Horrible compression test results? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

jakez · 10-06-2011, 03:35 PM

So my redtop overheated pretty badly the other night because I was driving a lot harder than normal and forgot to turn the fans on. Saw white smoke coming out of the exhaust at a red light and immediately jumped on the highway so I could keep it cool nonstop on the 20 minute ride home where I had some coolant/water waiting.

Dry test
1. 135psi
2. 145psi
3. 125psi
4. 138psi

Wet test (squirt of oil in each cylinder)
1. 160psi
2. 178psi
3. 175psi
4. 177psi

For all tests I cranked it 6 times, maybe should've done like 10 and gotten a higher reading. Spark plugs nice and tan. Engine was very warm also.

At least 2 adjacent cylinders aren't low, so hopefully the headgasket isn't totally fucked? As soon as I popped the radiator cap off (and let the steam and shit rush out) and started pouring coolant in the cars idle and temp was fine. And the car also seems to pull the same except in the top of 3rd/4th/5th it kind of breaks up a bit sometimes.

*fliprayzin240sx* · 10-06-2011, 03:38 PM

What do you mean Wet and Dry Test? Dropped oil in the cylinder? If thats what you meant, just having a blown HG wouldnt bump your compression.

jakez · 10-06-2011, 08:05 PM

Quote:

Originally Posted by fliprayzin240sx

What do you mean Wet and Dry Test? Dropped oil in the cylinder? If thats what you meant, just having a blown HG wouldnt bump your compression.

Yeah wet test as in a squirt of oil in the cylinder. I thought they were called dry/wet. You're saying the head gasket should be fine? 125 seems awfully low

s14fbs · 10-06-2011, 08:14 PM

sounds like u need rings reguardless with that low of a compression
u should do a leak down test

and maybe invest in a fan controller

*fliprayzin240sx* · 10-06-2011, 08:34 PM

Quote:

Originally Posted by jakez

Yeah wet test as in a squirt of oil in the cylinder. I thought they were called dry/wet. You're saying the head gasket should be fine? 125 seems awfully low

I'm saying a blown HG is the least of your worries. When you drop oil in the cylinder, it doesnt seal up the HG, just the rings. So just the fact that it bumped up means its sealing the rings.

Disconnect the crankcase hose to the T on the valvecover...I got a feeling you got some smoke coming out of there, or atleast got air pulsating out. That means air is getting thru the rings and pressurizing your crankcase...that means rebuild time.

Dpacro001 · 10-07-2011, 12:06 AM

buy a new engine

dpacro · 10-08-2011, 12:02 AM

I have a sr20det red top long bloc ready to go if you need.

jakez · 10-11-2011, 09:17 PM

Ok leak down test results are below.

Cyl #1 57%
Cyl #2 68% spark plug didn't look too good, kind of dark with light tan specs all over it, other 3 plugs look fine
Cyl #3 59%
Cyl #4 56%

I took the oil fill cap off and could hear air coming out of there. Didn't hear anything out the exhaust.

Car is drunk on coolant, I'm refilling it after almost every drive, and when I fill it to the neck and squeeze the radiator hose it bubbles every time I squeeze instead of releasing the bubbles once and for all, is that a problem? No coolant in the oil or oil in the coolant though. Startup is also really rough now and the engine shakes more than normal at startup and at idle.

Any ideas what I'm looking at replacing?

jakez · 10-11-2011, 09:37 PM

Also this was done with a tester from harbor freight that sets at 15psi, not sure if that makes a difference..

*fliprayzin240sx* · 10-12-2011, 03:03 PM

Yah, that engine's done. Time for a rebuild, new HG and fresh piston rings.

jakez · 10-12-2011, 03:15 PM

Quote:

Originally Posted by fliprayzin240sx

Yah, that engine's done. Time for a rebuild, new HG and fresh piston rings.

Ok so, trying to understand what I need to purchase to get it into good shape.

1. OEM head gasket
2. OEM pistons
3. OEM piston rings
4. OEM valve stem seals

Should be good to go with that hopefully.

Hoffman5982 · 10-12-2011, 03:45 PM

You don't necessarily need new pistons. But yeah, rings, stem seals, and a head gasket sounds right. Also, if you have oem head studs, you'll need to replace those.

*fliprayzin240sx* · 10-12-2011, 04:01 PM

Since you're pulling the rods off, might as well get some fresh bearings too and the cylinder could probably use some honing since you're slapping fresh rings.

Darren · 10-12-2011, 04:39 PM

Also, if the engine's ever been overheated ... probably should look at getting the block decked and the head resurfaced or your new HG isn't going to seal properly and you'll just have to do it all again...

KOME · 10-12-2011, 05:03 PM

Those numbers seem way far off from one another. In wet and dry.

Wets only got gonna temp seal your rings man. Just hope it's actually just your rings. Not that that's the best news.

Trap Star · 10-12-2011, 05:34 PM

Quote:

Originally Posted by jakez

Ok so, trying to understand what I need to purchase to get it into good shape.

1. OEM head gasket
2. OEM pistons
3. OEM piston rings
4. OEM valve stem seals

Should be good to go with that hopefully.

Why not just upgrade that shit while you're at it?

jakez · 10-12-2011, 05:54 PM

Quote:

Originally Posted by Trap Star

Why not just upgrade that shit while you're at it?

