Advice - Pistons - Comp Ratio...quench factor ?! Yes / No ?

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Advice - Pistons - Comp Ratio...quench factor ?! Yes / No ?

Post  bigblockfordfxstb on October 8th 2016, 12:58 pm

Hi All,

Well last time I was working on looking to why the motor was running hot, and found that head gaskets incorrectly installed. (not me engine machine shop! Evil or Very Mad )

Looking to rid the copper head gaskets, dome pistons to run normal pump gas plus few other mods... more street application.

Need to know if the piston / head combination is ok and not a known bad idea for detonation on getting the quench / squish right?!   Any thoughts ?

The current setup is running estimate 13.66 Static Comp
460 +.030 , D0VE 75cc Heads (some port work) , Stock Crank,Rods (floating),Stock Stroke
Piston Forged -12.10 (dome) (1.756 Comp Dist)
Copper Gasket thickness +.042 (4.4 bore)
Deck I am working on +0.010 (was a bit all over the shop with what I had to measure (new deck bridge on order))
Edelbrock torker - single plane 2.5k-6.5k-RPM, 850cfm-E85, Flat - Solid  (dont have exact spec around 512Lift / x x Duration), Crane Roller Rockers
C6 Auto estimate 2500Stall..

New Setup
Static Comp - 10.14 (estimate pending on final deck and head cc)

The bore needs to goto 040' as already past the 30' mark
Heads 75cc (70cc-75cc)
Pistons Dish KB +22.00CC

460 +.040, Stock Crank,Rods (floating), Stock Stroke
Bore 4.4 , Stroke 3.850, Rod 6.605
Heads 75cc (minus a 2-3 thou .003' *to be CC'ed again
Pistons +22.00cc KB138-040 Dish- Comp Distance 1.772cc
Deck .00 (working on this)
Head Gasket (felpro) 4.5Bore / 0.042 thickness (8265PT1)
New Cam - Hyd Flat Cam Kit - less radical than before - somthing to 5500RPM range
Considering a Dual Plane manifold (open to suggestions?)
Bin the Holley for Fitech bolt on replacement (600 or 800hp unit (only looking at 800 model with laptop option tuning(playing)) over playing with the holley...
C6 - Lower Stall...

 photo HEAD at 73CC -- New - Piston - KeithBlack_zpsgyrzhwbr.jpg

 photo TRW L2443N_zpssvujsjar.jpg

 photo head-CC-75_zpsxk86ympl.jpg

 photo 020_zpsbv6qgyvx.jpg


 photo heads_zpsjshpcdzg.jpg

bigblockfordfxstb

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Re: Advice - Pistons - Comp Ratio...quench factor ?! Yes / No ?

Post  bigblockfordfxstb on October 24th 2016, 7:52 am



Different rods ?

http://i77.photobucket.com/albums/j55/uotinam/rods1_zpsrzqjskvo.jpg

 photo rods1_zpsrzqjskvo.jpg


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Re: Advice - Pistons - Comp Ratio...quench factor ?! Yes / No ?

Post  Scott Foxwell on October 24th 2016, 10:51 am

Deck clearance and head gasket thickness determine quench clearance. You want your quench to be in the .040-.050 range so with zero deck and a .042 gasket your quench should be fine @ .042".

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Re: Advice - Pistons - Comp Ratio...quench factor ?! Yes / No ?

Post  bigblockfordfxstb on October 25th 2016, 3:18 am

Hi,

Thanks for reply.

Looking at my options as the old pistons and rods are floating pin, so limited to KB138 .40 so guess its settled...

https://www.summitracing.com/int/parts/uem-kb138ktm-040/overview/


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