Guest Posted March 7, 2002 Share Posted March 7, 2002 OK HERE I AM AGAIN I GOT THE BLOCK AND HE MEASEURED THE FACT THAT IT HAD BEEN BORED '30 OVER,DOES THAT MEAN BIGGER DISPLACEMENT?? IF SO HOW DO I GO ABOUT THAT? HERE IS THE RECIPE THE SELLER GAVE ME. 10 TO 1 COMPRESSION APPROX .500 CAM .4.60 LIFT FLAT TOP PISTONS FORGED STEEL CRANK ARP FASTENERS SHOT PEENG THE RODS PORTED HEADS I HAVE ABSOLUTELY LITTLE KNOWLEDGE OF WHAT MOST OF THIS STUFF EQUATES TO SO I NEED HELP. I WOULD LIKE YOUR INPUT ON A RECIPE (ON A BUDGET FOR 400-450BHP LIKE MOST OF YOU RECOMMENDED. ANS PLS TELL ME WHAT TO SHOP FOR FROM HEADS TO PISTONS TO CAMS. PLEEEEAAASEEEE. AND HOW DO YOU CALCULATE THE DISPLACEMENT (LITRES OF THE ENGINE ONCE COMPLETED) ALSO IF IT WONT BE A BOTHER TOSS AN EMAIL (THAT WORKS) SO I CAN GET BACK TO YOU AND ASK A FEW MORE QUESTIONS.(WOULDN'T MIND SOME TEL#'S EITHER) THANKS A LOT JAV240Z ("AN I-6 DOES NOT A SUPERCAR MAKE") Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted March 7, 2002 Share Posted March 7, 2002 you still did not give enough info to make valid guesses on what you have now but lets start from scratch heres how to figure displacement (engine size in cubic inches) http://www.smokemup.com/utilities/calc/displacement.cfm compression http://www.smokemup.com/utilities/calc/compression_ratio.cfm other usefull stuff http://members.aol.com/fastnuf1/calc.html now horsepower is mostly about air flow and effectively useing it so a great set of cylinder heads is mandatory,these are about the best for money spent, http://www.canfieldheads.com/sbc_2600.html get a good rotateing assembly put together if you don,t have a good one now, http://www.scatcrankshafts.com/smblckrotatingkits02.html e-mail me for more questions, prlangevin@hotmail.com Quote Link to comment Share on other sites More sharing options...
Guest Posted March 7, 2002 Share Posted March 7, 2002 TRIED THAT EMAIL ADDRESS BUT IT FAILED ME GRUMPYVETTE PLS EMAIL ME AT BAJEJU@AOL.COM AND ASK ME WHAT YOU NEED TO KNOW TO BE ABLE TO HELP ME THANKS AGAIN Quote Link to comment Share on other sites More sharing options...
utvolman99 Posted March 7, 2002 Share Posted March 7, 2002 Im not sure what "ported" heads your running or what you are planning on doing with the car but you need to be careful with 10:1 compression ratio. If you are running iron heads and want to use pump gas you really need to stick to >9.5:1 CR to avoid detonation. If you are running aluminum heads then you should be fine with 10:1. I dont know if your building your engine yourself or if you have an engine builder. If you are using an engine builder you probably should quiz him. He should know not to exceed 9.5:1 CR for pump gas. JMHO Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted March 7, 2002 Share Posted March 7, 2002 utvolman99 what you said about the static compression ratio and detonation is on the surface correct but its the DYNAMIC COMPRESSION RATIO not the static compression ratio that determines when or if youll have detonation problems,remember that piston is not compressing anything untill both valves are closed, now the main things that effect the DYNAMIC COMPRESSION RATIO are stroke, bore, rod length,and cam timeing.and yes iron heads are slightly more prone to detonation problems because they hold heat better in the combustion chamber.look this over and down load the program. http://cochise.uia.net/pkelley2/DynamicCR.html Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted March 7, 2002 Share Posted March 7, 2002 Ummm, JAVV, your posts are interesting, but please follow "proper" protocol by turning off your caps lock key so your posts aren't in all capital letters. It makes it appear that you're shouting, and makes your stuff hard to read. Thanks! Quote Link to comment Share on other sites More sharing options...
utvolman99 Posted March 7, 2002 Share Posted March 7, 2002 That is some good info grumpy. I also would suspect that the shape/condition of the combustion chamber would make a difference also. a somewhat smooth combustion chamber would stand less chance of having a "hot spot" that could ignite the charge. Whould this be correct? Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted March 7, 2002 Share Posted March 7, 2002 thats true , if you are interested about detonation read this, http://www.zhome.com/ZCMnL/PICS/detonation/detonation.html http://victorylibrary.com/mopar/cam-tech-c.htm http://www.rolexhaust.com/Technical/Analysis/Detonation.htm Quote Link to comment Share on other sites More sharing options...
Guest Thurem Posted March 20, 2002 Share Posted March 20, 2002 Grumpy I just downloaded the dynamic CRcalculator,from here http://cochise.uia.net/pkelley2/DynamicCR.html The one you recommended. My question is, what kind of dynamic compression ratio would be recommended to use with 87octane gas. My heads are Vortec,with the chambers are polished and I intend to build the motor with tight quench,ie. zero deckheight. The reason for the 87 octane requirement is, one I'm cheap, two I might wanna drive the car in Mexico (crappy gas) Thanks Thure Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted March 20, 2002 Share Posted March 20, 2002 if your stuck with crap gas I would try for an 8.3/1 dcpr and no higher than 8.5/1 tops on the dcpr. remember cylinder pressure =TORQUE but too much cylinder pressure + heat gets you DETONATION PROBLEMS so its a ballanceing act! BTW polishing the surface finish on the combustion chamber to a totally smooth finnish and very slightly rounding the combustiom chamber edges also helps prevent detonation problems and thats something you can do by hand with sand paper if you want to spend a very boreing day to make your engine run better (a 120 grit starting size and a 320 grit finish grit works ok) for this Quote Link to comment Share on other sites More sharing options...
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