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joesnow
 Post subject: Piston height
PostPosted: Sun Oct 28, 2018 4:08 pm 
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Joined: Thu Dec 23, 2004 9:35 pm
Posts: 270
Location: South Eatern Pa
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Just pulled the head and found I scored a remanufactured 225...
244np sealed power .030 pistons
Dang they are deep in the hole....
My head I'm going to use is cut .100
How deep are stock pistons?
Any suggestions?
Budget is small...
I have other stock engines to pick from...
Looking to put something together to race...

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Doctor Dodge
 Post subject: Re: Piston height
PostPosted: Sun Oct 28, 2018 4:40 pm 
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Joined: Sat Oct 12, 2002 11:22 am
Posts: 3740
Location: Sonoma, Calif.
Car Model: Many Darts and a Dacuda
Factory "blueprint" is .145 down in the cylinder... (-.145 compression height)
Most stock engines I measure are in the .180 to .200 negative compression height range.

You will need to cut the head AND the block to get the needed compression for decent DCR on a race engine using a performance cam.

Shorter custom push rods are needed once you get the compression ( focus on dynamic or "effective" compression) to a place to support a performance camshaft.

Try to take most of the deck height reduction material off the block because it has more mass and a thicker "deck".
Most of the "race" (big cam) SL6 engines I build need .100 off the block and .050 to .100 off the head...
and shorter push rods.
DD
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Greg Ondayko
 Post subject: Re: Piston height
PostPosted: Sun Oct 28, 2018 5:59 pm 
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Supercharged
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Joined: Sat Nov 27, 2004 8:03 pm
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Location: IRWIN PA
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My '69 dart uses stock pistons.
On stock 225 rods and crank in a 225 block.

Approx 0.100" off head and 0.100" off block.. and yes shorter push rods.


Greg

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joesnow
 Post subject: Re: Piston height
PostPosted: Mon Oct 29, 2018 6:03 am 
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EFI Slant 6

Joined: Thu Dec 23, 2004 9:35 pm
Posts: 270
Location: South Eatern Pa
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Ok thanks....I'll have to go through what all I have to work with...lancer parts n all.

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Greg Ondayko
 Post subject: Re: Piston height
PostPosted: Mon Oct 29, 2018 7:31 am 
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Supercharged
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Joined: Sat Nov 27, 2004 8:03 pm
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Location: IRWIN PA
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If you are using stock pistons and rods it will anywhere from -0.100" to -0.185" in the hole.

Unless you go to 198 type rods or Molnar Rods / K1 Pistions etc that is what you will have to work with.

Happy Building!

Greg

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Dart270
 Post subject: Re: Piston height
PostPosted: Mon Oct 29, 2018 9:11 am 
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Joined: Mon Oct 21, 2002 11:08 am
Posts: 17298
Location: Blacksburg, VA
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Gotta measure the actual piston-deck ht at TDC. Dial caliper is a good way. If not disassembling the shortblock, you can take 0.100-0.140" off a head to get compression up to 10 or 11:1, if you want.

Lou

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slantzilla
 Post subject: Re: Piston height
PostPosted: Mon Oct 29, 2018 6:36 pm 
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Joined: Thu Oct 17, 2002 7:27 pm
Posts: 14769
Location: Park Forest, Illinoisy
Car Model: 68 Valiant
My Valiant motor has the block and head shaved for 10:1. Yes, I have short pushrods.

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emsvitil
 Post subject: Re: Piston height
PostPosted: Mon Oct 29, 2018 6:49 pm 
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Supercharged

Joined: Thu May 12, 2005 11:50 pm
Posts: 6291
Location: So California
Car Model: 64 Plymouth Valiant
Isn't it Piston Depth with a slant ?

:lol:

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