Compression ? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

FastBack 240 · 04-29-2003, 03:30 PM

In the 95 240's what is the compression is the cylinders supposed to be? 1 and 2 are at like 115 and 3 and 4 are at like 125. Could this mean I need a new head gasket because I have smoke in my exhaust?

*AceInHole* · 04-29-2003, 04:10 PM

Standard is 179.
Low limit is 140.

Either you're measuring it incorrectly or you have major problems.
Is the engine warm when you're testing?? Do you have the throttle plate wide open?? Are all plugs taken out??

N1ceDrgn · 04-29-2003, 04:15 PM

Another option is stopping by a dealership and asking to see their FSM for the 240. Most places don't have a problem with letting you take a look. They might also photo copy some of the info for you too.

nismo_sr_20 · 04-29-2003, 04:26 PM

your compression is way low. . could be alot of things though gasket piston rings, piston walls valves

FastBack 240 · 04-29-2003, 06:59 PM

What im doing is just starting it cold at idle checking one cylinder at a time. The engine is cold to. When it warms up and i drive it, the car begins to smoke. The smoke is whiteish color.

N1ceDrgn · 04-29-2003, 07:12 PM

Almost sounds like a blown head gasket or bad rings. Try adding some water when the engine is running and if the smoke goes away chalk it up to bad rings/ cylinder or the head gasket.

FastBack 240 · 04-29-2003, 07:17 PM

Shiitt.......just put the motor in last week....now gotta take it all apart again.

FastBack 240 · 04-29-2003, 09:42 PM

How do I check the compression correctly? If it is the head gasket then wont there be water in the oil?

nismo_sr_20 · 04-30-2003, 02:15 PM

well check the compression. then if its still low. put a little oil in the cylinder. if that changes the compression dramatically then its your rings or cylinder wall. if not. check your oil for water. if you dont find anything make sure you got a good seal with the compression tester. if after that you cant find anything wrong it might be your valves not seating properly?????

*AceInHole* · 04-30-2003, 04:32 PM

Quote:

Originally posted by FastBack 240
How do I check the compression correctly?

To check compression correctly:
Setup:
1. Warm up the engine (run the car untill it reaches normal operating temperature).
2. Unplug the fuel pump fuse, and run car untill it stalls. Then crank the car a few more times. It should not kick over at all.
3. Unplug spark plugs (I also unplug the injectors as a step further).
4. Remove ALL spark plugs.
Testing:
5. Screw the compression tester fitting snugly into the first cylinder.
6. Attach compression gauge to the fitting, facing it so that you can see it from inside the car, or have someone watch it.
7. Press the gas pedal (the right most pedal) to the floor, or as far as it will go.
8. Crank the engine (by turning the key to the "start" position) for a few seconds, and repeat untill the gauge needle no longer raises.
9. Write down the cylinder number being tested, and the compression gauge reading.
10. Repeat "Testing" for the last 3 cylinders.

Quote:

If it is the head gasket then wont there be water in the oil?

Possibly, but not always. It will depend on where the gasket is leaking. I'm guessing since you said:

Quote:

Shiitt.......just put the motor in last week....now gotta take it all apart again.

that you have had the head off before, and put it back together once before. If this is the case, did you use a new head gasket (FSM says it's required to use a new head gasket whenever pulling the head off the block)?? Did you torque the head correctly (correct torque pattern, then un-torque, then re-torque to spec)???

mjjstang · 04-30-2003, 06:51 PM

Today I checked it again while warm but did it before reading your post. (1)was 175 (2) was 175 (3) was 182 and (4) was 169. What I did is while running I reved to safe margin(not redline) and then checked the gauge. Will this prove anything?

BY THE WAY THIS IS FASTBACK 240 JUST IN MY FRIENDS NAME.

mjjstang · 05-01-2003, 12:32 AM

well, fastback 240 Im going to pretend I know something, If your noticing smoke after driving and punching it, I would say it is your rings but you say compression is normal ( Actually I checked your Dam compression) so this cant be. also I might say you have bad valve seals which might actually raise your compression a bit. but usually you would notice smoke from bad seals while idling so this is probably not the reason. I dont know your problem but I do know that I would not have bought an engine from somebody I didnt know. I would have fixed your old engine for 50 dollars instead. Just my opinion. Good luck in finding your problem champ.

