Thin blue smoke on fresh rebuild, normal or not normal, that is the question?

[idrivemopar]

So, I fired up my 340, just rebuilt, most likely only a couple of hours on her, the builder did the cam break in, told me to change out the break in oil when I get her running, and I did that, refilled with Brad Penn 10w 40, oil pressure looks good, middle of the dash gage, but there is a bit of a cloud of thin blue smoke coming out the tail pipe, seems to increase as the engine warms. Did not happen the other day when I was running her with straight pipes and the break in oil still in the motor. Now it has fresh oil and full exhaust. Is this maybe the rings have not fully seated? Its got Keith Black hypereutectic pistons.

Any thoughts?

 

[Cranky]

What rings are in it? Moly filled usually break in pretty quick but regular cast can take longer. Also, the cylinder wall finish is important too. You have to have a smoother finish for moly vs cast....

 

[idrivemopar]

Not sure what was used for rings, but it was standard rebuild kit with just piston and cam upgrade, plus hardened valves etc.. But the motor was done by a reputable shop that's been around for 15 years.

 

[HEMI-ITIS]

Put some miles on it and see if the "blue" gets better or worse:thinker:

 

[idrivemopar]

It will be a while before she gets on the road, as I have no interior installed yet, and no windshield or steering wheel or draglink or tie rod ends. LOL

 

[snakeoil24]

When you rebuild a Motor you need to see the brake in thru. Don't let the engine sit if you have not completed the breakin. Usually what i do is wipe the cylinder walls with Graphite Powder to get a good break in. When we where kids we used Bon Ami cleanser thru carb to do this. very few people would admit to this today. Also Hyperutetic Pistons have special requirements for Piston wall clearances, so you need to check with your Re builder what they used for clearances and ring end gaps.

 

[idrivemopar]

Again, I am a rookie to this part of the process, so I agree, not to let the engine sit, I will run it frequently and hopefully be able to get in some short drives, of course winter is coming, so those may be limited, but at least I can run it a bit before then.

 

[superbeedave]

Here's a idea. Put car on jacks and every few days start it up and run it up to 50 or so and hold it for a min. or so then floor it for a second and let off so rpm's come down and speed comes down. I know this sounds crazy but maybe you can get the rings to seat in quicker then waiting for a few months to get it out on the road. It's just an idea!

 

[snakeoil24]

Here's a idea. Put car on jacks and every few days start it up and run it up to 50 or so and hold it for a min. or so then floor it for a second and let off so rpm's come down and speed comes down. I know this sounds crazy but maybe you can get the rings to seat in quicker then waiting for a few months to get it out on the road. It's just an idea!

wHAT IF IT FALLS OFF JACKS WHILE AT 50 MPH?

 

[bm02tj]

new exhaust pipes and mufflers have an oil coating on them so they form better and not wear the dies and mandrels

after it burns off you should be good

also Bon Ami cleanser was only used with chrome rings
you have a 99% chance your have moly rings

keep it warm and dry and if you start motor bring up to temp so you dry out every thing

 

[dvw]

new exhaust pipes and mufflers have an oil coating on them so they form better and not wear the dies and mandrels

after it burns off you should be good

also Bon Ami cleanser was only used with chrome rings
you have a 99% chance your have moly rings

keep it warm and dry and if you start motor bring up to temp so you dry out every thing

My race motor smoked until I made a pass. None since (9.25@146). Run it down the road and see what happens. If it's using oil after that, the first place I'd suspect is intake gaskets. You really have to screw up to get bad ring seal with today's technology and rings. Don't do any "backyard remedies". Take your time, break it in then go from there.
Doug

 

[idrivemopar]

Good point about the exhaust having oil coating, which may explain why it gets noticeable when it gets hot, and why I didn't see anything when running just open headers!!! Yes, taking my time with this process, and we will see what happens. Not a fan of having a running car in drive on jack stands, that's just an accident waiting to happen, but thanks for the suggestion.

- - - Updated - - -

Hey BM, I think you hit the nail on the head, just checked my other set of mid-pipes, and yes, has an oil coating on the inside, so it think that is what is causing the light smoke, as it has a sticky coating on the inside, corrosion protection I assume, and this explains why it does it more the longer it runs and hotter it gets.

 

[khryslerkid]

Is Brad Penn a synthetic oil?

X2 on the new pipe smoke...

 

[idrivemopar]

Its listed as a partial synthetic. And its green! Has a high concentration of zinc, and recommended by my builder so I am using it to stay in the 12 month 12k warranty on the motor.

 

[Cranky]

I've run lots of cars on stands before but you need to be smooth when running it and not be nailing it etc. Generally, I keep the front wheels on the ground and blocks in front and on the back side. Call your builder and ask him what rings are in it. I'm betting it's broke in already or almost is. Most new cars don't use moly rings and they break in pretty quick. If the machinist did a good job and got the cylinders round and true, it doesn't take very long.....

 

[Baller]

wHAT IF IT FALLS OFF JACKS WHILE AT 50 MPH?

Pull the drive shaft first.

 

[99ss]

how long did you run the break in oil for? Not that it will make a huge difference..... my guess is the rings aren't seated yet.. how many hrs on the engine?

 

[idrivemopar]

the builder did the initial break in, with several cycles over several hours going up to temp and doing 20 minute intervals I believe is what he said. I think its the coating on the exhaust pipe, as this was not a problem with just running straight pipes, only showed after running on the new exhaust.

 

[superbeedave]

wHAT IF IT FALLS OFF JACKS WHILE AT 50 MPH?

I have put them on jack stands for months I left them on and ran the car thru all four gears up to 60 mph and as long
as the stands are secured underneath shouldn't be a problem. Just be smooth cause it will jerk alot on you.

 

[idrivemopar]

You guys sound convincing, but I am still not going to do it with how my luck goes!