oil burning?

[SHOZ123]

If it is a PVC issue then it is really a ring problem. The PVC is sucking up the blowby that is caused by the rings leaking. The amount of condensed blowby in the intake should remain fairly constant. More than likely the problem is valve guides or seals. Auto-RX is the only thing I know of that will help with the rings other than replacing them.

 

[SHOguy 92]

If it is a PVC issue then it is really a ring problem. The PVC is sucking up the blowby that is caused by the rings leaking. The amount of condensed blowby in the intake should remain fairly constant. More than likely the problem is valve guides or seals. Auto-RX is the only thing I know of that will help with the rings other than replacing them.

uuummm.... if the pcv is plugged then it can't suck up any blowby, and we know there is blowby on sho's heck you can pull apart a 200k motor and see cross hatching on the cylinder walls. so if it can't suck up blowby then it has to go out the exhaust therefore.... tada blue smoke, and if it isn't totally plugged then that would explain the fine at times and bad other times issue. someone please tell me i am right here, because this sounds right too me.

also sorry about the no caps i'm at my friends and this keyboard has had pop spilt on it and it is all hay wire.

 

[SHOZ123]

The gunk in the intake and the carbon it turns into if exposed to enough heat is the blowby. All internal motors have blow-by because they rings are not perfectly sealed. It is aggravated by worn rings or rings with carbon build up between the ring and piston. It can't be blow-by if it doesn't blow by the rings

This carbon is what Auto-RX will clean out. It will also help them seal better resulting in a few more lost ponies and lower oil and fuel consumption.

 

[DHMag]

uuummm.... if the pcv is plugged then it can't suck up any blowby, and we know there is blowby on sho's heck you can pull apart a 200k motor and see cross hatching on the cylinder walls. so if it can't suck up blowby then it has to go out the exhaust therefore.... tada blue smoke, and if it isn't totally plugged then that would explain the fine at times and bad other times issue. someone please tell me i am right here, because this sounds right too me.

also sorry about the no caps i'm at my friends and this keyboard has had pop spilt on it and it is all hay wire.

the cross hatching is still evident in 200K mile motors because of the cylinder bore composition and the ring composition. its very common to still see the factory cross hatching on any mileage Yamaha engine, given its been routinely maintained.

if you do a search, youll find i chased a similar problem. i rebuilt my heads, installing new intake and exhaust valve stem seals. while this did reduce the smoke, it did not stop it. only later do i find out that at WOT, or high RPMs in the secondary range, the smoke is unburnt fuel.

as Ford told my dad when we was a mechanic for them back in the 60s, "if it doesnt burn a quart of oil in 1000 miles, its not a Quality Ford Engine."

 

[CheckerSHO]

...as Ford told my dad when we was a mechanic for them back in the 60s, "if it doesnt burn a quart of oil in 1000 miles, its not a Quality Ford Engine."

My 91 plus must have had a some extra ford quality in its motor, it went thru a quart every 3 days
WOT over 4krpm resulted in a complete smokescreen behind the SHO

 

[SHOguy 92]

as Ford told my dad when we was a mechanic for them back in the 60s, "if it doesnt burn a quart of oil in 1000 miles, its not a Quality Ford Engine."

Thats partially true, the SHO's engine should burn a quart of oil every 3000miles, every 1000 is too much. And yes a SHO should also burn fuel at high rpm's I have seen that on my car before especially since I have bad o2's but trust me I am not confusing the black smoke for blue. I'll have to give auto-rx a try, thanks guys.

 

[AutoSHO]

uuummm.... if the pcv is plugged then it can't suck up any blowby, and we know there is blowby on sho's heck you can pull apart a 200k motor and see cross hatching on the cylinder walls. so if it can't suck up blowby then it has to go out the exhaust therefore.... tada blue smoke, and if it isn't totally plugged then that would explain the fine at times and bad other times issue. someone please tell me i am right here, because this sounds right too me.

also sorry about the no caps i'm at my friends and this keyboard has had pop spilt on it and it is all hay wire.

