Edelbrock 60069 Heads

[JimNolan]

Joe-JDC,
    I'm having a set of C1AE heads reconditioned by a new machinist I've never dwelt with before. This is going on a 390 build I'm doing. And, I was telling him the problem with my 410 fouling the plug on one cylinder and going through leak down, compression and vacuum test. He has worked on FE's for a long time and he said you probably got a intake leak and my reliance on the vacuum test I did to eliminate the possibility of an intake leak wasn't justified. He said I could still get good readings because the motor was big.
What's your take on that. I'll be finding out tomorrow anyway when I lift the springs off that cylinder. Thanks

[Joe-JDC]

Did I understand you to say it only smokes when accelerating after a decel?  If so, then that sounds like you might have an intake leak on the #2 port.  Is your PCV hose routed to both planes? or one runner?  Is it using any oil?  Slow drain back on the right bank might also allow oil to pool and get by an exhaust guide and smoke on acceleration because of oil level covering the seal/guide.  The early Edelbrock heads did not have a good drain machined in them, so I hope you double checked that upon assembly.  If you have recent castings, they have a better placed oil drain back.  Joe-JDC

[CaptCobrajet]

Sure does sound like an intake gasket sucking oil.  It could have done it when you ran it hard at the strip.....It could still show good vacuum on a guage. 

[Barry_R]

Pressure checking the intake is possible.  A bit of a pain - but might be worth it on a real problem child.  We've found some really sneaky leaks doing it - like "blind hole" carb studs that vacuum leaked around the threads, and leaky pushrod holes through porosity in the castings that sucked oil.

Remove the rocker assemblies.  Plug ALL the vacuum passages.  Make a carb block-off plate (kinda like a motor lift plate) and drill a single hole in the carb area & thread it for 1/8" pipe.  Hook up a pump style radiator pressure tester and pump up 10 or 15 pounds of pressure - see if it holds.  You can hook up shop air and use the regulator from a leakdown tester for continuous checks - but you might need to turn off the air compressor to hear what's happening.  While its leaking you can listen & soapy water check for the places the air is going.  Be prepared to listen to seeping valves and hissing fittings that you thought were perfect.

[JimNolan]

Joe-JDC,
 I have the better heads. When I took the valve cover off (first time in 20K miles) there wasn't a lot of oil at all standing in head. All the components had a good oil film on them but no standing oil. The engine doesn't smoke while idling but if you rev the engine and let off the next time you rev it you'll see some smoke. The real smoke comes under load when you run it up through gears and let it coast for a bit. When you get on it the next time it looks like a freight train behind you. My buddy took a video of me drag racing and it didn't blow any smoke then. It was the next weekend that I went to a car show never putting any stress on the motor that it started smoking. The seals are going to be here this morning (love Summit, order one morning, get what you ordered before 12:00 the next morning) and I'll pull the intake spring on that cylinder and check the seal.

Barry R,
 I'll remember what you said about pressure checking an intake but if the valve seals are good the intake gets pulled anyway. I hate that too because I put a thin film of RTV on the bottom and top of each intake and exhaust opening to each cylinder as well as the water jackets, it's going to be a mess to clean up. The block was a remanufactured 352 for a passenger car that I had the machinist just clean up the deck to ensure geometry of the head intake angles. I felt secure using new heads/intake and the old Fel-Pro gaskets with RTV backup. I don't think I could put it together any better. This new guy that's doing my cast heads says my 25 lb. torque on the intake bolts should have been 35 lbs. though. Just to save some time of me asking,  please give me a part number of the intake gaskets you use on your builds.

[FirstEliminator]

   Not sure if this is the same pressure testing as was referred to above.

Here is a video I made of pressure testing the intake on a 351w.

https://www.youtube.com/watch?v=YBS56WRluDg

I could only control the volume of air that went in as I didn't have a regulator on it. But, you could hear the air escaping. It was coming through the crankcase. Putting my hand over the valve cover was fun to make music---but quite annoying to watch.

   My thought was the intake gaskets were leaking. The gaskets that came out showed lines of being compressed at the top, but faded towards the bottom. I replaced the intake gaskets with ones that had the printed ring around each port for sealing and the car idled a little better. It's still has a shake to it, just as bad as it ever was. Bothers the heck out of me actually. Thinking about it now, the machinist said he never had to take so much off a block to square the decks. I wonder if there is some misalignment between the intake port face of the head to the manifold. Maybe the intake needs to be resurfaced to make the surfaces parallel.

