I've known that I need new valve stem seals on my '85 since I bought it. Its slowly burning oil and getting on my nerves. The only method that i've changed seals is to remove the heads. I know there is a way to do it without taking the engine apart. Could someone enlighten me on this? I have a compressed air source (I hear its needed). Thanks.

 

Well, you definitel have to take each valve spring assembly apart to do it. I've never done it, but if you make sure the piston is at TDC (top dead center) and that the valves are fully closed, you might be able to do it. The reason for this is that you don't want the valve falling down into the cylinder, this is typically bad. Then you'll definitely have to remove the cylinder head. The question becomes, how far will the valve drop after you remove the keepers and retainer? Will you be able to assemble it without being able to hold the valve in place from the bottom. Another forum member may have experience with this.

 

There are some threads on here about changing springs and seals with the heads still on. You will need to thread some nylon cord into the cylinder (naturally leaving ample cord hanging from the plug hole to remove it) and then bring the piston to its top postion. Th cord prevents the valves from dropping into the cylinder. You could also use an air compressor (with a fitting installed into the plug hole) to create positive chamber pressure and hold the valves in place that way. I'm not sure of the specifics in either case, but have read about them here.

 

I have used both methods and they both work, but the nylon rope trick is much easier. Especially since there is very little clearance on the passenger side to get an air fitting into the sparkplug hole. Rope trick is faster and you don't have to worry about getting the piston exactly on TDC. As I said , I have done the job and It is time consuming but not that hard. Worst problem will be getting valve cover off, especially on passenger side where you have to remove the EGR tube where it goes over the Cover. Good Luck!!

 

done it...shade tree job, will take 4 hr the first time, 45min next time...you need a spring compressor -- lever thing that goes over the rocker stud and it pushes the spring down as you pull on the handle--most auto parts stores sell one for about $10...magnetic screwdriver to pick the valve keepers up after you push the spring down...small dab of chassis grease to stick the keeper in place while you let up on the spring after installing the new seal...a roll of paper towels to wipe each keeper half before reinstalling (a small chunk of crud could cause the keeper to not keep)....and about 4 feet of 1/4'' rope (i have an old briggs&strat starter rope that even has a handle on it, hangs on the wall for this or other odd jobs) to hold the valves up--done it with compressed air too, but the air hose is a pita, the air tries to push the piston down which could be big mess if a valve gets away, hate the hissing, etc

oops, above is ok if you're just changing the little o-rings on the upper end of the valve (they harden with age and usually are all you need to change)...if you have the lower ''umbrella'' oil shields and want to change those too, you will need to pick the springs off to do those.

 

On our 85's we don't have egr tubes in the way the hardest part is to get the valve covers off, especially the left side. The a/c compressor has a bottom bolt that you need to spin the clutch around to aline a slot in it so you can remove the bolt. The compressed air is easier if you have a compression testor with a 18" flex hose that you can quick release from your air line like mine. I removed guage and adapted air line quick disconnect. Threading a regular air line into the spark plug thread would be next to impossible especially on the left side. Compressor should hold with 125 psi or higher and good valve seating. If you hear air escaping out tail pipe or up through valve covers don't release valve as it means valve is not sealing because of piece missing or poor seating. One like this may fall inside motor. Next get a valve compressor and remove springs and keepers. The downside of the air is you have to stay at it if the air stops the valves fall!!!!!

 

All of the above, plus:

Compressed air: It is important to have the piston VERY close to exact TDC. Otherwise the air pressure will push the piston down the hole. If the engine is going to roll, it generally will do so as you apply the air pressure and not at the worst time.

Rope Trick: Rotate the engine to close to TDC, to minimize the amount of rope you have to stuff into the cylinder. After the rope stops feeding in, rotate the engine until you feel resistance in rotation. This pushes the rope tightly onto the valves. You need vary little additional rotation. Beware of knots forming in the rope, inside of the cylinder. Don't ask!

TDC. No air, no rope: The 1984, 1985, and 1986E (with iron heads) all use the same long block. With the piston at TDC, the valve drop is minimal. Not having the valve held tightly on it's seat can frustrate matters, but it can be done. You won't lose a valve as long as you remember to rotate the engine as you do each cylinder.

As a foot note, on older engines such as the subject 1985, the valve guides are likely warn to the point that new seals either won't be able to control the oil problem, or the movement of the valves in the loose guides will make short work of the new seals. It is only about a $20.00 gamble and if you win, you're a hero.

RACE ON!!!

 

Well with 110K miles on original valve seals, i'd say its a safe bet that replacing the seals will fix the problem or at least help it. The nylon rope idea sounds like the ticket for me. Thanks guys.