You cannot completely plug the PCV system, because it will result in seals blowing out of the motor. If you plugged the line from the TB to the Valve Cover, you should be alright, but Yamaha probably designed it that way for a reason. It does not allow fresh air to circulate through the crankcase.

Blowby is when combustion pressures blow past the rings instead of forcing the piston down in the bore. This results in the PCV system having a lot of air moving through it and back into the intake manifold.

 

[Rockledge]

Here's the funny thing, when MiltownSHO was up visit my dad had a dream one night about the PCV system being clogged or something He doesn't even own a SHO and never has yet he is always showing everyone who hasn't seen my SHO, explaining to them it isn't "normal"...?

So even your Dad has nightmares about your SHO, huh?

I bet you hit him up for cash sometimes when the SHO breaks down, right?

 

[SHOguy 92]

So even your Dad has nightmares about your SHO, huh?

I bet you hit him up for cash sometimes when the SHO breaks down, right?

Nope, I'm on my own quiet the poor one thank god I just got tax returns back, puts a smile on my face, even though I could drop that money down so fast on my car it isn't even funny He did spray the paint on my car and help me occastionally when I was fixing it from when the previous owner hit a deer with it. He loves the SHO and thinks it's amazing, everytime he sits in it he says it still just amazes him because its a taurus. I remember before I had my 90 I told him I wanted a SHO, but pretty much all he heard was "taurus" and cut off the SHO in his mind because it meant nothing. Back then I had never driven a manual so he went with me and test drove the 90 I'll never forget the smile it put on his face when he laid rubber at a 30mph roll in 2nd gear because he was "testing the clutch" Since then he has been a believer.

 

[Rockledge]

Nope, I'm on my own quiet the poor one thank god I just got tax returns back, puts a smile on my face, even though I could drop that money down so fast on my car it isn't even funny He did spray the paint on my car and help me occastionally when I was fixing it from when the previous owner hit a deer with it. He loves the SHO and thinks it's amazing, everytime he sits in it he says it still just amazes him because its a taurus. I remember before I had my 90 I told him I wanted a SHO, but pretty much all he heard was "taurus" and cut off the SHO in his mind because it meant nothing. Back then I had never driven a manual so he went with me and test drove the 90 I'll never forget the smile it put on his face when he laid rubber at a 30mph roll in 2nd gear because he was "testing the clutch" Since then he has been a believer.

Kinda like how it happened with me. I owned either a Taurus SLO or Sable for almost 10 years and never thought much about the SHO, I had heard bits and pieces about it, but it was a little too expensive for me, and I had other needs for a car at the time, it seemed. My 3.8L Sable was actually no slouch, either.

Anyway, one day I decide to take a look at a SHO which had been sitting in a used car lot for around 2-3 months, buried so far in the middle it was hard to get at. (I actually bought my the '97 GL from the same used car dealer about a year earlier).

So I tell the guy I want to look over the SHO, he pops the hood and I get my first look at the awsome Upper Intake and DOHC Yamaha design and I'm thinking "wow, what the **** is this?"

Next thing you know, I'm buckled tight in driver's seat, cruising somewhat slowly down the expressway in 4th gear, and after a little "getting used to" time, I decide it's time to romp on it. So I downshift into third and stomp on the the throttle good and hard, and after a slight miss or two (needed new plugs & wires), my soon-to-be Yamaha powerplant roared to life and began to deliver the torque and pull that we have all come to love.

And then, before I could even say to myself "hey, not too bad", those famous secondaries kick in, and the car actually starts pulling even more, and then all of a sudden I'm feeling some pretty wicked torque-steer, and now I'm thinking again "wow, what the **** is this" with a huge grin on my face.

And then ....oops, sorry I'm rambling now.

Long story short, one test drive and I was believer, too.