Compression test - Hyundai Forum: Hyundai Performance Forum
User Tag List

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 11 Old 08-15-2005, 11:36 PM Thread Starter
Senior Member
 
Join Date: Nov 2001
Location: , Non-US
Posts: 1,285
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Compression test

Hey guys!
I did a compression test today but wondering if it was done correct....
What i did was before the compression test i went for a nice hard drive so the car can reach operating temps quickly and when i had it at about 190-200F i shut the car off and parked it..
Then i removed all 4 spark plugs and disconnected the plug on the coil pack...
I then installed the compression gauge and while i had my gas pedal ALL the WAY to the floor i was cranking the motor for about 5-10 sec on each cylinder until it reached its MAX psi...
The engine cranked about 5 times to get 190psi but the funny thing is on all 5 cranks it preety much was reading like this.....First crank 120psi then 150,170,180 and then 190..The needle kept on jumping so it was it was building up pressure
It did the same on all 4 cylinders and was wondering if its normal that it needs to BUILD up the pressure on the gauge while cranking the motor for 5 -10sec...
OR should it jsut shoot up to 190psi


Thanks in advanced
2 UNIQ is offline  
Sponsored Links
Advertisement
 
post #2 of 11 Old 08-16-2005, 02:49 PM
Senior Member
 
Join Date: Dec 2003
Location: mandeville, LA
Posts: 160
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Re: Compression test

That sounds about right. If you would have had a lower reading on the first crank, and then slowly build up pressure, I would have been concerned.
Based on what you wrote, it sounds like you have a good engine.

95 Accent. Intrax Spings(great), Rage Vigor 15x6(great), Falken Ziex ZE-512 (awsome). If you are looking for rims for an X3 at dirt cheap prices, try discounttiredirect.
Next:Turbo with T25
picard is offline  
post #3 of 11 Old 08-16-2005, 03:06 PM
Senior Member
 
Turbowgn's Avatar
 
Join Date: Jul 2001
Location: Sierra Vista, AZ
Posts: 1,206
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Send a message via AIM to Turbowgn
Re: Compression test

Plus you need to disable the injectors so they are not washing down the cylinder walls.

Tim
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

96 Hyundai Elantra Wagon with 445whp/356ft lbs @ 25psi
11.59@125 1/4Mile
Turbowgn is offline  
 
post #4 of 11 Old 08-16-2005, 03:19 PM
Senior Member
 
JonGTR's Avatar
 
Join Date: Nov 2001
Location: San Antonio, TX
Posts: 1,673
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Re: Compression test

I don't have injector clips, so it's easy to pull their harness off for a test. They've never come off while driving.

2001 Hyundai Tiburon Turbo 60-1 - 270whp/268wtq
1987 Nissan 300ZX Turbo T3
I wiped my @ss with my 10 year warranty.
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
JonGTR is offline  
post #5 of 11 Old 08-17-2005, 02:04 AM Thread Starter
Senior Member
 
Join Date: Nov 2001
Location: , Non-US
Posts: 1,285
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Re: Compression test

Well i checked the compression ratio today but im not sure if im doing this correct but i kept on cranking the motor Till it stopped to read on the compression gauge..
If i only crank the motor 5 times it reads up to 180psi but more than 5 cranks while cranking the motor it will read to a MAX of 190psi....

What i did notice today is on the first crank i dont think it was 120psi as it was lower but clsoe to 90psi then 120,160,180

What should the first crank read at to be safe?

Finally is there a differnece if i was to drive the car hard to reach operting temps and then do a compression test as opposed to just letting the car idle till it reaches 190F ..
Is 190F a good operting temp figure
Thanks!
2 UNIQ is offline  
post #6 of 11 Old 08-17-2005, 12:25 PM
Senior Member
 
Turbowgn's Avatar
 
Join Date: Jul 2001
Location: Sierra Vista, AZ
Posts: 1,206
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Send a message via AIM to Turbowgn
Re: Compression test

No there is no difference in how you reach the operating temp, also if you look at every manual that explains how to do this check you need to turn the car over 5-7 times.

The first crank is going to be low, that is why they say to turn the motor over that many times as they do.

Tim
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

96 Hyundai Elantra Wagon with 445whp/356ft lbs @ 25psi
11.59@125 1/4Mile
Turbowgn is offline  
post #7 of 11 Old 08-17-2005, 01:33 PM
Senior Member
 
Join Date: Dec 2003
Location: mandeville, LA
Posts: 160
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Re: Compression test

Are you sure that your car was warmed up? The test results usally don't change that much over a short time.
I think that you are ok.
However, if you have to do something, put a tablespoon of oil in the cylinder, and do the test. If the results are the same, then your rings are ok.

95 Accent. Intrax Spings(great), Rage Vigor 15x6(great), Falken Ziex ZE-512 (awsome). If you are looking for rims for an X3 at dirt cheap prices, try discounttiredirect.
Next:Turbo with T25
picard is offline  
post #8 of 11 Old 08-17-2005, 10:37 PM Thread Starter
Senior Member
 
Join Date: Nov 2001
Location: , Non-US
Posts: 1,285
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Re: Compression test

Cool thanks for the help guys!
I just thought the first crank should be a higher number but by the 7th Crank my car reaches about 190psi

BTW i also took a look at my spark plugs and the tips have a Grey white color to it and around the threads on the spark plug its all black.Im not sure if this indicates a LEAN condition or a good mix..
If im not mistaken a golden brown color is a good mix...



[Edited by 2 UNIQ on Aug 17, 2005 8:53 PM]
2 UNIQ is offline  
post #9 of 11 Old 08-20-2005, 07:50 AM Thread Starter
Senior Member
 
Join Date: Nov 2001
Location: , Non-US
Posts: 1,285
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Re: Compression test

Sorry for the double post but i also forgot to mention since i didnt disconnect my Fuel pump when i did the compression test will it affect the figures in any way since it was spraying fuel?
I know its preety much just a mist that was spraying but just wanted to know the difference
Thanks!
2 UNIQ is offline  
post #10 of 11 Old 08-20-2005, 10:55 AM
Senior Member
 
Turbowgn's Avatar
 
Join Date: Jul 2001
Location: Sierra Vista, AZ
Posts: 1,206
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Send a message via AIM to Turbowgn
Re: Compression test

Rob, you want to disable the injectors or the pump. Cause it could give you a lower CR number than you actually have.

Tim
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

96 Hyundai Elantra Wagon with 445whp/356ft lbs @ 25psi
11.59@125 1/4Mile
Turbowgn is offline  
Sponsored Links
Advertisement
 
Reply

  Hyundai Forum: Hyundai Performance Forum > Technical Forums > Forced Induction and Nitrous Discussion


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not 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