Lower Intake Will Not Seal

[Diemondrio63]

Ever since I rebuilt my motor I can't get the Intake to seal to the heads. The engine is a 95 4.0 OHV. I asked the machine shop how much, (if any), they milled off of the heads and they said they took 4 thousands off. I then asked if that would be enough to make sealing the intake a problem and they said no! I've changed the intake since talking to the machine shop and that didn't change anything. I even paid top dollar ($63.00) for the Ford lower intake gasket just in case there was an issue with the previous one from Fel-Pro. Now I'm wondering if the heads were cut once before and that could be the problem. I'm putting a quart of oil in this thing every 200 miles. It runs like crap of course and is running rich. Smokes every time you get on it. I don't think it's in the combustion chambers for I have 150 pound of compression in all 6. Any help would be greatly appreciated, this thing is driving me nuts!
Oh... and no frickin engine codes either.

 

[Maniak]

When we rebuilt the motor on our '92 ohv we had to grind a little...

The lower intake was hitting the top of the timing cover. It wasn't much, but it was hitting. Our thinking was that if it was hitting before it was torqued down that it wouldn't seal. So, we ground a little off the top of the timing cover where they were touching and it sealed fine.

I'd at least look around there.. Maybe you have the same issue between the timing cover and lower intake.

~Mark

 

[StangsandMavs]

Wouldn't an intake leak cause it to run lean?

The only problem that I had with the lower intake was the short oil gasket in the back, where I didn't load up enough silicone... and they were the Felpro gaskets.

 

[Diemondrio63]

When we rebuilt the motor on our '92 ohv we had to grind a little...

The lower intake was hitting the top of the timing cover. It wasn't much, but it was hitting. Our thinking was that if it was hitting before it was torqued down that it wouldn't seal. So, we ground a little off the top of the timing cover where they were touching and it sealed fine.

I'd at least look around there.. Maybe you have the same issue between the timing cover and lower intake.

~Mark

I never thought of looking there but I sure will. Thanks...
Mark

 

[Diemondrio63]

Wouldn't an intake leak cause it to run lean?

The only problem that I had with the lower intake was the short oil gasket in the back, where I didn't load up enough silicone... and they were the Felpro gaskets.

The Ford mechanic at the garage said that because oil was being introduced into the cylinders via the intake it would run fat (rich).
I've used Fel-Pro all my life but they suck with sealing the lower intakes on the 4.0s. Three of the guys at the shop I go to are X Ford dealership mechanics, (the dealership closed down) and they said they've tried using Fel-Pro as well and they ended up going to the Ford gasket.
I just wish this thing would throw a code but nope...

 

[StangsandMavs]

I'd try smearing some silicone on both sides of the gaskets and retorquing them. If oil is getting into the cylinders, the plugs should show it.

With my 95 4.0L, since I didn't put enough silicone in place of that back gasket (Felpro tells you to use the silicone in lieu of the cork gasket... by not having enough silicone, oil just runs out of the back of the manifold and makes a lovely mess), I took it all apart, cleaned it up and reassembled without replacing the gaskets. It had been a couple months, too.

Are the surfaces between the lower and upper intakes in good shape? How about that middle piece that is held to the lower intake by the studs?

 

[Diemondrio63]

I'd try smearing some silicone on both sides of the gaskets and retorquing them. If oil is getting into the cylinders, the plugs should show it.

With my 95 4.0L, since I didn't put enough silicone in place of that back gasket (Felpro tells you to use the silicone in lieu of the cork gasket... by not having enough silicone, oil just runs out of the back of the manifold and makes a lovely mess), I took it all apart, cleaned it up and reassembled without replacing the gaskets. It had been a couple months, too.

Are the surfaces between the lower and upper intakes in good shape? How about that middle piece that is held to the lower intake by the studs?

The plugs definitely show signs of oil. As I had originally said I'm going thru a quart of oil every 200 miles and there's no leaks! It has to be leaking between the lower intake and the heads. How else could it get into the cylinders ya know. Strange thing is it's only the middle cylinders, #2 and #5. The plugs have been changed twice already and I'll probably have to change them again soon cause it's missing worse than normal. The plugs have the bridging affect.

