RB25DET compression. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

NA4NOW · 09-20-2006, 09:25 PM

This 240 Im looking at has a rb25det swap. I asked the owner to do a compression test. He said the lowest was 135, and the highest was 145.

Does this sound like its in spec.?

LB.Motoring · 09-20-2006, 09:33 PM

155 across the board is what you want...
those are a little low ^

but understandable

not tooo bad, but 135 is a little low...

eh? · 09-21-2006, 07:28 AM

About 170 is spec. If the psi range is within 10 the motor is usually ok. But 135 is very low. It's possible to just have a gauge that don't read correctly. Is there no way you can test yourself?

AS240 · 11-26-2009, 05:26 PM

bringing this one back from the dead.
i just compression tested my S2 rb25 while it was still warm. wot and fuel pump off. using a us general compression tester...i got 140 across all cylinders. the gauge didnt have a one-way valve so it would peak at 145 and drop back to 140. sound normal? i keep reading of people getting higher numbers and im a little concerned.

fcdrifter20 · 11-26-2009, 08:55 PM

over the years of natural wher and tear thats sounds about normal

Zacho · 11-27-2009, 12:04 AM

nissan manual says rebuild 129 psi.

however, many different ways to go about compression testing.

GSXRJJordan · 11-27-2009, 01:00 AM

Sounds like the motor's a little tired, but as long as they're all within 5 or 10 psi of each other, you're fine. Drive it.

eklips3 · 11-27-2009, 04:48 PM

between 135 and 145 is a tad low , but the motor is still good , just a little used. i say go for it and take good care of the motor

BlitzRPS13 · 11-27-2009, 06:24 PM

Did he do it warm or cold? Also it needs to be on a battery charger aswell.

AS240 · 11-28-2009, 04:26 PM

it was warm and the battery is a fresh optima red top. i got the motor about a year or so ago and have been dailying it in my s13 since. i pulled the valve covers when i got it and it looked prestine. only had ~20km. its a strong motor. i made 315whp on a mustang dino with the stock turbo. im just curious because a 35r or a hx35 are my next plans. thanks for the replies

BlitzRPS13 · 11-28-2009, 04:32 PM

I would go ahead with it then.. and if you blow it up.. put forged pistons in it. If not.. enjoy.

GSXRJJordan · 11-28-2009, 07:24 PM

Quote:

Originally Posted by BlitzRPS13

I would go ahead with it then.. and if you blow it up.. put forged pistons in it. If not.. enjoy.

Agreed 100% lol.

09-20-2006, 09:25 PM	#1
NA4NOW Leaky Injector Join Date: Jan 2006 Location: louisiana Age: 47 Posts: 138 Trader Rating: (0) Feedback Score: 0 reviews	RB25DET compression. This 240 Im looking at has a rb25det swap. I asked the owner to do a compression test. He said the lowest was 135, and the highest was 145. Does this sound like its in spec.?

09-20-2006, 09:33 PM	#2
LB.Motoring Post Whore! Join Date: Jul 2006 Location: SòCal♥ Age: 38 Posts: 5,840 Trader Rating: (1) Rides Gallery: LB.Motoring Feedback Score: 1 reviews	155 across the board is what you want... those are a little low ^ but understandable not tooo bad, but 135 is a little low... __________________ Robby Leuer

11-27-2009, 01:00 AM	#7
GSXRJJordan Post Whore! Join Date: May 2006 Location: San Diego, CA Posts: 9,135 Trader Rating: (19) Rides Gallery: GSXRJJordan Feedback Score: 19 reviews	Sounds like the motor's a little tired, but as long as they're all within 5 or 10 psi of each other, you're fine. Drive it. __________________ Jordan Innovations has a new web site! www.JordanInnovations.com -- All your favorite FD Pro Drifters love it, trust me -- www.JordanInnovations.com

11-27-2009, 04:48 PM	#8
eklips3 Zilvia Addict Join Date: Apr 2008 Location: Calgary Canada Age: 35 Posts: 626 Trader Rating: (3) Feedback Score: 3 reviews	between 135 and 145 is a tad low , but the motor is still good , just a little used. i say go for it and take good care of the motor __________________ 1992 240sx (RB20. 362whp@16psi)

09-21-2006, 07:28 AM	#3
eh? Zilvia Member Join Date: Apr 2005 Location: Orlando, FL Age: 44 Posts: 283 Trader Rating: (0) Feedback Score: 0 reviews	About 170 is spec. If the psi range is within 10 the motor is usually ok. But 135 is very low. It's possible to just have a gauge that don't read correctly. Is there no way you can test yourself?

11-26-2009, 05:26 PM	#4
AS240 Zilvia Addict Join Date: Jul 2007 Location: Austin, Tx Age: 35 Posts: 683 Trader Rating: (18) Feedback Score: 18 reviews	bringing this one back from the dead. i just compression tested my S2 rb25 while it was still warm. wot and fuel pump off. using a us general compression tester...i got 140 across all cylinders. the gauge didnt have a one-way valve so it would peak at 145 and drop back to 140. sound normal? i keep reading of people getting higher numbers and im a little concerned.

11-26-2009, 08:55 PM	#5
fcdrifter20 Post Whore! Join Date: Nov 2007 Location: riverside, ca Age: 37 Posts: 2,869 Trader Rating: (44) Feedback Score: 44 reviews	over the years of natural wher and tear thats sounds about normal

11-27-2009, 12:04 AM	#6
Zacho Zilvia Member Join Date: Jun 2007 Location: Canada Posts: 217 Trader Rating: (5) Feedback Score: 5 reviews	nissan manual says rebuild 129 psi. however, many different ways to go about compression testing.

11-27-2009, 06:24 PM	#9
BlitzRPS13 Zilvia Member Join Date: Jul 2007 Location: Edmonton, AB, Canada Posts: 244 Trader Rating: (3) Feedback Score: 3 reviews	Did he do it warm or cold? Also it needs to be on a battery charger aswell.

11-28-2009, 04:26 PM	#10
AS240 Zilvia Addict Join Date: Jul 2007 Location: Austin, Tx Age: 35 Posts: 683 Trader Rating: (18) Feedback Score: 18 reviews	it was warm and the battery is a fresh optima red top. i got the motor about a year or so ago and have been dailying it in my s13 since. i pulled the valve covers when i got it and it looked prestine. only had ~20km. its a strong motor. i made 315whp on a mustang dino with the stock turbo. im just curious because a 35r or a hx35 are my next plans. thanks for the replies

11-28-2009, 04:32 PM	#11
BlitzRPS13 Zilvia Member Join Date: Jul 2007 Location: Edmonton, AB, Canada Posts: 244 Trader Rating: (3) Feedback Score: 3 reviews	I would go ahead with it then.. and if you blow it up.. put forged pistons in it. If not.. enjoy.