Edelbrock 60069 Heads

[JimNolan]

Guys,
I'm having a heck of a time with my 410. Last week I went drag racing, everything OK. Drove the car that week, no problem. But, I went to a car show Saturday morning and it fouled a plug on #2 cylinder. I've done a compression check on that bank after running the engine a long time. #1-130lbs, #2 140lbs, #3-130lbs, #4-130lbs. ( I think #2 is high because of oil and crud that wasn't burnt) ( I did compression check with all cylinder plugs out).
The engine vacuum is 17 inches idling at 650 rpm. May fluctuate back and forth from 17-16 1/2 inches, more or less steady. I rev it and it goes to @8 inches and then to 26 inches before settling back on 17. Plug is always wet and when you take it down the road high vacuum on deceleration draws oil into cylinder and then burns it when you accelerate again. It will idle showing no smoke out the exhaust but when you put in under load it acts as if I've got bad rings. Changed wires and distributor cap, plugs too.
I called Edelbrock and ask them if they had trouble with valve seals popping off and they said it was unlikely. Cars got about 20K miles on it and @60 drag races. HELP. What do you think.

[machoneman]

Could have a dropped valve guide but more likely a bad valve seal. If you can do a leakdown test as well, that would rule out cylinder damage. Then, pop the intake spring on that cylinder using the rope trick, air or both. Did you check by hand the outer perimeter of that intake's valve spring for possible breakage?

[JimNolan]

I've got to weld a fitting on a spark plug to put air in the cylinder so while I'm at it I'll use my leak down gauges to check cylinder also. Don't really think I've got a bad cylinder though. Springs are in good shape.

[Heo]

maby intake gasket?

[machoneman]

Fel-Pro intakes?

[JimNolan]

Just did leak down test.  #4 good cylinder 70/80. #2 bad cylinder 70\80. By running 17 inches vacuum steady an intake leak doesn't seem possible or have I been confused on how to read a vacuum gauge.

[machoneman]

Leakdown #'s look good yet both valves are closed for said test. Agree that the high vacuum readings would be at odds with a bad intake gasket. Yet, what's clearly wrong is still a mystery. Oil then can only be entering via a messed up oil ring (would have zero effect on a compression test or leak-down test) the guide/valve seal or.... I'm also wondering about the intake itself especially an old OEM unit that may have develop a cracked runner on the bottom side.     

[JimNolan]

The intake is a Edellbrock RPM bought when I bought the heads. I used Fel Pro gaskets (the old style) and I laid a thin layer of High Temp RTV around each intake port, top and bottom as well as the water jackets. I never intended to take them off again and I never intended to take a chance of them leaking. The leak down test was done with a luke warm engine but the comparison is what I was looking for. If the engine had been hot I'd have gotten a better reading on the leak down.
I've got to be pulling this oil through the valve guides, can't figure out where else it could be coming from. Since I've got the fitting made now to put air in the cylinder I'll take the rockers off and put air in the cylinder and take the intake springs off and see what it looks like.

[fekbmax]

Fel-Pro intakes?

Dam.. I sometimes use reg old Mr gasket 202A's and never have had a prob like this.
Maybe a clearance or fitment issue .

[machoneman]

Actually, one more thing: the pushrod area on the RPM, like all FE intakes, is exposed to oil on a number of sides compared to other engines. With some high lift cams, one sometimes has to ream or bore out the p-rod holes to avoid rubbing. But, IIRC, the RPM's p-rod holes are well placed and likely did not need to be opened up. Could a casting flaw in this area be present?

[Joe-JDC]

Do you know if the heads had teflon seals, or viton seals on the guides?  The teflon will let oil by very easily if one of them has been dinged anywhere along the assembly process.  I refuse to use teflon on anything for the street because I have seen the oil streaking out the guides on so many heads that have come to me for porting.  For race, and yearly refresh, teflon works, but not long term for the street.  Joe-JDC

[JimNolan]

Joe-JDC, Edelbrock uses the 9726 Viton seals on my 60069 heads. They claim they don't have any problems but I've found forums on the internet that says they've had them pop off under street use after 5000 miles. Tomorrow I'm pulling the springs and checking the seals. I'll change the seals on the problem cylinder just to be safe. Advance Auto sells their valve seals. I've heard horror stories about the Teflon seals, right now I wish I had the old umbrella seals, I know they last a long time.

[Nightmist66]

I've heard horror stories about the Teflon seals, right now I wish I had the old umbrella seals, I know they last a long time.

I'm not sure about that, the umbrella get old and brittle and break and are less than ideal for oil control. Teflon are touchy, but viton are a good option. Jmo.

[JimNolan]

I was just kidding about the umbrella seals but best of my recollection the one's on my 1966 Fairlane GT I owned were still good at 120,000 miles. I really don't know how far advanced you get when you put valve seals on your car that lasts 20,000 miles. And intake gaskets is another one. Don't remember needing to check those at 20,000 miles either. I love progress. lol

[Joe-JDC]

Unfortunately the problem that many run into is that these aluminum heads grow more than iron heads with heat cycle, and the clearances need to be correct for oil control at running temperatures.  Some of the guides are not finished to the proper sizes, and that causes one stem to be either tighter or looser than it should be, and it will use oil after the seal wears a small amount.  A guide that is tight to start will scratch the stem if it does not seize the valve, and those scratches can wear on the seal over time, causing oil to seep by at a slightly greater rate.  The bigger the valve stem, the bigger the problem.  Also, some of these viton style seals are color coded for intake and exhaust usage, and if someone puts the wrong seal on the wrong valve, they wear quicker.  There are seals that are made for .500 guides, .530 guides, and if you mix those up, the .530 seal will pop off a .500 guide.  Of course they should have been correct from Edelbrock.  I have found heads that had seven guides properly sized, and the eighth guide was not touched after installation other than deburr the end where it was driven in.  Human error, someone just forgot to double check themself.   Just saying.  Joe-JDC