94 3.slow drinks oil

[RangerNielsen]

So I've been driving the truck for 4 days, and I got a check oil light today. So I checked it and there's oil up to the hash marks but not on them. The valve cover gaskets are dry and I can't find any leaks. The truck is a single cat with a 4' 3" straight pipe after that. Possible issues?

 

[RangerNielsen]

4 feet long, 3 inch diameter.

 

[RonD]

I would park it in a clean spot, underground lots are good, go have lunch.
When you come back put a pencil in front of each front tire then back out and have a look.
Pencils are to get an idea where oil is dripping, in relation to the front tires.

How many miles on the engine?

How do the spark plugs look, they can often tell you if you are burning the oil vs dripping it.

 

[RangerNielsen]

it either has 170 or 270. its only a 94 so im guessing 170. i havent looked at the plugs yet, but i plan to soon. Ive been looking for clean spots to park and theres no oil at all on the ground when i leave.

 

[RangerNielsen]

Alright, so the truck has been on a back burner due to finances and the wheel bearings. I pulled the spark plugs and the cylinder on the drivers bank, middle cylinder had oil practically dripping off it. (see image). as stated above, the truck had a single cat and 4 foot long, 3" diameter pipe welded to the cat. Would this be piston rings?

 

[RangerNielsen]

I also failed emissions a while back. Cruise passes, but idle failed (4.5x legal limit). The truck has 1 cat, to a 3" pipe to a raptor muffler, no tail pipe. When I changed to oil, it was black, only about 1000 miles on it. I put heavier weight (15w-40 diesel) in it, and new tune up, and the truck ran a lot better (despite having a missfire), and I started blowing A LOT of grey exhaust out the muffler.

Does it sounds like I have blown piston rings, or a bad PCV valve? I am also going to put my cats, int. pipe and muffler from my '88, and run the 3" pipe as a stack (already has a hole in the bed, dumbass previous owner) in the '94 for laughs and emissions, hopefully I'll pass, and then I'll start getting a new cat-back for the '94.

 

[Tractor Dan]

Having a similar issues right now with my 94. It has a 91 or 92 motor in it but essentially the same motor. I'm having an issue on the same plug on the drivers side and passenger side. I took the upper intake and valve covers off last friday. It's at my mechanics now as i'm back in class. It could be valve guide seals or piston rings based on the symptoms because they are somewhat similar to mine as far as oil consumption except not all my plugs looked that bad. I would start with checking the valve guide seals and then go from there. If those are good then from what i understand it's piston rings most likely.

 

[RangerNielsen]

Yeah. With the truck being semi straight piped, I think my rings are gone. I think I managed to blow a head gasket today between coolant and a cylinder, so I think a rebuild will be sooner than I anticipated.

 

[Tractor Dan]

Straight piping it or semi straight piping it shouldn't cause an issue. My 97 was cut off just behind the flange after the cut and a glass pack put on it. Ran it like that till i sold it this year and the guy is still running it that way as far as i know. I never had any oil consumption issues. Other than usual oil consumption like any engine.

 

[RangerNielsen]

Straight piping it reduces the back pressure which ruins piston rings.

 

[RonD]

This is just an FYI since I see the "back pressure" thing alot.
Any back pressure at an exhaust port is bad.

It is a myth from a misunderstanding of how exhaust systems are "tuned" for an engine.

Multi-cylinder exhaust systems work by velocity, which if done right, lowers the pressure at the un-open exhaust ports.
When exhaust valve opens the exhaust volume is push into the header pipe, this creates a velocity in that pipe, when it gets to the collector(larger pipe) the velocity lowers the pressure in the unused pipes.

Where the "back pressure" confusion came from was when some one decided "if a 1.5" pipe is good a 2" pipe must be better".
So they tried it, and lost power???? WTF!!!!
Oh.............the engine must need "back pressure" from the smaller pipe to work better........I am a genius

Oops, not a genius, wrong cause and effect.
What the 2" pipe did was to reduce the velocity and as a result it increased the pressure at the exhaust ports, so larger pipe caused "back pressure".

The size of the header pipe needs to be correct for the volume of the cylinder, a size to keep velocity high which then keeps pressure at the exhaust ports low.

Actual exhaust design is above my pay grade, lol, there are pulse counts and numerous other factors that occur at different RPMs.
But one thing I know, back pressure is bad, ask any one with a clogged Cat.


Long straight pipes wouldn't hurt rings, bad or limited oil supply will cause excessive wear, running rich washes oil off cylinder walls, gritty carbon build up causes sandpaper effect, lots of things cause rings to wear out early.

 

[RangerNielsen]

I stand corrected. When I bought the truck, it had oem headers, manifold, and y pipe. Then they cut one cat out and welded a 4 foot long, 3" diameter pipe to it, (possibly had a stack, the pipe ends a t the back of the cab and there's a hole in the bed right above it). Is this not bad for the engine, per say?

 

[RonD]

I stand corrected. When I bought the truck, it had oem headers, manifold, and y pipe. Then they cut one cat out and welded a 4 foot long, 3" diameter pipe to it, (possibly had a stack, the pipe ends a t the back of the cab and there's a hole in the bed right above it). Is this not bad for the engine, per say?

No, not bad for the engine.

Although removing the Cat and not putting another one in is a $2,500 Federal offense.
Also just a bad idea for those around you that breath air.

 

[RangerNielsen]

They only removed one of them, haha. I don't pull the cats out since then it can't pass emissions. But I know a lot of people that do.