Never planned on dumping build kind of money into this SR motor,but never planned on screwing up and overheating either lol. If I'm going to drop it off at a shop to have work done it'll be for a 1jzgte engine like my buddy just did with the same car. But I don't want something that powerful in this type of car, so right now I'm just looking at getting it running nicely again.

10-11-2011, 09:17 PM	#8
jakez Zilvia Member Join Date: Jun 2011 Location: United States Age: 40 Posts: 163 Trader Rating: (2) Feedback Score: 2 reviews	Ok leak down test results are below. Cyl #1 57% Cyl #2 68% spark plug didn't look too good, kind of dark with light tan specs all over it, other 3 plugs look fine Cyl #3 59% Cyl #4 56% I took the oil fill cap off and could hear air coming out of there. Didn't hear anything out the exhaust. Car is drunk on coolant, I'm refilling it after almost every drive, and when I fill it to the neck and squeeze the radiator hose it bubbles every time I squeeze instead of releasing the bubbles once and for all, is that a problem? No coolant in the oil or oil in the coolant though. Startup is also really rough now and the engine shakes more than normal at startup and at idle. Any ideas what I'm looking at replacing? __________________ '93 240SX SE Coupe SR20DET Red Top / '06 300C SRT-8 / '03 E55 AMG

10-11-2011, 09:37 PM	#9
jakez Zilvia Member Join Date: Jun 2011 Location: United States Age: 40 Posts: 163 Trader Rating: (2) Feedback Score: 2 reviews	Also this was done with a tester from harbor freight that sets at 15psi, not sure if that makes a difference.. __________________ '93 240SX SE Coupe SR20DET Red Top / '06 300C SRT-8 / '03 E55 AMG

10-12-2011, 03:03 PM	#10
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	Yah, that engine's done. Time for a rebuild, new HG and fresh piston rings. __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

10-12-2011, 03:45 PM	#12
Hoffman5982 Post Whore! Join Date: Jan 2009 Location: Definitely NOT FL.... Age: 33 Posts: 2,504 Trader Rating: (25) Feedback Score: 25 reviews	You don't necessarily need new pistons. But yeah, rings, stem seals, and a head gasket sounds right. Also, if you have oem head studs, you'll need to replace those. __________________

10-12-2011, 04:01 PM	#13
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	Since you're pulling the rods off, might as well get some fresh bearings too and the cylinder could probably use some honing since you're slapping fresh rings. __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

10-06-2011, 03:35 PM	#1
jakez Zilvia Member Join Date: Jun 2011 Location: United States Age: 40 Posts: 163 Trader Rating: (2) Feedback Score: 2 reviews	Horrible compression test results? So my redtop overheated pretty badly the other night because I was driving a lot harder than normal and forgot to turn the fans on. Saw white smoke coming out of the exhaust at a red light and immediately jumped on the highway so I could keep it cool nonstop on the 20 minute ride home where I had some coolant/water waiting. Dry test 1. 135psi 2. 145psi 3. 125psi 4. 138psi Wet test (squirt of oil in each cylinder) 1. 160psi 2. 178psi 3. 175psi 4. 177psi For all tests I cranked it 6 times, maybe should've done like 10 and gotten a higher reading. Spark plugs nice and tan. Engine was very warm also. At least 2 adjacent cylinders aren't low, so hopefully the headgasket isn't totally fucked? As soon as I popped the radiator cap off (and let the steam and shit rush out) and started pouring coolant in the cars idle and temp was fine. And the car also seems to pull the same except in the top of 3rd/4th/5th it kind of breaks up a bit sometimes. __________________ '93 240SX SE Coupe SR20DET Red Top / '06 300C SRT-8 / '03 E55 AMG Last edited by jakez; 10-06-2011 at 08:31 PM..

10-06-2011, 03:38 PM	#2
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	What do you mean Wet and Dry Test? Dropped oil in the cylinder? If thats what you meant, just having a blown HG wouldnt bump your compression. __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

10-06-2011, 08:14 PM	#4
s14fbs Zilvia FREAK! Join Date: Apr 2009 Location: candy mountain Age: 35 Posts: 1,543 Trader Rating: (11) Feedback Score: 11 reviews	sounds like u need rings reguardless with that low of a compression u should do a leak down test and maybe invest in a fan controller __________________ http://strictlycoolstuff.tumblr.com/

10-07-2011, 12:06 AM	#6
Dpacro001 BANNED Join Date: Oct 2011 Location: montreal Age: 45 Posts: 3 Trader Rating: (0) Feedback Score: 0 reviews	buy a new engine

10-08-2011, 12:02 AM	#7
dpacro Zilvia Member Join Date: Sep 2011 Location: montreal Age: 45 Posts: 283 Trader Rating: (3) Feedback Score: 3 reviews	I have a sr20det red top long bloc ready to go if you need.

10-12-2011, 04:39 PM	#14
Darren Zilvia Addict Join Date: Apr 2010 Location: kelowna, bc, canada Age: 49 Posts: 680 Trader Rating: (1) Feedback Score: 1 reviews	Also, if the engine's ever been overheated ... probably should look at getting the block decked and the head resurfaced or your new HG isn't going to seal properly and you'll just have to do it all again...

10-12-2011, 05:03 PM	#15
KOME Zilvia Addict Join Date: Dec 2010 Location: En mi casa Age: 34 Posts: 619 Trader Rating: (7) Feedback Score: 7 reviews	Those numbers seem way far off from one another. In wet and dry. Wets only got gonna temp seal your rings man. Just hope it's actually just your rings. Not that that's the best news.