 

[StangsandMavs]

Then I'd try the silicone...

Otherwise, other possibilities might be... ugh... headgasket (which probably isn't the case since you've got good compression), valve seals, or valve guides.

 

[Diemondrio63]

A Possible Fix

Then I'd try the silicone...

Otherwise, other possibilities might be... ugh... headgasket (which probably isn't the case since you've got good compression), valve seals, or valve guides.

The trouble with silicone is that when it comes in contact with gas there's going to be trouble, the gas will eventually gel it up.
I've just talked to the guy at the machine shop that had re-done my heads. He said that he's aware of this problem due to poor design of the intake gasket port sizes. If you take and really look the the size of the gasket the holes are bigger than the actual size of the port, which is completely ridiculous! Therefore when you torque them down it's pulling the rubber seal away from the port on the head. So... what's the fix... he said that he has been using: 3M super weatherstrip and gasket adhesive. It comes in yellow and black, he uses the yellow so it shows up better. After cleaning the head with brake cleaner he coats it pretty good all around the ports, let's it sit for a minute, then places the gasket on making sure it's straight. Then waits a few minutes again, this stuff dries really fast, then coats the top of the gasket as well, let's it set up for a minute and then puts the intake on and torques it down.
He said that since he's been doing this he's never had one leak again. He started using the weatherstrip/gasket adhesive on the newer chevy small blocks because the intake/exhaust ports on the head are closer than they were before making the gasket harder to seal.
I'm going to take their advice because these old boys have been around for over 40 years. Spite the fact that they once held a speed record for the fastest street car at Maple Grove, PA!
I shall let you know what happens...

 

[Maniak]

<snip> he said that he has been using: 3M super weatherstrip and gasket adhesive. It comes in yellow and black, he uses the yellow so it shows up better. </snip>

Just an FYI.. another name for that stuff is "gorilla snot" I've used it on the intake, but I"ve used it before and that stuff works really well. It seals about anything.

~Mark

 

[Runnin'OnEmpty]

Just an FYI.. another name for that stuff is "gorilla snot" I've used it on the intake, but I"ve used it before and that stuff works really well. It seals about anything.

~Mark

Known to me as 'yellow death', and it's been around forever.
It's worth a try......

 

[Diemondrio63]

Gorilla Snot huh... Yellow Death... I like that! Thanks for renaming it for me guys.
Today it's to be warm out, mid 40's, so we'll see what happens. If after the re-seal project it snots oil this X is gonna see yellow death alright, I think I'll burn it!

Wish me Luck...
Mark

 

[Diemondrio63]

Well by God that fixed it!

What I ended up doing was basically gluing the gasket to the heads. I made sure that the adhesive was completely dried before I put the intake on. I put just a light coat on top of the gasket and put the intake on right away being that it dries so fast. I even used the old gasket. The so-called old gasket was from Ford and only on for two months, that's why I used it again.
But then that night I acquired a squeak coming from the right lower ball joint. Gee... all the ball joints were just replaced last summer! That made me investigate only to find that the lower control arm on that side is bent! Then last night I acquired another squeak and that's coming from the left side upper control arm bushings!
Oh boy!

 

[chance942]

Ever since I rebuilt my motor I can't get the Intake to seal to the heads. The engine is a 95 4.0 OHV. I asked the machine shop how much, (if any), they milled off of the heads and they said they took 4 thousands off. I then asked if that would be enough to make sealing the intake a problem and they said no! I've changed the intake since talking to the machine shop and that didn't change anything. I even paid top dollar ($63.00) for the Ford lower intake gasket just in case there was an issue with the previous one from Fel-Pro. Now I'm wondering if the heads were cut once before and that could be the problem. I'm putting a quart of oil in this thing every 200 miles. It runs like crap of course and is running rich. Smokes every time you get on it. I don't think it's in the combustion chambers for I have 150 pound of compression in all 6. Any help would be greatly appreciated, this thing is driving me nuts!
Oh... and no frickin engine codes either.

Hope it works awhile for ya.