Need help with pistons

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Aug 10, 2006 | 09:36 AM

shortbed1

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From: beaufort

Need help with pistons

Help fellows I've talked about this piston issue here before. Let me tell ya what i've done. I got a stock 69 460. Tore it up so i decided to rebuild it with some good parts. i will have a stock crank eagle h beams standard length got them free dove heads decent port job i went looking for a forged piston for floating pins and stock compression ? 10:5to1 and couldn't find them. Origanally bought a set of speedpro lw2602f which are flat top and was told that the compression would be to high. So i have a parts guy freind that said he would order me a set of custom pistons from je i told him i wanted a duplicate of the stock except forged , lightend and bushed the pistons came in and the dish is .195 deep way deeper than the stock i dont know if this is going to change compression or not i still have the speedpro piston also, someone said i could mill the top?? of piston to lower compression but i was told that i would still be over 11:1 to high for street driven which is what this will be. Im doing this because i want to spray about 200hp nitrous shot on it. These JE pistons are real nice lookin pieces but i dont want to instal them and have about 8:1 compression. MAN i need help on this. Thanks in advance chuck

Aug 10, 2006 | 02:03 PM

monsterbaby

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From: iowa

Ok, first thing you need to do is actually measure how much dish you have, then you can calculate what your compression will be. How I would measure it would be take a piece of plexiglass to cover the piston and drill 2 holes in it about 1/8" diameter (one to put water in and one to let air out) next install the piston into a ring compressor so it's even with the edge and put some grease around the piston to keep the water from going down the sides, then with a syringe (you cna get them at a vets office expecially if you anywhere near any livestock farmers) I use a 10cc for doing head CC measurements but in this probably a 3 or 5cc would work best, just fill it up keeping track of how much water you put in there, when the air is all gone and the water fills the space thats your CCs. It might not be as bad as you think.

Aug 10, 2006 | 02:17 PM

William

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From: Sun River St. George

Go to the KB Silvolite site and using their compression ratio calculator program and figure out what compression ratio you want based on how you expect to use this engine. A good general compression ratio for daily driver is 8.5 to 9 to 1 and if you can afford mid grade or higher octane fuel 9 or 9.5 to 1. Your choice of camshaft, head gaskets and cylinder heads all must be taken into consideration. The KB calculators will help you do that. A good machine shop is critical to building an engine that will live and perform the way you want. Anyone can give you a list of "bench racer" parts and you will wind up with an unhappy outcome. Are you a racer, street/performance or daily driver/commuter? Makes a big difference! My engine is a driver using mid grade fuel and goes like a bat out of Bagdad! If you want I'll PM you with specifics. If you race go here www.460ford.com!

Aug 10, 2006 | 02:25 PM

monsterbaby

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From: iowa

William, the calculator isn't going to do him any good until he figures out what CC dish the pistons actually are, then calculating compression is possible but without that figure your not going to figure anything out.

Aug 10, 2006 | 09:09 PM

shortbed1

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From: beaufort

Thanks u guys for responding, monsterbaby i did what u said with the plexiglass the only syringes i have are for my insulin so they only hold 1/2 cc. it took very close to 51 syringes full so approx 26 cc. I went to kb web sight and put in all the pertinant info and it looks like ill be around 9:3to1.Which is ok for me might have to rethink my cam selection but what the hay. My cam is a comp cam xe284h pretty stout hydraulic. what u think 466, roller rockers, dove heads, stainless valves, 3 angle valve job, porting on exhuast, 2800 stall, 3

0 gear, c6 trans, edelbrock air gap and holley 750 vac. allmost forgot the 225 shot of nitrous it has a compu car plate adjustable from 150 to 400hp thanks again, chuck

Last edited by shortbed1; Aug 10, 2006 at 09:13 PM.

Aug 15, 2006 | 05:41 PM

shortbed1

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From: beaufort

cam selection

Hey monsterbaby was really wondering what u thought about my combo especially the cam i have with the compression that ill be running. I'm not concerned about idle issues but really curious about performance with this setup gross valve lift is .584 int .588 ext duration at .006 tappet lift 284 296 110.0 lobe seperation. thanks again for any help u can give gotta love this site great info. chuck