blow by

[Dgc]

ok kids heres a question. 440 sat 40 yrs since on the road it turned freely so we dropped the pan cleaned out lots of sludge fresh oil an filter , sprayed some oil in plug holes turned by wrench a few times spun nice fired it up not a bit of noise runs strong but has some blow by. yes I will prob tear down hone rering and fresh bearings but may try to free up rings with out tearing down mm oil soak or some atf it only has 37 k on it . does anyone have a different sugestion?

 

[Ranger16]

The GM procedure for freeing up the rings on a Northstar uses your soak method with Techron. Just one more chemical to consider.

 

[69L48Z27]

How are you measuring this blow by? Are you saying the compression is all over the place or is there physically smoke out of the tailpipe? If it's the later, make sure it oil and no a rich condition. I had a very similar situation this summer. Not quite 40 years but a long time. I had a white/blue smoke that I thought was oil but it's rich condition. I expected black smoke but it's not.

 

[MarPar]

 

[Dgc]

How are you measuring this blow by? Are you saying the compression is all over the place or is there physically smoke out of the tailpipe? If it's the later, make sure it oil and no a rich condition. I had a very similar situation this summer. Not quite 40 years but a long time. I had a white/blue smoke that I thought was oil but it's rich condition. I expected black smoke but it's not.

their is smoke from breather cap and tail pipe it also may be the oil is not returning throu heads properly and getting past valves from the top will be pulling valve covers soon just going one step at a time

 

[dvw]

How many valve seal parts were in the pan?
Doug

 

[PurpleBeeper]

How many valve seal parts were in the pan?
Doug

You know, Doug had a great point. You might want to change the valve seals on the motor & do a compression check before you start pulling it out....just sayin'

69 has a good point too...."maybe" it's just rich and needs the carb worked on.

 

[wilmacmike]

A mixture of acetone and ATF at a ratio of 50/50 works well at un sticking the rings. You can also use Sea Foam, but I think the ATF mixture is more aggressive.
Pour it through the spark plug holes, let it sit for a few days. Turn the engine over by hand. Pull the plugs, and clean them up.

Put some rags over the spark plug holes to catch the liquid as you crank it over with the starter.
Re install the plugs and fire it up. I have had to do this procedure to several motors that have not run in 20 to 30 years. some times I had to do it 2-3 times to get the compression (rings un stuck) up.

It worked well.

Also as already mentioned, I would replace the valve stem seals. They will be hard and possibly broken/cracked letting oil down into the intake valves.
You may be able to still find the valve stems seals with the top teflon seal lips on them. They always worked for me.

Have fun and God Bless America

 

[oldbee]

I did like wilmacmike after mine sat for 20+. Used a good couple squirts of Marvel Mystery oil in each hole and let it sit for a week. Also pre-lubed thru distributor hole before I fired it up.

 

[Dgc]

How many valve seal parts were in the pan?
Doug

their was nothing in pan but old oil gummed up looked it over very careful

 

[69L48Z27]

Valve seal smoke usually clears up in the first few minutes of being cold. You said it was pushing out the breather, that would be a good indicator of blow by. It would take crank case pressure to push oil out, more that normal pressure anyway.

Does the car drive or is it not roadworthy? Curious how it runs under load.

 

[Dennis H]

PCV on that one?

 

[oldbee]

I can remember seating new moly rings ago. Procedure was about 1/2 throttle to 50mph, then coast back down. Do it like 5-6 times in a row- rings were seated. If driveable, maybe try that so high vacuum on coast maybe moves rings around a little more?

 

[Dgc]

Valve seal smoke usually clears up in the first few minutes of being cold. You said it was pushing out the breather, that would be a good indicator of blow by. It would take crank case pressure to push oil out, more that normal pressure anyway.

Does the car drive or is it not roadworthy? Curious how it runs under load.

she runs good I take it out in my development but im in pa and it doesnt have a state inspection sticker on it yet and since the tail lites are out and its almost all bare metal im sure it would stick out like a sore thumb if I took it on highway lol .Im a old motor head from back in the day have done many project cars most of the time I have just rebuilt the engines but with this one id like to see what I have first. if i soak it a few times and the rings free up id like to drive it to see how she runs it only has 38k on it so may not need rebuilt

 

[Ranger16]

I can remember seating new moly rings ago. Procedure was about 1/2 throttle to 50mph, then coast back down. Do it like 5-6 times in a row- rings were seated. If driveable, maybe try that so high vacuum on coast maybe moves rings around a little more?

This reminds me of the procedure to free stuck rings on the Northstar. I'm quoting this from one of the GM powertrain engineers who developed it. Basically, drive it like you stole it. WOT to redline and then let it back down. Two or three applications where recommended along with a monthly preventive maintenance dose.
Disclaimer: That said, the Northstar is probably a little beefier and was built with this treatment in mind, but the point is the same. Wind it up as tight as you dare and let it back down. The high cylinder pressures and temps on acceleration followed by the ring flutter on Decel should free up the rings (if they are stuck).

 

[Darthomas]

Marvel. Mystery. Oil.


Sea-effing-Foam.

And Aero-effing-Kroil.
Aero Kroil is the smell of mechanical SUCCESS.
I wear it as a cologne.
A few dabs behind the ears and down my neck and I feel like I can accomplish anything.
Except repair my broken family.

 

[miller]

Would be up to you, but I've done this before, in a pinch. Yeah, before anyone says it, I'm probably half nuts!

But, sludge has gotta go...drain the oil, but leave the filter on. Put in ONE quart of oil, and a gallon of clean kerosene. Just run the motor at idle, until you hear the tappets start to click.
Then, drain it all real good, along with replacing the filter. (Used to do that once a year.)

Won't help much on hung rings, but might help washing some of the crud out. Motor that old, needs a little flush.