RE: cam ready
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RE: cam ready - 3/23/2007 7:59:15 PM
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machineman
Posts: 58
Joined: 3/11/2007
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quote:
ORIGINAL: GRIFF
I was thinking about this a little and I think we can figure out more if we knew the piston spec. Is there a name or part # on the piston. Can you get a picture of the piston and post it maybe someone can match it up. Question for the machine shop guys.. is there a way to measure the piston volume like you would head volume?? Once we have this we can figure out the compression ratios, static and play with the dynamic on cam choice. 300 ft/lb is bs for your 400 by the way.
Is this a flat top, dish or a dome?
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Chris Crossont
A.H.M. Performance
Baltimore, MD
http://www.ahmperformance.com
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RE: cam ready - 3/23/2007 11:02:20 PM
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machineman
Posts: 58
Joined: 3/11/2007
Status: offline
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quote:
ORIGINAL: GRIFF
Dished, I was thinking you could find tdc clamp a piece of plexiglass on the deck with a hole drilled in it use a heavy oil in a measured ml container and fill keeping track on how much was used... just a thought
Try this. You need a jar that is graduated in cc's, some liquid such as alcohol and clay or play-dough. Take the clay and smash it into the dish. Make sure it is filling in all the gaps. Then take a razor and trim the excess so you are left with a flat piston after the clay is in place. Fill the jar to about half. making sure it is even with a number or line. Now, take that clay out (you can ball it up at this point to make it easier to handle) and drop it gently into the liquid. The gain in liquid height is the amount of cc's in the piston dish.
We have found that this is easier than trying to keep liquid running past the rings, etc. It is a lot less messy too.
_____________________________
Chris Crossont
A.H.M. Performance
Baltimore, MD
http://www.ahmperformance.com
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RE: cam ready - 4/7/2007 3:09:10 PM
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cc82z28
Posts: 14
Joined: 11/10/2006
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If it's a stock type dish with 2 small valve reliefs cut into them, then they may be -16cc dish pistons which is what I am running in my 400. With the vortec heads and the fact that you have decked the block, I think your comprssion is going to be higher than you think. Go to campbellenterprises.com, they have math calculator for figuring it out. Just fill int the necessary numbers and it will calculate your numbers. My engine with a -16cc piston, .025" in the hole deck, .038", head gasket and a 62cc head figures out to 9:95:1 compression.
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RE: cam ready - 4/11/2007 10:17:12 AM
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rat454
Posts: 159
Joined: 12/6/2006
Status: offline
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quote:
ORIGINAL: GRIFF
Something to look at when calculating compression also is some of the pistons dont achieve the .025 deck height I have one now with the replacement dish pistons that is more like .040 (measuring from the highest point) I think they put the pin location higher for some reason.
this may also be due to the rod center to center being off a little. when they sized the rod they may have ground more of the rod end than the cap and or taken more metal out of the rod end of the hole. or if only one rod was resized. Also if the crank grinder got off just a little on the stroke on one journal it could also throw it off, but ususally that shows up in the two cylinders that share the journal.
either way the compression ratio won't be drastically effected.
G
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71 Camaro roller cam 454 LS6 tremec TKO 600 5 speed 2.56 gears,t-top, New Mexico plate "RAT454"
74 Monte Carlo 95 LT1 drive train swap, full computer
77 C10 short step 4x2 454 T-400 hugger orange 496 rwtq
67 Buick Electra 225, 430 tire burner
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