351W head gasket leaking oil.

[Rebostar]

Hey folks,
I just wanted to ask the forum if anyone has found the 351W metal Fel-Pro head gaskets to leak oil?
I ran my engine again yesterday for the second time after re-sealing the pan oil leak. It no longer leaks oil. I do however have a very slow oil leak on the outer head to block seam, mostly at the front and rear sides below where the head oil scavage passages are. I've rebuilt lots of engines and R&R'd lots of heads. I've always used the Felpro composite gaskets and never had them leak on new heads and a decked block untill now. The Felpro gasket kit I just used had metal head gaskets in the kit. I've never used those before but thought I'd try them out. All the cyinder bores and water passages had a seal bead around them top and bottom on the gaskets. The bolt holes and scavage passeges did not. All bolts torqued to 100/110 short/long per the Edlebrock installation instructions. ARP bolts used with proper lube. No water leaks, not smoking at all so nothing is getting into the combustion chambers. Spark plugs are clean and dry.

Has anyoune else ever had any oil seepage issues with these metal head gaskets?

Right now my plan is to replace the head gaskets just before I'm ready to install the engine/ trans assy. Any thoughts?

Allyn
aka Rebostar

[Bob Cowan]

No, never.

There are no pressurized oil passages in the cylinder head. An oil leak through a MLS head gasket would indicate that there is damage to the head or block deck surfaces.

The leak is probably coming from somewhere else, like a valve cover.

[StangRacer]

Like Bob suggested, it is probably a leaking valve cover gasket. You can put some talcum powder around the valve covers and heads then blow it off with low pressure compressed air to help trace the leak.

When you had the heads and block decked did the machinist put a finish on them compatible with a MLS gasket? If the machinist put a finish on the heads and block for a composite gasket the MLS gaskets are not going to seal. MLS gaskets require a very smooth finish to seal.

[Norm B]

A leak at the China wall/intake manifold location can also cause oil to appear at the location you’re seeing.

[Rebostar]

Hey guys, thanks for the input.
First thing I did was ensure the valve covers were not leaking. Good felpro rubberized gaskets, bolts torqued, lower valve cover seam bone dry. The only oil passages in the new Edlebrock heads are the scavage passages, there are no pressure passages. The seepage is comming from directly below those scavage passages. I did not know about the block/head finnish required for the metal gaskets or I would not have installed them. They came in the overhaul kit. I'll replace them with composite gaskets. While I'm at it I'll make sure the "china wall' front and rear is sealed.
Thanks again for the positive input.
Allyn

[burchfieldb]

Hey guys, thanks for the input.
First thing I did was ensure the valve covers were not leaking. Good felpro rubberized gaskets, bolts torqued, lower valve cover seam bone dry. The only oil passages in the new Edlebrock heads are the scavage passages, there are no pressure passages. The seepage is comming from directly below those scavage passages. I did not know about the block/head finnish required for the metal gaskets or I would not have installed them. They came in the overhaul kit. I'll replace them with composite gaskets. While I'm at it I'll make sure the "china wall' front and rear is sealed.
Thanks again for the positive input.
Allyn

You may want to check what the ARP torque specs are, I know they are different from other bolts.

[Mike.Bray]

Check out Cometic MLS head gaskets. Hard to beat.

[Rebostar]

You may want to check what the ARP torque specs are, I know they are different from other bolts.

Thanks, I went with the recomended torque from Edelbrock as the aluminum head torque is different (higher) than the Ford factory spec. I believe the ARP bolt recomendation matched the Edelbrock value.

[CraigS]

I had the rear china wall seeping on mine. I knew it was redneck as can be, but I cleaned the area thoroughly w/ brake cleaner, a rag, and compressed air. Then smeared a coating of Permatex Ultra Grey over it. Surprisingly it sealed it for a couple of years before I had another reason to pull the intake.

[Bill Elliott]

I had same type of problem. Found the leak was coming from the top of the head where the ears on the head gasket are. They do not go all the way up to the china wall. Took the intake off and put some Ultra Grey in that area , problem solved. The oil showed up at the bottom tabs of the head gasket so it was really tricky finding the source of it.