Oh BTW no he did not take the actual head off, we took nothing off besides the water pump which we sealed and gasketed and also the A/C mount from the old engine (the screws didnt line up on the new one.)

kandyflip445 · 05-01-2003, 12:39 AM

WTF???Are you checking the compression with the car RUNNING!?!?!?!?

Umm...if you are you need to READ WHAT ACE SAID AGAIN. Having fuel in the cyl while checking comp. with throw the reading off because it will not compress. Oh, and I like to disconnect the wire going to the primary of the ignition coil. Just incase there is anything flammable where the wires are hanging there isn't any spark.

ridebmx · 05-01-2003, 02:40 AM

simply stated above, and with bad rings the smoke would usually be blue because you would be burning it, if the smoke is white your are burning coolant, does your exaust smell sweet, or all nasty like burning oil *rant* I hate that smell nothing worse then getting behind a pos car/truck that is burning extreme amounts of oil, its almost as bad is take a motor apart down to the block, that nasty burnt oil smell is so nasty *end rant* anyways test your compression right, and its not good to keep driving while your buring coolant, i could go and explain, but just so you know its not the best for your motor

FastBack 240 · 05-01-2003, 03:40 PM

I kinda have a good idea of what it is. The smoke thankfully has gone away a little bit at a time. When I was taking the old motor out I accidently got some used oil down the exhaust. Upon the engine being warm it would smoke. The first test drive was the worst and its only gotten better. The cat was I think drowned in oil so thats why it was bad. The smoke is blue and is really rank. Thanks for all your help. By the way I check my compression and it was fine. Thanks again!

*AceInHole* · 05-01-2003, 04:11 PM

Glad to help. It seems that a lot of people have been going about testing certain things in the wrong way lately, though...... this has to be at least the 3rd time I've explained checking compression over the past month or so (not necessarily on this board alone thougH).

mjjstang · 05-01-2003, 04:33 PM

was my last post right about the rings and seals or was it full of bs?????

Oh also.. Sorry to burst your bubble champ but yesterday in your driveway, the smoke looked worse than the day we first started it up.

*AceInHole* · 05-01-2003, 04:40 PM

Quote:

Originally posted by mjjstang
was my last post right about the rings and seals or was it full of bs?????

Oh also.. Sorry to burst your bubble champ but yesterday in your driveway, the smoke looked worse than the day we first started it up.

If the smoke is blue and smells, it might be the rings. Could even be a torn valve seal, though. Doing a dry vs. wet compression test (wet is when you drop a bit of oil into the cylinder and comp test) should tell if it's the rings.

FastBack 240 · 05-01-2003, 09:10 PM

Hey champ my bubble is still in tact because yesterday it was raining therefore the smoke was alot thinker because of the moisture in the air.....also champ its not nearly as bad today. Thanks CHAMP.

ITS THE FUKCIN OIL IN MY EXHAUST....JUST GOT TO BURN IT OUT!!!

v8blakdak · 05-29-2004, 09:05 AM

Quote:

Originally Posted by FastBack 240

Hey champ my bubble is still in tact because yesterday it was raining therefore the smoke was alot thinker because of the moisture in the air.....also champ its not nearly as bad today. Thanks CHAMP.

ITS THE FUKCIN OIL IN MY EXHAUST....JUST GOT TO BURN IT OUT!!!

its been a lil over a year now... hows that engine running?

mjjstang · 05-29-2004, 06:12 PM

Why........................

kandyflip445 · 05-30-2004, 05:19 AM

Quote:

Originally Posted by mjjstang

Why........................

04-29-2003, 03:30 PM	#1
FastBack 240 Zilvia Addict Join Date: Dec 2002 Location: Motor City......MI Age: 39 Posts: 859 Trader Rating: (0) Feedback Score: 0 reviews	Compression ? In the 95 240's what is the compression is the cylinders supposed to be? 1 and 2 are at like 115 and 3 and 4 are at like 125. Could this mean I need a new head gasket because I have smoke in my exhaust?

