Disappointing compression number on my Sr20det - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

xcye12 · 09-02-2004, 02:05 PM

I just did a cold compression test on my Sr20det that I am about to install.
Here is the result:
#1 136psi
#2 138psi
#3 96psi
#4 98psi

I phoned the vender, he said that once I installed engine and warmed it up the compression would go back to normal.

The thing warries me here is the inconsistancy of the numbers. It seems that there are problems with #3 and #4 cylinder.

Any suggestions? What should I do here? Should I return the engine to the vender?

Thanks for any help!

Eternal_240Sx · 09-02-2004, 02:10 PM

through my experiences, even though the engine is cold it still should be consistant no matter what. I highly doubt that a simple warm up would fix something like that.

Eternal_240Sx · 09-02-2004, 02:12 PM

also, after you install the engine it can be very difficult to return if the vender blames the problem on install. So its really up to you.

*HaLo* · 09-02-2004, 03:31 PM

Compression testing does not change from cold to hot... ask for an exchange...

wootwoot · 09-02-2004, 04:19 PM

definitely ask for an exchange.

sepulchral · 09-02-2004, 04:28 PM

thats fucking ridiculous, my heart goes out to you, ask for an exchange, don't they compression test the motors before they ship them?

Oh yes and if he wont do an exchange ask for compensation suchas pistons, rods etc.. thats terrible compression for an sr. Use legal force if nothing else works

sepulchral · 09-02-2004, 04:29 PM

Oh yeah and compression doesnt change from when u start it up thats just a myth cuz some of the valves might be open or something but it doesnt really matter because you turn the crank anyways.

DuffMan · 09-02-2004, 06:17 PM

On my motor the compression was 145, 140, 125, 125 when it was cold. When it warmed up it was about 150, 150, 145, 145 so it can get better when it warms up. Probably the valves seal better when their hot due to expansion. 96 is worse though, but maybe it will be okay, hard to tell.

wootwoot · 09-02-2004, 06:33 PM

yes there is a difference between hot and cold, wet and dry. but you use those differences to diagnose the problem. it doesnt mean thats its ok that they are low cold and high(er)warm.

xcye12 · 09-02-2004, 08:08 PM

Here are numbers again ... After pouring oil into cylinder #2, and #3:

#1 140
#2 176
#3 141
#4 119

Any throughts?

**mrmephistopheles** · 09-02-2004, 08:42 PM

are you testing at WOT?

uiuc240 · 09-02-2004, 09:39 PM

do a leak down test...it'll tell you even more than a simple compression test. then you'll know if it's the rings or the valves that aren't sealing up.

Eric

xcye12 · 09-02-2004, 10:50 PM

Pouring oil into all four cylinders.

159
153
152
152

The battery is a little weak now!

*HaLo* · 09-02-2004, 11:02 PM

are you actually putting oil in the spark plug holes?

sr240mike · 09-02-2004, 11:02 PM

This may sound dumb but how do you compression test it out of the car? I've only done a leakdown test with it out.

*HaLo* · 09-02-2004, 11:03 PM

plug the battery on the starter and crank her up.

sr240mike · 09-02-2004, 11:37 PM

Thanks halo. So was there any oil in the car when you first cranked it xcye12?

xcye12 · 09-03-2004, 10:21 AM

Yes, I put oil in through the spark plug hole.

Yes, there is oil in the oil pan. I drained and refilled engine oil before doing any testing. I also found that there was only about 1.5 to 2 litter of oil in the engine before I drained it.

*HaLo* · 09-03-2004, 01:07 PM

Quote:

Originally Posted by xcye12

Yes, I put oil in through the spark plug hole.

Yes, there is oil in the oil pan. I drained and refilled engine oil before doing any testing. I also found that there was only about 1.5 to 2 litter of oil in the engine before I drained it.

Are you sure that is a good idea? Oil should never get in the combustion chamber... of course compression will be higher, oil does not compress...

balmo · 09-03-2004, 01:13 PM

good thing it evened out when you put oil on the spark plug hole. consistently check the compression. if there is still a big drop bet. 2 and 3, go ask for an exchange. goodluck

xcye12 · 09-03-2004, 02:21 PM

Quote:

Originally Posted by HaLo

Are you sure that is a good idea? Oil should never get in the combustion chamber... of course compression will be higher, oil does not compress...

A little bit oil in the combustion chamber does not do any harm. One teaspoon or two are all fine.

Maybe the engine was just too dry when I was doing the initial testing. It might have been sitting some where for years. Or someone had tested the first two cylinders with oil in them.

I will do one more test tonight after the oil drain away a little from the cylinders.

