hi all,

there was a post shortly that impressed me. Friend of mine has a 78 302, which shows the following symptoms:
a) smokesalot
b) back spark plugs
c) a lot of air being pushed out the rocker covers. Spits a lot of oil. seems like a lot of pressure.

the compression test seemed good. and i tried pouring teaspoon of oil in chamber which didn't help compression.
So from that I understand it can only be the valve seals. (all cylinders same and stock heads)

Is this something visible with rocker covers off and can they be replaced with only rocjker covers off or do we need to take the heads off?

thanks for any ideas

 

Kalli,
The valve springs need to come off in order to get to the seals. If you have a source of air to keep the valves up while you use a spring compressor to remove the locks and springs, yep it can be done on the car.

 

yup, if you dont have compressed air you can bring the piston to the top of the cylinder and still do it, however you'll have to make sure the piston is all the way up on each cylinder so its time consuming.... although having the piston up even with air is added insurance against dropping a valve.

i'd be looking at guides though if its that bad. valve seals bad wouldnt cause excessive smoke from the valve cover vents, since they werent a positive style seal anyways.

 

Hey Kali,

As far as it blowing oil out the rockers my new engine does that.
I have to do a oil separator inline pcv system. Due to my supercharger.

2 things to check does he have a baffle in the valve cover?
2nd does he have the pcv hooked up?

Doesnt seem like much but after quite a bit of research on this I will use mine for sure.

The other symptoms does sound like he is leaking oil into the cylinders.
Also tuning on the carb choke may clear up some of the smoke.
look for oil coming out of the tail pipe. I have had that on old worn out engines before.
If its bad it will fowl the plugs out with oil. I had to run non fowlers on my old 283 impalla.
LOL IDK if you can even buy those anymore.

 

we have the gear for it, which is good news. it's a compressor tester where you can attach the 'screw' to an air compressor. I'm aware that it's not a guarantee for not dropping valcves. but it sounds like it could be a good idea.
The carb is new and I adjusted that one, runs smooth and choke is hooked up peoperly. I'll check on his PCV as well. I'll discuss it with him and we'll go from there.

is there anything that we should see with valve covers off that would indicate bad seals?

 

I've read that you can remove the plugs and stuff a rope into the cylinder to hold the valves up.

 

I heard the rope thing too.. In fact I think it is in one of my books as how to replace the seals..

 

If you can physicaly see them look for cracks or other obvious forms of damage - otherwise not much else to see. I'm in agreement with My77 stang -there may be guide wear out issues to contend with also. But if you're on the cheap, trying new seals without tearing it down is a good idea. I've also seen bad valve cover gskts cause oil to fill the spark plug wells and find its way into the cyl thru the tapered seats the plugs rest on. Since you got it apart, I'm sure you'll replace the valve cover gaskets any way so this concern will go away. And look into the baffle in the valve cover because it will make one heck of a difference in both leakage and PCV valve oil asperation action if it's not there.