Rhythmic smoke puffing out of oil input breather cap

[AnthonyG]

About a month ago Rhythmic crankcase smoke puffing out the oil neck intake tube started after I brought the rpm's up on a ride to blow out some carbon as I rarely drive the car very fast or hard so once in a while to clean it out before putting away at the end of the season I do. Engine is an 8BA 5 yrs old w 2000 miles on it built by United Engine Specialists Jerry Livingston, Wichita Ka.. It seemed to diminish after using Seafoam engine cleaner & compression was a bit better & more consistent @ about 75psi but came back a couple weeks ago. Checked compression again and found cyl 2 weak again 30psi to 95psi. This time removed right head to check cyl's for damage, saw none after a thorough inspection of #2 & top of piston & other 3 on that side all looked good. Also there is no smoke coming from tail pipes first time nor this time, exhaust looked fine. I can't think of what would cause this condition so I guess ill pull engine remove oil pan and check inside lower end? This engine has always had what I thought was a lot of mechanical noise but chalked off to the nature of Flattys as a novice to them. Any ideas or direction?

[Ggmac]

Aren't you also having the pvc issue ?
Have you hooked up a vacuum gauge ? Vacuum gauge will tell you conditions of motor . It's a lot easier than pulling apart your motor , DONT FORGET, when it gets cool a lot more smoke is visual !

[AnthonyG]

No, the question about the PCV was a question on why the PVC one way valve was needed. Answers made sense, to prevent backfire igniting fumes in crank case. My pcv was not working when testing to eliminate this problem so I hooked up vacuum hose direct to vac port w/o pcv for test ride. Replaced w new pcv the next day. These engines were designed w no pcv in mind & running w just draft tube which I tested as well shouldn’t let the crankcase smoke come out the oil input neck unless draft tube is clogged. I cleaned draft tube & if I plug the oil input the Rhythmic puff puff puff comes out the draft tube. Pretty sure shouldn’t come out in that way from either?

[AnthonyG]

Ggmac, sorry I didn’t realize that thread continued. I went & saw ur post & posted again “AnthonyG's Avatar
Re: PCV process
I have an electronic dist w no vac advance. Which is why it doesn’t notice the vac loss I guess. It is an 8BA, sorry should’ve said in 1st post.”

[AnthonyG]

Ggmac, sorry I didn’t realize that thread continued. I went & saw ur post & posted again “AnthonyG's Avatar
Re: PCV process
I have an electronic dist w no vac advance. Which is why it doesn’t notice the vac loss I guess. It is an 8BA, sorry should’ve said in 1st post.”

[AnthonyG]

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The Rhythm of the puffs indicate one cyl. causing, assuming #2. Not sure I’ll see anything from underneath but at a loss what else to do?

[aussie merc]

sounds like classic sitting syndrome you leave it sitting and it will seize up [ nature of the beast] valves will be open and air gets in causing the rings and valves to start to seize leave it long enough and it wont even turn over answer simple USE IT it was designed and built to be used and enjoyed mean while some MM oil might free things up Plugs out and soak and retry LOTS OF LUCK

[tubman]

I have always said that the worst thing you can do is to leave these things sit. Get them out and exercise them. I just finished cleaning the carbs on my old Yamaha snowmobile that I had let sit for 7 years. The good news is that I got it running; the bad news is that there were 4 carburetors that needed to be completely disassembled and cleaned.

[AnthonyG]

So u think put the head back on and just run it?

[tubman]

I'd try that (but use new gaskets). What do you have to lose?

[JSeery]

Anthony, you may have missed something on the PCV valve discussion, it does a lot more than protect from a backfire. When you install the PCV system you are creating a large vacuum leak and this involves more than vacuum advance on the distributor. You are allowing air to enter the intake manifold that has not gone through the carburetor ventures. So, you are leaning the A/F ratio way out. It is now running lean. The PCV valve limits the amount of air (vacuum) leakage at high intake vacuum conditions (idle and constant speeds). At low vacuum conditions the PCV allows more crankcase air into the intake. Under these conditions the engine is less sensitive to the vacuum leakage. It still has an impact on the A/F ratio during acceleration however and most likely the carburetor would need a power valve or accelerator pump adjustment to correct this.

[Tinker]

Typically a blowby issue.... but chastise me...

MMO it. Sticky valve from sitting. Simple, cheap, and if it doesn't work. well your out $6.

You need to run it hard for a bit, so... maybe when it's warm.

.

[AnthonyG]

Got the new Felpro composite gaskets will install head w new Spark Plugs after clearance check, put MMO thru it & in the gas tank & run it as much as possible thru the winter. & hope she straightens out. To JSeery, I only did the one test drive to see if it still was pushing the smoke tru the oil neck. Next day put new pcv valve in it. Thx for the additional information & the site w all the info to.
Thx guys

[Bored&Stroked]

Question: Did you ever do a compression check in the past with this new engine? Do you know if it ever had good compression in all cylinders? Maybe the rings never seated in it? I would do what the other say and run it hard a few times -- full acceleration and lots of RPM changes and see if the compression gets better. If that doesn't work (and the valves are seating/sealing well), then you might need to pull it down, have the cylinders honed and put new rings in it -- and then run it hard to ensure that seat well.

Good luck!
B&S

[AnthonyG]

Thx B&S, that’s the plan.

[Ggmac]

Originally Posted by AnthonyG

Thx B&S, that’s the plan.

If you don't fix it , it's about to just get worse , sell it to me or trade me for one or two of mine ! I think I have one I can make smoke continuous, on all 8 cyl !
Seriously, I think the random low compression is either a faulty gauge or less possibly a floating piece of carbon , which I've seen happen .
Good luck and keep us posted , watch those knuckles when torquing.

[frnkeore]

I'm late to this but, here is my take on it.

Normally you will get that with a broken ring or broken ring land. It usually won't cure itself. Since yours has stopped doing once, my guess is that a ring is sticking in it's groove.

I think you'd be better served by putting the MM, in the offending cylinder, let it set one day, then spin the engine, first with the plug out, then again with it in. Let it set, one more day and drive it.

It can't be the valves, as they can only leak to the intake or exhaust. Valve guilds, can't leak enough, to cause a puff.

[Tinker]

Well on a new engine I guess you could have a ring broke. or bad install Also if you just bench run this you could have glazed the cylinders. Interested in the results.

[4dFord/SC]

"Rhythmic Smoke" sounds like the name of a new wave band

[Bored&Stroked]

Originally Posted by 4dFord/SC

"Rhythmic Smoke" sounds like the name of a new wave band

Or possibly Reggae . . . depending on the type of smoke!