Oil misting from dipstick tube - blowby?

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1974PlymouthDuster

1974PlymouthDuster

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Hi guys - Rebuilt the 74 Duster 318 - mild performance - Ebrock 4bbl, Comp Cams 278 cam, stock manifolds and stock heads. Nothing crazy

Since rebuilding, I have a oil leak that seems to be getting worse. It is coming from front passenger side of engine.

Here is a video showing oil misting from the dipstick tube at idle.
[ame]http://youtu.be/tiKerkIL5hk[/ame]

Mopar Perf Valve Covers: Passenger side has fill hole going to a twist-on PCV valve, routed to rear pcv port on carb.

Driver Side valve cover has a standard fill cap. With the cap on (video), good amount of misting. As soon as I remove the cap (venting driver side valve cover), the misting immediately stops.

After running, a few tablespoons of oil are left on the ground, beneath the same area (dipstick tube)

I also have a twist-in breather cap for testing, seems to have same misting/leaking with that too.

Does this just need to be driven more, to seat the rings fully or what?

Probably have 100~ miles since rebuild.

Thanks guys - appreciate any input.

-Ryan
 
Yes that is excessive blow by. The fact that it stops when you take the oil cap off confirms this. Weather or not it will get better with more run time? I doubt it, I've built many of engines and have never experience this on a good built. I would suspect you may have broke a piston ring when you installed the pistons. But hey this is my 2 cents.
 
Is the pcv valve hooked up and working ?

Hook up the other breather to the air cleaner with a rubber hose.

How full is the engine oil?
 
He stated this in the original post.



Mopar Perf Valve Covers: Passenger side has fill hole going to a twist-on PCV valve, routed to rear pcv port on carb.
 
How about a picture of the top end? That would help.(the video ,didn't load). Thinking PVC system,in a different way.
 
GEO said:
Is the pcv valve hooked up and working ?

Hook up the other breather to the air cleaner with a rubber hose.
Click to expand...

My thoughts as well. You need a constant vacuum in the crankcase (however slight) and you need a setup that will accommodate plenty of volume of blow-by (the driver's side valve cover needs to be plumbed to the air filter). This setup also allows fresh air from the air cleaner to drawn down into the crankcase as well.
 
It needs a breather in the opposite side valve cover than the PCV valve. That should stop the misting. Also, it is too early in the game to condemn anything yet. Rings can take 1K or more miles to break in properly.
 
That is extremely excessive. Exactly what was involved in this build..New pistons/bore and hone job or just a re-ring? I find people have very different ideas of what is a rebuild. J.Rob
 
So far the most important question here is how much oil is in it. After we get a handle on that we can get down to business trying to figure out why its coming out the dipstick. I had a slanty start to do this, but it had well over 100K.
 
I suspect rings not seated properly, upside down, broken, etc..
.If that's the case you'll have some oil in the cylinders too. Oil on the plugs, blue smoke. Run a compression test.
 
Hi guys - Thanks so much for all the ideas- I'm going to try to respond to all:

I have seen this thread, and another thread, mention the specificity of "PCV = Drivers Side, Breather= Passenger Side" - Why do the sides matter? I have them switchted right now, as the pass side valve cover has the hole in the rear, and I was trying to keep it clean, with a nice straight shot to the back of the carb (1/4" npt on edelbrock carb)

Absolutely ZERO smoke, or anything coming out of exhaust - Cleanest the pipes have ever blown on this car (since rebuild)

The stripped short block was taken to Carquest in Northridge, Harlan is their machinist - Has a pretty good reputation in the San Fernando Valley - I took block to him when I realized I couldn't afford Valley Head Service, as they were doing the cylinder heads and broke the bank. (All SoCal places for my distant A-body people =) )

#2 Piston was rusted to cyl wall, so he overbored the entire engine 30 over, I brought him the Keith Black Pistons and their matching moly rings (KB167-030). http://www.summitracing.com/parts/uem-kb167-030 All other bearings were standard thickness.

The engine is the casting right after 1976-> (casting #4006730) (the thinwall casting everyone talks about) Everyone who has looked at this engine has agreed that it is a virgin block - no rebuilds ever.

Heads are real boring casting: #4027163 Nothing crazy done to them.

Comp Cams K-Kit was used - K20-223-3.

The initial oil dumped was 5quarts Mobil 1 synthetic 5w-30 with a added bottle of Lucas zinc Break In additive - I know this wasn't anywhere close to the proper way to do it.

