I'm beginning to scratch my head on this one.....

Scenario- a '84 T/A with a stock 305 engine. Bone stock, no mods on it.

A few weeks ago I noticed while in the driver's seat and having just shut down the engine while hot some smoke coming up from the cowl area on the driver's side. Popping the hood open I got the smell of burning oil and noticed the smoke coming up on the driver's side of the engine block. As far as I could tell (I'm not 100% sure on this) the smoke looked like it was coming from the exhaust manifold just below the edge of the valve cover. It was only a little bit of smoke but seeing any sort of oil burning on the exhaust manifold is a bit disconcerning....

My first thought was that my valve cover gaskets had gone out. I pulled the valve covers and wasn't dissapointed to find that the gaskets were so hard they pretty much had turned to plastic. Ok, new set went in, and I even steam cleaned what I could reach around the driver's side valve cover and exhaust manifold to get rid of any oil that was still there.....

Imagine my dissapointment after having driven the car around that it was still doing the same damn thing.... .....

Am I missing something here? Or should I wait a while for give whatever oil residue that I had missed with the steam cleaning to burn off before I start panicking?


Thanks....
David

 

The VC gaskets may have just been misaligned. Use small dabs of a fast drying cement around the perimeter of the covers to keep the gasket alighned while your installing it. Also make sure that the covers are straight and that the areas around the bolts arnt all bent up and make sure not to use the cork ones. Ive had very good luck with the felpro rubber gaskets.

 

How long did you drive the car for? If it was jsut a few minutes it may have still been slightly burning it off, although usually if its still smoking, its still leaking...

 

Urg.......NOW you tell me not to use cork Those covers were a PITA to get in and out. I used a set of Felpro hi-temp gaskets, but they were cork. But then again the gaskets they had replaced were cork- and that set I had installed about 10 years ago and had not had any problems with them until now....

I did check the covers before I reinstalled to make sure the seating area hasn't been dented or warped- one bolt area was squished slightly but I tapped it straight again.

When I installed the gaskets and just before I dropped the cover in place I made sure that the corners were over the cast boss in each corner of the cylinder head, then cinched the nuts down in a cross-pattern. I didn't go too tight though as I was afraid I'd crush the gasket......

Oh- drove the car today for about a total operating time of a half-hour - most of it highway time.....

 

I found that on installing new gaskets they tend to press down a tad due to the heat and the bolts can become loose. I had to retorque the last set, but that was only after a week of use. Go around the entire bottom of the valve cover and try to feel if the gasket is seated correctly.

 

'84 huh... Perimeter style bolts.

Here's what I did. I bought a set of the Mr. Gaskets Ultra Seal Extra Thick gaskets and 2 of the Moroso Valve Cover Hold Down Tabs. I then made sure the valve cover flanges were pretty flat, especially around the bolt holes. I then put RTV on the corners of the gaskets, and stuck them to the valve cover. Then put the valve covers back on, used longer bolts to go through the Hold Downs and Extra Thick Gasket, and torqued them down.

No more leaks, didn't even try to leak. There were previously 4 sets of valve cover gaskets replaced on the engine, because it would NOT seal. This did the trick though.

 

Hmm- the problem with going with the Mr. Gasket setup is that the heads have studs that go thru the valve covers and is held on with nuts. Between the nuts and the valve cover there's a slightly bowed metal bar with a hole drilled in it that also slips on the stud. So when the nut is tightened down the pressure is transfered along the length of the bar, rather than just at the point where the nut tightens down. It'd be a pain I think to pull those studs and switch to bolts.......

I'll go ahead and recheck the gasket fitting along the bottom edges of the cover, and if it seems to be positioned correctly, and tightening it down doesn't help then I'll break down and pull the cover again and replace the gasket with the Felpro rubber versions.

Also, I did install the gaskets dry- no sealant applied to either side of the gasket.....

 

You shouldnt need any sealents... They should seal fine on their own. Just make sure the gasket surfaces are clean.

 

I use cork with no gasket sealer usually and they dont leak. Sometimes some heads just dont want to seal without sealant (when using cork).

 

BTW given the symptoms I've seen, I take it that the only possible source for the leak would be from the valve cover, right? That is, there's no other possible source of a leak that can somehow make its way over/down to the exhaust manifold area and burn off there? I have no reason to suspect this, just wanted to make sure all my bases were covered

I did check under the engine on the possibility that the oil might be dripping down onto the lower pipes of the exhaust. That way the smoke would make it's way up past the exhaust manifold and give the illusion that it's burning off at that point. However, I didn't find anything...

As I mentioned before, from what I could tell it LOOKS like the manifold itself is the source of the smoke, but I didn't spot a area where I actually saw the oil burning off.

 

Its possible to have an oil leak where the manifold is. Check around teh back and around the dist. area for oil.

 

Quite popular spot for a leak too. Another popular one is the oil pressure fitting on the back behind the intake. Happens there a lot, just not sure if the oil would make its way to the manifolds or not. I guess it could.

 

Hmm- and that oil pressure fitting looks like a Xmas tree with all the sensors hanging off of it...... I'll get back there with a rag and some degreaser and clean the area up (it's got some oil caked back there and some of it does look recent), then run the engine while taking a look around back there......