04-29-2003, 04:10 PM	#2
AceInHole Autox Technician Join Date: Dec 2001 Location: New Haven, CT Age: 44 Posts: 3,961 Trader Rating: (0) Rides Gallery: AceInHole Feedback Score: 0 reviews	Standard is 179. Low limit is 140. Either you're measuring it incorrectly or you have major problems. Is the engine warm when you're testing?? Do you have the throttle plate wide open?? Are all plugs taken out?? __________________

04-29-2003, 04:15 PM	#3
N1ceDrgn Zilvia Member Join Date: Nov 2002 Location: SoCal Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	Another option is stopping by a dealership and asking to see their FSM for the 240. Most places don't have a problem with letting you take a look. They might also photo copy some of the info for you too. __________________ ..working on something that is slowly getting built up and restored..

04-29-2003, 04:26 PM	#4
nismo_sr_20 Join Date: Jan 2003 Location: florida Age: 42 Posts: 40 Trader Rating: (0) Feedback Score: 0 reviews	your compression is way low. . could be alot of things though gasket piston rings, piston walls valves __________________ But officer the sign said 85

04-29-2003, 07:12 PM	#6
N1ceDrgn Zilvia Member Join Date: Nov 2002 Location: SoCal Posts: 259 Trader Rating: (0) Feedback Score: 0 reviews	Almost sounds like a blown head gasket or bad rings. Try adding some water when the engine is running and if the smoke goes away chalk it up to bad rings/ cylinder or the head gasket. __________________ ..working on something that is slowly getting built up and restored..

04-29-2003, 06:59 PM	#5
FastBack 240 Zilvia Addict Join Date: Dec 2002 Location: Motor City......MI Age: 39 Posts: 859 Trader Rating: (0) Feedback Score: 0 reviews	What im doing is just starting it cold at idle checking one cylinder at a time. The engine is cold to. When it warms up and i drive it, the car begins to smoke. The smoke is whiteish color.

04-29-2003, 07:17 PM	#7
FastBack 240 Zilvia Addict Join Date: Dec 2002 Location: Motor City......MI Age: 39 Posts: 859 Trader Rating: (0) Feedback Score: 0 reviews	Shiitt.......just put the motor in last week....now gotta take it all apart again.

04-29-2003, 09:42 PM	#8
FastBack 240 Zilvia Addict Join Date: Dec 2002 Location: Motor City......MI Age: 39 Posts: 859 Trader Rating: (0) Feedback Score: 0 reviews	How do I check the compression correctly? If it is the head gasket then wont there be water in the oil?

04-30-2003, 02:15 PM	#9
nismo_sr_20 Join Date: Jan 2003 Location: florida Age: 42 Posts: 40 Trader Rating: (0) Feedback Score: 0 reviews	well check the compression. then if its still low. put a little oil in the cylinder. if that changes the compression dramatically then its your rings or cylinder wall. if not. check your oil for water. if you dont find anything make sure you got a good seal with the compression tester. if after that you cant find anything wrong it might be your valves not seating properly????? __________________ But officer the sign said 85

04-30-2003, 06:51 PM	#11
mjjstang Post Whore! Join Date: Apr 2003 Location: Michigan Posts: 2,654 Trader Rating: (5) Feedback Score: 5 reviews	Today I checked it again while warm but did it before reading your post. (1)was 175 (2) was 175 (3) was 182 and (4) was 169. What I did is while running I reved to safe margin(not redline) and then checked the gauge. Will this prove anything? BY THE WAY THIS IS FASTBACK 240 JUST IN MY FRIENDS NAME.

05-01-2003, 12:32 AM	#12
mjjstang Post Whore! Join Date: Apr 2003 Location: Michigan Posts: 2,654 Trader Rating: (5) Feedback Score: 5 reviews	well, fastback 240 Im going to pretend I know something, If your noticing smoke after driving and punching it, I would say it is your rings but you say compression is normal ( Actually I checked your Dam compression) so this cant be. also I might say you have bad valve seals which might actually raise your compression a bit. but usually you would notice smoke from bad seals while idling so this is probably not the reason. I dont know your problem but I do know that I would not have bought an engine from somebody I didnt know. I would have fixed your old engine for 50 dollars instead. Just my opinion. Good luck in finding your problem champ. Oh BTW no he did not take the actual head off, we took nothing off besides the water pump which we sealed and gasketed and also the A/C mount from the old engine (the screws didnt line up on the new one.) Last edited by mjjstang; 05-01-2003 at 12:35 AM..

