I'm working on a stroker project that I picked up second hand and I'm trying to figure out what recipe the guy was building. So far I've found that I have a 258 crank (4 weight), 258 Rods (5.875 length 352 casting) pressed on KB 3241HC pistons ( 18cc dish - 1.592 pins). I also have a 96 block that has been bored (.30), line bored, and had the deck cleaned up. I guess where I'm falling down is that on the machine shop receipt it states that the deck was trued but no material was removed, it was just trued but not milled down any. With these parts shouldn't I have to mill the deck surface and dish the pistons to 22cc? It looks like its ready to be assembled but I wondering if there was an oops or am I messed up?
Thanks
Dean
"You'll bunk with private Joker. He's silly and he's ignorant but he's got GUTS and guts are enough!"
You don't NEED to deck the block, but it is recomended to tighten up the quench height.
The dishing of the pistons is to lower the compression, which has been raised from decking the block.
So...If I don't deck the block will the thing run on pump gas? I think the smart thing to do is put the thing together and check the deck height to see if the block really has been cut. What kind of measurement should I be looking for from the top of the piston to the top of the deck?
Thanks
Dean
"You'll bunk with private Joker. He's silly and he's ignorant but he's got GUTS and guts are enough!"
The way you are now, if the deck is at stock height you would be around .080-.082 quench height with a .043 head gasket.
You are correct the best thing to do is mock up the engine and measure the distance from the piston at TDC to the deck. It would be around .040-.038. The closer you can get to zero the better quench you have and the less chance for preignition or ping, but then you have to dish the pistons or remove from the combstion chamber to lower the compression because too much compression is as bad for ping as a bad quench.
The best case would be to have a zero deck height. Then the quench would be the thickness of your head gasket.
The machine shop may have billed to check the block deck for flatness, they may not have removed any material if it was within spec. Look at the deck surface for a stamped number as it is traditional to mark the deck with the amount of material removed. IE .005 might be stamped on the surface if a light cut has been done for flatness.
John
