Oil In Cylinder...

[KiLLeR2001]

Car info: Rebuilt SR20DET Redtop, bone stock.

So I pulled my spark plugs today (brand new put them in yesterday). And noticed they were gray/whiteish... Possible lean AFR? Then I look down into the cylinders and notice that there's oil in #2. A week beforehand I did a compression test and I got 140psi across the board. Cranked the engine over and shot most of the oil out of the cylinder and did another compression test on #2... Turned out a little higher 150psi... Piston rings done?

What else can be causing oil to collect in my #2 cylinder only? Keep in mind this was a fully rebuilt engine I broke in with conventional 10w-30 oil. Then at 1600 miles I switched to Royal Purple Synthetic 10w-30 not too long ago, the oil just started leaking recently because when I checked a couple days ago there was no oil collecting in either of the cylinders.

I'm going to crack open the valve cover tomorrow night after work and see if I can find anything irregular going on.

[GSXRJJordan]

Plugs should be kind of a dull grey/brown. If there's pitting around the electrode, and it's chalky, then it's lean.

It's possible your oil control ring on #2 is not up to snuff... what compression ratio are your pistons? If they're OEM, then your 140psi across the board is low.

It's not uncommon for a little oil in the cylinder to up the readings - usually it means that you have worn rings. The fact that you just rebuilt suggests it's something else though.

[KiLLeR2001]

Plugs should be kind of a dull grey/brown. If there's pitting around the electrode, and it's chalky, then it's lean.

It's possible your oil control ring on #2 is not up to snuff... what compression ratio are your pistons? If they're OEM, then your 140psi across the board is low.

It's not uncommon for a little oil in the cylinder to up the readings - usually it means that you have worn rings. The fact that you just rebuilt suggests it's something else though.

My older plugs were the dull gray/brown color. The spark plug looks fine other than the tip being a gray/white. And yes they are OEM S15 pistons, I did the compression test when the car was hot with the throttle wide open, and all spark plugs taken out. 140psi.

[mifesto]

i dont think the oil there will cause a higher number since according to nissan spec, you are suppose to bring the engine up to operating temp anyhow. 140 is alittle low but i learned recently to not trust those compression tests 100%. i've seen such huge variables in test methods that can effect number.

biggest concern is the chalky spark plugs, usually means lean condition and possibly detonation.

[Sileighty_85]

i dont think the oil there will cause a higher number since according to nissan spec,

if adding some oil to the cylinder changes your Compression result, that suggests your rings are worn. 150PSI is OEM

maybe that injector is getting clogged throw some fuel inector cleaner in your tank or Ohm out that injector to see if it is still with in spec per FSM.

[just1pepsi]

oil in a cylinder will cause a sealling effect raising compression - Oil can be getting in their either through a problem w/ the oil ring, or a leaky valve seal. I'd clear all the oil out, let it sit overnight, check for oil again and do a compression test again just to make sure.

If its been running lean, it will burn up the rings. Does the end of the plug look okay? or does it look like its missing some material? also look at the insulator around the electrode.

[mifesto]

theres always gonna be alil oil there lol. oil raising compression results seem to suggest u have to pour abit of oil there. he is describing (in my assumption) just oil residue.

anyhow i would recommend for this person to do a cold compression test as 'just1pepsi' said after letting it sit overnight.

[KiLLeR2001]

if adding some oil to the cylinder changes your Compression result, that suggests your rings are worn. 150PSI is OEM

maybe that injector is getting clogged throw some fuel inector cleaner in your tank or Ohm out that injector to see if it is still with in spec per FSM.

I've already put injector cleaner in and I've ohm'd all my injectors. They all came out at 11.5ohms.

oil in a cylinder will cause a sealling effect raising compression - Oil can be getting in their either through a problem w/ the oil ring, or a leaky valve seal. I'd clear all the oil out, let it sit overnight, check for oil again and do a compression test again just to make sure.

If its been running lean, it will burn up the rings. Does the end of the plug look okay? or does it look like its missing some material? also look at the insulator around the electrode.

The plugs look normal except for the color of the tip being gray/whiteish.

edit: Tried cranking engine over with #2 spark plug out and the oil doesn't seem to be shooting out, whats the best way to remove the oil from the cylinder? Also, the amount of oil in the cylinder doesn't reach the tip of the spark plug at all, but its definitely there.

[just1pepsi]

Well, I posted based on the assumption that there was substantial oil in there.. there will always be a little oil in the cylinder as mifesto suggested.

