i was blowing blue pretty bad, so i went and got my valve seals changed, which helped a lot, but now, when my car idles, or when im in stop go traffic, i still blow a bit of blue...sometimes when i start the car i blow blue too.

any ideas why? thanks

 

common wear and tear, worn valve guides

 

when they replaced my valve seals, would they not have checked those, or replaced them??

 

Repairing valve guides (knurling) is only a temporary repair. The guides will wear faster and begin leaking again in short order. Replacing valve guides (machining and pressing in replacements) is a more permanent solution. In either case, the heads have to be removed from the engine and carted off to a machinist. If you weren't willing to pay for that, they weren't going to do it.

However, when the valve springs were removed for seal replacement, the mechanic should have checked for guide wear and stem clearance, and advised you of the situation.

 

in other words, when they did my seals, they could have easily done the valve guides too?

 

Not really easy, the heads would have to come off, and then a full valve job is usually done at the same time and spring pressures/new springs installed.

 

so this would be an expensive job i take it?

 

I'm not sure about labor rates in the Northwest, but "expensive" is a relative term. There is a good chance that at least part of the wear is on the valve stems themselves. To correctly perform the repair, the heads would be removed, vlaves and springs removed, heads would be hot-tanksed for cleaning. At this point, a MagnaFulx test should be done to reveal any possible cracking in the head castings. If the heads are viable, the guides would be machined oversize, then new bronze guides would be pressed in place. The guides would be finish reamed to the correct valve stem size, then new valves would be installed (requiring that the valves and seats be ground). New seals would be installed, and the springs would be reinstalled and shimmed to the correct height. The heads would then be ready for installation.

If you can get all this done "inexpensively", it may be worth it.

However, among we, the enthusiasts, there is a phenomenon often called a "cascade effect".

The reasoning is that once the stock valves are removed, it makes good sense to install larger, lighter, stronger aftermarket valves to improve flow and reliability. Of course, these valves will work best with larger valve bowls, and since the heads are already at the machinist, bowl porting is the reasonable course of action. Since the bowls and valves are now larger, it would be logical to enlarge the port runners to make the entire intake tract more conducive to flows. And every good mechanic would polish at least the exhaust valve bowls and runners after such rework. And since the heads are already stripped and the guides have been replaced, machining the guides for positive Teflon valve seals is only reasonable, since they work so much better than the 'O' ring seals or umbrellas. The new set of valves should also get new ratainers, and since the retainers are being changed it would only make sense to upgrade the springs and machine the spring pockets as necessary, since they are already in the shop. And of course, no one would remove a head without installing screwed rocker studs in place of the factory "pull-outs".

As you can see, the process can get long and costly as you follow the cascade of logic.

It may be better in the long run to save some cash for replacement heads and live with the oil burning for a while longer. Replacement heads will already have larger valves and ports, new guides, new springs, and screwed studs. The previous method will net you a repaired set of factory heads that probably flow a little better. Replacement heads will get you new heads that definitely flow better and have all new parts.

Weigh the advantages and disadvantages, and decide. If you ever though about different heads, this may be your opportunity. If you can perform the machining yourself, the cost of building factory heads can be negligible. If you're paying someone an hourly rate to do the work, the aftermarket heads may be the better bargain.

 

You may have a leaky head gasket too.
A leaky head gasket sometimes shows a bluey vapoury exhaust
smoke at idle , that looks like bad valve seals.

 

nope, they were right on the money before with the worn valve guides, no doubt about it. Before it was a lot worse because his seals were old and brittle, now that the seals have been replaced the oil doesn't leak down between the stem and guide as much only when he shuts the engine off and lets it sit for a while, this is when a little bit flows down and this is why he gets it during start up. It's only a temporary fix though, eventually they will get worse again. Like mentioned before I would use this as an excuse to get new performance heads, or learn to live with the blue smoke. The only concern that comes to mind seeing as I just did mine today is, how likely are you to pass SMOG with it blowing smoke??

 

Who's Blue?

 

Well we can all see what's on TomP's mind.

 

LOL! That's twice I laughed out loud at work today (once this post, once in the body/interior forum) because of this website; you guys are gonna get me in trouble.

 

by the way, if i remove my pcv valve, i dont blow any blue, but when i put it back in, i blow on start up, idleing, stop-go traffic, etc...

does that mean anything?

 

anyone? ^^

 

how does the car run with no pcv in it? does it run fine or is she sluggish?

 

maybe your pvc valve is shot buy a new one they are cheap. The valve may be stuck shut causing pressure .

 

Means oil is getting up into the pcv valve.

NON factory valve cover sometimes do not have a baffle
under where the pcv valve goes.
If this is the cast you can remove a baffle form an old factory valve cover and attach it in your aftermarket covers.
Just make sure of locating it properly cause it has to fit between the rockers.

The other cover needs to be vented to the air cleaner

 

baffle? what do ya mean

 

inside the valve cover there is a metal strip like thing that sits over the spring assembly...helps the oil return better and keeps it off the pvc....if you look where you fill the oil you should see some metal just inside the hole..covering the springs.

 

Some NON factory valve covers also have the PCV hole in the wrong spot ( right over top a rocker) Then the rocker shoots
oil right onto the pcv valve. Suppossed to be between the rockers.

Look in a factory valve cover, you'll see.