460 Compression Ratio - 460 Ford Forum
Engine Tech A place to discuss all 385-series engine tech and theory.

User Tag List

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 25 (permalink) Old 05-21-2009, 11:13 AM Thread Starter
Member
 
Join Date: Nov 2008
Posts: 55
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
 
460 Compression Ratio

Would anyone know the approximate compression of a 460 using a replacement 460 pistons (1973-1979) with a set of DOVE heads? The engine now has D3VE heads and is probably in the range of 7.5:1--8.0:1 compression. I figure losing almost 20cc in the combustion chamber should maybe bump compression into the 9.0:1+ range. Any thoughts?
bbfguy1 is offline  
Sponsored Links
Advertisement
 
post #2 of 25 (permalink) Old 05-21-2009, 11:22 AM
RJP
Senior Member
 
Join Date: Jan 2006
Posts: 1,067
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
 
Rebuilder pistons with the 22 cc "bathtub" dish, a zero deck [10.295-10.300"] and the D0VE-C heads 75-77 cc should yield about 9.7-9.8 to 1 C/R
RJP is offline  
post #3 of 25 (permalink) Old 05-21-2009, 01:32 PM
Senior Member
 
The Mad Porter's Avatar
 
Join Date: Jan 2006
Location: Tacoma, WA.
Posts: 7,023
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 105 Post(s)
 
Cool

Quote:
Originally Posted by RJP View Post
Rebuilder pistons with the 22 cc "bathtub" dish, a zero deck [10.295-10.300"] and the D0VE-C heads 75-77 cc should yield about 9.7-9.8 to 1 C/R

That is the key !!! 22 cc dish pistons at ZERO deck.

The typical builder piston has a 1.752" compression height. These pistons would require a deck height of 10.282". In an uncut early block that would net .018" below deck. Darned near .040" below deck in a late 10.322" deck height block.

My calc says:
9.91 to 1 at 0 deck with a 72 cc chamber
9.66 to 1 at 0 deck with 75 cc chamber
9.5 to 1 at 0 deck with a 77 cc chamber
9.15 to 1 at .018" below deck on early block
8.8 to 1 at .040 below deck in a later block.

We have had to deck the later blocks some .035" or a tick more to get 0 deck with the short compression height builder and sealed power pistons.

I have noted early 460's that were unopened and they are typically .010" below deck and a small dish. The later engines were .030" or better with a much larger piston dish OEM.

When I started checking piston compression heights, dish volumes and such I was shocked at the miserable oem c/r in the later engines.


Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
http://R-H-P.biz

"ReinCarNation High Performance" (253)-988-6648


http://www.facebook.com/SMJRHP#!/SMJRHP
The Mad Porter is online now  
post #4 of 25 (permalink) Old 07-13-2009, 11:03 PM
Junior Member
 
Join Date: Nov 2007
Posts: 35
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
 
Send a message via AIM to swamperspecial
so how do you know what the dish of the pistons are if it is given in inches. For example, summit sells a piston with .240 oblong recess deep. is this a 22cc dish?

1979 F150 4X4. D60 rear, D44 front with 4.10s. 35 inch MT. C6 with E40D wide ratio kit. 220HP 306ftlbs to the ground with a 400M....while i'm building a real big block
swamperspecial is offline  
post #5 of 25 (permalink) Old 07-14-2009, 11:22 AM
Senior Member
 
The Mad Porter's Avatar
 
Join Date: Jan 2006
Location: Tacoma, WA.
Posts: 7,023
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 105 Post(s)
 
Cool

Quote:
Originally Posted by swamperspecial View Post
so how do you know what the dish of the pistons are if it is given in inches. For example, summit sells a piston with .240 oblong recess deep. is this a 22cc dish?
Sounds like it. Can you link to a pic of what you are referring to???



Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
http://R-H-P.biz

"ReinCarNation High Performance" (253)-988-6648


http://www.facebook.com/SMJRHP#!/SMJRHP
The Mad Porter is online now  
post #6 of 25 (permalink) Old 07-14-2009, 11:25 AM
Senior Member
 
Chuck Stevens's Avatar
 
Join Date: Mar 2006
Location: ELIMINATOR dealer Somis, CA
Posts: 2,227
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
 
My philosophy has been: if "they" won't give you the REAL numbers on the product they are trying to sell to you...I'm not interested in buying it, no matter how "good" the deal is.

Some people can break a cannon ball, in a sand box, with their bare hands.
Chuck Stevens is offline  
post #7 of 25 (permalink) Old 07-14-2009, 03:18 PM
Senior Member
 
Join Date: Nov 2007
Location: Conyers, GA
Posts: 480
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
 
Send a message via AIM to OldRedFord
Quote:
Originally Posted by The Mad Porter View Post
Sounds like it. Can you link to a pic of what you are referring to???


I am assuming they are:

http://www.summitracing.com/parts/STL-H418P/

Now this got me to wondering about my combo again.

With stock chamber size D3's and stock deck height (D1ve block)

http://www.summitracing.com/parts/UEM-KB137-STD/

Would those get me to 10 to 1 c/r or so? Not my final piston choice or source, just wonder.

