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Oil smoke revisited

General engine tech -- Drag Racing to Circle Track

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Belgian1979
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Oil smoke revisited

Post by Belgian1979 » Mon Jun 01, 2020 6:30 am

I have numerous threads out here about a smoking problem while under deceleration. I did a lot to combat this and recently used a smoke machine to check for intake leaks and such but found none.
I was ready to pull the heads next winter to have the guides redone, but today I started particularly paying attention to what it did on slow speeds. It seems to also blow some blue smoke while taking a corner. Some speed, just not hard cornering.
Is this something that is tied to the guides?

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Re: Oil smoke revisited

Post by mag2555 » Mon Jun 01, 2020 9:16 am

My buddy had such a issue with a fully brand new motor that we built.

After a ton of checking things out and playing with the Carb and pulling valve springs to look at the seals it was found to be oil / temperature related and the bottom line was found to be that the heads where assembled from the supplier with valve seals for 3/8" stem valves, and not 11/16" ' and yes even though they where for 3/8" stems, they still did drag on the stems, but only very lightly.

The very strange thing was that even though the motor had seen a easy 1.5 hours of running on the engine break in stand with mufflers bolted right to the headers, it was only once the motor was in the car with a full Exh system on it did the blue smoke show up

My guess is that the seals where bagged wrong by the manufacturer and the builders helper that assembled the heads did not notice the ease fit of the seals on the valve's!

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Re: Oil smoke revisited

Post by Belgian1979 » Wed Jun 03, 2020 9:45 am

Thanks. I'm pretty sure that I have the right size seals. Bought them myself and choose the correct one. This was part of an initial plan of attack.

Is there any rock solid way to test valve guides while on the engine. (tried the wiggle test, but find it not very accurate to say the least)

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Re: Oil smoke revisited

Post by BCjohnny » Wed Jun 03, 2020 11:31 am

If oil is puddling the the rockers due to feed/return issues, depending on valve layout, cornering could be a factor in overwhelming the (tired) seals
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Belgian1979
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Re: Oil smoke revisited

Post by Belgian1979 » Wed Jun 03, 2020 5:04 pm

The seals are not tired. Oil return is basically stock (didn't modify - Dart pro 1 alu 215 heads)

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Re: Oil smoke revisited

Post by cardo0 » Fri Jun 05, 2020 11:44 pm

Just a WAG but another possible problem could be deep spring pockets allowing oil to puddle up high enough to get sucked into the guide. This was a known problem on some early AFR sbc heads with huge spring pockets for huge double springs.

Any pictures with the valve covers off?
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Belgian1979
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Re: Oil smoke revisited

Post by Belgian1979 » Sat Jun 06, 2020 6:03 pm

My springs are 1.550's and double and yes, the valves are also longer than standard (.100" comes to mind). Cannot tell you how much deeper these would be.

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Re: Oil smoke revisited

Post by midnightbluS10 » Sat Jun 06, 2020 11:53 pm

mag2555 wrote:
Mon Jun 01, 2020 9:16 am
My buddy had such a issue with a fully brand new motor that we built.

After a ton of checking things out and playing with the Carb and pulling valve springs to look at the seals it was found to be oil / temperature related and the bottom line was found to be that the heads where assembled from the supplier with valve seals for 3/8" stem valves, and not 11/16" ' and yes even though they where for 3/8" stems, they still did drag on the stems, but only very lightly.

The very strange thing was that even though the motor had seen a easy 1.5 hours of running on the engine break in stand with mufflers bolted right to the headers, it was only once the motor was in the car with a full Exh system on it did the blue smoke show up

My guess is that the seals where bagged wrong by the manufacturer and the builders helper that assembled the heads did not notice the ease fit of the seals on the valve's!
How would seals for stems that are 6/16" only very lightly drag on stems that are almost twice the thickness @ 11/16? That's a 5/16" difference from one to the other. Logic says it would drag more than slightly?
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Re: Oil smoke revisited

Post by Kevin Johnson » Sun Jun 07, 2020 12:39 am

11/32

versus

12/32

ypost

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Re: Oil smoke revisited

Post by steve cowan » Sun Jun 07, 2020 2:33 am

Belgian1979 wrote:
Mon Jun 01, 2020 6:30 am
I have numerous threads out here about a smoking problem while under deceleration. I did a lot to combat this and recently used a smoke machine to check for intake leaks and such but found none.
I was ready to pull the heads next winter to have the guides redone, but today I started particularly paying attention to what it did on slow speeds. It seems to also blow some blue smoke while taking a corner. Some speed, just not hard cornering.
Is this something that is tied to the guides?
i was reading some of your other comments etc on this,
does the engine show oil consumption by oil level?
have you disconnected PCV and checked how much oil goes in catch can overtime?
i ran a set of pro 1 heads for a couple of years and i dont think there is a issue with spring seats holding to much oil.
has this been a issue since the engine was built?
good rocker geometry on assembly?
sorry for all the questions just trying to get thought process going
steve c

Belgian1979
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Re: Oil smoke revisited

Post by Belgian1979 » Sun Jun 07, 2020 5:20 pm

I've always had oil consumption. However, I had a problem with the manifold (vacuum chamber - ITB manifold). This has been meanwhile corrected.

It does show up on the dip stick. However, I do not drive the car alot and it seems to be rather erratic. Sometimes it doesn't show, and then all of a sudden it is...I have to admit that this could also be due to the the accusump which fills differently depending on the temp of the oil (I think).

I use shaft rockers and yes geometry is good (was set correctly, but haven't checked it after the build anymore).

Compression test doesn't show anything either. All cyls are within 2-3 psi from eachother and 2-3 psi from new.

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Re: Oil smoke revisited

Post by Belgian1979 » Sun Jun 21, 2020 11:23 am

I watched it more closely today and it seems to indeed smoke especially after a longer fast turn. Indifferent if left or right. Not sure what to do with that one though.

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Re: Oil smoke revisited

Post by GRTfast » Sun Jun 21, 2020 11:29 am

Belgian1979 wrote:
Sun Jun 21, 2020 11:23 am
I watched it more closely today and it seems to indeed smoke especially after a longer fast turn. Indifferent if left or right. Not sure what to do with that one though.
Well if it is oil pooling in the heads and flooding the valve seals under lateral load, then it makes sense that it would do regardless of cornering direction.
Take the risk of thinking for yourself, much more happiness, truth, beauty, and wisdom will come to you that way. -Hitchens

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Re: Oil smoke revisited

Post by Belgian1979 » Sun Jun 21, 2020 1:51 pm

What can I do to resolve this?

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Re: Oil smoke revisited

Post by GRTfast » Sun Jun 21, 2020 1:55 pm

Belgian1979 wrote:
Sun Jun 21, 2020 1:51 pm
What can I do to resolve this?
Not sure, I was just commenting based on logic. I've never tackled this issue. Forgive me if this has already been asked in the thread, but is the engine tilted back at all in it's mounted position? having the back of the engine lower helps the oil find the drains.
Take the risk of thinking for yourself, much more happiness, truth, beauty, and wisdom will come to you that way. -Hitchens

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