2.9 smoking heavily and consuming massive amounts of oil

[Zapper]

so my 1986 2.9 has been consuming roughly a quart every 150 miles, so about a quart every week i have replaced the valve seals due to them being crusty and not really doing much to seal and it lessened the smoke a lot. But it is still burning pretty bad, i checked compression and i have about 110psi on all 6 cylinders, at idle it hazes a decent amount and when engine braking or just decelerating it just bellows smoke out of the exhaust after a few seconds, if i tap the throttle it lets out a large cloud, and under heavy throttle at 4000+ rpm it lets out a consistent cloud of blue smoke and somehow it isn't fouling out the sparkplugs i have looked up a couple TSBs on alldata and one that caught my attention was about the intake gaskets but i couldn't see that being the case since my plugs are clean. my 2.9 does have the factory early design cylinder heads that have a ford oval casted on them next to valve spring and i wonder if it is possible that they are cracked and allowing oil to escape into the exhaust. so does anyone have any other ideas, no it is not pcv related since it does it even when it is vented to atmosphere and Egr is fully blocked off and disconnected at the electrical plugs and vacuum is disconnected to it because it kept pissing off the 1991 2.9 ecu i put in it.

 

[rusty ol ranger]

A cracked head could cause oil consumption. In theory. Seems like ive never heard of it around here though. 99% of the time it just turns into a steam engine.

You can rule out the intake gasket.

Its burning a quart every 150miles?? And not fouling the piss out of the plugs??

Compression seems a bit on the low side...but acceptable. My worn 2.9's usually pull around 120-125psi.

Compression was close in number on all 6?

Wondering if you got a bad oil ring (or a few)

 

[Zapper]

A cracked head could cause oil consumption. In theory. Seems like ive never heard of it around here though. 99% of the time it just turns into a steam engine.

You can rule out the intake gasket.

Its burning a quart every 150miles?? And not fouling the piss out of the plugs??

Compression seems a bit on the low side...but acceptable. My worn 2.9's usually pull around 120-125psi.

Compression was close in number on all 6?

Wondering if you got a bad oil ring (or a few)

yup compression was within 1-2 psi on all 6 cylinders

 

[Mechrick]

Sounds like exhaust guides/seals.

 

[rusty ol ranger]

Sounds like exhaust guides/seals.

He changed those

 

[rusty ol ranger]

yup compression was within 1-2 psi on all 6 cylinders

Its gotta be the scraper rings at this point i would think. Unless the block is cracked...which ive never heard of on a 2.9

 

[Mechrick]

He changed those

Smoke on decel is almost always oil running down the exhaust stem getting into the exhaust. Because the spark plugs are clean it's probably not intake guides/seals or rings.

What about clogged oil returns? that would cause the same problem.

 

[rusty ol ranger]

Smoke on decel is almost always oil running down the exhaust stem getting into the exhaust. Because the spark plugs are clean it's probably not intake guides/seals or rings.

What about clogged oil returns? that would cause the same problem.

Engine breaking puts alot of stress on rings...

 

[Zapper]

Engine breaking puts alot of stress on rings...

yes it does, but for it to just randomly start doing this doesnt seem right, and my engine doesnt have any blow b

 

[Mechrick]

With that amount of oil, the plugs would have black crusty barnacles on them, and they would be fouling out if the oil is in the combustion chamber.

Oil from the exhaust stems/seals would collect in the exhaust port and manifold, then ignite when tipping in the throttle.

 

[rusty ol ranger]

yes it does, but for it to just randomly start doing this doesnt seem right, and my engine doesnt have any blow b

Blowby would be caused by bad compression and oil rings or wall wear.

 

[gaz]

@Zapper

I would pull the heads, have them both inspected and a performance valve job performed by a reputable machine.

For the cost of a new set of gaskets, head bolts and the valve job (no dought the valve guides are bad, possibly the valve seats), you will either fix it or eliminate some wear components that should have been replaced anyway.

If you routinely hit 4,000 RPM, it sounds like you aren't getting full power from your engine, I rarely bury 2,700 RPM as the max torque for a 2.9l is 2850.

CORRECTION, the max torque RPM for the 2.9l is 2600...thank you @rusty ol ranger

 

[rusty ol ranger]

@Zapper

I would pull the heads, have them both inspected and a performance valve job performed by a reputable machine.

For the cost of a new set of gaskets, head bolts and the valve job (no dought the valve guides are bad, possibly the valve seats), you will either fix it or eliminate some wear components that should have been replaced anyway.

If you routinely hit 4,000 RPM, it sounds like you aren't getting full power from your engine, I rarely bury 2,700 RPM as the max torque for a 2.9l is 2850.

Max torque on a 2.9 is 2600rpm. HP is 4600

 

[Zapper]

@Zapper

I would pull the heads, have them both inspected and a performance valve job performed by a reputable machine.

For the cost of a new set of gaskets, head bolts and the valve job (no dought the valve guides are bad, possibly the valve seats), you will either fix it or eliminate some wear components that should have been replaced anyway.

If you routinely hit 4,000 RPM, it sounds like you aren't getting full power from your engine, I rarely bury 2,700 RPM as the max torque for a 2.9l is 2850.

if im going to pull the heads i may aswell just put on a set of updated ones. and sure they make max tourqe below 3k but they dont run out of power until 5400 rpm my 2.9 is very rev happy with a couple degrees of extra base timing, hell i towed about 9k lbs at 45mph at probably 4k rpm. which is probably what started this hell. i could probably pull the heads and send em over to Kidd Perfomance here in idaho but they will probably be to damaged for me to want to repair them and it would probably be cheapest to just buy some new 89TM castings
here is a video link to show just how much it smokes

 

[Cees Klumper]

I got 2 new ProMaxx Performance heads for my 2.9 and am happy with the results.

FORD 2.9 NEW FULL - PROMAXX Performance Products

ProMaxx Performance developed/designed this cylinder head from the OE casting 86TM. This is a direct bolt on cast iron cylinder head to replace your factory casting. Year: 1989-1992 Models: Bronco II, Ranger Engine Size: 2.9L V6

promaxxperformance.com