I contacted the vender already. I was told if the compression did not reach normal after I installed and warmed it up, he would refund the money to me. That sounds good to me. But I still do not want to waste time to go through another installation if that happens.

SlamMan · 09-03-2004, 06:23 PM

Who was your vendor if I may ask?

wootwoot · 09-03-2004, 07:54 PM

tell him ok but they are swapping it out the second time while you watch and you want compensation for gas and time consumed

xcye12 · 09-03-2004, 11:23 PM

Quote:

Originally Posted by SlamMan

Who was your vendor if I may ask?

I will wait and see how things go. You can send me a PM by the end of this month. I may be able to tell you who he is.

09-02-2004, 09:39 PM	#12
uiuc240 Nissanaholic! Join Date: Apr 2002 Location: Naperville, IL Age: 46 Posts: 2,093 Trader Rating: (0) Feedback Score: 0 reviews	do a leak down test...it'll tell you even more than a simple compression test. then you'll know if it's the rings or the valves that aren't sealing up. Eric __________________ 2002 Mazda Protege5 1989 S13 w/SR20DET (sold)

09-02-2004, 11:02 PM	#14
HaLo from Canada, eh! Join Date: Sep 2001 Location: Montreal, Quebec Age: 46 Posts: 5,201 Trader Rating: (0) Rides Gallery: HaLo Feedback Score: 0 reviews	are you actually putting oil in the spark plug holes? __________________ -> HaLo Race Car: '98 E36 BMW M3 Daily Drivers: '23 Audi Q4 e-tron & '13 VW Touareg SOLD: 01 GPW Honda S2000 PARTED: 93 Pearl White 240SX LE Fastback w/SR20DET SOLD: 93 Super White 240SX SE Convertible w/Silvia Front

09-02-2004, 11:02 PM	#15
sr240mike Zilvia FREAK! Join Date: Apr 2004 Location: California, Norcal biiaatch Posts: 1,185 Trader Rating: (0) Feedback Score: 0 reviews	This may sound dumb but how do you compression test it out of the car? I've only done a leakdown test with it out. __________________ TWO IN THE COOT, ONE IN THE POOT

09-02-2004, 11:03 PM	#16
HaLo from Canada, eh! Join Date: Sep 2001 Location: Montreal, Quebec Age: 46 Posts: 5,201 Trader Rating: (0) Rides Gallery: HaLo Feedback Score: 0 reviews	plug the battery on the starter and crank her up. __________________ -> HaLo Race Car: '98 E36 BMW M3 Daily Drivers: '23 Audi Q4 e-tron & '13 VW Touareg SOLD: 01 GPW Honda S2000 PARTED: 93 Pearl White 240SX LE Fastback w/SR20DET SOLD: 93 Super White 240SX SE Convertible w/Silvia Front

09-02-2004, 11:37 PM	#17
sr240mike Zilvia FREAK! Join Date: Apr 2004 Location: California, Norcal biiaatch Posts: 1,185 Trader Rating: (0) Feedback Score: 0 reviews	Thanks halo. So was there any oil in the car when you first cranked it xcye12? __________________ TWO IN THE COOT, ONE IN THE POOT

09-02-2004, 02:05 PM	#1
xcye12 Leaky Injector Join Date: Feb 2004 Location: Canada Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	Disappointing compression number on my Sr20det I just did a cold compression test on my Sr20det that I am about to install. Here is the result: #1 136psi #2 138psi #3 96psi #4 98psi I phoned the vender, he said that once I installed engine and warmed it up the compression would go back to normal. The thing warries me here is the inconsistancy of the numbers. It seems that there are problems with #3 and #4 cylinder. Any suggestions? What should I do here? Should I return the engine to the vender? Thanks for any help!

09-02-2004, 02:10 PM	#2
Eternal_240Sx Zilvia Addict Join Date: Dec 2002 Location: norcal, bay area Age: 41 Posts: 674 Trader Rating: (1) Feedback Score: 1 reviews	through my experiences, even though the engine is cold it still should be consistant no matter what. I highly doubt that a simple warm up would fix something like that. __________________ Life is good in the bay.

09-02-2004, 02:12 PM	#3
Eternal_240Sx Zilvia Addict Join Date: Dec 2002 Location: norcal, bay area Age: 41 Posts: 674 Trader Rating: (1) Feedback Score: 1 reviews	also, after you install the engine it can be very difficult to return if the vender blames the problem on install. So its really up to you. __________________ Life is good in the bay.

