Compression check numbers

1105

I AM the random post master...bow down

May 3, 2003

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Daytona Bch, FL

Dec 3, 2003

#1

• Dec 3, 2003

• #1

I removed my smog equipment and decided to do a compression check on my car at the same time and come up with these numbers.

1. 160
2. 155
3. 155
4. 160
5. 150
6. 150
7. 150
8. 150

are these goos numbers to be getting? My dad thought that I might have a bad piston ring and suggected that I do a check. Also, I took a picture of my spark plugs while they were out... tell me what you think about them. It seems to be the further back on the block they are, the leaner they become

 

TrueBlue95GT

Member

Sep 29, 2003

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Connecticut

Dec 3, 2003

#2

• Dec 3, 2003

• #2

Those are good numbers. They're all about the same and at a normal pressure. My plugs are the same way.

 

Rootus

Officially Addicted

Feb 8, 2003

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Portland, Oregon

Dec 3, 2003

#3

• Dec 3, 2003

• #3

Those compression numbers look good. But [a few of] those plugs look bad, yikes. Definitely lean towards the back. Stock intake?

Dave

 

GTJake

Founding Member

Oct 28, 2002

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Ann Arbor, MI

Dec 3, 2003

#4

• Dec 3, 2003

• #4

Mine did that after the Eddy Preformer so I just cranked up the fuel pressure until they looked good.

Jake

 

1105

I AM the random post master...bow down

May 3, 2003

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Daytona Bch, FL

Dec 3, 2003

#5

• Dec 3, 2003

• #5

I have the edelbrock performer intake... i dont have a fuel pressure reg so I cant crank it up unless I pull the vac hose... but then it'll just be at 40psi all the time

 

Rootus

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Feb 8, 2003

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Portland, Oregon

Dec 3, 2003

#6

• Dec 3, 2003

• #6

I'm surprised that you would see a lean condition with the Edelbrock intake -- the stock one is known for having flow discrepancies between cylinders, but the Edel is pretty dang good at evening all that out. My plugs are just uniformly black .

Dave

 

VibrantRedGT

"STANGNET'S PENGUIN SMACKER"

15 Year Member

Nov 29, 1999

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154

Boca Raton, Florida

Dec 3, 2003

#7

• Dec 3, 2003

• #7

Numbers are good but 3 of those plugs are really white. Could be just the picture quality though.

 

5

5.0GT-Neal

Founding Member

Sep 24, 2002

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Dec 3, 2003

#8

• Dec 3, 2003

• #8

yah the numbers are good and consistent..

neal

 

OinkAodeOink

Founding Member

Jun 5, 2002

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Daytona bch, Florida

Dec 4, 2003

#9

• Dec 4, 2003

• #9

good comp #'s.. doubt you have a bad piston/ring with those #'s.

Look at plug #1.. its pitch black, obivously runnin pretty rich on that cylinder. The rest look just like mine did when i had bolt ons. These cars run lean to begin with.

About the mis.....

*Quoted from another post*

"it might not be a missfire at all. it could be your balancer is going bad and causing a vibration thus acting like a missfire. that's what it sounds like to me. they usually go bad around 100k miles so i'd check to see if any rubber is sticking out the back of your harmonic balancer. if it is, then it's junk."

Last time we checked your balancer had a nice whobble to it, and i bet you the rubber has worked its way out. This would defintalty make the car shake like it has a mis. The balancer would be the first thing ide replace, if it were me. your engines at stake

 

1105

I AM the random post master...bow down

May 3, 2003

3,841

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Daytona Bch, FL

Dec 4, 2003

#10

• Dec 4, 2003

• #10

I guess a balancer and some new o2's are next on my list of things to get for my car. Which balancer should I buy when I go to get one?

 

str8stang036

New Member

Dec 28, 2002

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Miami

Dec 4, 2003

#11

• Dec 4, 2003

• #11

What would be some bad compression #`s? I plan on doing the test myself next week.

 

R

rockin_rick

Member

Oct 9, 2003

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Dec 4, 2003

#12

• Dec 4, 2003

• #12

It's my understanding that the actual numbers are not that important (within reason), as long as they are all within 10% of each other. Perhaps someone else could confirm/deny this claim.

Rick