205 PSI in all cylinders on rebuilt KA24DE with 9:0:1, why is this happening to me? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

jonnybonds84 · 04-24-2010, 05:13 PM

So I went today and did a compression test on my KA24DE, the resulsts were 205 on all 4 cylinders. I rebuilt the engine with Supertech 9:0:1 pistons. Can anyone tell me why this is happening, the compression should be lower cause of the lower compression pistons. I scared this is going to destroy my engine and this is my daily driver. What should I do? Should I retard the timing or something? I use 91 gas. HELP ME JESUS, I IS SCUURRRED!

NINJASPY · 04-24-2010, 05:19 PM

cylinder compression/leak down test and compression ratio or piston are two different things. having equal pressure amongst all cylinders is good.

jonnybonds84 · 04-24-2010, 05:26 PM

Quote:

Originally Posted by NINJASPY

cylinder compression/leak down test and compression ratio or piston are two different things. having equal pressure amongst all cylinders is good.

I've read that but if I did a Cylinder Compression test and got that result wouldn't that mess with my AFR and potentially mess up my engine? The FSM states that it should be 170-180 High and since I'm getting 205ish in all cylinders I think that's bad, would'nt I need to tune it for higher compression?

WISH ONE · 04-24-2010, 05:33 PM

how long did you crank your engine for when you did the comp test???

jonnybonds84 · 04-24-2010, 05:36 PM

Maybe five cranks or something. Is there a set number of times? I read that 5 seconds should be good. I don't see how that would matter though, is not like it would add compression if you do it longer, the compression peak wouldn't change I would think.

Lr308 · 04-24-2010, 05:44 PM

Your piston ring gap might be tight. When you break in the motor the gap should spread. For NA you should have tighter gaps too.

jonnybonds84 · 04-24-2010, 05:50 PM

The motor should have around 1500-2000 miles in it already. The ring gap are pre done with the supertech rings, I checked them and they were good too. Is it going to mess with my AFR? Should I do anything to my timing?

jonnybonds84 · 04-24-2010, 06:29 PM

Help me Jesus!

mxexux · 04-24-2010, 07:15 PM

If you ball honed the cylinders which I hope you did since you replaced the rings then I don't see what you are freaking out about. Let the engine break in and retest. Also, did you change cams. Valve timing will also affect cylinder compression.

greenman100 · 04-24-2010, 07:19 PM

Quote:

Originally Posted by jonnybonds84

Help me Jesus!

I bet your compression gauge is fubared

negrosx13 · 04-24-2010, 07:36 PM

you lower the compression!! sooo you have more air thats gets compressed in the chamber.. soo then?! its bit high,possible from changed cams or etc...dont kill yourself guy!!! its better then having 90psi or lower

jonnybonds84 · 04-24-2010, 07:41 PM

I had the machine shop hone the cylinders but the engine has about 1500 miles on it. I'm just worried because the FSM says it should be at 170-180 psi. Stock cams are in there but so far no one has sad anything bad. I though since the I lowered the compression I would have lower cylinder compression numbers.

Hashiriya415 · 04-24-2010, 07:44 PM

restriction in exhaust, wiped out exhaust cam lobes, just unbolt the exhaust mani and re test, look inside to make sure valves are opening, but hang crank to see.

jonnybonds84 · 04-24-2010, 09:42 PM

I have a Hot shot header, test pipe with a 3 inch exhaust at the end. What do you mean by "hang crank to see."

***S14DB*** · 04-24-2010, 09:52 PM

Why did you do the Compression Test?

Om1kron · 04-24-2010, 09:55 PM

is the car running like shit? he's probably doing the test because it's not running right.

spooled240 · 04-24-2010, 10:31 PM

retest with another gauge

Pacman · 04-24-2010, 11:07 PM

Quote:

Originally Posted by jonnybonds84

I'm just worried because the FSM says it should be at 170-180 psi.

