quench Q's
#173316
12/23/08 12:10 PM
12/23/08 12:10 PM
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Lincoln Nebraska
RapidRobert
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BB w 915 closed chamber heads. The dished pistons I have in mind have the perfect deck height which would give me good quench (.035") but the problem is that the diameter of the perimeter around the dish is .445" wide as opposed to a much larger quench area on a legitimate set of quench pad pistons. I can get these very cheap but if this will not be enough FLAT AREA to give me effective quench even though the piston to head distance is correct(.035") then I need to move on. What do you guys think? Thank you for your time.
live every 24 hour block of time like it's your last day on earth
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Re: quench Q's
[Re: RapidRobert]
#173318
12/23/08 01:40 PM
12/23/08 01:40 PM
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Moved to N.E. Tennessee
GomangoCuda
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You want a reverse dome piston. Only the area under the combustion chamber should be dished. the other side should be flat with no dish to maintain quench. Keep looking, they're out there.
In theory, there is no difference between theory and practice. In practice, there is.
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Re: quench Q's
[Re: Get-X]
#173319
12/23/08 01:42 PM
12/23/08 01:42 PM
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Posts: 36,040
Lincoln Nebraska
RapidRobert
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with good quench we could run a CR in the mid 10's on pump gas, no way that high without it. This fantasy buildup is a 440 block, 4.250" 440 source crank, 7.1" chevy rods & some eGay 403 olds cast pistons for just over $100. Problem is the non machined ring around the dish is only .445 wide but with a CH of 1.595, bore of 4.351"(std) it'd work ex for the not enough quench area. Might have to just spend the extra & get it right.
live every 24 hour block of time like it's your last day on earth
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Re: quench Q's
[Re: RapidRobert]
#173320
12/23/08 01:47 PM
12/23/08 01:47 PM
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Posts: 4,712
Moved to N.E. Tennessee
GomangoCuda
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Quote:
some eGay 403 olds cast pistons for just over $100
What are you going to do about valve notches?
Should look like this. Also called a D shaped dish. Unfortunately they are going to cost hundreds more than those Olds cast pistons.
Last edited by GomangoCuda; 12/23/08 01:52 PM.
In theory, there is no difference between theory and practice. In practice, there is.
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Re: quench Q's
[Re: RapidRobert]
#173321
12/23/08 03:11 PM
12/23/08 03:11 PM
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1_WILD_RT
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Quote:
with good quench we could run a CR in the mid 10's on pump gas, no way that high without it. This fantasy buildup is a 440 block, 4.250" 440 source crank, 7.1" chevy rods & some eGay 403 olds cast pistons for just over $100. Problem is the non machined ring around the dish is only .445 wide but with a CH of 1.595, bore of 4.351"(std) it'd work ex for the not enough quench area. Might have to just spend the extra & get it right.
Why would you use the olds piston when Brandon sells the dished quench piston for that combo?? With 84cc heads & the 17cc dish pistone, deck height set at 10.720 & a .039 gasket you get 10.35 C/R...Why fight it?
Edit recalculated with 81cc head (typical 915) & 10.725 deck height (.044 quench) 10.51 C/R
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Re: quench Q's
[Re: 1_WILD_RT]
#173322
12/23/08 03:43 PM
12/23/08 03:43 PM
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Lincoln Nebraska
RapidRobert
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alright you guys' expertise has persuaded me to do the right thing here, that & I just think I'd be uncomfortable with a GM part in there, heck I had a hard enough time using an aftermarket HEI module & only then because it was given to me. Thanks guys for taking your valuable time to guide me with this.
live every 24 hour block of time like it's your last day on earth
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Re: quench Q's
[Re: RapidRobert]
#173323
12/23/08 03:45 PM
12/23/08 03:45 PM
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1_WILD_RT
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Quote:
alright you guys' expertise has persuaded me to do the right thing here, that & I just think I'd be uncomfortable with a GM part in there, heck I had a hard enough time using an aftermarket HEI module & only then because it was given to me. Thanks guys for taking your valuable time to guide me with this.
If your worried about a GM part ya better lose the 7.1 rod & the .990 pin..  
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Re: quench Q's
[Re: 1_WILD_RT]
#173326
12/23/08 03:54 PM
12/23/08 03:54 PM
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Lincoln Nebraska
RapidRobert
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I used one of those custom brackets that tucks the hei up under the dist, was a noticeable improvement making the ecu/ballast/& wiring dissappear.
live every 24 hour block of time like it's your last day on earth
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Re: quench Q's
[Re: RapidRobert]
#173329
12/23/08 04:33 PM
12/23/08 04:33 PM
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1_WILD_RT
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Quote:
I remember when Holley came out with those projection setups. When you got it right was it good?
FWIW I worked as a electronic engine controls specialist for a Ford L/M dealer for years, so I have a pretty good background with electronics..Here's the story that I posted about it a few years back...
I ran a Holley Pro jection DFI system, it ran great....Sometimes...It had no memory capabilities, so the only way to find a problem was to be watching the laptop when it screwed up...If it were a hard fault, no problem, but intermittent problems weren't so easy...The first time I fired it up it had a failed injector...replaced TB assy under warranty...Next a intermittent air charge sensor, it was quicker to just buy one, only $50.00, running pretty good, took a road trip to LA, lost a MAP sensor about 15 miles from home, luckily it made the other 600 or so miles...Running good again, drove it most of the summer, not as consistent as the carter carb but way cooler to be able to pop the hood & say "Yeah its Injected"...  Another road trip, Sacramento, on the way there I start getting a surge, about 40 miles from home the surge starts feeling worse, I pull off the freeway & the car dies...Call AAA & tow it home...Lost a fuel pump, leaned out & cracked a manifold...As it turns out the exhaust wound up fighting me for three years after that till I got both the warpt flanges & the other manifold replaced as well...You know the carter runs really consistent I think FI is a good thing, I just feel Holley did a cheap half-a$$ job of it & used the cheapest components that the bean-counter in charge of purchasing could find...
I think that covers it...
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