did a compression test today

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malloynx

Member
Mar 30, 2005
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well after boosting my motor hard for the past 1.5 yrs, i finally did a compression test. i've always had a bit of blowby; but my motor always made good HP. I did a compresion test to put my mind at ease. tell me what you think.. remember i have a "loose" motor and that is the way i wanted it done. running on ross pistons and rings.. the motor was only half warm.( the t-stat didn't open). here are the results

cyl 1... 155psi
cyl 2... 152psi
cyl 3... 160psi
cyl 4... 160psi
cyl 5... 160psi
cyl 6... 158psi




open to all comments.... i have beat the hell out of this enigne and it's still ticking. hooah for the 7m!!!
 
B

bluepearl

New Member
Jul 21, 2005
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The 7M is a great motor if built right and kept full of oil. If not you, Who did the work for ya?
 
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pimptrizkit

thread killer
Dec 22, 2005
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shouldn't the motor be at operating temps??


none the less , great test, i belive the spec is no more then 14psi difference between all the cylinders in range, and 155psi or was it 145psi , eh cant remember..
 
M

malloynx

Member
Mar 30, 2005
877
1
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NC
yea, motor should be at operating temp. mine was close.

specs are 156 is good with a low of 128psi.

no more than 14psi between cylinders..


i still wanna know where my oil is going
 
suprahero

suprahero

naughty by nature
Staff member
Aug 26, 2005
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Numbers look good. I think it's funny that I beat the heck out of my car and race it every chance I get. I hardly ever touch a wrench to it. My wife's has a new motor, and it seems I've worked on it non stop since I've got it. I just finished her new hg and seals and HOPEFULLY won't work on it for a while.


Isn't it about time you made us another video of a dyno or street pulls or something? Maybe just a trip to WalMart.......................:biglaugh:
 
Nick M

Nick M

Black Rifles Matter
Sep 9, 2005
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I was expecting a quart every 500 miles...or something. The faster the turbo spins, the easier the bearing can pull oil in. Smoke on a heavy load then?

Are you pulling 21-22 inches of vacuum?
 
M

malloynx

Member
Mar 30, 2005
877
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nick, i'm losing a good bit.. i have to add oil all the time. i pull 22inches of vac and the compression test was good. i don't really notice any smoke; as i'm not really watching for it. i'm just wondering why my motor is eating oil.

i'm still putting down 500rwhp on 21psi... any ideas
 
Nick M

Nick M

Black Rifles Matter
Sep 9, 2005
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If you have the undercover on, it can be tough to see an oil leak.

I haven't seen a heavy oil burner that wasn't smoking at least some.. Makes me wonder what is going on. You don't have the cloud of smoke on cold start ups do you?
 
M

malloynx

Member
Mar 30, 2005
877
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NC
nick... no smoke on start-up...

i do have a small rear-main leak that i discovered and i'm sure i'm losing some ever so slighty from the valve covers. i really try and stay on top of my motor.

i do run a "loose" motor.. i have a large piston to wall, and my ring gap are on the high side.. i did this on purpose to the high boost with possible nitrous in the future
 
M

MRSUPRA

New Member
Apr 11, 2005
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Hey Mike, what piston rings are you using? I have a freind that was using Ross piston rings and his engine was burning oil for a long time. I beleive he told me that he called Ross and they said the piston rings take thousands of miles before they fully seal. Either way, I wouldn't worry about it too much, since you have a strong engine with good compression.
 
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