Below the intake vac leak

[Viperwolf1]

Any guesses as to which ports were leaking and sucking in oil?

It only seemed to leak during cold starts. Once it was warm I couldn't tell there was a problem. Took a while to figure out what was going on. I pinched off the PCV hose and still had suction at the valve cover side of the breather hose.

 

[Mark]

That's wierd isn't it?? Once you torque your manifold bolts or studs the gasket should seal those intake ports without worry.
Phil, what kind of symptoms were you having that tipped you off?

 

[NJB71]

Hey Viperwolf, It looks like u didnt rtv around the ports?, i used a felpro gasket1250, but still used a small bead of rtv around each port....

 

[broncnaz]

Probably once everthing warmed up it kinda sealed itself or enough oil was getting sucked up to kinda seal the leak.
Didnt happen to recheck the intake bolt torques before you removed it did you? I find a lot of aluminum intakes do tend to loosen up. I usually recheck them after the first 500 miles or so.

 

[Mark]

Hey Viperwolf, It looks like u didnt rtv around the ports?, i used a felpro gasket1250, but still used a small bead of rtv around each port....

Coolant ports definitely, but I didn't (don't) think it's necessary around air ports.

 

[NJB71]

true, but when i just did my efi swap and i was removing the manifold, (engine is new, about 600miles on it, as broncnaz pointed out, the bolts need to be retorqued-i didnt, no leaks but sure it would of developed, as i was removing the bolts(easily, scary) the manifold was rtv'ed around coolant and intake, not sloppy, they had nice clean thin bead around all ports and so I repeated the process on my explorer lower

 

[Viperwolf1]

That's wierd isn't it?? Once you torque your manifold bolts or studs the gasket should seal those intake ports without worry.
Phil, what kind of symptoms were you having that tipped you off?

It had rough cold starts. Occassional popping in the exhaust and the idle wouldn't stabilize until it ran for about 30 seconds. I spent a lot of time trying to figure out what was wrong with the EFI. Once I noticed the oil started disappearing I was on to the culprit.

 

[Viperwolf1]

Hey Viperwolf, It looks like u didnt rtv around the ports?, i used a felpro gasket1250, but still used a small bead of rtv around each port....

No, I figure felpro would have run the silicone bead around both sides if it was needed. My problem really stems from the intake sitting too high between the heads. The block and heads have both been milled. The lower edge of the manifold just catches the silicone bead at the bottom. Time for more milling.

 

[Viperwolf1]

Probably once everthing warmed up it kinda sealed itself or enough oil was getting sucked up to kinda seal the leak.
Didnt happen to recheck the intake bolt torques before you removed it did you? I find a lot of aluminum intakes do tend to loosen up. I usually recheck them after the first 500 miles or so.

I think you're right about the oil acting to plug the leak. As I was removing the manifold I could tell the middle bolts were a little on the loose side. It's almost impossible to retorque these bolts without removing half the EFI.

 

[76 bronco J]

>>>> I'm surprised that gasket didn't start to deform also...... as mentioned in a couple of other threads, Ford racing & Fel-Pro both now consider the regular soft black cardboardish printo-seals as race gaskets for short term use while also allowing quick easy trimming of the port size . http://classicbroncos.com/forums/showthread.php?p=1488292&highlight=fel+pro+1250#post1488292 ..... >> thread started on 1250 & 1262 gasket info>http://classicbroncos.com/forums/showthread.php?t=135536&highlight=1250+gasket.....

 

[NJB71]

I think you're right about the oil acting to plug the leak. As I was removing the manifold I could tell the middle bolts were a little on the loose side. It's almost impossible to retorque these bolts without removing half the EFI.

amen, was thinking about that for when i put 500 + miles on mine, the upper has to come off

 

[70_Steve]

It had rough cold starts. Occassional popping in the exhaust and the idle wouldn't stabilize until it ran for about 30 seconds.

Installed my lower probably two months ago, just got it running last weekend with the same idle problems. Never thought about having to pull the upper to retorque!!

Have you pulled your plugs to see what those two cylinders (and the other two on that side) looked like?

 

[Viperwolf1]

Installed my lower probably two months ago, just got it running last weekend with the same idle problems. Never thought about having to pull the upper to retorque!!

Have you pulled your plugs to see what those two cylinders (and the other two on that side) looked like?

I have pulled the plugs and they didn't look any different than any of the others. Not white from the leanness nor black from the oil.

 

[getfuzzy]

Was there any sign of oil in the upper intake.

 

[Broncobowsher]

I have had 5.0s that were real touchy about intake gaskets. Explorer upper on N352 heads (not recomended) took some very careful alignment to get the intake to sit on the heads just right. It was VERY easy to get one end a little out of alignment. That is what looks like happend to you. Just th gasket looks good. Mine was so touchy the only way to get the intake properly installed was to pull the engine and install the intake while on the engine stand. No amount of persueding would get it to line up while in the frame.

I was so glad the truck left...

 

[Viperwolf1]

Was there any sign of oil in the upper intake.

No oil in upper. That PCV issue was previously dealt with. I hand hammered out a two-layer baffle.

 

[Viperwolf1]

I have had 5.0s that were real touchy about intake gaskets. Explorer upper on N352 heads (not recomended) took some very careful alignment to get the intake to sit on the heads just right. It was VERY easy to get one end a little out of alignment. That is what looks like happend to you. Just th gasket looks good. Mine was so touchy the only way to get the intake properly installed was to pull the engine and install the intake while on the engine stand. No amount of persueding would get it to line up while in the frame.

I was so glad the truck left...

My problem is the big ports on the heads and the lack of material on the bottom edge of the intake. There's only about .070" at the bottom of the intake sealing the ports. I dropped the intake off today to be milled. It should sit .030" further down when I get it back. I also ordered the Felpro 1250s3 gaskets.

 

[Viperwolf1]

Got the intake back. Had .030" taken from both sides which makes it sit .030" lower. Got the 1250s3 gaskets in. Not sure if I like them much better than the 1250 gaskets. They have a steel core which is good but they lack the EGR cutouts (had to cut my own), they lack the tabs at the bottom to hold the gasket in place (had to use high tack to glue the gasket in the correct place) and the water ports are huge. Almost too big to seal on the head side upper corners. There's about 1/8" of gasket sealing those corners. I used studs instead of bolts so I could position the intake precisely. So far it's looking good.

Tip: Never assume that you can carefully remove the filter baskets from the injectors then reuse them after cleaning the injectors. Then, after ruining the first one, think you can just find them locally. You can't.

 

[73azbronco]

Viper, it looks like your intake has been machined? try something, if you have some plastigage, remove the gaskets, reinstall the intake with some plaistigage around one of the offending intake runners and see if you can see any diff in tolerance top to bottom. it looks like the bottom is farther away from the head your using.

edit, we are cross posting, yours has been machined, are you sure it's true with your heads? Lastly, which heads, those do shift a little during install, maybe not square?

 

[Viperwolf1]

Too late. It's already on and it ain't coming off, unless it leaks. I know the intake and head surfaces are true. A few thousands would be made up by the gasket. The reason it was leaking before is because the bottom edge of the intake ports met the gasket on only a .070" strip. It was even on all the ports that way. Now it'll be a .100" strip.

I pitty the guy that inherits this engine from me. Everything is custom and the parts on it won't fit any other engine.