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

240_de_Ville · 10-25-2007, 10:27 AM

ok a buddy of mine has these numbers on his sohc ka...90, 60, 60, 60... what would be the cause of the compression loss? i was thinkin about buyin his 240 and putting my engine in his shell...since mine has seen better days. but if it was something somewhat cheap to fix then i would just fix his since it has less miles on it. any suggestions? and no droppin an sr in it at this time is not an option.

ROADKILLS13 · 10-25-2007, 10:37 AM

its probly bad rings or seals. how many miles on the car?

bo2o · 10-25-2007, 10:40 AM

check if the valve cover has blowby.
try opening the throttle while doing a compression test, then try a wet.
and did you try it while the motor was warm?
just pick up another sohc. those things are cheap! i have another in my garage just sittin for just incase times.

240_de_Ville · 10-25-2007, 10:47 AM

i'm not too sure how he tested it. but he said he'd take 500 for it and i know the tires on it are worth 300 by themselves...soo...i was just hopin it was a simple gasket and that way i would have 2 runnin 240's. but i think i'm gonna put my engine it his and combine the best of the 2 and sell the other one.

but more info on the compession loss is still need for a final decision...thanks

Dream240 · 10-25-2007, 11:00 AM

There's really three basic parts to compression.

1. Pistion rings/piston condition
2. Valve seal/timing condition
3. Spark plugs/gaskets condition

With three cylinders being at the same level, it's quite posssible that the 90 is due to excessive carbon buildup in the cylinder. Try some fuel treatment and Sea Foam to see if the levels don't change.

The rule for compression is as long as they are all within 12 psi(IIRC) of each other then your fine. Low compression numbers across the board are just a sign of a worn motor.

240_de_Ville · 10-25-2007, 04:14 PM

well i think i am goin to get his 240 i will definatly try what you guys said i hope it works cause i really dont want to swap the engines. lol if i wanna do all that work i would want a better engine for it. thanks again

240_de_Ville · 10-27-2007, 10:08 PM

thanks for the info guys. i have another thread with a "poll type" question but i didn't think it belonged in here but i wanna try to get as many opinions as possible this is the link....

http://www.zilvia.net/f/showthread.p...07#post1613307 check it out and let me know what you think i should do

10-25-2007, 10:27 AM	#1
240_de_Ville Join Date: Mar 2005 Location: slidell, la Posts: 42 Trader Rating: (0) Feedback Score: 0 reviews	compression loss ok a buddy of mine has these numbers on his sohc ka...90, 60, 60, 60... what would be the cause of the compression loss? i was thinkin about buyin his 240 and putting my engine in his shell...since mine has seen better days. but if it was something somewhat cheap to fix then i would just fix his since it has less miles on it. any suggestions? and no droppin an sr in it at this time is not an option. __________________ i like fried chicken with my rice.

10-25-2007, 10:40 AM	#3
bo2o Zilvia FREAK! Join Date: May 2006 Location: 626 socal! Posts: 1,315 Trader Rating: (7) Feedback Score: 7 reviews	check if the valve cover has blowby. try opening the throttle while doing a compression test, then try a wet. and did you try it while the motor was warm? just pick up another sohc. those things are cheap! i have another in my garage just sittin for just incase times. __________________ fS! *vlsd ! slim fans ! hid kits ! lug nuts !* http://www.zilvia.net/f/search.php?d...earchuser=bo2o ^^^click^^^

10-25-2007, 10:47 AM	#4
240_de_Ville Join Date: Mar 2005 Location: slidell, la Posts: 42 Trader Rating: (0) Feedback Score: 0 reviews	i'm not too sure how he tested it. but he said he'd take 500 for it and i know the tires on it are worth 300 by themselves...soo...i was just hopin it was a simple gasket and that way i would have 2 runnin 240's. but i think i'm gonna put my engine it his and combine the best of the 2 and sell the other one. but more info on the compession loss is still need for a final decision...thanks __________________ i like fried chicken with my rice.

10-25-2007, 11:00 AM	#5
Dream240 Nissanaholic! Join Date: Dec 2002 Location: Inland Empire, California Age: 46 Posts: 2,188 Trader Rating: (8) Feedback Score: 8 reviews	There's really three basic parts to compression. 1. Pistion rings/piston condition 2. Valve seal/timing condition 3. Spark plugs/gaskets condition With three cylinders being at the same level, it's quite posssible that the 90 is due to excessive carbon buildup in the cylinder. Try some fuel treatment and Sea Foam to see if the levels don't change. The rule for compression is as long as they are all within 12 psi(IIRC) of each other then your fine. Low compression numbers across the board are just a sign of a worn motor. __________________ Don't mess with my monkey...he's loaded.

10-25-2007, 04:14 PM	#6
240_de_Ville Join Date: Mar 2005 Location: slidell, la Posts: 42 Trader Rating: (0) Feedback Score: 0 reviews	well i think i am goin to get his 240 i will definatly try what you guys said i hope it works cause i really dont want to swap the engines. lol if i wanna do all that work i would want a better engine for it. thanks again __________________ i like fried chicken with my rice.

10-25-2007, 10:37 AM	#2
ROADKILLS13 BANNED Join Date: Oct 2007 Location: nyc Age: 39 Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	its probly bad rings or seals. how many miles on the car?

10-27-2007, 10:08 PM	#7
240_de_Ville Join Date: Mar 2005 Location: slidell, la Posts: 42 Trader Rating: (0) Feedback Score: 0 reviews	thanks for the info guys. i have another thread with a "poll type" question but i didn't think it belonged in here but i wanna try to get as many opinions as possible this is the link.... http://www.zilvia.net/f/showthread.p...07#post1613307 check it out and let me know what you think i should do __________________ i like fried chicken with my rice.

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