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Quench vs. C/R vs. Fuel octaine
#502160
10/20/09 04:23 PM
10/20/09 04:23 PM
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Joined: Jul 2004
Posts: 1,101
Retired now in Tennessee
Chi_Town_Runner
OP
super stock
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OP
super stock
Joined: Jul 2004
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Retired now in Tennessee
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I'm in the porocess of building a 383/438 stroker. On the KB calculator my computations come out as follows Heads = 84cc Piston Head volume = 4(valve reliefs on flat top pistons) Gasket Thickness = .029 Gasket Bore -= 4.350 Cylinder Bore = 4.310 Deck clearance = .010 Stroke = 3.750 Computes to STATIC compression of 10.203 adding rod length = 6.760 Valve timing @ 6* Intake closing point = 38* Dynamic CR = 9.472 I am trying to keep the quench at .040 so if I were to use a head gasket of .039 I would have the block decked for 0 deck clearance. Will this run on the 91 octain I have available to me. If not what do I need to do to keep the quench but lower compression (if I have too)? Thanks  Frank
Remember - 2 wrongs don't make a right - but 3 rights make a left!
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Re: Quench vs. C/R vs. Fuel octaine
[Re: Chi_Town_Runner]
#502161
10/20/09 06:56 PM
10/20/09 06:56 PM
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Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
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Posts: 36,040
Lincoln Nebraska
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Quote:
Will this run on the 91 octain I have available to me. If not what do I need to do to keep the quench but lower compression (if I have too)?
With those numbers I believe so and I'd make sure of all my measurements to get em exactly where I want them. If you go w full floating pins you can mock everything up, measure & easily pull the pistons to machine them for an exact zero deck height to go with your .039" gaskets. If needed you can enlarge/polish the chamber(s) with your porting burrs/tootsie rolls. Doesn't take much material to be removed.
Last edited by RapidRobert; 10/20/09 07:07 PM.
live every 24 hour block of time like it's your last day on earth
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Re: Quench vs. C/R vs. Fuel octaine
[Re: dynorad]
#502163
10/20/09 07:37 PM
10/20/09 07:37 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
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I Live Here
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Columbia, CT
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as it calculated, no. But I think your number for the intake valve closure is off. What cam is it? You need the spec for .050 lift... not .005 or .006 lift....
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Quench vs. C/R vs. Fuel octaine
[Re: moper]
#502164
10/20/09 07:54 PM
10/20/09 07:54 PM
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Joined: Jul 2004
Posts: 1,101
Retired now in Tennessee
Chi_Town_Runner
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OP
super stock
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They are full floating pins, The cam (not yet purchased) is Comp Cams XR274HR-10 Hydraulic Roller (let the solid guys begin  ) Duration I/E = 274/282 Duration I/E @ .50 = 224/230 Lift I/E = .538/.534 More thoughts Frank
Remember - 2 wrongs don't make a right - but 3 rights make a left!
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Re: Quench vs. C/R vs. Fuel octaine
[Re: 64Post]
#502170
10/20/09 09:57 PM
10/20/09 09:57 PM
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Joined: Jul 2004
Posts: 1,101
Retired now in Tennessee
Chi_Town_Runner
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OP
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Joined: Jul 2004
Posts: 1,101
Retired now in Tennessee
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Thanks, Quote:
At 6000' emphasis should be placed on cylinder pressures, otherwise you'll end up with a dog of a motor.
But now how to alter or adjust cylinder pressure without effecting C/R or can't you?
Remember - 2 wrongs don't make a right - but 3 rights make a left!
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Re: Quench vs. C/R vs. Fuel octaine
[Re: RapidRobert]
#502173
10/20/09 11:13 PM
10/20/09 11:13 PM
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Joined: Jul 2004
Posts: 1,101
Retired now in Tennessee
Chi_Town_Runner
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The cam has not yet been purchased. I'm taking the block to the machinist on Thursday so at this point I can make any adjustments with no downside. Thanks Frank
Remember - 2 wrongs don't make a right - but 3 rights make a left!
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Re: Quench vs. C/R vs. Fuel octaine
[Re: Chi_Town_Runner]
#502174
10/21/09 08:15 AM
10/21/09 08:15 AM
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Joined: Jan 2003
Posts: 74,974
U.S.S.A.
JohnRR
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I Win
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U.S.S.A.
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Frank , what heads , iron or alum ? Closed chamber or open ? As far as machining each piston for perfect quench ... first off that's  , second , it's impossible unless he had A CUSTOM piston made because a quench head piston for a 383 stroker DOES NOT EXIST , so if it's the custom the last thing I would be doing is cobbling up a $1000 set of pistons.
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Re: Quench vs. C/R vs. Fuel octaine
[Re: JohnRR]
#502175
10/21/09 09:04 AM
10/21/09 09:04 AM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
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I Live Here
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Columbia, CT
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Like John said... easier to get tthe machining right then individually fit each piston..
I agree at 6000' you want more squeeze... I confess I'm a sea level guy so how much is too much I am not sure. I do know Comp doesnt publish the intake closing event but you should be able to get it from them by phone if you ask.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: Quench vs. C/R vs. Fuel octaine
[Re: JohnRR]
#502176
10/21/09 09:49 AM
10/21/09 09:49 AM
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Joined: Jul 2004
Posts: 1,101
Retired now in Tennessee
Chi_Town_Runner
OP
super stock
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OP
super stock
Joined: Jul 2004
Posts: 1,101
Retired now in Tennessee
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Heads 440source stealth 84 cc Pistons are flat top with 2 valve reliefs Compression height 1.320" Thanks for any additional input. I'll be on the phone today to Comp re specs. As I said, the cam has not been purchase yet so I have flexability with that. Any thought on that? I may post a new thread re: cam selection. Frank
Remember - 2 wrongs don't make a right - but 3 rights make a left!
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Re: Quench vs. C/R vs. Fuel octaine
[Re: moper]
#502178
10/21/09 11:13 AM
10/21/09 11:13 AM
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Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
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Quote:
as it calculated, no. But I think your number for the intake valve closure is off. What cam is it? You need the spec for .050 lift... not .005 or .006 lift....
 my cam is a little [Email]259@.006[/Email], [Email]208@.050[/Email] hydraulic roller, 112LSA installed at 108, and my intake close point, going by .006" lift advertised is ~57.5 degrees ABDC.... 0.50 duration is 32 degrees ABDC....mine is a 318, 9:1 measured, no quench (.083" quench distance), and runs on 87 octane.
I'm guessing the number you really need to use to determine DCR is going to be closer to 60 deg. ABDC....
EDIT, seeing the cam you choice, 274 .006 intake duration (what comp uses for "advertised duration"), if installed at 106 ICL, would net you an intake close point 63 degrees ABDC, not 38. the KB calculator says to use .050 ICP+15 degrees, which nets 53 deg. ABDC. using .006 numbers you get
8.2 DCR, using the KB method nets 8.8....it should run fine on 92 or 93, you may have to be a little conservative with your distributor's timing curve.
Last edited by patrick; 10/21/09 11:21 AM.
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