It's not a factory engine anymore. Those specs shouldn't mattter now. Give it more time to break in.

mrchomponthis · 04-24-2010, 11:12 PM

was your car at operating temperature?

importdude · 04-24-2010, 11:22 PM

Quote:

Originally Posted by jonnybonds84

The motor should have around 1500-2000 miles in it already. The ring gap are pre done with the supertech rings, I checked them and they were good too. Is it going to mess with my AFR? Should I do anything to my timing?

supertech rings are NOT predone

im sure that is not your problem but i hope you spec'd them correct

Hashiriya415 · 04-25-2010, 12:50 AM

I don't know what you are saying about your rings, those have to be set once the block is honed and you place your rings inside and check with a feeler gauge to set them to spec that you want, and also keep them in order. But doubt that will increase the CR so much. I meant is hand crank and look at your exhaust valves while you got your exhaust mani/header off. But prior to this you could just remove the mani/header and run compression, if compression goes to normal you have clog in exhaust, if it don't check to see if valves are opening up through the exhaust ports on the head with a light and hand crank, or crank with starter but wear some goggles in case you have something inside that wants to shoot out at you at 200psi, that's why I say hand crank, to be safe.

R_G · 04-25-2010, 01:22 AM

WARM UP YOUR ENGINE
When testing compression always open your throttle fully open to each cylinder.

jonnybonds84 · 04-25-2010, 11:37 AM

The Supertech rings that I have were, it said it in the papers for the specs but I still checked them. Are you guys ready for this, I didn't open the throttle when I cranked it, LOLOLOLOL. You guys are AWEsome, I'll do it again.

greenman100 · 04-25-2010, 01:00 PM

Quote:

Originally Posted by jonnybonds84

The Supertech rings that I have were, it said it in the papers for the specs but I still checked them. Are you guys ready for this, I didn't open the throttle when I cranked it, LOLOLOLOL. You guys are AWEsome, I'll do it again.

closed throttle lowers compression psi.

your compression gauge is fubared

JVD · 04-25-2010, 01:03 PM

LOL

can't wait until he opens the throttle and gets like 250psi

hahaahha

GunmetalSR · 04-25-2010, 01:37 PM

Quote:

Originally Posted by JVD

LOL

can't wait until he opens the throttle and gets like 250psi

hahaahha

roflmao wow so wait are u suppose to open the throttle? huh i dodnt know that and are u jus suppose to spin the crank or actually start it?
i did it with no spark plugs in any cylinder and jus cranked a few times and my numbers were 125 125 95 105<-this equals shit lulz

jonnybonds84 · 04-25-2010, 02:17 PM

So my numbers will be higher huh, great.

jspaeth · 04-25-2010, 04:38 PM

Ok, this is so cake.

Pull fuel pump fuse. Start car a couple time to flush fuel pressure.

Pull ALL spark plugs.

Check each cylinder.....While cranking keep throttle ALL THE WAY OPEN.

Let it crank like 5-7 times per cylinder or so.

The gauge reads and holds the maximum pressure obtained.

DONE

orion::S14 · 04-25-2010, 04:38 PM

Quote:

Originally Posted by jonnybonds84

So my numbers will be higher huh, great.

Dude, are you comprehending any of what people said above?

It's VERY LIKELY that your compression gauge sucks, and is reading really high. If you want a new scale to match your compression gauge, let's just say that the FSM indicates 215psi for a fresh rebuild on a 9.5:1 motor.

There, you're showing 205, and a stock motor should be 215. You're fine.

...

See what they're getting at? Try again, with a new gauge. You cannot shave the head enough to bump the compression enough to blow a 205.

- Brian

negrosx13 · 04-25-2010, 05:26 PM

^^^nice got this info to him before i could..i looked over the fsm..lol

04-24-2010, 05:13 PM	#1
jonnybonds84 Zilvia Addict Join Date: Feb 2008 Location: Dania Beach, FL Posts: 795 Trader Rating: (12) Feedback Score: 12 reviews	205 PSI in all cylinders on rebuilt KA24DE with 9:0:1, why is this happening to me? So I went today and did a compression test on my KA24DE, the resulsts were 205 on all 4 cylinders. I rebuilt the engine with Supertech 9:0:1 pistons. Can anyone tell me why this is happening, the compression should be lower cause of the lower compression pistons. I scared this is going to destroy my engine and this is my daily driver. What should I do? Should I retard the timing or something? I use 91 gas. HELP ME JESUS, I IS SCUURRRED! __________________ *SPENCER DOUGHERTY* RIP ME OFF. SEARCH HIS REVIEW THREAD.

04-24-2010, 05:33 PM	#4
WISH ONE Post Whore! Join Date: Aug 2006 Location: orange county ca Posts: 2,738 Trader Rating: (13) Feedback Score: 13 reviews	how long did you crank your engine for when you did the comp test??? __________________ PARTING/SELLING MY COUPE. PM ME.

