StarGeneral

Hi guys, before my engine started acting up (turned out to be bad gas). I was having a problem with leaking valve covers. The story goes like this:

My stock valve covers leaked a little bit of oil from the lip around the bolt holes because the cover had been overtorqued there and the gasket split in two (cork gasket). I removed the stock valve covers to replace the gaskets since this was causing oil to pool around my spark plugs and burn off, making a mess and a horrible smell, also I didn't want oil leaking into the spark plug hole.
When I pulled the covers, I realized that one cover had been tightened so tight in the past that all the bolts holes actually had semi-circle tears in the metal around where the lip of the bolt screws down. I decided that the only way to get them to seal up again was to buy some new covers.

I ended up getting some Spectre stamped steel chrome covers from a local auto parts store for about 40 bucks. I also got new bolts and some spreader triangles and bars in case they didn't seal right (I could tell they were lighter than my stock covers).
I installed them the first time using standard thickness cork gaskets, gluing them to the cover using permatex, and cleaning the sealing surface of the head using brake cleaner. I let the covers sit and cure with the Hi-tack and then bolted them on, starting from the center and working my way out evenly. I turned them hand tight with a bit and extension and then gave them about a 1/2 turn to snug them up.

The passenger side valve cover sealed nicely, but the driver side cover leaked badly around the lower bolt holes closest to the brake booster.
I removed one of the triangles on the corner and placed them so that those two bolt holes had spreader triangles on them...same problem.

Torqued the covers down a little tighter, same problem.
Replaced gasket on that side with another cork gasket, this time running a small bead of silicone sealer on the bottom half of the gasket which I let cure for a few hours before starting the vehicle....same problem. I made sure to peen the valve cover bolt holes back out and laser straight before remounting the cover, since they do warp very easily (made of thin metal).
Bought expensive steel-core cork gasket and resealed cover using silicone again on the head side, in addition to siliconing the actually bolts....worked for a while but then started leaking again.

Im basically tearing my hair out because the passenger side cover has never leaked and some of the bolts were barely hand tight when I checked them! The first time I mounted that cover it did not leak, but yet no matter what I've tried on the driver side it leaks from any place it can.

I've thought maybe the drain return was plugged on that part of the head but I've checked it before and it is not plugged unless it is deep down inside...crankcase pressure should be normal, I don't get oil blowing out of dipstick tube or filler while driving, and I have a PCV system that works, with a breather on the passenger side cover and a valve on the other. When I remove the valve I see a slight puff of smoke but no shooting oil.

Im considering just getting some more pricey aluminum valve covers since I can't get this driver side one to mount right. If I do go that route, what would be some of my less expensive but good options for a 455?

70cutty

Try Mr. Gasket Ultra-Seal Valve Cover Gaskets 5875. They are thicker than cork gasket. I didn't use anything to tack or glue them, took valve covers off couple of times and re-use the same gasket with no problems.

I got some plain chrome valve covers that are brand new, never installed. I could sell them to you for $20 plus the ride if you want.

StarGeneral

Ill check out those gaskets...I am reluctant to even purchase a new set of gaskets because I have replaced this gasket 3 times, and cork should seal up just fine considering these covers are brand new, I don't have excess crankcase pressure, and the head rail is clean and not damaged.

I would take you up on purchasing those covers, but whatever covers I buy next need to be made of thicker steel than the ones I just bought, because this one that is not working is a brand new stamped steel chrome cover...

GAOldsman

Yep try those gaskets mentioned above or the Fel-Pro Perma-Dry VS13403R (about $10) http://www.summitracing.com/parts/fe...ake/oldsmobile

I would also suggest ditching the autoparts store cheapo chinesium chrome crap for some factory ones or Edlebrock or similar. Stay away from any chinesium crap for any of the tins. (Valve covers, timing chain cover or oil pan) As these are almost guaranteed TO leak

The torque specs are very light and if you are using anything but a 1/4 drive ratchet you are bound to over tighten the bolts causing the gasket to smush out and distort the valve cover. 3 ft lbs max torque. You should have a "feel" for this by now

oldcutlass

Before you replace the gaskets fix the lip around the valve cover mounting holes so it will sit flat. I use weather strip cement and lightly coat the valve cover and the gasket separately wait about 15 mins. and then stick the gasket to the valve cover. Mount and tighten the bolts lightly until the cover is snug.

joe_padavano

^^^This!

Chinesium aftermarket covers will never seal as well as stock. With ten valve cover bolts properly torqued, you don't need spreaders, either. Be sure the valve cover sealing rail is flat, use good quality gaskets, clean the threads of the bolts, and torque carefully.

