compression distance help???
Postmaster
Joined: Jun 2005
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it's the distance from the center of the wrist pin to the very top of the piston.........
shorter CH will leave the piston down the cylinder lowering the compression.
chart http://victorylibrary.com/mopar/deck-height.htm
shorter CH will leave the piston down the cylinder lowering the compression.
chart http://victorylibrary.com/mopar/deck-height.htm
Freshman User
Joined: Dec 2006
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ok, so when I am looking at pistons I need to find some that have the same or longer compression height than stock 351w pistons, not shorter... next question, how much longer can I go on compression height before I run into deck clearence issues? looking at somewhere around 480 valve lift... and would like to see 9.5:1 comp ratio
Postmaster
Joined: Jun 2005
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do the math stroke 3.5 / 2 = 1.75 + the rod 5.954 = 7.704 + 1.796 CH = 9.500 Deck
so on a 9.5 deck you should look for a piston with a 1.796 Compression heigth..or close to it.
get the piston as close to the top as you can...for good quench you want it tight to the head...decking the block is always a good thing to do, it gets the deck nice and straight and you can raise compression a lot quicker than planing the heads. .010 out of the hole is a very doable thing....
so on a 9.5 deck you should look for a piston with a 1.796 Compression heigth..or close to it.
get the piston as close to the top as you can...for good quench you want it tight to the head...decking the block is always a good thing to do, it gets the deck nice and straight and you can raise compression a lot quicker than planing the heads. .010 out of the hole is a very doable thing....
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Hotshot
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From: south louisiana
Valve clearance to the pistons isn't just dependent on total lift, it's also just as dependent on duration and the actual timing events. The contact points are on the exhaust stroke as the piston chases the exhaust valve up the bore, then at or close to TDC, the intake valve starts to open, then it chases the piston back down the bore after TDC. For a .480 lift cam to have problems, the duration would have to be extremely long and have lots of overlap to cause a problem.
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its an edelbrock cam, 2182 I think... the .480 is an approximation of the lift... it may be 482 or something. I can look it up, but I'm not really going for 12:1 or anything... want to be able to run on 87 or 89 octane.
I'm gonna start another thread for my next question, but I will leave it here too since it is somewhat related... anyone know the compression chamber size for a 75-77 granada 351w head? not sure of the casting numbers on them, but its a 2bbl windsor
I'm gonna start another thread for my next question, but I will leave it here too since it is somewhat related... anyone know the compression chamber size for a 75-77 granada 351w head? not sure of the casting numbers on them, but its a 2bbl windsor
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