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Oil on plugs after rebuild.

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Old 08-27-2017, 03:34 PM   #21
LenWoodruff
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To further continue this story. I got the car back from the engine builder and the compression test was 120 for all of the cylinders. Seems low but they are all the same.

I have driven the car about 170 miles since the new plugs.

I did notice that at 75 MPH the Oil Pressure was at about 75 LBS. That seems high to me.

I checked #6 which was the worse one of the ones I checked earlier and it is oiled on 1 side.

I put a mark on that side and when the plug was installed the mark was pointing up.

To me that would mean the oil is coming from the intake???

Also I did a bore scope of the piston top and it looks oily to me?

Does it seem like the culprit is a leaking manifold gasket?

Here are the pictures I took.












Last edited by LenWoodruff; 08-27-2017 at 03:40 PM.
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Old 08-27-2017, 04:32 PM   #22
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pull off the carb and use your bore scope to look at the back side of the intake valves. if the oil leak is caused by the manifold or the valve guide seal the back side of that intake valve will look different than the ones showing no oiling. if the back side looks the same the oiling problem is caused by piston ring problem

Last edited by PAmotorman; 08-27-2017 at 04:35 PM.
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Old 08-27-2017, 04:40 PM   #23
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Quote:
Originally Posted by LenWoodruff View Post
Thanks guys I hope so to.

They did true up the heads which are factory.

The aluminum intake was not touched. It is factory L82 too.
If you mean the heads were milled then depending on the angle and how much material was machined off you will have a mismatch in angles between the intake and the heads.

Which in turn will prevent the intake sealing properly with the heads and causing oil to enter the intake runners.

I would try and get some answers from the shop that milled the heads.
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Old 08-27-2017, 07:11 PM   #24
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Quote:
Originally Posted by PAmotorman View Post
pull off the carb and use your bore scope to look at the back side of the intake valves. if the oil leak is caused by the manifold or the valve guide seal the back side of that intake valve will look different than the ones showing no oiling. if the back side looks the same the oiling problem is caused by piston ring problem
I will take a look at that tomorrow.
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Old 08-27-2017, 07:12 PM   #25
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If you mean the heads were milled then depending on the angle and how much material was machined off you will have a mismatch in angles between the intake and the heads.

Which in turn will prevent the intake sealing properly with the heads and causing oil to enter the intake runners.

I would try and get some answers from the shop that milled the heads.
The heads were trued up with a .015 cut. Would that be enough to cause a intake gasket leak?
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Old 08-28-2017, 01:28 PM   #26
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Any chance some of the rings were installed upside down?
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Old 08-28-2017, 02:02 PM   #27
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Any chance some of the rings were installed upside down?
or the oil ring expander overlapped.
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Old 08-28-2017, 02:23 PM   #28
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Any chance some of the rings were installed upside down?
Possible but is there anyway to check without tearing down the engine?
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Old 08-28-2017, 02:24 PM   #29
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or the oil ring expander overlapped.
You mean where the corrugation is overlapped and doesn't keep the rings flat against the cylinder wall?
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Old 08-28-2017, 03:06 PM   #30
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Quote:
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You mean where the corrugation is overlapped and doesn't keep the rings flat against the cylinder wall?
if you are not careful the oil ring expander that causes the oil ring rails to press against the cylinder wall can be installed with the ends over lapped and not putting enough pressure on the rails and they will not remove the excess oil from the cylinder wall.

Last edited by PAmotorman; 08-28-2017 at 03:07 PM.
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Old 08-28-2017, 04:11 PM   #31
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if you are not careful the oil ring expander that causes the oil ring rails to press against the cylinder wall can be installed with the ends over lapped and not putting enough pressure on the rails and they will not remove the excess oil from the cylinder wall.

Anyway to check for that possibility?
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Old 08-28-2017, 04:27 PM   #32
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Anyway to check for that possibility?
not unless you remove the piston from the engine.
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Old 08-28-2017, 04:39 PM   #33
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not unless you remove the piston from the engine.
Thanks for confirming. I thought that would be required.
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Old 08-28-2017, 04:40 PM   #34
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How much oil are we talking about? In 700 miles on a fresh rebuild. I'd be a bit leery of ripping a fresh engine apart for oil consumption unless it was really blowing blue out the tailpipe. Back in GM's 454 days they wouldn't even talk to you unless it was over a quart in 500 miles..

If someone stacked an oil ring expander, a magnet on the drain plug will tell you quick. You could stick each cylinder with a borescope and see the scratch on the cylinder wall.
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Old 08-28-2017, 04:58 PM   #35
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How much oil are we talking about? In 700 miles on a fresh rebuild. I'd be a bit leery of ripping a fresh engine apart for oil consumption unless it was really blowing blue out the tailpipe. Back in GM's 454 days they wouldn't even talk to you unless it was over a quart in 500 miles..

If someone stacked an oil ring expander, a magnet on the drain plug will tell you quick. You could stick each cylinder with a borescope and see the scratch on the cylinder wall.
I drove 125 miles on a cruise Saturday and it used 1/2 quart of oil. That's a lot to me.
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Old 08-28-2017, 06:20 PM   #36
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You should do as PAmotorman suggests and have a look down the intake manifold on runner #6 with your borescope. Look closely at the seam between the head and intake for signs of a leak, and then look a little further to see if the oil is coming from the intake valve guide.
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Old 08-28-2017, 06:45 PM   #37
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Quote:
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You should do as PAmotorman suggests and have a look down the intake manifold on runner #6 with your borescope. Look closely at the seam between the head and intake for signs of a leak, and then look a little further to see if the oil is coming from the intake valve guide.
Thanks I will do that. I pulled some of the plugs then marked them with a black marker for the side the plug was oiling on. All of then show the oil side up.

I assume that means it is coming from the intake?
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Old 08-29-2017, 01:49 AM   #38
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He said all of the cylinders were at 120. He said that was ok because of the low 9.5 to 1 compression.
This would be unacceptable to me. I would expect 120 from maybe a '40's flathead motor........ 9.5:1 is not what I would consider a low compression motor either. What cam timing did you use, can you post the grinder and part number?

Last edited by techinspector1; 08-29-2017 at 01:53 AM.
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Old 08-29-2017, 07:11 AM   #39
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120 is way low to me. It seems your rings are not seating.
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Old 08-29-2017, 08:45 AM   #40
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This would be unacceptable to me. I would expect 120 from maybe a '40's flathead motor........ 9.5:1 is not what I would consider a low compression motor either. What cam timing did you use, can you post the grinder and part number?
It is the factory L82 Cam Blueprinted from Crane 3863151
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