2002 Ford Ranger 4x4
1972 Ford F100 Sport Custom
460, C6, 9" rear, lwb
OldRedFord is offline  
post #8 of 25 (permalink) Old 07-14-2009, 05:34 PM
Senior Member
 
The Mad Porter's Avatar
 
Join Date: Jan 2006
Location: Tacoma, WA.
Posts: 7,023
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 105 Post(s)
 
Cool

Quote:
Originally Posted by OldRedFord View Post
I am assuming they are:

http://www.summitracing.com/parts/STL-H418P/

Now this got me to wondering about my combo again.

With stock chamber size D3's and stock deck height (D1ve block)

http://www.summitracing.com/parts/UEM-KB137-STD/

Would those get me to 10 to 1 c/r or so? Not my final piston choice or source, just wonder.
Your cam choice and intended use are the criteria used to determine appropriate c/r for the application. Which fuel you wish to use is of course a factor also. Do the above first before choosing a piston combo and an arbitrary static c/r figure.

The answer to your question. 22 cc dish at 0 deck with large chamber d3's wil be close to 10 to 1.



Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
http://R-H-P.biz

"ReinCarNation High Performance" (253)-988-6648


http://www.facebook.com/SMJRHP#!/SMJRHP
The Mad Porter is online now  
post #9 of 25 (permalink) Old 07-14-2009, 05:44 PM
Senior Member
 
Join Date: Nov 2007
Location: Conyers, GA
Posts: 480
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
 
Send a message via AIM to OldRedFord
Quote:
Originally Posted by The Mad Porter View Post
Your cam choice and intended use are the criteria used to determine appropriate c/r for the application. Which fuel you wish to use is of course a factor also. Do the above first before choosing a piston combo and an arbitrary static c/r figure.

The answer to your question. 22 cc dish at 0 deck with large chamber d3's wil be close to 10 to 1.


Cam...Crane Cam duration 288/292 lift 522/530. This is the engine for my F100. Street/strip vehicle. Cam card lists 9.5-11.0 c/r. Pump gas would be nice.

2002 Ford Ranger 4x4
1972 Ford F100 Sport Custom
460, C6, 9" rear, lwb
OldRedFord is offline  
post #10 of 25 (permalink) Old 07-14-2009, 06:12 PM
Senior Member
 
The Mad Porter's Avatar
 
Join Date: Jan 2006
Location: Tacoma, WA.
Posts: 7,023
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 105 Post(s)
 
Cool

Quote:
Originally Posted by OldRedFord View Post
Cam...Crane Cam duration 288/292 lift 522/530. This is the engine for my F100. Street/strip vehicle. Cam card lists 9.5-11.0 c/r. Pump gas would be nice.
Iron heads / pump premium...

10 to 1 is ok with tight quench at 466 inches.



Scotty J. "AKA" The "Mad Porter"
"EMC 2006" 3rd place finisher
Ported BBF iron head specialist & Aluminum heads from all sources.
Custom ground cams
See our products in the Vendor for sale section
Customized crate engines
http://R-H-P.biz

"ReinCarNation High Performance" (253)-988-6648


http://www.facebook.com/SMJRHP#!/SMJRHP
The Mad Porter is online now  
post #11 of 25 (permalink) Old 07-14-2009, 06:35 PM
Senior Member
 
kjett's Avatar
 
Join Date: Nov 2007
Location: Springfield, VA
Posts: 2,353
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
 
So what would compression be on a D1 block with a set of SRP flat tops be at zero deck with a set of D3's that have been shaved .030? I was figuring around 9.5 or 10-1, but if a 22cc dish is there, would this get me closer to 11-1?
kjett is offline  
post #12 of 25 (permalink) Old 07-14-2009, 06:46 PM
Senior Member
 
DJOHAGIN's Avatar
 
Join Date: Jan 2006
Location: Santa Clara, CA
Posts: 2,649
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
 
Quote:
Originally Posted by kjett View Post
So what would compression be on a D1 block with a set of SRP flat tops be at zero deck with a set of D3's that have been shaved .030? I was figuring around 9.5 or 10-1, but if a 22cc dish is there, would this get me closer to 11-1?
With 90cc chambers, you would have around 10.2 to 1.



Dave
DJOHAGIN is offline  
post #13 of 25 (permalink) Old 07-14-2009, 06:53 PM
Senior Member
 
kjett's Avatar
 
Join Date: Nov 2007
Location: Springfield, VA
Posts: 2,353
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
 
so from a 22cc dish to a flat top on a zero deck block with D3's only gains .2 in compression? Seems almost a waste of my time to put them in, I figured it would be better than that.
kjett is offline  
post #14 of 25 (permalink) Old 07-14-2009, 08:53 PM
Junior Member
 
Join Date: Nov 2007
Posts: 35
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
 
Send a message via AIM to swamperspecial
so, what compression ratio would those pistons create with a set of dove heads?

1979 F150 4X4. D60 rear, D44 front with 4.10s. 35 inch MT. C6 with E40D wide ratio kit. 220HP 306ftlbs to the ground with a 400M....while i'm building a real big block
swamperspecial is offline  
post #15 of 25 (permalink) Old 07-14-2009, 09:01 PM
Senior Member
 
kjett's Avatar
 
Join Date: Nov 2007
Location: Springfield, VA
Posts: 2,353
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
 
They are supposedly 11:1 on 72cc heads, so figure from there.
kjett is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the 460 Ford Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome