sr20 compression test results - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Landers · 02-11-2008, 10:15 AM

So yeaaaaa out of sheer boredom at work i decided to do a compression test on my motor and this is what i came up with:
Engine is moderatly warm.

CLY1=105psi
CYL2=105psi
CYL3=104psi
CYL4=103psi

When i searched for compression test results i saw people coming up with 140psi numbers and new SR motors should be around 200psi...this blew me away, i didnt think that compression numbers were supposed to be that high. Should i pull the head and check her out?? This is a stock sr with stock boost, stock cams just the normal bolt ons, FMIC, Tubular mani, exhaust. Thanks guys

DirtyS14 · 02-11-2008, 10:59 AM

What is your elevation?

Put a teaspoon of motor oil in a cylinder and test it. If the compression goes up its most likely your rings. If it doesn't go up then it could be a headgasket issue or valves seals etc etc.

Landers · 02-11-2008, 11:35 AM

Elevation is about 500ft nothing that would effect that. The power hasn't felt weak or anything i just did this compression test out of randomness. The motor has never been refreshed to my knowledge, it should have stock pistons and such.

garagelu · 02-11-2008, 11:37 AM

warm your engine to normal operating temps and test it again. You should have more normal numbers. Also make sure you test with the throttle body open. You should be getting number around 150-155.

tig_tech · 02-11-2008, 11:45 AM

Also,crank it enough until the gauge stabilizes the highest reading. I would also leak down your motor as well.

bestos02 · 02-11-2008, 12:12 PM

my experience has been that EVEN numbers across the board like you have got - are good news.

i did a test on one of my VW 1.8t last year. with 2 different air devices. first run i was seeing 135-140s acrooss the board,

the 2nd run, 2 days later, i was seeing 180s across the board, different measuring device (probably better) and different day.

gotta be a warm motor, just be slow taking out the spark plugs, warm threads are tender.

***S14DB*** · 02-11-2008, 12:25 PM

You have cams or stock? TB held open?

Landers · 02-12-2008, 06:56 AM

throttle body open, yes i let it stabalize i let it crank over about 5 times and the gauge maxed out after about 3 cranks. When i did the test when the motor was hot it came out to 98-95psi numbers. Stock cams. I think im gonna do a leakdown sometime this week. thanks guys

khoadogg · 03-26-2008, 10:37 AM

so wat were the leakdown results? I"m in the same process with my honda motor.

*wangan_cruiser* · 03-26-2008, 10:43 AM

Quote:

Originally Posted by tig_tech

Also,crank it enough until the gauge stabilizes the highest reading. I would also leak down your motor as well.

isnt it you need to crank the motor 3 times at most by FSM?

adictd2b00st · 03-26-2008, 10:49 AM

You really shouldn't have to crank it more than 3-4 times

slideways2004 · 03-26-2008, 06:40 PM

4 times should be max. on my first sr, i got 150 in the first 3 and 155 in the last. on my current motor, i'm too scared to do a test. its running fine and i don't wanna start getting all paranoid

02-11-2008, 10:15 AM	#1
Landers Zilvia Junkie Join Date: Jan 2007 Location: W Mass. Age: 37 Posts: 561 Trader Rating: (3) Rides Gallery: Landers Feedback Score: 3 reviews	sr20 compression test results So yeaaaaa out of sheer boredom at work i decided to do a compression test on my motor and this is what i came up with: Engine is moderatly warm. CLY1=105psi CYL2=105psi CYL3=104psi CYL4=103psi When i searched for compression test results i saw people coming up with 140psi numbers and new SR motors should be around 200psi...this blew me away, i didnt think that compression numbers were supposed to be that high. Should i pull the head and check her out?? This is a stock sr with stock boost, stock cams just the normal bolt ons, FMIC, Tubular mani, exhaust. Thanks guys __________________ d-faction.com

02-11-2008, 11:35 AM	#3
Landers Zilvia Junkie Join Date: Jan 2007 Location: W Mass. Age: 37 Posts: 561 Trader Rating: (3) Rides Gallery: Landers Feedback Score: 3 reviews	Elevation is about 500ft nothing that would effect that. The power hasn't felt weak or anything i just did this compression test out of randomness. The motor has never been refreshed to my knowledge, it should have stock pistons and such. __________________ d-faction.com

02-11-2008, 11:45 AM	#5
tig_tech Zilvia Junkie Join Date: Dec 2007 Location: J-ville Age: 40 Posts: 455 Trader Rating: (25) Feedback Score: 25 reviews	Also,crank it enough until the gauge stabilizes the highest reading. I would also leak down your motor as well. __________________

02-11-2008, 12:25 PM	#7
*S14DB* AFC #1 Join Date: Oct 2003 Location: 昨晩あなたのお母さんの家 Posts: 20,181 Trader Rating: (3) Feedback Score: 3 reviews	You have cams or stock? TB held open? __________________ Comments should be taken as Opinions not as Statements of Fact

02-12-2008, 06:56 AM	#8
Landers Zilvia Junkie Join Date: Jan 2007 Location: W Mass. Age: 37 Posts: 561 Trader Rating: (3) Rides Gallery: Landers Feedback Score: 3 reviews	throttle body open, yes i let it stabalize i let it crank over about 5 times and the gauge maxed out after about 3 cranks. When i did the test when the motor was hot it came out to 98-95psi numbers. Stock cams. I think im gonna do a leakdown sometime this week. thanks guys __________________ d-faction.com

02-11-2008, 10:59 AM	#2
DirtyS14 Zilvia Member Join Date: Sep 2007 Location: Odaroloc Posts: 190 Trader Rating: (2) Feedback Score: 2 reviews	What is your elevation? Put a teaspoon of motor oil in a cylinder and test it. If the compression goes up its most likely your rings. If it doesn't go up then it could be a headgasket issue or valves seals etc etc.

02-11-2008, 11:37 AM	#4
garagelu Nissanaholic! Join Date: Aug 2005 Location: Atlanta, GA Age: 40 Posts: 1,856 Trader Rating: (60) Feedback Score: 60 reviews	warm your engine to normal operating temps and test it again. You should have more normal numbers. Also make sure you test with the throttle body open. You should be getting number around 150-155.

02-11-2008, 12:12 PM	#6
bestos02 Join Date: Jul 2007 Location: MD Age: 44 Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	my experience has been that EVEN numbers across the board like you have got - are good news. i did a test on one of my VW 1.8t last year. with 2 different air devices. first run i was seeing 135-140s acrooss the board, the 2nd run, 2 days later, i was seeing 180s across the board, different measuring device (probably better) and different day. gotta be a warm motor, just be slow taking out the spark plugs, warm threads are tender.

03-26-2008, 10:37 AM	#9
khoadogg Nissanaholic! Join Date: Oct 2003 Location: San Jose, CA Age: 41 Posts: 2,423 Trader Rating: (11) Feedback Score: 11 reviews	so wat were the leakdown results? I"m in the same process with my honda motor. __________________ AIM SoarinStrong[B]STRONG 6iX[B] RB single turbo ///Work AMKREAD 180sx

03-26-2008, 10:49 AM	#11
adictd2b00st Zilvia Addict Join Date: May 2003 Location: OH Age: 43 Posts: 695 Trader Rating: (4) Feedback Score: 4 reviews	You really shouldn't have to crank it more than 3-4 times

03-26-2008, 06:40 PM	#12
slideways2004 Nissanaholic! Join Date: Apr 2005 Location: Houston Age: 38 Posts: 1,706 Trader Rating: (6) Feedback Score: 6 reviews	4 times should be max. on my first sr, i got 150 in the first 3 and 155 in the last. on my current motor, i'm too scared to do a test. its running fine and i don't wanna start getting all paranoid

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