Side of Intake Leaking Oil

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RD_Racing
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Side of Intake Leaking Oil

Post by RD_Racing » Thu Apr 12, 2018 8:23 pm

Im getting fresh oil squeezed out on the side of my intake where it meets the head, mainly in the center of the intake and appears to be on both the top and bottom side of the gasket (see photo with arrows).. I assume its coming from the lifter valley but why? Its a fresh build and i have a valve cover breather evac system hooked up and verified that it has good vacuum.. Its a SBC 406 with a 1206 intake gasket..

The funny thing is that it never gets any worse and doesnt puddle up or drip off the motor but if i wipe it down it just keeps appearing again as soon as i fire it up..

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Re: Side of Intake Leaking Oil

Post by cgarb » Thu Apr 12, 2018 10:18 pm

Is it possible it's leaking at the valvecover and puddling there?

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Re: Side of Intake Leaking Oil

Post by RD_Racing » Thu Apr 12, 2018 10:28 pm

cgarb wrote:
Thu Apr 12, 2018 10:18 pm
Is it possible it's leaking at the valvecover and puddling there?
I verified the wall from the valve cover gasket to the intake gasket is bone dry from one end to the other.

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Re: Side of Intake Leaking Oil

Post by Baprace » Thu Apr 12, 2018 10:33 pm

How close was the manifold to china wall ? I have had some new intakes that lay right on the china wall and they have to be milled so the intake does not bottom out.

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Re: Side of Intake Leaking Oil

Post by RD_Racing » Thu Apr 12, 2018 10:38 pm

Baprace wrote:
Thu Apr 12, 2018 10:33 pm
How close was the manifold to china wall ? I have had some new intakes that lay right on the china wall and they have to be milled so the intake does not bottom out.
I had a pretty good gap (probably 1/8" to 3/16") and used the black high temp permatex instead of the rubber seal that came with the intake gasket

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Re: Side of Intake Leaking Oil

Post by MadBill » Thu Apr 12, 2018 11:22 pm

This is perplexing for several reasons:
1. You mention that the PCV system is functional, so at anything less than say 75% throttle, the valley should be running a slight vacuum and any oil would have to swim upstream to appear at the manifold/head joint.
2. The leakage path to the valley is over 2" long and must skirt one or more ports operating mostly at high vacuum, so one would expect the oil to migrate, if anywhere, into a port instead of out the top.
A few suggestions:
1. Is there any trace of oil burning/consumption?
2. Per above, verify where the leak emerges relative to ports.
3. You could do a leak test by blocking all vents, fitting a hose to the dipstick tube and pressurizing the engine with lung power to check for air sounds and pressure bleed off.
4. Has the manifold been on the engine before? It could have a bad but localized warp...
5. If it's still a head-scratcher, when you have the manifold off stick little bits of solder wire at each end of the China walls and high and low at all four manifold flange corners, plus at the leak area, moderately torque down the manifold then check the solder thickness. Ideally the lowers should all be the same and the uppers somewhere between the same and perhaps 0.010" more.
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Re: Side of Intake Leaking Oil

Post by cgarb » Thu Apr 12, 2018 11:50 pm

If you have access to a "smoke machine" to help find leaks...they do work. I used one my that the dealership my Dad works for has to find an evap leak in my wifes Durango. Pump the smoke in the crankcase and look for areas its leaking out of...just would need to plug up the major leak holes first like the breather holes and dipstick.

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Re: Side of Intake Leaking Oil

Post by BOOT » Fri Apr 13, 2018 12:12 am

Did you use sealer on those intake bolts?
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Re: Side of Intake Leaking Oil

Post by RD_Racing » Fri Apr 13, 2018 9:53 am

BOOT wrote:
Fri Apr 13, 2018 12:12 am
Did you use sealer on those intake bolts?
The intake holes in the heads are blind holes so no need for any sealant.

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Re: Side of Intake Leaking Oil

Post by RD_Racing » Fri Apr 13, 2018 10:26 am

Good questions which I listed the answers below
MadBill wrote:
Thu Apr 12, 2018 11:22 pm
This is perplexing for several reasons:
1. You mention that the PCV system is functional, so at anything less than say 75% throttle, the valley should be running a slight vacuum and any oil would have to swim upstream to appear at the manifold/head joint.
2. The leakage path to the valley is over 2" long and must skirt one or more ports operating mostly at high vacuum, so one would expect the oil to migrate, if anywhere, into a port instead of out the top. I have been chasing a plug fouling issue since I first fired this motor up so maybe this is all related.. I tried reducing the IFR's and also increasing the IAB's and it didn't make any noticeable difference so maybe im sucking some oil in the intake
A few suggestions:
1. Is there any trace of oil burning/consumption? Possibly.. I do have a plug fouling issue but there is never any actual oil residue on the plug
2. Per above, verify where the leak emerges relative to ports. This morning I went out to take a better picture and the oil was gone so I assume it seeped back in
3. You could do a leak test by blocking all vents, fitting a hose to the dipstick tube and pressurizing the engine with lung power to check for air sounds and pressure bleed off. This is something I will try over the weekend
4. Has the manifold been on the engine before? It could have a bad but localized warp... YES!!! Its a modified Edlebrock street ram and I had a professional company weld the top of the runners and port them so they match a #1206 gasket.. Im 1/2 tempted to just buy a new tunnel ram that is already port matched to a 1206 gasket
5. If it's still a head-scratcher, when you have the manifold off stick little bits of solder wire at each end of the China walls and high and low at all four manifold flange corners, plus at the leak area, moderately torque down the manifold then check the solder thickness. Ideally the lowers should all be the same and the uppers somewhere between the same and perhaps 0.010" more. Before I installed the intake I did a dry test fit and visually it looked like it was a good fit.. I also took a straight edge to the entire length of the port sides of the intake and visually didn't see any warpage but that doesn't mean the fit wasn't a perfect mate to the heads.. This kinda sucks, I really took my time putting this all together too... On a final note, when I put my car in gear it drops about 500-600rpm and wants to stall and Im assuming this is all related

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Re: Side of Intake Leaking Oil

Post by rfoll » Fri Apr 13, 2018 11:09 am

I have had several Edelbrock manifolds that had poor machining and sat crooked in the valley. I verified with several blocks and different heads on each block.
So much to do, so little time...

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Re: Side of Intake Leaking Oil

Post by JoePorting » Fri Apr 13, 2018 11:33 am

It's probably dripping down from the valve cover.
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Re: Side of Intake Leaking Oil

Post by RD_Racing » Fri Apr 13, 2018 12:06 pm

JoePorting wrote:
Fri Apr 13, 2018 11:33 am
It's probably dripping down from the valve cover.
The wall under the valve cover is totally dry. Also, if that were the case I would think the oil would still be there and not seep back down into the intake after sitting for a few hours.

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Re: Side of Intake Leaking Oil

Post by RD_Racing » Fri Apr 13, 2018 12:10 pm

Here is a picture of a dry fit I did without the gaskets in place

Image

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Re: Side of Intake Leaking Oil

Post by R.Olds » Fri Apr 13, 2018 12:32 pm

I would guess the gasket is wicking oil....seen it many times.

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