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63 SS convertible 67 SS 4 spd
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Discussion Starter · #1 ·
Here is my issue. Engine is using a fair bit of oil. Doesn't smoke while running or sitting that I can notice. Not sure about when I let off the throttle and let compression slow the car. Nothing I can see in the mirror.
Compression check shows all cylinders at 150 - 155 psi. Leak down shows less than 4% on the worst cylinder. Number 2 and 4 cylinder the plugs are fouled with what I assume is oil. Top picture
IMG_2082.jpg
The other cylinders the threads of the plug are wet and the bottom of the electrode seems fouled but the electrode tip is dry. Second picture.
IMG_2081.jpg
My thoughts after doing lots of reading is oil getting down the valve stem? Or, could it be something to do with the intake manifold gasket or something else? Never changed valve seals but seems like something I'm capable of doing but I don't want to fix something that is not the problem.
Thanks,
Victor
 

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Small block chevy? Aftermarket heads? I have a set of Holley aluminum heads on my engine and had a similar issue. It has positive type seals. I replaced them all and problem solved.
 

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1969 Nova . . 2dr . . Chino Valley,Az USA
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5,137 Posts
Morning Victor . .

Before I got too your second picture ................... I thought - - "valve seals" .

I have replaced them in a few cars . . . w / V-8's . . . easy too do (if you have an 'air compressor' ) .
When I did mine . . . I just used the " o-ring type seal " ; on my brother's Ford truck , we used the
' cup type seal' .
Really not that hard . . . . and Will Make Some Difference . . . (meaning : some 'smoking & using oil' ) .

. . . jim
 

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63 SS convertible 67 SS 4 spd
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950 Posts
Discussion Starter · #5 ·
Small block chevy? Aftermarket heads? I have a set of Holley aluminum heads on my engine and had a similar issue. It has positive type seals. I replaced them all and problem solved.
It is a 327. Stock cast iron heads. Aluminum Winters intake. I did a leak down test twice just to make sure. Worst cylinder was 4%. What are positive type seals? Most everything I read says to use umbrella type seals.
 

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1973 Custom hatchback
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Not disagreeing with any of the above but before I went to that effort and expense I would re torque your intake manifold. If they tighten put in clean plugs and see if the problem is gone. Note that if the gasket has ben sucked into the intake it may not seal, In which case you'd want to remove the intake and replace the gasket. t.

#2 and I believe #4 intake manifold bolts protrude through the head into the intake runner. If they are loose oil can and will be drawn down into the combustion chamber. If all or many of the intake manifold bolts are loose oil can be drawn down into many of the cylinders, anywhere the intake manifold gasket is loose, more so under WOT when the pressure differential between the internal engine and intake runners is at its greatest. Usually at that point smoke its pretty obvious in the exhaust.

Hope this helps, GL
 

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63 SS convertible 67 SS 4 spd
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Discussion Starter · #7 ·
I haven't done anything yet so I will give the intake bolts a check this morning. Easiest thing to try. One bolt above the #4 cylinder was weeping oil. I took it out and put sealant on it and put it back in but that's as far as I went. Thanks for the input.
 
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