probly in the wrong section but i figured you guys might give better advice i need help figuring out my dcr i triyed doing it myself and didnt like my numbers hoping im wrong


248/254 .615 .622 114

intake centerline 110

duration @ .006 297 307



VALVE EVENTS @.050 INT 14 BTDC 54 ABDC
EXH 65 BBDC 9 BTDC

BORE 3.905
4.00 STROKE
6.125 RODS
PISTONS .020 OUT OF HOLE -7.05CC DIAMONDS
62-64 CC HEADS WITH .045 GASKETS

 

I got around 10.6-1 SCR and 7.46:1 DCR. Assuming your intake lobe is symetrical (probably not) and your intake valve closes at 78.5 ABDC @.006. The past 2 motors I've built and every motor I build from this point will have SCR dictated by IVC.

 

bump!!!!!!!

 

Not like the answer I gave you? More cam info itself (what lobes) could get a more accurate result. What did you wind up with static compression?

 

i posted in both at the same time but thread got moved i ended up with 10.6 and 7.53

 

Is this your current installed setup?

 

Without a definitive advertised IVC, I'm getting a SCR of 11.3-11.6 and a DCR (assuming .006 IVC of 78.5) of 8.03-8.2, depending upon the chamber size of 62-64cc. These are basically the same results I get when I use this online calculator: http://www.csgnetwork.com/compcalc.html. Not sure what the discrepancy is between the different results.

Heads
Chamber volume (cc) 64.000

Gasket
Gasket compressed thickness (in) 0.045
Gasket Bore (in) 3.910

Block
Deck clearance (in) (+ below the deck, - above the deck) -0.020
Stroke (in): 4.000
Cylinder Bore Diameter (in) 3.905
Piston disk volume (cc) (+ for dish, - for dome) 7.050
Connecting Rod length (in) 6.125
Advertised Intake Closing timing (angle) in degrees ABDC 78.500

 

Crap, I was doing that for stock stroke. Jim is correct.

 

No its his current build not in the car yet.....he is building a 383 and only lacks the heads but he wanted to see if he was doing the math right....we both thought the 7.53 he was getting was off.......ITs the Texas Giant cam from TSP incase that helps u guys.

 

Posted in your other thread:

With 62cc heads:


With 64cc heads:

 

The calculator linked above doesn't account for top ring land volume which will slightly affect both SCR and DCR.