 10.4, 9.4, or 8.9:1, respectively. The compression ratios for both engines are calculated with the piston situated 0.005-to-0.020-inch below the deck surface.
Although the top ring land on both forgings is 0.300-inch down from the piston deck, the ring packs differ; the 454 manages 5/64-inch widths for the top and second rings, and a 3/16-inch oil scraper. The 502 uses 1/16, 1/16, and a 3/16-inch oil ring. Considering the use of 2.190-inch intake and 1.88-inch exhaust valves for both engines, valve pockets for the 454 are 0.270-inch on the intake and null for the exhaust valve. The 502 provides a 0.280-inch pocket for the intake and nothing for the exhaust.
Piston pins are Trend premium 8620 chrome-moly (case-hardened alloy steel); H-13 and 9310 endurance alloy pins are optional. The H-13 is through-hardened (same hardness throughout) and is ideal for drag race applications, especially in the presence of a power adder. A 9310 pin is chrome-moly steel made from aircraft-certified bar stock, however it is not recommended for power-adder engines.
454 bore size/part #: 4.270 PN12703
4.280 PN12704
4.310 PN12706
502 bore size/part #: 4.470 PN12701
4.500 PN12702
4.530 PN12703
For more information contact, visit www.DiamondRacing.net
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