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429 Performance cam valve/piston clearence issues?
Im building up a 429 performance engine. Im using the stock crank (which as been gas nitrided) new rods and pistons that are stock dimensions. I calculated the pistons should be about .050 under deck height at TDC (top dead center). The cam that i want to run which is harder to pick out then i ever anticipated is gonna have max lift of about .560ish...With that lift will i be running into piston vavle clearence issues with a stock pushrods???
Im trying to save time with this info so i dont have to do a mach up to see if ill have the clearence problems which i normally do. also im running a cam duration of 235 intake - 245 exhaust im trying to make max power but best streatability...any remarks on this combo would be appreciated Thanks Vince |
Seems pretty mild to me compared to many, but I am not a 429 guy. I'm sure others will chime in.
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Vinstang I would do a mach up just in case if i was you. Are you using the 2.08 or the 2.25 intake valves. I am building a 429 as well but i am using a 460 crank and stock size rods and 11.1 pistons and the big valve, cam is going to be around 305 adv duration and 610 lift. 72cc heads, i will mach up for sure. good luck
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If you want to be sure, you're going to have to put the heads on with clay on top of the pistons and rotate the crank several times. Then pull the heads off and mike the clay and see what you end up with.
Tim |
You might want to check out my engine build thread here:
http://www.clubcobra.com/forums/show...4&pagenumber=1 I used clay and did a "test" assemble to check for valve to piston clearance issues (427 vs 429 but the principle is the same). During this procedure I ALSO discovered my push rods were to short. It's just good "buiseness" to do a "dry assemble" on your motor and check ALL clearance issues. .050 below deck piston height and a "nominal" lift in the 500's should leave plenty of clearance I would think. Check out the "Squish and Quench" section of my build regarding piston deck height issues and WHY I like "zero deck piston height" whenever possible. Edit: With the clay, after you've hand rotated the engine a few cranks, just cut the clay in half on the top of the piston. Measure the depth of the clay from the valve impression (if any) to the top of the piston. Should be at least or around .100 thousand. |
u never said if ur useing a hyd cam or solid, plus ur 560 lift is soooooo small, at least use a 588 to 605, 588 hyd clear ,with .020 in the hole ,even if u deck the heads .010,ur pistion .050 in the hole? this engine will run a little warmer than most
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