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Originally Posted by N0DIH I am not that familliar with the dimensions of the Quad 4 pistons, but you don't want to mess up the quench. You can mess with the other side, but the quench area is cruicial to helping manage and eliminating pinging. Typically around 0.040". Alum rods increases that by around 0.040 to 0.080. And if it has 4 valve relief's, are they in the correct position for the 4.9L? Same with N* pistons. BEing the 4.9L shares pistons with the 3.4L Chevy V6, pistons and rings should be plentiful and cheap. Sick puppies like me read websites like KB-Silvolite.com. It is interesting to find out what works with what... |
N* pistons are a very common hotrodding upgrade for the 4.9L engines..the "quench" area that you speak of on the N* pistons, 4 concave little etchings on the surface of the piston,is actually notfor that, but to create turbulence in the combustionchamber, which leads to cleaner, more efficient burning for the fuel. I was talking to BUd of Bu'd outback, a specialty shop out in arizona that specializes in hot rodding the 4.9L and N* engines, and he was telling me that gM originally put those concave 1/4-moon shaped etchings on the head around the outside of thevalves, but too many test heads were failing and cracking because of the lack of available space on the head because of having 4 valves per cylinder, so they put them on the pistons instead. anyways.. the N* pistons will actually burn cleaner than the 4.9L pistons. I dont know how well the quad 4 pistons will burn, but i talked with a friend who puts 4.9L engeins in fieros, he did the quad 4 piston swap, and said that the compresison is actually 8.5:1 without head work if you use the quad 4 pistons.