StarGeneral

Yeah I always hammer the holes and make sure they are laser straight before re-mounting the gasket...I've done this about 3 times, with fresh gaskets each time...Considering I was able to mount the gasket right the first time on the passenger side, and I have done this before, I'm starting to think the issue lies with increased pressure or oil on the driver side, I'll have to check my oil return carefully near the brake booster.

I'm sure my valve covers are made of cheap steel because they are so much lighter than my stock ones (and beleive me I'd reuse them if one wasn't broken), however most stamped steel valve covers, including edelbrocks, seem to be in the $30-$50 range for a pair, which is what I payed for mine...

StarGeneral

I think what I'm going to do is just bite the bullet and put the one good stock valve cover I have back on the driver side. Its going to look ghetto with 1 chrome cover and 1 silver one, but you know what, I'd feel a lot better with it looking ghetto and not leaking and dropping 5 bucks on a quart of oil every 2 days. Plus when I get to work I'm so worried that I'll find it is leaking again my stomach starts to turn...I think its worth the little bit of time it'll take me to re-do it for the 4th time.

Larrys'66

SG,

I have some stock red ones that need a good cleaning, if your going back to stock covers. They are listed in the parts for sale section with a picture. If they would help you, make me an offer. I would rather them get used than sit around anyhow.

Larry

Killian_Mörder

I'd hammer them straight. Then use only silicone. The surfaces should be absolutely oil-free. Brake cleaner spray will degrease well

rocketraider

Andres, make sure your drainback holes are open and oil isn't pooling in the rocker area. An unfolded wire clothes hanger will work fine for this. Holes are in bottom corners of the heads.

On valve cover bolt torque specs, the manuals always said fully driven, seated and not stripped.

StarGeneral

I checked the drainback holes before putting on the new cover by sticking my pinky in there. Seemed clear, could only stick it so far as I felt kind of a sharp metal peice closing off most of it, ditto on the other side of the head, but they felt exactly the same so I'm sure those are supposed to be there.

Lady72nRob71

The holes are kinda closed off at the bottom but opened at the top. I suspect they are like this to help keep small items like keepers from falling through the holes and into the engine.

StarGeneral

Update: have since installed the stock valve cover on the driver side, this time I used RTV both to glue the gasket to the cover, and to glue the gasket to the head. Torque all bolts a quarter turn past hand tight, let it cure overnight...hasn't leaked since and never looking back...

nsnarsk65cutlass

Ya no doubt those chrome china junk parts never works out.Nick

oldcutlass

I would not have glued them to the head. No harm, just makes it that much harder the next time, plus in most cases you cannot take the valve covers off and reuse them.

StarGeneral

Yeah, I hate using RTV at all, but no matter what I tried without using RTV it would not work....I noticed when I took the chrome one off to inspect the gasket for breakage it was not broken, but the gasket came off of the valve cover very easily (despite the Hi-tack being applied liberaly). The hi-tack looked like it gelled and actually made a bad seal every time I pulled the covers. I am now reconsidering the usefullness of this product altogether....

Smitty275

Valve cover bolts get 8-10ft/lbs of torque according to service manuals. Its enough to make them stay tight and not enough to damage a factory valve cover. In the late 70's the factory used straight silicone on valve covers. Not sure if this was across the board or as a trial period. Personally with the issue the OP is having, a set of good factory valve covers or higher quality aftermarket covers should make a big difference. Maybe watch for a set of the cast valve covers offered by a multitude of different companies with their name on them. They are rigid enough and seal up very well.
I never put any kind of sealer on cork gaskets except at the corners of an oil pan. Sealers let the gasket slide and skoosh out from the pressure and can actually cause more issues than they solve.

StarGeneral

Just as an update on this, I hadn't had problems since putting the factory valve cover back on last month. But yesterday after taking an extended drive at highway speed the valve cover started spewing oil out of the same spot again....right below the oil dipstick in the valley between the exhaust manifold and spark plug.

Im starting to convince myself that this is impossible and the oil must be shooting out of the dipstick tube....but there is no oil anywhere else so I find that hard to beleive. I don't have abnormal pressure in my crankcase from what my oil pressure gauge is telling me, so I don't think its rings....

EDIT: PCV valve was plugged. I beleive this cause extra crankcase pressure and oil may have been shooting out of the dipstick. Will test and post back.

rocketraider

Grasshopper, you are learning more and more!

Wouldn't hurt to put a new PCV hose on and clean out the port on the carb too. When I got my 74 Hurst that one was almost completely plugged with goo.