Notices

Compression numbers on your Low compression set ups.

Thread Tools
 
Search this Thread
 
Old 09-21-2006, 08:46 AM
  #1  
Honda-Tech Member
Thread Starter
 
The Lobster's Avatar
 
Join Date: Sep 2004
Location: Morgantown, WV, bewbies
Posts: 4,056
Likes: 0
Received 0 Likes on 0 Posts
Default Compression numbers on your Low compression set ups.

So i just did a compression test with motor warm/hot
220-240-230-240

now i have 9:1 cp pistons, zex stage 3 cams, rev hard valves, isky valve springs/retainers, 3 angle valve job, PnP head

i believe i have a blown headgasket as sometimes when i start up a puff of smoke comes out. I am losing little coolant somewhere. I smell it on start up.

anyways i was wondering if those numbers are remotely right. when ih ad a 10:1 compression i only had about 210-220 compression. How am i getting such a higher compression numbers with a lower compression set up? with 240 i would think i have a high 10 ratio.

what do you guys have?
Old 09-21-2006, 09:31 AM
  #2  
Member
 
99B16Si's Avatar
 
Join Date: Dec 2002
Location: Tampa, Fl, US
Posts: 1,740
Likes: 0
Received 2 Likes on 2 Posts
Default

i get 180-185 with my 8.8:1 motor

there will be a small variance across different compression testers
Old 09-21-2006, 09:44 AM
  #3  
Honda-Tech Member
iTrader: (1)
 
Boosted Chemist's Avatar
 
Join Date: Apr 2004
Location: Dark Side of the Moon
Posts: 8,760
Likes: 0
Received 0 Likes on 0 Posts
Default Re: (99B16Si)

185 across the board cp 9:1 and supertech flat valves and milled head and decked block with the sleaves install so im figureing around 9.2:1? who knows.
Old 09-21-2006, 10:11 AM
  #4  
fjt
Honda-Tech Member
 
fjt's Avatar
 
Join Date: Jun 2002
Location: Texas
Posts: 1,659
Likes: 0
Received 0 Likes on 0 Posts
Default

8.5:1 CR..cold engine.. 165PSI on all 4
Old 09-21-2006, 10:14 AM
  #5  
Honda-Tech Member
Thread Starter
 
The Lobster's Avatar
 
Join Date: Sep 2004
Location: Morgantown, WV, bewbies
Posts: 4,056
Likes: 0
Received 0 Likes on 0 Posts
Default

so wtf is up with my motor! why am i pulling 240 psi on some cylinders for a 9:1 compression motor.
Old 09-21-2006, 10:33 AM
  #6  
Honda-Tech Member
 
SFlCrx's Avatar
 
Join Date: Nov 2004
Location: Delray Honda, Florida, USA
Posts: 713
Likes: 0
Received 0 Likes on 0 Posts
Default Re: (The Lobster)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by The Lobster &raquo;</TD></TR><TR><TD CLASS="quote">so wtf is up with my motor! why am i pulling 240 psi on some cylinders for a 9:1 compression motor.</TD></TR></TABLE>

it also depends on how many times you turn in over. Also if you have any oil or maybe even coolant in the cylinder when you do the test it will up you compression. do a wet compression test pour a cap of oil in each cylinder when you do it should jump up 20-40 psi unless there was oil in there already
Old 09-21-2006, 10:59 AM
  #7  
Honda-Tech Member
Thread Starter
 
The Lobster's Avatar
 
Join Date: Sep 2004
Location: Morgantown, WV, bewbies
Posts: 4,056
Likes: 0
Received 0 Likes on 0 Posts
Default Re: (SFlCrx)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SFlCrx &raquo;</TD></TR><TR><TD CLASS="quote">

it also depends on how many times you turn in over. Also if you have any oil or maybe even coolant in the cylinder when you do the test it will up you compression. do a wet compression test pour a cap of oil in each cylinder when you do it should jump up 20-40 psi unless there was oil in there already </TD></TR></TABLE>

i turned each one over 10 times

what does it prove if i do wet compression test? and ill hit 260 psi.
Old 09-21-2006, 11:35 AM
  #8  
Honda-Tech Member
 
urbansi's Avatar
 
Join Date: Dec 2004
Location: Chicago area, us
Posts: 2,636
Likes: 0
Received 0 Likes on 0 Posts
Default Re: (The Lobster)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by The Lobster &raquo;</TD></TR><TR><TD CLASS="quote">

i turned each one over 10 times

what does it prove if i do wet compression test? and ill hit 260 psi. </TD></TR></TABLE>
If you do a wet compression test and the numbers go up that much it points to a ring problem, but with that high of numbers in the first place i wouldnt worry about it at all. Dont people usually only crank the car over like 5-6 times?
Old 09-21-2006, 11:39 AM
  #9  
Honda-Tech Member
iTrader: (1)
 
Boosted Chemist's Avatar
 
Join Date: Apr 2004
Location: Dark Side of the Moon
Posts: 8,760
Likes: 0
Received 0 Likes on 0 Posts
Default Re: (The Lobster)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by The Lobster &raquo;</TD></TR><TR><TD CLASS="quote">

i turned each one over 10 times

what does it prove if i do wet compression test? and ill hit 260 psi. </TD></TR></TABLE>

maybe you have massive amounts of carbon build up?
Old 09-21-2006, 11:56 AM
  #10  
Member
 