To get the oil out, really all you can do is crank the engine w/o the plug in.. or pull the head (alot of work) .. you could put a little gas in there to thin out the oil (wait a few minutes) and crank it (with the plug out.) be extra careful if you do that, dont blow yourself up accidently.

If you had a lot of oil in the cylinder the plug would be oil fouled. You might just be getting a little blow by, which will happen until the engine gets broken in all the way.. how many miles are on the new engine? did they reuild both the bottom and top end?

http://www.densoiridium.com/howtoreadusedplugs.php <-- what different type of plugs look like in varying engine conditions

[coolcatracing]

Did the plug have any wet oil on it when you removed it? Many people mistake oil on the pistons as a motor problem when there was simply oil in the plug tubes which drained onto the piston once the plugs were removed. Oil in the cylinders will always raise the compression unless the rings have a perfect seal to begin with which rarely happens.

[KiLLeR2001]

Well, I posted based on the assumption that there was substantial oil in there.. there will always be a little oil in the cylinder as mifesto suggested.

To get the oil out, really all you can do is crank the engine w/o the plug in.. or pull the head (alot of work) .. you could put a little gas in there to thin out the oil (wait a few minutes) and crank it (with the plug out.) be extra careful if you do that, dont blow yourself up accidently.

If you had a lot of oil in the cylinder the plug would be oil fouled. You might just be getting a little blow by, which will happen until the engine gets broken in all the way.. how many miles are on the new engine? did they reuild both the bottom and top end?

http://www.densoiridium.com/howtoreadusedplugs.php <-- what different type of plugs look like in varying engine conditions

If I had to say from those pictures my plug looks like the normal conditioned one. So I think I'm ok there...

The oil amount in cylinder #2 does not touch the spark plug at all. My other three cylinders do not have any oil at all in the cylinders (which brings up my concern).

Currently there's about 1900 miles on the new engine. Rebuilt both top and bottom end to stock settings using OEM S15 pistons. I switched from conventional oil to synthetic oil at 1600 miles.

[just1pepsi]

you could attribute that to the break in process.. I like at least 3k on the engine before its really "broken in" . Does it run okay?

I suppose it could also be that you have valve guides running a little loose on that cylinder which will let oil get by everytime the valve opens or if the engine sits and that valve hangs open.

a compression test wont reveal that if the valve is seating all the way. What can happen though if the valve guides run loose for too long, is they start to wear, which will eventually lead to a sticky valve or a bent valve since there is way too much play to start with. I wouldnt instantly assume thats the issue though.. If it runs okay, I'd put some more miles on it and see what happens, just keep an eye out for smoke out the tail pipe.

[KiLLeR2001]

you could attribute that to the break in process.. I like at least 3k on the engine before its really "broken in" . Does it run okay?

I suppose it could also be that you have valve guides running a little loose on that cylinder which will let oil get by everytime the valve opens or if the engine sits and that valve hangs open.

a compression test wont reveal that if the valve is seating all the way. What can happen though if the valve guides run loose for too long, is they start to wear, which will eventually lead to a sticky valve or a bent valve since there is way too much play to start with. I wouldnt instantly assume thats the issue though.. If it runs okay, I'd put some more miles on it and see what happens, just keep an eye out for smoke out the tail pipe.

It runs ok except for the fact if I go WOT it'll start misfiring. If I gradual throttle about 1/2 throttle up into the RPMS it will never sputter. (I've gotten to 6k with no sputtering)

I'd like to note on initial startup I do hear what I would think is a lifter tapping sound, it goes away once the car warms up though... (Probably need to bleed the lifters)

[just1pepsi]

Sounds like maybe you are having some valvetrain issues then. is it backfiring out the exhaust or into the intake mani?

[KiLLeR2001]

Sounds like maybe you are having some valvetrain issues then. is it backfiring out the exhaust or into the intake mani?

I'd say the exhaust. I've had little stuttering problems, and I've had a big misfire, almost sounded like some liquid shooting out the tailpipe. My exhaust doesn't smell like anything at idle though, and it only smokes when I first start the car up in the morning.

[KiLLeR2001]

So yeah, I left my car in the garage and took my dads truck to work. There was oil in the cylinder when I left this morning at 11am. When I got home at 10pm, all the oil = no longer in cylinder. Piston rings done? Cylinder warped?

[GSXRJJordan]

The cylinder's not going to warp all on it's own... didn't you do a slight bore/rehone the block when you rebuilt it? They would know really fast if it was out of round.

To be honest, it sounds like nothing serious is wrong. It's not perfect, and that's bound to bother you, but I'd say the only way to really know if anything's wrong is to drive it until you get more symptoms :/