Cause of blue smoke out of exhaust pipes?

[Fran Blacker]

Note the star wheel on spring compressor in dadsbee post #6. If you weld a 3/4" nut on to star wheel you can use a socket on it. Makes it a little easier.

 

[moparedtn]

I've used the rope trick to tighten the crank bolt.
I love this idea for holding the valves up!

Never thought of that. Great tip, thanks!

 

[JimCoronette]

Note the star wheel on spring compressor in dadsbee post #6. If you weld a 3/4" nut on to star wheel you can use a socket on it. Makes it a little easier.

Just ordered mine on Amazon.
https://www.amazon.com/gp/product/B07GQ52H9R/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Going to weld the nut on it so I can use an air ratchet.

 

[Don Frelier]

If it's a fairly new rebuild on the motor it could just be ring seal.
My 383 would smoke cold on and off for the first 20-25 runs.
Then one day it magically disappeared.
I've changed valve seals with both air and a rope.
I kind of prefer the rope method.
A good valve spring compressor is a must for that job.

 

[Rusty 72]

I use the rope trick and be sure to pull that oil pan because they will definetely be in the pan and plug the pickup.

 

[dadsbee]

I use the rope trick and be sure to pull that oil pan because they will definetely be in the pan and plug the pickup.

I was fortunate with HP's dual dampner springs, as they retained all the pieces.

 

[PBR1]

Just did valve seals 2 weeks ago on a 440. No rope or air just brought it to TDC did 1 and 6 cylinders then rotated another 90 degrees and then did another 2 cylinders that were on TDC. Every 90 degrees there are 2 cylinder at TDC. The valves do not drop far. I used the Proform lever spring compressor which worked good but on the 2 rear cylinders the hood hingers and brake booster caused issues so I used a long 1/2 drive rachet and a deep well socket to make a L shaped handle instead of the straight handle on the Proform tool and it worked great. Get some green transmission assembly lube and put it on the keepers and valve stem to hold them in place when you put the retainer and spring back on. If the valve drop a bit pull it back up with a magnet after you compress the spring. The trick to the trans assembly lube is put a dab of it on a small screwdriver then stick the keeper to it and put it on the valve.

 

[MoparDanMan]

Hi All,

What could be the causes of blue smoke upon startup out of a 440’s exhaust pipes?

Is this a serious concern?

How can it be fixed?

If it clears within seconds ( which since you said on startup) it is most likely valve seals or guides. Bad rings would smoke all the time.

 

[MoparDanMan]

Air and piston at the top? How do you keep the piston from going back down under the pressure you're putting on the cylinder? I do that for leak down on aircraft engines and you'd better have a damn good hold on the end of the prop.

I've never done the rope trick, but I do the compressed air all the time. I use a socket and a breaker bar to keep the engine from rotating.

 

[vict]

Why I use a rope and I don't see how you could leave any in the cylinder. Stuff some rope in, piston up and it holds the valves in place cushioned by the rope for zero damage. Air.. piston at bottom and you lose the air supply, then the valves go clink...
View attachment 949089 View attachment 949090

Nice professional response to the question. One of the best I have seen!

 

[MEC7]

Blue smoke is usually a sign of oil being burned. This could mean a lot of things. If it is at start up only, could be valve seats.

Hi All,

What could be the causes of blue smoke upon startup out of a 440’s exhaust pipes?

Is this a serious concern?

How can it be fixed?

 

[racinguy25]

Why I use a rope and I don't see how you could leave any in the cylinder. Stuff some rope in, piston up and it holds the valves in place cushioned by the rope for zero damage. Air.. piston at bottom and you lose the air supply, then the valves go clink...
View attachment 949089 View attachment 949090

Love this idea, I have never heard of it. Great idea. Thanks

 

[kbfallon]

Yes, most likely bad valve seals. How old is the engine? If it is an original engine with cast iron heads then the oil seals are most likely as hard as a rock. That is, if they even exist at all. After 50 years they have probably disintegrated into dust and are in the oil pan.

They probably still exist.....likely plugging up the oil pump screen.

 

[Bo duke]

Va

Hi All,

What could be the causes of blue smoke upon startup out of a 440’s exhaust pipes?

Is this a serious concern?

How can it be fixed?[/QUOTEValve seats worn. Causing blow by

 

[Billccm]

Well was this job ever completed? Any updates, or advice?

 

[BSB67]

While you have each spring off, give the valve stem a good tug in all directions as a "wobble test". If you can feel them move you may have more problems.

Personally, every time I've gone down the path of changing valve stem seals I've ended up installing new guides. But that was old, mostly original stuff. But I see folks are still knurling guides, so you never know what could be lurking below

Of course, fix the seals first and see what you get.

 

[BSB67]

Air and piston at the top? How do you keep the piston from going back down under the pressure you're putting on the cylinder? I do that for leak down on aircraft engines and you'd better have a damn good hold on the end of the prop.

If you put the piston at true TDC, it will stay there just fine.

But rope is a proven technique, simple, no special tools.

 

[BSB67]

............ and be sure to pull that oil pan because they will definetely be in the pan and plug the pickup.

Every original Mopar that I've taken apart has had valve seal chunks lodged in the pick-up. I suspect every BB Mopar made that lasted ten years ended up with seal chunks in the pick-up. They all ran fine, and had good oil pressure. The oil pick-up screen is simply doing its job. And guess what, the seal pieces will be other places too. Personally, I would not go chasing after the seal remnants, they're fine where they're at.

 

[dadsbee]

Pull the covers and just get a good flashlight and look in through the valve springs to see if your seals are cracked or broken in half just lying in there. If the seals are toast... you can stuff a rope in each cylinder and bring the piston up towards TDC and it will hold the valves in (cushioned by the rope). Valve compressor tool (about 20 bucks) will compress the spring so you can remove the valve spring keepers and then the springs. Change both valve seals and reinstall the springs, compress again and put the stem keepers back in place. Repeat for each cylinder. Simple as that if it has stock rockers...

While you have each spring off, give the valve stem a good tug in all directions as a "wobble test". If you can feel them move you may have more problems.

Not sure what @Mark Barnes disagrees with, but I guess we all get our opinion!

 

[Mark Barnes]

Not sure what @Mark Barnes disagrees with, but I guess we all get our opinion!

I disagree with ANY blue smoke coming out of the exhaust! (kidding)
I unknowingly fat fingered the red x on my tablet. My apologies. Please proceed.