Intake manifold pulling oil

-
Screamin demon72

Screamin demon72

Active Member
Joined
Feb 22, 2018
Messages
29
Reaction score
15
Location
Athens ohio
I’m having trouble with my 408 la stroker pulling oil out of lifter valley around intake runners and coolant is coming out around the coolant ports. I have tried 2 different intakes, Iv tried every felpro gasket, Edelbrock gasket, summit gasket, and just got a accuseal .125” thick gasket, Iv tried stock bolts, aep bolts, tried cork end seals, no corn end seals and just silicone. I also lightly sanded intake mounting face with a sharpening stone to verify the flange was flat and it was. The head to block angles are identical to the intake angle. Can’t get it to stop leaking oil around ports. Blowing a bunch of blue smoke and plugs are fouling out

C71643CF-5353-42DF-9249-2D95EB9EEF05.jpeg
 
2 things come to mind right off the bat:
1.) Were your heads cut, and if so, how much?
2.) Did you remove the locating pins on the china walls, or at least drill new holes for them in the bottom of the intake manifolds?
 
Heads were not cut, they are Eddie rpm heads. Just had fully ported and valve job done. Block was not decked either. Pins are out of China walls also
 
Make sure your intake bolts are able to go deeper into the head than the thickness of the intake flange. I would take the intake to be trued up at the machine shop. But check the fitment without gaskets first to see how loose or tight it is. If it's on the loose side, (I like to see them almost snap into place like a puzzle piece!) take two sets of Felpro 1213 gaskets (.060 thick) and put a skim coat (use a body filler squeegie) of Ultra Grey Permatex (high stregnth silicone, use a body filler squeegie) on the blank sides that don't have the neoprene. Sandwich them together, and put another thin skim coat on the side that goes on the cylinder head on the large surface, almost to the neoprene. Bolt them to the heads by themselves and let them set up before before removing the intake bolts. Skim coat the intake flange side of the gasket almost to the neoprene. Lay the Ultra Gray (I recommend caulk gun tubesof the stuff!) and install the intake and torque it down. Dont forget to put thread sealer on the intake bolts. It's best to let it set a few hours and then retorque it if you have to do this, there's going to be quite a bit of compressing of those gaskets going on as it takes a set. It's not a bad idea to pre-fit everything dry beforehand to make sure you've got enough room. Sometimes, you'll need a little thinner second generic parts store paper gasket to have it fit properly. OR SOMETIMES, EVEN A THIN PAPER GASKET BETWEEN THE 1213 FELPROS. I've had very good success with this method with getting loose fitment of intakes to seal up. Good Luck, let us know how this works for you!
 
Use this on both sides of the gasket around the ports & silicone on the end rails....

Amazon product ASIN B007TWXI1K
It's what Japanese motorcycle manufacturers have used since the sixties to seal engine cases with no gasket... I've used it on intake gaskets for over thirty years & it's never let me down...
 
WOW, I’ll have to remember that! I’ve used YamaBond R before (Yamaha’s case sealant, but basically the same) for its intended purpose and I bet it’s a miracle for leaky intakes. For it to hold two stroke motorcycle cases together without leaking in place of a gasket (fuel/oil mix and primary compression), it just about has to indestructible.
 
Hint, hint: I will bet it wouldn't be leaking with factory parts, ie factory intake & heads.

Sounds like machining error have left gaps that are not sealing...
 
I put ultra grey down Intake flange and down the head, haven’t tried 2 gaskets stacked together but I ordered the .125” thick SCE gasket. I can try 2 gaskets stacked as well. Iv never had a problem getting it to seal up before I got valve job and porting done, using same head gasket I used before and nothing was done to either face of the head so nothing should be different
 
Just curious, did the heads go back onto the cylinder banks that they came from? What intake are you using?
 
Yes same block, just took heads off for valve job and porting. First 2 sets of gaskets I had an air gap intake that was on it before I had heads done, same exact intake. Switched to a street strip dominator. Motor needed a single plane anyways but both intakes had the same results with leaking coolant and pulling oil
 
If everything you stated is correct that you have checked what else could it be but the porting. Look at the plugs and see if you can point to certain cylinders or is it all of them. There are times a genius will destroy a set of heads not having a clue of what they are doing.

We had a guy come here and we Sliced a set of Viper heads for a porter so he would know how far he could go. The heads he ported are here right now to get welded and repaired he ported through pin holes. There are times you can't fix stupid. Making a port larger is not as important as changing the characteristic of flow.

Bigger is not always better. My wife told me its not how long it is , Its how long it lasts. LOL

100_0163.JPG


100_0164.JPG


100_0165.JPG


100_0166.JPG


100_0167.JPG


100_0168.JPG


100_0180.JPG
 
Oldmanmopar said:
If everything you stated is correct that you have checked what else could it be but the porting. Look at the plugs and see if you can point to certain cylinders or is it all of them. There are times a genius will destroy a set of heads not having a clue of what they are doing.

We had a guy come here and we Sliced a set of Viper heads for a porter so he would know how far he could go. The heads he ported are here right now to get welded and repaired he ported through pin holes. There are times you can't fix stupid. Making a port larger is not as important as changing the characteristic of flow.

