piston number - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 01-25-2004, 07:57 PM
Member
 
Join Date: Sep 2003
Location: duluth mn
Posts: 612
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
piston number

these are the numberes off the pistons that were in my block.
H423Np
08700-16-8
they are 4 reaif vavel and they are sunk down in the piston. the hole center isown from the outer side of the piston. the sides of the piston are even with the block. what comp ratio are thes pistons

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 01-25-2004, 08:39 PM
NorthStar's Avatar
Member
 
Last photo:
Join Date: Feb 2003
Location: Minnesota
Age: 51
Posts: 847
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I recognize that number the dish is -13 CCs

works out to about 8 to 1 with a 76 CC head
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 01-25-2004, 09:27 PM
Member
 
Join Date: Sep 2003
Location: duluth mn
Posts: 612
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
are summits pistons kit like this? so it these pistons are even with the deck does that mean the block has been decked

??????????????????????

Last edited by 78 chevy truck; 01-25-2004 at 09:27 PM.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 01-25-2004, 09:59 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,658
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
it would mean the blocks been decked .040 or so, since these pistons have .020 off the tops, as for the pistons summit carry`s they carry a lot, which pistons? what are the numbers? look on the blocks deck on the passengers side, if the suffix code isn`t present the blocks been decked.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 01-25-2004, 10:01 PM
Member
 
Join Date: Sep 2003
Location: duluth mn
Posts: 612
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
there is a c all bye it self no other letteres
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 01-25-2004, 10:07 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,658
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
ok then, the blocks been decked. what are the numbers of the pistons from summit?
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 01-25-2004, 10:37 PM
Member
 
Join Date: Sep 2003
Location: duluth mn
Posts: 612
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
idk it is just a rebuild kit with all the stuff to rebuild it there are no numberes
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 01-25-2004, 11:44 PM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,658
Wiki Edits: 0

Thanks: 15
Thanked 59 Times in 56 Posts
the basic kit from summit with cast pistons has the same pistons avalible in flat top or dish top, both have .020 off the tops.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 01-27-2004, 04:26 PM
Member
 
Join Date: Sep 2003
Location: duluth mn
Posts: 612
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
so will this work with my block then
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 01-27-2004, 08:21 PM
NorthStar's Avatar
Member
 
Last photo:
Join Date: Feb 2003
Location: Minnesota
Age: 51
Posts: 847
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Since its probably impossible for you to know how much was taken off the block its important for you to measure where youre pistons are at when on TDC right now with the dished pistons in there.

Your old piston H423NP has 1.550 compression distance.

If you buy the ones I told you about earlier H345NCP they have a slightly taller height of 1.560 so they will only work if the dished ones are down at least .010.


If the dished pistons are from .010 to zero try this piston H597P its a flat top too but has exact same height as the dished ones you have now 1.550 but they use a different ring set. And they probably cost more.


Heres the math

stock deck height 9.025

piston height 1.560
rod length 5.7
half the stroke (3.48/2)=1.74

add those all up = 9.000

So you see they are allowing you .025 to be decked off the block before pistons are popping out the holes. If you figure it with the 1.550 height pistons then you could deck .035 off. Ideally you want them to be flush with deck but dont sweat too much if theyre down a little bit. But you dont want them to go past.

Also the rod length and stroke of each journal probably arent exactly to spec so there will be variation from cylinder to cylinder.


You can also use a thin head gasket to achieve the "magic" .040 quench distance if pistons are not at zero deck height. Thats a whole other bunch of digging to see what thickness of gaskets are available.


Savvy?

Last edited by Greg Latvala; 01-27-2004 at 08:32 PM.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 01-27-2004, 09:04 PM
Member
 
Join Date: Sep 2003
Location: duluth mn
Posts: 612
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
can i use my old pistons and put new rings in? what would my comp be the have been milled to 72 cc. i cant aford a new block on a tite budget
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 01-27-2004, 09:22 PM
NorthStar's Avatar
Member
 
Last photo:
Join Date: Feb 2003
Location: Minnesota
Age: 51
Posts: 847
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sure you can. How many miles are on them? It important to make sure that the carbon that builds up in groove is removed. Or you could end up with rings not being able to fully compress and be forced against cylinder wall.

Compression Ratio Calculator
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 01-28-2004, 07:49 AM
Member
 
Join Date: Sep 2003
Location: duluth mn
Posts: 612
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
i got 9 to 1 one with the pistons i have and a 0035 gasket hight that right

i never market the pistons takeing them out will this matter if i re ring them and not put them in the same holl
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 01-28-2004, 10:30 AM
STUPID is as STUPID does...
 
Last wiki edit: Crankshaft Coalition Wiki Last photo:
Join Date: Nov 2003
Location: Stupidville, USA
Posts: 1,713
Wiki Edits: 1

Thanks: 11
Thanked 81 Times in 75 Posts
Yes it will matter if the engine was rebuilt with those pistons. If it was done correctly each bore would have been sized to a specific piston and swapping them hap-hazzardly around may get you some tight bores and some loose bores. Look at the pistons and you may find a bore number already stamped in them that was done during the previous rebuild.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 01-28-2004, 11:02 AM
Member
 
Last photo:
Join Date: Sep 2003
Location: Vero, FL
Age: 47
Posts: 227
Wiki Edits: 0

Thanks: 0
Thanked 3 Times in 2 Posts
Has anyone measured the true compression height of a H345 piston. I noticed some other threads on this site referenced these as "sucker pistons" with .020 lopped of the piston top. That would mean the compression height is actually 1.54 and not the 1.56 listed by Federal Mogul. I am in the process of ordering a kit for my 30 over 350 block but don't want to get stuck with "sucker pistons" since my block has never been decked and am also running 76cc heads.

Oddly, the Federal Mogul catalog shows the H345 piston with a compression ratio of only 8.34 to 1 with the 76cc head. Seems kind of low for a 1.56 compression height and .040 thick gasket unless of course the piston is destroked .020 which I think is another term for ".020" lopped off the top off the piston".

When I use .085" for deck height I come up with 8.4 to 1 instead of the 9.0 to 1 ratio with a .040 deck height. 8.4 is pretty close to their reference of 8.34 leading me to believe the H345 has a compression height of 1.54. I came up with .085" as an estimate of .045" down the hole and .040" thick head gasket.

Federal Mogul lists the H631p30 as a 8.6 to 1 piston it only has two valve notches but still lists dish volume as -5cc's the same as the H345. The H631 must have a true compression height of 1.56?

Last edited by Goldduster360; 01-28-2004 at 02:27 PM.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
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:

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.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

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



All times are GMT -6. The time now is 03:07 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.