   I don't want to hi-jack the thread with some 351w stuff, but perhaps there is some info hidden in my rambling that sparks an idea.

   thanks,
      Mark

[JimNolan]

Mark,
   When I put the engine together I bought a used Streetmaster intake because Jay B. raved about it so much. Even wrote a book about it. I set it down on my new Edelbrock heads and I swear you could rock it back and forth. It was warped real bad. So, I ordered the Edelbrock RPM intake. When I set it down on the heads it was rock solid, the holes lined up very well and trying to use a feeler gauge top and bottom of each corner showed it was sitting flat. I've never had leaks front or back using RTV as gaskets for that area and for 20K miles this engine has run great. I'll watch your video. Thanks for the reply.

[JimNolan]

Just got through taking valve spring off #2 intake. Wasn't anything wrong with the seal.

[ScotiaFE]

Do you restrict the oil feed to the rockers?
On my Ed's I have a .070" plug in the heads and have LOTS of oil up top.
I could even put a smaller hole plug in and still have lots of oil in the heads.
I have watched the rockers with a cut open cover and the oil was spilling over the top. 
The Ed's also have a smaller than stock oil return hole and I drill it out larger.
And also work the drain back between the head and intake.
Could you be flooding the heads?

[JimNolan]

I don't use drip rails under the rocker stands but there is no oil to amount to anything on top of the head when I take the valve covers off. I've got a Precision Pumps oil restrictor in there and besides that. I've put 20K miles on this motor without problems. It happened all of a sudden.
One of the guys I flew with has a bore scope that we're going to look at the cylinder wall with. I won't be able to see the oil control ring but I'll be able to see if there's damage to the cylinder wall.
After that I'll pull the intake. And, I lied to you guys, I thought I used a old style Fel Pro intake gasket. My intake gasket has the word Edelbrock all over it.

[Joe-JDC]

It is sounding more and more like an intake gasket failure.  Joe-JDC

[JimNolan]

It is sounding more and more like an intake gasket failure.  Joe-JDC

Joe, you know it's probably an intake leak. But, now you can say that a vacuum gauge doesn't always detect intake leaks. At least mine didn't.

[My427stang]

It is sounding more and more like an intake gasket failure.  Joe-JDC

Joe, you know it's probably an intake leak. But, now you can say that a vacuum gauge doesn't always detect intake leaks. At least mine didn't.

I would add that an intake gasket leak RARELY shows on a gauge.  If you think of the volume of a couple/three pistons dropping in sequence, and the size of the intake plenum, a small leak will likely not show on the total vacuum shown on the gauge, although it will change a/f mixture and add oil dilution for that specific cylinder.  Matter of fact I am considering unhooking a PCV on the truck I am working on tomorrow (396 FE) to see how much the vac gauge changes.  That'll be a 3/8 hose off #4 port, so it should be dramatic  compared to a seepy gasket:)

Your problem sounds like an intake leak. 

BTW, I saw you mention umbrella seals, get their perceived success out of your head   They were oil deflectors, not seals, they did OK compared to Chevy O-rings, and for long term, they likely outlast Teflon seal (but not outseal at the beginning, regardless I hate those hard plastic seals), but compared to modern positively located Viton, unbrellas are not very good.

[Nightmist66]

A quick easy test for a vacuum leak on an intake gasket(non FE) or any vacuum hose, connection, etc, is to spray either carb or brake cleaner around the suspected area and watch the idle and/or a/f ratio(for efi) to change while doing it. You can also use a propane bottle for a torch with a small nozzle and valve to do the same thing. This would be a little harder on an FE unless you had a cut open valve cover to control the oil while running, and you would probably want to go the propane route to not dilute the oil too much with the cleaner just in case.

[JimNolan]

Well, the intake is off, cleaned up and new gasket ready to put back on. The drivers side gasket looked good, the passenger side gasket had slide somewhat when it was installed and I had numerous places on #2 intake that only covered a small portion of the gasket. The gasket itself was broken in to between #2 and #3. Don't ask me, I have no idea. If this isn't the problem it's missed a good chance anyway.
I plan on using "the right stuff" this time and covering the head side of the gasket with a thin layer of RTV. I think I'll let it set for a couple hours before I put another thin layer of RTV on the intake side of the gasket. Then I'll install the intake.
Thank each and every one of you for you help and suggestions. Jim