04-24-2010, 05:36 PM	#5
jonnybonds84 Zilvia Addict Join Date: Feb 2008 Location: Dania Beach, FL Posts: 795 Trader Rating: (12) Feedback Score: 12 reviews	Maybe five cranks or something. Is there a set number of times? I read that 5 seconds should be good. I don't see how that would matter though, is not like it would add compression if you do it longer, the compression peak wouldn't change I would think. __________________ *SPENCER DOUGHERTY* RIP ME OFF. SEARCH HIS REVIEW THREAD.

04-24-2010, 05:44 PM	#6
Lr308 Leaky Injector Join Date: Mar 2008 Location: Milwaukee Posts: 84 Trader Rating: (1) Feedback Score: 1 reviews	Your piston ring gap might be tight. When you break in the motor the gap should spread. For NA you should have tighter gaps too. __________________

04-24-2010, 05:50 PM	#7
jonnybonds84 Zilvia Addict Join Date: Feb 2008 Location: Dania Beach, FL Posts: 795 Trader Rating: (12) Feedback Score: 12 reviews	The motor should have around 1500-2000 miles in it already. The ring gap are pre done with the supertech rings, I checked them and they were good too. Is it going to mess with my AFR? Should I do anything to my timing? __________________ *SPENCER DOUGHERTY* RIP ME OFF. SEARCH HIS REVIEW THREAD. Last edited by jonnybonds84; 04-24-2010 at 06:24 PM..

04-24-2010, 05:19 PM	#2
NINJASPY Zilvia FREAK! Join Date: Oct 2007 Location: So-cal Los Angeles 626 Age: 40 Posts: 1,009 Trader Rating: (13) Feedback Score: 13 reviews	cylinder compression/leak down test and compression ratio or piston are two different things. having equal pressure amongst all cylinders is good.

04-24-2010, 06:29 PM	#8
jonnybonds84 Zilvia Addict Join Date: Feb 2008 Location: Dania Beach, FL Posts: 795 Trader Rating: (12) Feedback Score: 12 reviews	Help me Jesus! __________________ *SPENCER DOUGHERTY* RIP ME OFF. SEARCH HIS REVIEW THREAD.

04-24-2010, 07:15 PM	#9
mxexux Zilvia Junkie Join Date: Jun 2008 Location: SoCal 949 Posts: 363 Trader Rating: (9) Feedback Score: 9 reviews	If you ball honed the cylinders which I hope you did since you replaced the rings then I don't see what you are freaking out about. Let the engine break in and retest. Also, did you change cams. Valve timing will also affect cylinder compression.

04-24-2010, 07:36 PM	#11
negrosx13 Zilvia Addict Join Date: Feb 2009 Location: Houston,tx Posts: 948 Trader Rating: (14) Feedback Score: 14 reviews	you lower the compression!! sooo you have more air thats gets compressed in the chamber.. soo then?! its bit high,possible from changed cams or etc...dont kill yourself guy!!! its better then having 90psi or lower __________________ MORE BACON STRIPS

04-24-2010, 07:41 PM	#12
jonnybonds84 Zilvia Addict Join Date: Feb 2008 Location: Dania Beach, FL Posts: 795 Trader Rating: (12) Feedback Score: 12 reviews	I had the machine shop hone the cylinders but the engine has about 1500 miles on it. I'm just worried because the FSM says it should be at 170-180 psi. Stock cams are in there but so far no one has sad anything bad. I though since the I lowered the compression I would have lower cylinder compression numbers. __________________ *SPENCER DOUGHERTY* RIP ME OFF. SEARCH HIS REVIEW THREAD.

04-24-2010, 07:44 PM	#13
Hashiriya415 Zilvia FREAK! Join Date: Jun 2007 Location: San Francisco Age: 33 Posts: 1,007 Trader Rating: (22) Feedback Score: 22 reviews	restriction in exhaust, wiped out exhaust cam lobes, just unbolt the exhaust mani and re test, look inside to make sure valves are opening, but hang crank to see.

04-24-2010, 09:42 PM	#14
jonnybonds84 Zilvia Addict Join Date: Feb 2008 Location: Dania Beach, FL Posts: 795 Trader Rating: (12) Feedback Score: 12 reviews	I have a Hot shot header, test pipe with a 3 inch exhaust at the end. What do you mean by "hang crank to see." __________________ *SPENCER DOUGHERTY* RIP ME OFF. SEARCH HIS REVIEW THREAD.