05-01-2003, 12:39 AM	#13
kandyflip445 Post Whore! Join Date: Sep 2002 Location: Arden, NC Age: 40 Posts: 4,460 Trader Rating: (1) Rides Gallery: kandyflip445 Feedback Score: 1 reviews	WTF???Are you checking the compression with the car RUNNING!?!?!?!? Umm...if you are you need to READ WHAT ACE SAID AGAIN. Having fuel in the cyl while checking comp. with throw the reading off because it will not compress. Oh, and I like to disconnect the wire going to the primary of the ignition coil. Just incase there is anything flammable where the wires are hanging there isn't any spark.

05-01-2003, 02:40 AM	#14
ridebmx Zilvia Junkie Join Date: Mar 2002 Location: Michigan Age: 41 Posts: 379 Trader Rating: (0) Feedback Score: 0 reviews	simply stated above, and with bad rings the smoke would usually be blue because you would be burning it, if the smoke is white your are burning coolant, does your exaust smell sweet, or all nasty like burning oil rant I hate that smell nothing worse then getting behind a pos car/truck that is burning extreme amounts of oil, its almost as bad is take a motor apart down to the block, that nasty burnt oil smell is so nasty end rant anyways test your compression right, and its not good to keep driving while your buring coolant, i could go and explain, but just so you know its not the best for your motor __________________ I like my car, you may not...You like your car, I may not...To each there own, right? waiting for the sunken look to be cool..lol

05-01-2003, 03:40 PM	#15
FastBack 240 Zilvia Addict Join Date: Dec 2002 Location: Motor City......MI Age: 39 Posts: 859 Trader Rating: (0) Feedback Score: 0 reviews	I kinda have a good idea of what it is. The smoke thankfully has gone away a little bit at a time. When I was taking the old motor out I accidently got some used oil down the exhaust. Upon the engine being warm it would smoke. The first test drive was the worst and its only gotten better. The cat was I think drowned in oil so thats why it was bad. The smoke is blue and is really rank. Thanks for all your help. By the way I check my compression and it was fine. Thanks again!

05-01-2003, 04:11 PM	#16
AceInHole Autox Technician Join Date: Dec 2001 Location: New Haven, CT Age: 44 Posts: 3,961 Trader Rating: (0) Rides Gallery: AceInHole Feedback Score: 0 reviews	Glad to help. It seems that a lot of people have been going about testing certain things in the wrong way lately, though...... this has to be at least the 3rd time I've explained checking compression over the past month or so (not necessarily on this board alone thougH). __________________

05-01-2003, 04:33 PM	#17
mjjstang Post Whore! Join Date: Apr 2003 Location: Michigan Posts: 2,654 Trader Rating: (5) Feedback Score: 5 reviews	was my last post right about the rings and seals or was it full of bs????? Oh also.. Sorry to burst your bubble champ but yesterday in your driveway, the smoke looked worse than the day we first started it up.

05-01-2003, 09:10 PM	#19
FastBack 240 Zilvia Addict Join Date: Dec 2002 Location: Motor City......MI Age: 39 Posts: 859 Trader Rating: (0) Feedback Score: 0 reviews	Hey champ my bubble is still in tact because yesterday it was raining therefore the smoke was alot thinker because of the moisture in the air.....also champ its not nearly as bad today. Thanks CHAMP. ITS THE FUKCIN OIL IN MY EXHAUST....JUST GOT TO BURN IT OUT!!! Last edited by FastBack 240; 05-01-2003 at 09:13 PM..

05-29-2004, 06:12 PM	#21
mjjstang Post Whore! Join Date: Apr 2003 Location: Michigan Posts: 2,654 Trader Rating: (5) Feedback Score: 5 reviews	Why........................ __________________ I was going to, but I can not think of a sig less than 75 characters.