bhg or blown ring? sr ??s

[Garber]

i picked up a s14 with and sr a few months ago. its been very reliable and i havnt done a whole lot with it. i decided to take it to the track last weekend...

when i got home i noticed i have acquired a lot of blowby... i just did a compression check. these are the numbers

cyl 1- 157psi
cyl 2- 90psi
cyl 3-156 psi
cyl 4- 160 psi

i added half a cap of oil to cyl 2 and it went to 110psi. i thought maybe i didnt add enough so i added another cap.. it went to 120psi.


my undestanding is that after adding a capful of oil, it should jump up to almost normal numbers... which it did not.

it runs great... no misfire. doesnt burn oil. doesnt burn coolant. no oil in the coolant, no air in the coolant. there seemed to be a small amount of milkshake in the oil when i was doing the comp check this morning, but it has been sitting for the past week in the cold... so maybe it was just moisture?

here is a pic of my plugs. it appears to be running lean from looking at these... except for cylinder 2, which is much browner

http://sphotos.ak.fbcdn.net/hphotos-ak-ash2/hs613.ash2/156564_1716328715911_1469010013_1792543_3397713_n. jpg

[nismoman]

I'm gonna say most likely rings. My buddies integra did the same thing when he had a cracked sleeve. But Nissans don't do that as often.

[Garber]

i thoght if it was a ring the compression would jump up to almost normal after adding oil?

[mct3351]

Classic broken piston ring land symptoms. The compression rings in that cylinder may or may not be broken. You're either going to have to change the piston in that cylinder or source another long block. Sorry about it :(

[Garber]

Classic broken piston ring land symptoms. The compression rings in that cylinder may or may not be broken. You're either going to have to change the piston in that cylinder or source another long block. Sorry about it :(


no problem. im used to this kind of stuff lol. too bad it happened the same time my festiva went down as well.

is it possible to replace the rings while it is still in the engine bay? i know it is with some cars and some its much easier to just pull the motor.


also, can anyone shed some light on my spark plugs? arent they a little lean looking?

[Zerolift Autolab]

Excessive blow by on the SR engines is likely a Cracked Ring Land on the piston.
It will run relatively decent even with this issue.
But 90% of the failures we have seen is either cylinder 3 or 4.
Let me know if I can help with anything.
Thanks,
Robert

[mct3351]

The piston and rings could be changed with the engine in the car but there would be no advantage to doing it that way as it'd be easier to just pull the motor out. You are going to have to replace the piston and rings in the number 2 cylinder. At the very least you will need another head gasket, one stock piston of the appropriate grade and a ring set (only sold in sets of 4 for stock pistons).

They look okay but very little qualitative information can be gained from reading spark plugs. There are many other very important factors that should be considered also (timing, boost, fuel octane, tune). Did you have a wideband? I've grown to value my wideband as much as my oil pressure gauge over the years.

no problem. im used to this kind of stuff lol. too bad it happened the same time my festiva went down as well.

is it possible to replace the rings while it is still in the engine bay? i know it is with some cars and some its much easier to just pull the motor.


also, can anyone shed some light on my spark plugs? arent they a little lean looking?

[Garber]

it is sad that i am just now noticing that my cas was cranked the entire way clockwise by the previous owner.:-/

are you guys 100% sure that it is a ring land or ring? and not a valve seal or headgasket? it would be such a pain to tear it all down to find out it was something simple like that.



i would imagine it would be smart to upgrade the pistons and rings from oem if im rebuilding anyway right?


oh a happier note, i did trap 109mph in the 1/4 with a stock sr before it blew:)

[nismoman]

Well you gotta take the head off either way, so you will know immediately what it is. If the timing way way off it may have caused detention which will easily blow the rings. Weather or not you upgrade the internals depends on your power goals. Oem pistons and rings are inexpensive for modest power goals. Sorry dude but the only way to do it right is pull the motor and inspect it.

[modulation]

Unless you have crazy boost or something I'd bet $20 it's a BHG.
I've seen alot of bad head gaskets, but very few blown rings on SRs.

[Garber]

Well you gotta take the head off either way, so you will know immediately what it is. If the timing way way off it may have caused detention which will easily blow the rings. Weather or not you upgrade the internals depends on your power goals. Oem pistons and rings are inexpensive for modest power goals. Sorry dude but the only way to do it right is pull the motor and inspect it.


if im pulling the motor, id rather wait to pull the head until its out of the car. but if its only a hg, i wont need to pull the motor... i guess i should drive it a little and see if the moisture in the oil goes away.

[nismoman]

Moisture in the oil?? Shouldn't really ever see that. Have you drained the oil? if it's got water in it that answers the question.

[Garber]

ive heard that after letting a vehicle sit and only driving it short distances can accumulate moisture in the oil making it look like a bhg. driving at full temp allows it to be evaporated.

personally ive never seen this from experience. but ive only been around 22 years lol.

[nismoman]

I've owned Many different Nissans and never seen water in the oil except when I blew a head gasket on a KA. It was nasty though it was milky looking, really bad. But if you at least drain the oil you can get a good look.

[modulation]

I've owned Many different Nissans and never seen water in the oil except when I blew a head gasket on a KA. It was nasty though it was milky looking, really bad. But if you at least drain the oil you can get a good look.

Yeah you have a bad head gasket.

[nismoman]

Yeah you have a bad head gasket.

Not me I was talking to the OP.