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  #1  
Old 10-13-2000, 10:53 PM
Sanman Sanman is offline
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I'm building a 440 mostly for street use. I have ported 906 heads and plan on using a hughes 3038BL camshaft. What are the best pistons for this application? I have heard good things about Keith Black's hypereutectic pistons. I was thinking about KB236. They recomend a maximum of .06 quench distance. With 906 head (polished chambers), .04 head gasket what could I expect the quench distance to be? I can mill the heads to get the quench right, but will my compression ratio be too high then?

Would I be better of with forged pistons?
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Old 10-14-2000, 01:11 AM
seventybee seventybee is offline
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i just put a 440 together and bought everything from hughs.the pistons are the KB quench dome style. i used the 452 heads ,had then shaved 50 thou.gasket matched and template ported. hugh's told me to have a 40 to 55 thou quench. after i asembled the shot block i stuck a head on wih out the gasket and the pistons would just,i mean just tuch the head.iwas abit worried so i gave them a call and they said that i was right on the money. with the 43 thou head gasket on,it was a good quench. well i put themotor in this spring and put around 15,00 miles on it with no problems and lot of HP.rev's fast. very happy with hughs.
mybe they ment 4 to 6 thou with out the gasket???

hope this helps

------------------

use it or loose it!
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  #3  
Old 10-14-2000, 03:17 AM
PRO PRO is offline
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KB has revised the quench deck to chamber clearance to .035 but up to .070 is still acceptable,beyond that your not taking advantage of the design.It will depend on the actual block deck heigth(they vary no more than .020 usually)and rod length,be sure to have your rod length checked and discard any that are more than .005 out.Ive built 4 BB mopars with these pistons & the clearance was so close that I only had to modify one by milling the heads .020 also dont forget you can buy .020 thick(compressed)head gaskets which can help you adjust quech clearance.To check use a test head gasket(new but reused)and clay on top of the quench dome and torque down the head and ratate a full crankshaft revolution,be sure to have adequate assembly lube in the rod bearings,enough to make up for no oil pressure...........PRO....
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Old 10-14-2000, 03:34 AM
451Mopar 451Mopar is offline
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Keith Black has several 440 "Quench" pistons, even some that are extra tall so you can machine the quench area down.

Blueprinting a quench engine takes a bit more machine work since you need to do:
1. Parellel deck the block to make sure the piston deck height is the same front to back, and preferably side to side also.
2. Mill the heads for the proper quench distance and also make sure the quench distance is the same on all the cylinders.
3. The rod distance can also affect this, but they are usually pretty close to equal length.
4. you need to blueprint the compression ratio. Measure the head cc's and deck clearance so you can re-calculate the new head volume after milling for the proper quench. Then order the pistons that acheve the Compression ratio you want.
I have a 360 small block with the KB232 (9.0:1 compression, dished quench pistons.)
From my calculations after decking the block (which was way taller than spec and the deck height was different end-to-end and side-to-side) and milling the heads I will probbly end up with somewhere around 9.5:1 to 9.7:1 compression. I will equalize (by polishing) the chambers after milling to get 9.5:1 which is what I want. The quench should come out right at 0.040", with the piston 0.002" down in the bore, and zero quench clearance with out the head gasket. The compresses head gasket is about 0.038" thick.
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  #5  
Old 10-14-2000, 05:06 AM
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440 Jim 440 Jim is offline
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Sanman,
You are on the right track. 0.040-0.060 quench is right (0.040 ideal). Trial fit/assemble and measure everything. IMHO, a 440 with iron heads and the HE3038 cam will tolerate about 10-10.5 CR with 93 octane. I like a little more cam HE 3844, but that is your call and depends on the car, converter, gear, etc...
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  #6  
Old 10-14-2000, 06:30 AM
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rumblefish360 rumblefish360 is offline
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I got a question. When is it to close. I'll give you my latest confusing seen.
The MoPar book will say to have .050 between piston & head.
Edelbrock (tech.line) said .035 was O.K.
If i'm running zero deck K-B pistons in my 360, & a Felpro gasket @ .039 thick. Don't you think thats to close.
Hey, I know when this thing revs up real high, there a bit of strech going on in there. A piston to head bangers ball is going to happen.
What would be a safe limit? I'm cuting my pistons i tell ya!
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Old 10-14-2000, 08:14 AM
451Mopar 451Mopar is offline
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I'm using 0.040" quench on my 360, but it is a RV engine in a truck with 3.23:1 gears and 30" tall tires. I doubt the engine will be reved much over 5,000 RPM.
I think higher RPMs and/or aluminum rods would require more clearance.
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  #8  
Old 10-15-2000, 04:34 AM
Billydelrio Billydelrio is offline
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Rumblefish, I had the same worry on my 273. It uses closed chamber heads and half dome pistons. I got carried away with the mill and ended up with the flats of the pistons out of the block .002". I read somewhere that rod stretch could be as much as .059" and got worried. I went ahead with the project having only .036" clearance between the flat of the piston and the head. I did have to notch the dome quite a bit for valve clearance. Any ways, I shift a 7500 and "don't think" that I have been experiencing interference.
Billy
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  #9  
Old 10-15-2000, 05:58 AM
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rumblefish360 rumblefish360 is offline
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You don't think..lol I guess you would know if you did though.
I'm useing a lil'caution. This may be the last one for a while. Ya know what i mean.
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