I'm going to change over to standard 10w-30, as the initial oil and filter should come out now anyway, and I will report back.
 
Address the PCV/ Breather issues 1st. As a lot of members already stated, you need air to flow into the crankcase as the PCV Valve allows crankcase gasses to be sucked out. If you suspect a problem with the rings do a Cylinder Leak-down test(NOT a compression test) on it & see how much blow by you get. Anything more than 10% on a fresh rebuilt broken in engine is excessive.
My guess is that it's the lack of a breather on the 1 side that's causing your problem.

Good luck.
 
As soon as I remove the cap (venting driver side valve cover), the misting immediately stops.
Click to expand...

Your PCV valve won't work if you don't have a breather on the other side. It's kind of like opening a window in your house during the summer. You don't get any air flow through the house until you open another window.
 
So what about a breather on the outher side that has a hose hook up from the breather than to the air filter to carb does that work.
 
The initial oil dumped was 5quarts Mobil 1 synthetic 5w-30 with a added bottle of Lucas zinc Break In additive - I know this wasn't anywhere close to the proper way to do it.

I'm going to change over to standard 10w-30, as the initial oil and filter should come out now anyway, and I will report back

I never use synthetic to break in, use regular oil with the additive and a breather cap. Synthetic is good for after break in. I had trouble with synthetic and the rear main seal with a very minor leak. I returned to regular and no more leak. That stuff is really slippery!!
 
Hey guys - I think everyone may have been somewhat spot - on with the solutions...

https://plus.google.com/photos/103610739631795757387/albums/5956713608991682225
I stopped by Pep Boys and bought every grommet, breather and pcv valve that looked like it might fit. $67.

Got home, played around a little with left cap on, right cap off, etc. Still misting.

Pulled off the Twist-In PCV I built this thing with initially, [ame="http://www.amazon.com/gp/product/B002ZMKMMM/ref=wms_ohs_product?ie=UTF8&psc=1"]Amazon.com: Mota Performance A70136 Chrome Plated Twist On Valve Cover Oil Filler Breather Cap with PCV Tube 2-3/8" Diameter: Automotive[/ame]

The 90 degree adapter I screwed in initially ( [ame="http://www.amazon.com/gp/product/B0045LNDP4/ref=wms_ohs_product?ie=UTF8&psc=1"]Anderson Metals Brass Hose Fitting, 90 Degree Elbow, 3/8" Barb x 1/4" Male Pipe: Amazon.com: Industrial & Scientific[/ame] ) Had good constant vacuum at idle.

I moved to the PCV side, and I went to pull off the PCV to Carb hose. As I pulled off the tube, the entire foam filter element came off attached to the hose, as if it had been sucked in to the hose from the valve. (see pictures) This obviously seems like all, or almost all my problems - the foam was preventing any vacuum from reaching the valve cover.

The synthetic surely didn't help, and it appears that there was 5-quarts initially added.

I changed the oil and the filter, and put 4 quarts of nice old boring Chevron 10-30.

That 4 quarts read right in middle of the dipstick area.

The funny part is that all those grommets and adapters were un-needed.

One question for the crew out there - Now the PCV valve has no element inside, but nothing is leaking or misting or dripping. This going to cause a problem ?

So, to confirm the setup now:

Passenger Side Valve Cover: PCV valve without any foam element inside
Drivers Side Valve cover: Twist-in breather cap (looks like this one: [ame="http://www.amazon.com/Mr-Gasket-2061-Twist-On-Breather/dp/B00068OK98/ref=pd_sim_sbs_auto_1"]Mr. Gasket 2061 Valve Cover Twist-On Breather : Amazon.com : Automotive[/ame] )

Since the oil and filter change, and PCV re-arrangement, the oil pressure at idle has gone from 80 (90 to 100 on a quick rev), to 40 psi (60-80 on quick rev)

Also - took pictures of the magnetic drain plug - some filings on there - will keep eye on that too for next oil change.
 
Are you certain you installed the rings correctly (ring gaps 120 degrees from each other) also are you sure you installed the rings with the dot on top or beveled edge facing up???
 
Short block was assembled by a builder in the area who has a good reputation, so I can't answer 100%, but with the PCV thing resolved, and the leak completely stopped, I think they're ok.

Plus, no smoke in exhaust, so I'm going to play on the notion the rings are correct?
 
Keep an eye on it and run it.
You have not put enough miles on the engine to seat the rings.
I would rather see 40 psi at idle than the pressure you were seeing before.
PVC on one valve cover and breather on the other side.
 
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