Bigger is not always better. My wife told me its not how long it is , Its how long it lasts. LOL

View attachment 1716072439

View attachment 1716072440

View attachment 1716072441

View attachment 1716072443

View attachment 1716072444

View attachment 1716072445

View attachment 1716072446
Click to expand...
Hahaha Hahaha awesome I like your wife's quote lol
 
I thought about that, the head guy did very good work, gasket matched to ports and improved flow. New valve seals, springs, the whole 9 yards and they turned out very well. Nothing was touched on the face that the intake sets against on the head. Used a strait edge on it and it’s perfectly flat on head as well as intake and the gaskets are always wet around the ports. On old gaskets you can see where the oil gets sucked up right at bottom of the ports. I’ll try to get a picture of the old gaskets if I can find them. Almost as if it’s not sealing across the bottom.

All the plugs have oil baked on them. Second set of plugs since this has been happening
 
Screamin demon72 said:
I thought about that, the head guy did very good work, gasket matched to ports and improved flow. New valve seals, springs, the whole 9 yards and they turned out very well. Nothing was touched on the face that the intake sets against on the head. Used a strait edge on it and it’s perfectly flat on head as well as intake and the gaskets are always wet around the ports. On old gaskets you can see where the oil gets sucked up right at bottom of the ports. I’ll try to get a picture of the old gaskets if I can find them. Almost as if it’s not sealing across the bottom.

All the plugs have oil baked on them. Second set of plugs since this has been happening
Click to expand...
How did you verify the intake face angle is matching the head face angle? What method?
 
Used a digital angle ruler and also used a digital angle finder, zero to the block then set it against the head, same with intake
 
Screamin demon72 said:
Heads were not cut, they are Eddie rpm heads. Just had fully ported and valve job done. Block was not decked either. Pins are out of China walls also
Click to expand...
can you verify with certainty that the block wasn't decked? a lot can happen in 50 years...

i had the same problem that i chased my *** on-- even so far as changing the heads and intake out. turns out the block had been decked on a previous build.

prior to the guy owning the car the PO had the motor built and even though it had a refresh before the problem cropped up neither he, nor the current owner were nuts and bolts guys so that wasn't something that was on their radar. to make matters worse, the machinist/engine builder had long passed his use or freeze by date. all the paperwork i had from the work done was a cam card.

anyway, a hearty +1 to motorcycle/powersports sealants. motoseal, threebond 1184, hylomar are all good choices.
 
Screamin demon72 said:
Used a digital angle ruler and also used a digital angle finder, zero to the block then set it against the head, same with intake
Click to expand...
Next time the intake comes off, clean all the old gasket and sealant from everything. Get pictures of how the intake gasket looks on the head and then on the intake.
Place the intake on the heads with NO gaskets, then use feeler gauges at the top and near the bottom of the intake, between the intake and head. This is not precise, but it’s a start. I assume no feeler gauge fits at the top and some thickness will fit at the bottom.
 
The guy I bought block from drag races with me and he got it out of a junk yard several years ago and didn’t use it for a while, had it punch out .30 and he says they did not deck it. The intake sealed prior to the head work so still scratching my head on why it won’t seal now. The head guy doesn’t have a mill to deck the surface either and told me he didn’t mess with faces of the head. I’m going to go in depth and check everything you guys have mentioned and check everything 3 times and see what I come up with
 
Are you sure the intake is not bottoming on the china walls? If it is and you torque the intake on, the intake ports will suck in oil from the bottom exactly as you are seeing. Ask me how I know.
 
as long as we're throwing around WAG's and SITD's... maybe an issue with the head locating dowels? maybe the heads didn't go back on the sides they were taken off of and one of them has just enough shift/out of spec on the pin to throw the whole thing? that could explain the issue of having the problem after the removal of the heads.

i didn't see if you answered but is it problematic on both sides or just one bank?
 
I will check tomorrow to see what year the block is, can’t remember off the top of my head

Intake isn’t bottoming out on China walls I did verify that. Even without gaskets it is close but when gaskets are on there is about an 1/8” gap after it’s torqued down

I did see the other day that the heads are on different sides than they came off of before head work was done and I wondered if that could be an issue. I checked angles again and one side is 132.1 degrees and the other side is 131.7 degrees so I didn’t think that was enough to throw it off but what do you guys think?
 
Also it’s a problem on both banks but it’s worse on passenger side. Drivers side doesn’t leak quite as bad
 
1 degree will subtend .015" per inch. Even a tenth of a degree could cause an issue, but reading angles is the wrong way to do it. Angles are incredibly hard to measure accurately and I wouldn't trust any method outside of a metrology lab.

You need to do the feeler gauge check described above. Engine precision is measured in .001" increments or smaller. It's not uncommon for aftermarket parts to be slightly off. There are multiple ways to check the interface of the intake and head. My favorite I've read about but never tried was to use small Lead shot between the head and intake. Torque it, then measure the crushed thickness. Small diameter Lead solder wire could probably also be used. Calipers or a micrometer will be necessary to check for the amount of taper.

If it's consistently leaking at the bottom of the ports and it's not bottoming on the China wall, then the heads or the intake are off. There's no doubt about it. If it wasn't, you wouldn't be sucking oil after so many different gaskets.
 
You must log in or register to reply here.
-

Back
Top