09-02-2004, 03:31 PM	#4
HaLo from Canada, eh! Join Date: Sep 2001 Location: Montreal, Quebec Age: 46 Posts: 5,201 Trader Rating: (0) Rides Gallery: HaLo Feedback Score: 0 reviews	Compression testing does not change from cold to hot... ask for an exchange... __________________ -> HaLo Race Car: '98 E36 BMW M3 Daily Drivers: '23 Audi Q4 e-tron & '13 VW Touareg SOLD: 01 GPW Honda S2000 PARTED: 93 Pearl White 240SX LE Fastback w/SR20DET SOLD: 93 Super White 240SX SE Convertible w/Silvia Front

09-02-2004, 04:19 PM	#5
wootwoot Post Whore! Join Date: Jan 2004 Location: sarasota florida biatch Age: 39 Posts: 3,850 Trader Rating: (0) Feedback Score: 0 reviews	definitely ask for an exchange.

09-02-2004, 04:28 PM	#6
sepulchral BANNED Join Date: Mar 2004 Location: Midlothian. VA Posts: 2,050 Trader Rating: (0) Feedback Score: 0 reviews	thats fucking ridiculous, my heart goes out to you, ask for an exchange, don't they compression test the motors before they ship them? Oh yes and if he wont do an exchange ask for compensation suchas pistons, rods etc.. thats terrible compression for an sr. Use legal force if nothing else works

09-02-2004, 04:29 PM	#7
sepulchral BANNED Join Date: Mar 2004 Location: Midlothian. VA Posts: 2,050 Trader Rating: (0) Feedback Score: 0 reviews	Oh yeah and compression doesnt change from when u start it up thats just a myth cuz some of the valves might be open or something but it doesnt really matter because you turn the crank anyways.

09-02-2004, 06:17 PM	#8
DuffMan Post Whore! Join Date: Oct 2001 Location: in a cardboard box Posts: 2,517 Trader Rating: (0) Feedback Score: 0 reviews	On my motor the compression was 145, 140, 125, 125 when it was cold. When it warmed up it was about 150, 150, 145, 145 so it can get better when it warms up. Probably the valves seal better when their hot due to expansion. 96 is worse though, but maybe it will be okay, hard to tell.

09-02-2004, 06:33 PM	#9
wootwoot Post Whore! Join Date: Jan 2004 Location: sarasota florida biatch Age: 39 Posts: 3,850 Trader Rating: (0) Feedback Score: 0 reviews	yes there is a difference between hot and cold, wet and dry. but you use those differences to diagnose the problem. it doesnt mean thats its ok that they are low cold and high(er)warm.

09-02-2004, 08:08 PM	#10
xcye12 Leaky Injector Join Date: Feb 2004 Location: Canada Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	Here are numbers again ... After pouring oil into cylinder #2, and #3: #1 140 #2 176 #3 141 #4 119 Any throughts?

09-02-2004, 08:42 PM	#11
mrmephistopheles Magnanimous Justice Distribution Service Join Date: Mar 2002 Location: BFE Age: 23 Posts: 14,372 Trader Rating: (9) Rides Gallery: mrmephistopheles Feedback Score: 9 reviews	are you testing at WOT?

09-02-2004, 10:50 PM	#13
xcye12 Leaky Injector Join Date: Feb 2004 Location: Canada Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	Pouring oil into all four cylinders. 159 153 152 152 The battery is a little weak now!

09-03-2004, 10:21 AM	#18
xcye12 Leaky Injector Join Date: Feb 2004 Location: Canada Posts: 54 Trader Rating: (0) Feedback Score: 0 reviews	Yes, I put oil in through the spark plug hole. Yes, there is oil in the oil pan. I drained and refilled engine oil before doing any testing. I also found that there was only about 1.5 to 2 litter of oil in the engine before I drained it.

09-03-2004, 01:13 PM	#20
balmo Zilvia Junkie Join Date: Aug 2003 Location: bay area Age: 46 Posts: 319 Trader Rating: (0) Feedback Score: 0 reviews	good thing it evened out when you put oil on the spark plug hole. consistently check the compression. if there is still a big drop bet. 2 and 3, go ask for an exchange. goodluck

09-03-2004, 06:23 PM	#22
SlamMan Join Date: Sep 2004 Location: Colorado Posts: 6 Trader Rating: (0) Feedback Score: 0 reviews	Who was your vendor if I may ask?

09-03-2004, 07:54 PM	#23
wootwoot Post Whore! Join Date: Jan 2004 Location: sarasota florida biatch Age: 39 Posts: 3,850 Trader Rating: (0) Feedback Score: 0 reviews	tell him ok but they are swapping it out the second time while you watch and you want compensation for gas and time consumed

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