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Author
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Topic: High compression questions
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Kyle
Gearhead Posts: 400
From: Sumner, WA
Registered: Dec 2001
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posted 02-25-2004 02:29 PM
   
I'm looking at purchasing a 347 stroker kit, for the Fairlane, made up of Scat cast crank and I-beam rods, and Keith Black dome pistons. The pistons have a 10.6cc hollow dome, and, taking into account the 60cc Victor Jr. head chambers and a .041" compressed head gasket, and a -.015 deck, would put me at right about a 13.3:1 compression ratio.So, with the aluminum heads and an iron block: -What octane fuel will I most likely need to use? -Are there any special timing requirements when running a comp. ratio that high? I know that detonation really needs to be kept under control, espically with hyperutectic pistons. ------------------
Kyle Laramore '63 Fairlane: Under Re-construction '66 Mustang Coupe: 289, Offy intake, Crane Blazer hyd. camshaft, Autolite 4100 carb, Headman long tube headers, 3spd tranny, 8" rear, 3.80 gears '70 Mach 1: 351C-2V, Weiand intake, 750 holley, Flowtech long-tube headers, MSD ignition, C6 trans, CJ converter, 9" track-loc rear, 3.50 gears, Flowmaster 2.5" mandrel exhaust w/ 3-chamber mufflers Words to build engines by: "Never Assume!" My Photo Page
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steve'66
Gearhead Posts: 8826
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 02-26-2004 05:20 PM
114 octane Kyle, or alcohol.I don't like hyper pistons above 8-1 compression.  SteveW
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Tea'sGrabber
Gearhead Posts: 276
From: Seattle, Wash.
Registered: Feb 2003
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posted 02-26-2004 06:08 PM
Kyle... Are you saying the piston is.015 below the deck or are you taking .015 off the block???? 13.3:1 is alot of compression with a KB piston. To take advantage of it your going to have to spin the motor pretty high... I'm real close to 13:1 and and I run VP C-16 or C-14+.... My timing is locked out @ 35.... ------------------
Todd 71 Mav Grabber All orig 306 cu.in. Cast Iron heads. Carillo Rods.Best et. 10.71 @ 124 thru the mufflers.
http://mustangsandmore.50megs.com/MembersPics/TeasGrabber.html
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Kyle
Gearhead Posts: 400
From: Sumner, WA
Registered: Dec 2001
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posted 02-26-2004 06:27 PM
The piston is will be .015 down in the block. Do you not like a KB piston at that compression because of the increased possibility of detonation?
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steve'66
Gearhead Posts: 8826
From: Sonoma,CA,USA
Registered: Mar 2000
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posted 02-26-2004 08:54 PM
quote:
Originally posted by Kyle:
The piston is will be .015 down in the block. Do you not like a KB piston at that compression because of the increased possibility of detonation?
Raising the compression increases combustion chamber pressure just like a little boost or a shot of n2o. Sure it increases the chance of detonation, and the increased h.p. and rpms. KBs are for street engines not race engines. IMHO anyway, Melissa has a necklace from a small piece of BBC piston from a rival of hers. It was the largest chunk of his KB piston with a hole drilled in it on a string. It is expremely light weight stuff.  She won't let it get near the Mustang, it's like cryptonite.  SteveW
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Tea'sGrabber
Gearhead Posts: 276
From: Seattle, Wash.
Registered: Feb 2003
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posted 02-27-2004 11:24 AM
.015 in the whole will probably promote detonation at that CR. you could probably get away with a forged flat-top if you zero deck them and mill the heads a bit. have you bought all your pieces yet??? If not... my motor's 4 sale???????? it's fresh and alot cheaper than were you going.... ------------------
Todd 71 Mav Grabber All orig 306 cu.in. Cast Iron heads. Carillo Rods.Best et. 10.71 @ 124 thru the mufflers.
http://mustangsandmore.50megs.com/MembersPics/TeasGrabber.html
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SteveLaRiviere
Administrator Posts: 43152
From: Saco, Maine
Registered: May 99
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posted 02-27-2004 02:56 PM
That kind of compression ratio with hypers is suicide.------------------
'70 Mustang Mach 1 351C 4V/FMX/3.25 Open
'70 Mustang Convertible 250 I6/3 speed/2.79 Open
'72 Mustang Sprint Hardtop 351C 4V/FMX/4.30 Trac Loc
'94 F-150 XL 5.8L/E4OD/3.55 Limited Slip
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Kyle
Gearhead Posts: 400
From: Sumner, WA
Registered: Dec 2001
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posted 02-27-2004 04:07 PM
Well, I think i'm going to ditch the hyper piston idea. I wasn't too happy about using those types of pistons anyway. I mean, why would you buy a part that you know has a history of breaking up? I've heard all the stories about hyper pistons vs. forged pistons, and I would rather save for the forged ones.Tea's: I have the Vic. Jr heads, but I havn't bought any of the other parts yet. I am interested in what you are selling, so I will email you. Thanks all for guiding me in the right direction!
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