Did one last night and i got #1-#4, 190-200-195-175 Does this sound normal? 60K miles

1-3 sounds good, 4 seems a little low.



FU Tuning

thats what i thought and i can smell a hint of oil from the exhaust too. someone said check valve cover gasket. but there was a little oil on the #1 plug so i dunno whats going on.

They should all be within 10% of the highest number. #4 is 25PSI low vs. the 20PSI the spec allows. Not really low but I would try a Leakdown Test and see where exactly it's leaking.



I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26

Team Vision Racing (aka hypsy) wrote:They should all be within 10% of the highest number. #4 is 25PSI low vs. the 20PSI the spec allows. Not really low but I would try a Leakdown Test and see where exactly it's leaking.

I could not remember the exact %, so I did not want to say. I agree with a leakdown test as well.



FU Tuning

ive got the leak down tester as well. ill have my dad help me with that.

John Higgins wrote:

Team Vision Racing (aka hypsy) wrote:They should all be within 10% of the highest number. #4 is 25PSI low vs. the 20PSI the spec allows. Not really low but I would try a Leakdown Test and see where exactly it's leaking.

I could not remember the exact %, so I did not want to say. I agree with a leakdown test as well.

It's 10-15% according to the manual. I always go by the 10% though.



I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26

may want to try cylinder 4 on more time, you have to make sure you crank it over the same amount of time on every cyliinder, you may have been short one compression stroke.

how long am i supposed to do it for? i held the key for 5 seconds, my dad said i really only need to hold it for 3. ill try them again later.

You don't count seconds you count compressions strokes. Pull all the plugs out and watch the gauge as you cank the car. You'll see the needle move with each compression stroke. You want 5 strokes for an accurate reading.



I used to race cars, now I race myself.
5K PB: 24:50
10K PB: 54:26

My LD9 that is in my car right now is 43psi below the others 3. You can smell her burning the oil.
hypsy is correct.



PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO

gonna just ask here instead of making a new thread. What do you guys think compression should be on a 110k mile eco. Also, would oil viscosity make a difference in compression?

Holy ancient thread Batman!!! For the sake of relevancy, oil viscosity will have no bearing on compression readings. As far as compression readings on a high-mileage engine, I generally go with no less than 75% of the factory specs, and no more than 10% variance between cylinders.




Currently #4 in Ecotec Forced Induction horsepower ratings. 505.8 WHP 414WTQ!!!
Currently 3rd quickest Ecotec on the .org - 10.949 @ 131.50 MPH!!!

so 160 155 165 160 wouldnt be like OMG need a new motor bad?

anything special to a compression test on a supercharged motor. anything about the bypass valve position I need to know. I read on here in a few threads that 185-225 is good, and in other threads that as low as 147 is good...

Those numbers are fine was it cold or warm compression test its supposed to be warm so numbers will come up more if it was done cold.

if your smellin oil it could be your intake manifold the 04s have a TSB for an over sized PCV hole GM recommends replacing the manifold my buddy is dealin with his right now he works at the dealer



JBO since July 30, 2001

Seafoam piston soak over night drive it then retest


see ya!

After 30k miles boosted at 100k total miles on my cav the numbers were 210-209-183-208, completely stock engine, never even had the valve cover off, last I heard its still running around in Ohio with 130k+ on it



1989 Turbo Trans Am #82, 2007 Cobalt SS G85

novaracer wrote:Seafoam piston soak over night drive it then retest

wtf is up with this Seafoam I'm hearing so much about all the sudden...



Buddy Club Ecotec Cavalier
* More to come *

Look it up. Zmax piston soak works as well but it cost too much. It does break down carbon


see ya!

as long as its not like mine... 190-184-200-70 LOL



13.22 @ 105.2