04-24-2010, 09:52 PM	#15
*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	Why did you do the Compression Test? __________________ Comments should be taken as Opinions not as Statements of Fact

04-24-2010, 09:55 PM	#16
Om1kron Post Whore! Join Date: Sep 2004 Location: Simi Valley, CA Age: 40 Posts: 6,879 Trader Rating: (15) Feedback Score: 15 reviews	is the car running like shit? he's probably doing the test because it's not running right. __________________ Wayne

04-24-2010, 10:31 PM	#17
spooled240 Post Whore! Join Date: Mar 2008 Location: San Diego, CA Posts: 4,138 Trader Rating: (27) Feedback Score: 27 reviews	retest with another gauge

04-24-2010, 11:12 PM	#19
mrchomponthis Zilvia Addict Join Date: Mar 2009 Location: fghjghjfg Age: 33 Posts: 877 Trader Rating: (11) Feedback Score: 11 reviews	was your car at operating temperature? __________________ CHOMPONWHAT?

04-25-2010, 12:50 AM	#21
Hashiriya415 Zilvia FREAK! Join Date: Jun 2007 Location: San Francisco Age: 33 Posts: 1,007 Trader Rating: (22) Feedback Score: 22 reviews	I don't know what you are saying about your rings, those have to be set once the block is honed and you place your rings inside and check with a feeler gauge to set them to spec that you want, and also keep them in order. But doubt that will increase the CR so much. I meant is hand crank and look at your exhaust valves while you got your exhaust mani/header off. But prior to this you could just remove the mani/header and run compression, if compression goes to normal you have clog in exhaust, if it don't check to see if valves are opening up through the exhaust ports on the head with a light and hand crank, or crank with starter but wear some goggles in case you have something inside that wants to shoot out at you at 200psi, that's why I say hand crank, to be safe.

04-25-2010, 01:22 AM	#22
R_G Zilvia Junkie Join Date: Feb 2010 Location: Monterey Bay/Watsonville Posts: 388 Trader Rating: (0) Feedback Score: 0 reviews	WARM UP YOUR ENGINE When testing compression always open your throttle fully open to each cylinder. __________________

04-25-2010, 11:37 AM	#23
jonnybonds84 Zilvia Addict Join Date: Feb 2008 Location: Dania Beach, FL Posts: 795 Trader Rating: (12) Feedback Score: 12 reviews	The Supertech rings that I have were, it said it in the papers for the specs but I still checked them. Are you guys ready for this, I didn't open the throttle when I cranked it, LOLOLOLOL. You guys are AWEsome, I'll do it again. __________________ *SPENCER DOUGHERTY* RIP ME OFF. SEARCH HIS REVIEW THREAD.

04-25-2010, 01:03 PM	#25
JVD Nissanaholic! Join Date: Feb 2005 Location: Alberta, Canada Age: 32 Posts: 1,820 Trader Rating: (0) Feedback Score: 0 reviews	LOL can't wait until he opens the throttle and gets like 250psi hahaahha

04-25-2010, 02:17 PM	#27
jonnybonds84 Zilvia Addict Join Date: Feb 2008 Location: Dania Beach, FL Posts: 795 Trader Rating: (12) Feedback Score: 12 reviews	So my numbers will be higher huh, great. __________________ *SPENCER DOUGHERTY* RIP ME OFF. SEARCH HIS REVIEW THREAD.

04-25-2010, 04:38 PM	#28
jspaeth Nissanaholic! Join Date: Mar 2006 Location: Philadelphia suburbs Age: 37 Posts: 2,347 Trader Rating: (7) Rides Gallery: jspaeth Feedback Score: 7 reviews	Ok, this is so cake. Pull fuel pump fuse. Start car a couple time to flush fuel pressure. Pull ALL spark plugs. Check each cylinder.....While cranking keep throttle ALL THE WAY OPEN. Let it crank like 5-7 times per cylinder or so. The gauge reads and holds the maximum pressure obtained. DONE __________________ Daily driven

04-25-2010, 05:26 PM	#30
negrosx13 Zilvia Addict Join Date: Feb 2009 Location: Houston,tx Posts: 948 Trader Rating: (14) Feedback Score: 14 reviews	^^^nice got this info to him before i could..i looked over the fsm..lol __________________ MORE BACON STRIPS

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