B18 CYA's Avatar
 
Join Date: Nov 2003
Location: Nowhere, in, Canada
Posts: 2,325
Likes: 0
Received 0 Likes on 0 Posts
Default

doesn't matter exactly how many times you crank it over. Just crank it over until the compression on the guage doesn't get any higher. On my 8.2:1 motor i get roughly 165 across the board
Old 09-21-2006, 12:21 PM
  #11  
Member
 
rebo0t's Avatar
 
Join Date: Aug 2005
Location: Oakland, CA
Posts: 4,574
Likes: 0
Received 0 Likes on 0 Posts
Default

on my 9:1 i get 165 across... something wrong? motor has 280 miles currently. did a fast break in
Old 09-21-2006, 11:36 PM
  #12  
Member
 
rebo0t's Avatar
 
Join Date: Aug 2005
Location: Oakland, CA
Posts: 4,574
Likes: 0
Received 0 Likes on 0 Posts
Default

?
Old 09-21-2006, 11:42 PM
  #13  
Member
 
B18 CYA's Avatar
 
Join Date: Nov 2003
Location: Nowhere, in, Canada
Posts: 2,325
Likes: 0
Received 0 Likes on 0 Posts
Default Re: (rebo0t)

well it is also going to depend on other things not just the compression of your pistons.

milled head?
headgasket thickness?
flat valves?

etc.
Old 09-22-2006, 03:23 AM
  #14  
Honda-Tech Member
 
g2turbo's Avatar
 
Join Date: Aug 2002
Location: Cincinnati, OH, USA
Posts: 2,273
Likes: 0
Received 0 Likes on 0 Posts
Default Re: (B18 CYA)

9:1 .... 180psi accross the board after about 50 miles on the motor. I have yet to check again recently with 500-600 miles now. Probably about the same.
Old 09-22-2006, 03:30 AM
  #15  
Honda-Tech Member
 
Jay_Sensing's Avatar
 
Join Date: Aug 2005
Location: I miss the east coast, TX, USA
Posts: 2,695
Likes: 0
Received 1 Like on 1 Post
Default

Compression testers are not calibrated so you really can't compare what one will read to the other. I have two and there is a 30 psi difference between the two of them and they are both the same brand.

The difference between the cylinders is where you need to look and your's are pretty close so I wouldn't stress.
Old 09-22-2006, 08:29 AM
  #16  
Honda-Tech Member
Thread Starter
 
The Lobster's Avatar
 
Join Date: Sep 2004
Location: Morgantown, WV, bewbies
Posts: 4,056
Likes: 0
Received 0 Likes on 0 Posts
Default

ill redo it with another tester.

motor was built 900 miles ago.

im sorta stressed cause i dont want to blow my motor when i go get it turboed and tuned.

240 is just way to high for a low comp motor. but as i said agian im do another test with another tester just to make sure.
Old 09-22-2006, 02:38 PM
  #17  
Member
 
rebo0t's Avatar
 
Join Date: Aug 2005
Location: Oakland, CA
Posts: 4,574
Likes: 0
Received 0 Likes on 0 Posts
Default

my head was milled but i compensated with a cometic .49 gasket, skunk2 non-flat valves, ported head, ctr cams... i believe the pistons are actually 9.2. maybe its my compression tester? hmmmmm
Old 09-22-2006, 05:26 PM
  #18  
Honda-Tech Member
 
joppe's Avatar
 
Join Date: Apr 2005
Location: Finland
Posts: 236
Likes: 0
Received 0 Likes on 0 Posts
Default

~8:1 dohc zc and 160psi in all cylinders.
Old 09-22-2006, 05:45 PM
  #19  
Member
 
adseguy's Avatar
 
Join Date: May 2004
Location: Nashville, TN, U.S.A
Posts: 2,992
Likes: 0
Received 0 Likes on 0 Posts
Default Re: (Jay_Sensing)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jay_Sensing &raquo;</TD></TR><TR><TD CLASS="quote">Compression testers are not calibrated so you really can't compare what one will read to the other. I have two and there is a 30 psi difference between the two of them and they are both the same brand.

The difference between the cylinders is where you need to look and your's are pretty close so I wouldn't stress.</TD></TR></TABLE>

I always stress that. Mine has read low from day 1, no problem the numbers are always consistant
Old 09-22-2006, 06:19 PM
  #20  
Honda-Tech Member
 
Dr. D-Series's Avatar
 
Join Date: Dec 2004
Location: Bronx, NY
Posts: 1,352
Likes: 0
Received 0 Likes on 0 Posts
Default

7.5:1 D15.

150 across cold.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
gc8dc95
Drag Racing
11
02-16-2009 04:29 PM
soon2bdropped
Tech / Misc
20
10-03-2007 06:28 PM
zoom545
Acura Integra
8
11-22-2005 09:04 AM
K20 EG
All Motor / Naturally Aspirated
4
06-17-2003 11:26 AM



Quick Reply: Compression numbers on your Low compression set ups.



All times are GMT -8. The time now is 11:04 AM.