Blow by out the breather

[canadiancarguy]

I just came home from a trip down south and I got stuck with 91 octane in a town that was all they had, I put octane boost in but I think the gas was no good. I notice a lot of blow by coming out the breather now, almost like a tail pipe under the hood. Is this a head gasket or piston rings? The oil and coolant are still separate and it doesn't seem to be going through oil. I did notice every time I came under boost there was a faint bell going off, so I tried not to boost it rest of the way home but I think the damage is done.

[BrooklinsFinest]

first of all, that sucks bro.

Sounds to me like its a valve problem. Either stuck open or not seating properly causing a loss in compression and forcing air/gasses out of the breather. That being said I'd try a compression test to see if any one of the cylinders has little or no compression. Either way It sounds like the head is going to have to come off to fix the issue. Generally if it was a piston ring or bore problem, the boost would force the dipstick out and splash oil all over the engine bay, or if it were a head gasket you'd have oil in the antifreeze and a lot of sweet smelling smoke out the tailpipe along with over heating.

best of luck.

[canadiancarguy]

Yeah, I was wondering if it was something else, because on my grand national and turbo T/A it made a heck of a mess under the hood and they wouldn't build boost very well. The car also has slight tick with a phht phht noise at idle, which makes me think of a burnt valve.

[G-Rock]

Could always pop off your oil cap and set it on top of the cap threads, if it starts hovering i'd lean more towards rings. Or just hold your hand over it and you'll be able to feel a noticeable pulse of air. Good luck.

[canadiancarguy]

I can definately feel pressure when I hold my hand over the crankcase recirculation pipe. I removed it from the intake plumbing and put a breather filter there. I will try and take a video and do a compression test tomorrow. The car runs normal and has oil pressure and builds boost like normal, but I am not blowing oil from anywhere.

[Billy_Jack]

first of all, that sucks, i had the same issue a couple months ago and it turned out to be broken ringlands. i too thought it may be the valves and the compression test seemed to lean towards that (no change with wet/dry test). only thing you can do is tear it apart.

[canadiancarguy]

I am thinking of going with swapping in another long block. $2800 is not too bad and it is local. Then I can build the other one up down the road. I have been playing around with the idea of putting a 2.6 in an older car.

I bet I have broken ring lands too or broken rings, because it happened instantly and not over a period of time. Also the car is running normal so a hole in a piston or head gasket is not likely in my mind, but then again I am no mechanic.

[NismoS-tune]

nothing wrong with 91. I've run 87 on a Japanese tune, afr were fine.

[redsun]

Sounds like cracked ringlands to me. Only way to be sure is to do a leak down test,compression test wont always show much difference across the cylinders whereas a leak down will give a conclusive result and a better clue as to wether it is an issue with the head or the bottom end.
In 10 years of working on RBs I have never seen a cracked piston ring but tonnes of cracked ringlands.
The best advice I can give is when you repair/replace your engine get it remapped to run safely (detonation free) on 91 octane. If it is a car you drive on the road you will encounter a situation where only lower octane fuel is available.
Sorry to hear the bad news, fingers crossed its something simple.

[canadiancarguy]

Well one of the cylinder has basically no compression. The furthest one back. A couple others are little on the low side still normal. The car is supposed to be tuned for 91 octane, but there are a couple gas stations that my car doesn't like. Costo and PetroCan my car seems to hate those 2.

[GTRADDICT]

#6 cylinder is Mr. Lean.