200416

[Rebostar]

Thanks again for all the great input. The last run was to pressure test my FE expansion tank. Held pressure at 180'. No leaks, so its off to the chrome platers with it. While its gone I'll pull the heads and replace the head gaskets with composite ones. I'll be sure to seal the "china wall" where it intersects the heads both front and rear. I'll want to test run it one more time to ensure I've plugged all the leaks when I get the FE expansion tank back from the platers. I have about a week to 10 days left with the wiring. When thats done I'll be looking to install the engine and transmission so I'll need the engine ready to go.

Allyn

[bobl]

I've found the same problem that Bill Elliot refers to. Fel Pro MLS gaskets are a bit short of reaching the top of the china wall, leaving a nice void if you don't get sealant in there. Guaranteed oil leak! No such problem with Cometics or fiber gaskets.

[CraigS]

After you reinstall the heads get a set of studs for the intake, set the intake gaskets on dry and set the manifold in place. Now look at front and rear china walls clearance to the intake. Probably a decade ago an FFR owner was having problems w/ intake gaskets leaking coolant. Short version of a long story; his combination of heads and intake had the intake sitting on the china walls so it could not adequately compress and seal the intake gasket. Since reading that I have always checked clearance. This will give you an idea of how thick of a bead you need on top of the walls. Also note that the feel of a nice steel nut on a steel stud beats the heck out of a bolt going into aluminum as you torque and retorque the intake after each hot cool cycle.

[Railroad]

While the engine is still in the car, I would pull the intake and check for the short fingers on the Fel Pros.
The present head gaskets are holding compression. Just a wipe of sealer and re install the intake is a lot less work, for the same results.

[Rebostar]

While the engine is still in the car, I would pull the intake and check for the short fingers on the Fel Pros.
The present head gaskets are holding compression. Just a wipe of sealer and re install the intake is a lot less work, for the same results.

The engine is on a run stand. Not in the car yet. However, a careful examination of the intake to head and china wall will be in order. The heads are not leaking anything but a very slow oil seepage, so I might be able to get away with re-sealing the china wall and intake gaskets. I'll have a set of head gaskets handy in case I cant find a "smoking gun".
Allyn

[rich grsc]

The head gaskets AREN"T leaking oil. The gaskets hold compression, how could they leak pressure free oil?

[Rebostar]

The head gaskets AREN"T leaking oil. The gaskets hold compression, how could they leak pressure free oil?

There are three interfaces between the block, heads and intake manifold. The oil is seeping from one of those interfaces!! Read my fisrt post to see where the oil is showing up!

[Norm B]

I swear the corner where the block, head and intake manifold meet is designed by Ford to leak. Very careful attention to gasket placement and sealant usage is required during engine assembly. After market parts and machining can make sealing this area even more difficult. The first engine I built was leak free. This one is weeping out of a few spots. On my list of things to do but, still trying to decide if I want to replace the intake manifold. It is a Procomp unit and may be the source of a couple of issues that I am currently having.

Norm

[Rebostar]

I swear the corner where the block, head and intake manifold meet is designed by Ford to leak. Very careful attention to gasket placement and sealant usage is required during engine assembly. After market parts and machining can make sealing this area even more difficult. The first engine I built was leak free. This one is weeping out of a few spots. On my list of things to do but, still trying to decide if I want to replace the intake manifold. It is a Procomp unit and may be the source of a couple of issues that I am currently having.

Norm

Norm
I think your correct. I've never had a SBF leak like this one. The only differance that I can see is, this is the first time I used the metal head gaskets supplied with the overhaul gasket kit. The composite Felpro gaskets "interlock" where the head gaskets meets the intake gaskets. They were engineered to mate up and prevent any leaks at that corner. Coupled with a liberal squeese of Ultra Grey I've never had a leak there. The metal gaskets did not "interlock" with the intake gaskets. I suspect this is where the leaks are coming from. It could be that I did not get the china wall properly sealed at the head/intake juction. I'm a bit skeptical about that as all four corners are leaking. I could have botched one or two...but all four! They are seeping at all four corners at the head to block seam. We'll find out soon enough. I plan to remove the intake manifold and do a forensic anlysis. If there is no smoking gun I'll swap out the head gaskets with the standard Felpro composite along with the matching intake gaskets.
Allyn